Initial revision

1 files changed, 5015 insertions, 0 deletions

diff --git a/generic/tkTextDisp.c b/generic/tkTextDisp.c
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+++ b/generic/tkTextDisp.c
@@ -0,0 +1,5015 @@
+/* 
+ * tkTextDisp.c --
+ *
+ *	This module provides facilities to display text widgets.  It is
+ *	the only place where information is kept about the screen layout
+ *	of text widgets.
+ *
+ * Copyright (c) 1992-1994 The Regents of the University of California.
+ * Copyright (c) 1994-1997 Sun Microsystems, Inc.
+ *
+ * See the file "license.terms" for information on usage and redistribution
+ * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+ *
+ * SCCS: @(#) tkTextDisp.c 1.124 97/07/11 18:01:03
+ */
+
+#include "tkPort.h"
+#include "tkInt.h"
+#include "tkText.h"
+
+/*
+ * The following structure describes how to display a range of characters.
+ * The information is generated by scanning all of the tags associated
+ * with the characters and combining that with default information for
+ * the overall widget.  These structures form the hash keys for
+ * dInfoPtr->styleTable.
+ */
+
+typedef struct StyleValues {
+    Tk_3DBorder border;		/* Used for drawing background under text.
+				 * NULL means use widget background. */
+    int borderWidth;		/* Width of 3-D border for background. */
+    int relief;			/* 3-D relief for background. */
+    Pixmap bgStipple;		/* Stipple bitmap for background.  None
+				 * means draw solid. */
+    XColor *fgColor;		/* Foreground color for text. */
+    Tk_Font tkfont;		/* Font for displaying text. */
+    Pixmap fgStipple;		/* Stipple bitmap for text and other
+				 * foreground stuff.   None means draw
+				 * solid.*/
+    int justify;		/* Justification style for text. */
+    int lMargin1;		/* Left margin, in pixels, for first display
+				 * line of each text line. */
+    int lMargin2;		/* Left margin, in pixels, for second and
+				 * later display lines of each text line. */
+    int offset;			/* Offset in pixels of baseline, relative to
+				 * baseline of line. */
+    int overstrike;		/* Non-zero means draw overstrike through
+				 * text. */
+    int rMargin;		/* Right margin, in pixels. */
+    int spacing1;		/* Spacing above first dline in text line. */
+    int spacing2;		/* Spacing between lines of dline. */
+    int spacing3;		/* Spacing below last dline in text line. */
+    TkTextTabArray *tabArrayPtr;/* Locations and types of tab stops (may
+				 * be NULL). */
+    int underline;		/* Non-zero means draw underline underneath
+				 * text. */
+    Tk_Uid wrapMode;		/* How to handle wrap-around for this tag.
+				 * One of tkTextCharUid, tkTextNoneUid,
+				 * or tkTextWordUid. */
+} StyleValues;
+
+/*
+ * The following structure extends the StyleValues structure above with
+ * graphics contexts used to actually draw the characters.  The entries
+ * in dInfoPtr->styleTable point to structures of this type.
+ */
+
+typedef struct TextStyle {
+    int refCount;		/* Number of times this structure is
+				 * referenced in Chunks. */
+    GC bgGC;			/* Graphics context for background.  None
+				 * means use widget background. */
+    GC fgGC;			/* Graphics context for foreground. */
+    StyleValues *sValuePtr;	/* Raw information from which GCs were
+				 * derived. */
+    Tcl_HashEntry *hPtr;	/* Pointer to entry in styleTable.  Used
+				 * to delete entry. */
+} TextStyle;
+
+/*
+ * The following macro determines whether two styles have the same
+ * background so that, for example, no beveled border should be drawn
+ * between them.
+ */
+
+#define SAME_BACKGROUND(s1, s2) \
+    (((s1)->sValuePtr->border == (s2)->sValuePtr->border) \
+        && ((s1)->sValuePtr->borderWidth == (s2)->sValuePtr->borderWidth) \
+        && ((s1)->sValuePtr->relief == (s2)->sValuePtr->relief) \
+        && ((s1)->sValuePtr->bgStipple == (s2)->sValuePtr->bgStipple))
+
+/*
+ * The following structure describes one line of the display, which may
+ * be either part or all of one line of the text.
+ */
+
+typedef struct DLine {
+    TkTextIndex index;		/* Identifies first character in text
+				 * that is displayed on this line. */
+    int count;			/* Number of characters accounted for by this
+				 * display line, including a trailing space
+				 * or newline that isn't actually displayed. */
+    int y;			/* Y-position at which line is supposed to
+				 * be drawn (topmost pixel of rectangular
+				 * area occupied by line). */
+    int oldY;			/* Y-position at which line currently
+				 * appears on display.  -1 means line isn't
+				 * currently visible on display and must be
+				 * redrawn.  This is used to move lines by
+				 * scrolling rather than re-drawing. */
+    int height;			/* Height of line, in pixels. */
+    int baseline;		/* Offset of text baseline from y, in
+				 * pixels. */
+    int spaceAbove;		/* How much extra space was added to the
+				 * top of the line because of spacing
+				 * options.  This is included in height
+				 * and baseline. */
+    int spaceBelow;		/* How much extra space was added to the
+				 * bottom of the line because of spacing
+				 * options.  This is included in height. */
+    int length;			/* Total length of line, in pixels. */
+    TkTextDispChunk *chunkPtr;	/* Pointer to first chunk in list of all
+				 * of those that are displayed on this
+				 * line of the screen. */
+    struct DLine *nextPtr;	/* Next in list of all display lines for
+				 * this window.   The list is sorted in
+				 * order from top to bottom.  Note:  the
+				 * next DLine doesn't always correspond
+				 * to the next line of text:  (a) can have
+				 * multiple DLines for one text line, and
+				 * (b) can have gaps where DLine's have been
+				 * deleted because they're out of date. */
+    int flags;			/* Various flag bits:  see below for values. */
+} DLine;
+
+/*
+ * Flag bits for DLine structures:
+ *
+ * HAS_3D_BORDER -		Non-zero means that at least one of the
+ *				chunks in this line has a 3D border, so
+ *				it potentially interacts with 3D borders
+ *				in neighboring lines (see
+ *				DisplayLineBackground).
+ * NEW_LAYOUT -			Non-zero means that the line has been
+ *				re-layed out since the last time the
+ *				display was updated.
+ * TOP_LINE -			Non-zero means that this was the top line
+ *				in the window the last time that the window
+ *				was laid out.  This is important because
+ *				a line may be displayed differently if its
+ *				at the top or bottom than if it's in the
+ *				middle (e.g. beveled edges aren't displayed
+ *				for middle lines if the adjacent line has
+ *				a similar background).
+ * BOTTOM_LINE -		Non-zero means that this was the bottom line
+ *				in the window the last time that the window
+ *				was laid out.
+ */
+
+#define HAS_3D_BORDER	1
+#define NEW_LAYOUT	2
+#define TOP_LINE	4
+#define BOTTOM_LINE	8
+
+/*
+ * Overall display information for a text widget:
+ */
+
+typedef struct TextDInfo {
+    Tcl_HashTable styleTable;	/* Hash table that maps from StyleValues
+				 * to TextStyles for this widget. */
+    DLine *dLinePtr;		/* First in list of all display lines for
+				 * this widget, in order from top to bottom. */
+    GC copyGC;			/* Graphics context for copying from off-
+				 * screen pixmaps onto screen. */
+    GC scrollGC;		/* Graphics context for copying from one place
+				 * in the window to another (scrolling):
+				 * differs from copyGC in that we need to get
+				 * GraphicsExpose events. */
+    int x;			/* First x-coordinate that may be used for
+				 * actually displaying line information.
+				 * Leaves space for border, etc. */
+    int y;			/* First y-coordinate that may be used for
+				 * actually displaying line information.
+				 * Leaves space for border, etc. */
+    int maxX;			/* First x-coordinate to right of available
+				 * space for displaying lines. */
+    int maxY;			/* First y-coordinate below available
+				 * space for displaying lines. */
+    int topOfEof;		/* Top-most pixel (lowest y-value) that has
+				 * been drawn in the appropriate fashion for
+				 * the portion of the window after the last
+				 * line of the text.  This field is used to
+				 * figure out when to redraw part or all of
+				 * the eof field. */
+
+    /*
+     * Information used for scrolling:
+     */
+
+    int newCharOffset;		/* Desired x scroll position, measured as the
+				 * number of average-size characters off-screen
+				 * to the left for a line with no left
+				 * margin. */
+    int curPixelOffset;		/* Actual x scroll position, measured as the
+				 * number of pixels off-screen to the left. */
+    int maxLength;		/* Length in pixels of longest line that's
+				 * visible in window (length may exceed window
+				 * size).  If there's no wrapping, this will
+				 * be zero. */
+    double xScrollFirst, xScrollLast;
+				/* Most recent values reported to horizontal
+				 * scrollbar;  used to eliminate unnecessary
+				 * reports. */
+    double yScrollFirst, yScrollLast;
+				/* Most recent values reported to vertical
+				 * scrollbar;  used to eliminate unnecessary
+				 * reports. */
+
+    /*
+     * The following information is used to implement scanning:
+     */
+
+    int scanMarkChar;		/* Character that was at the left edge of
+				 * the window when the scan started. */
+    int scanMarkX;		/* X-position of mouse at time scan started. */
+    int scanTotalScroll;	/* Total scrolling (in screen lines) that has
+				 * occurred since scanMarkY was set. */
+    int scanMarkY;		/* Y-position of mouse at time scan started. */
+
+    /*
+     * Miscellaneous information:
+     */
+
+    int dLinesInvalidated;	/* This value is set to 1 whenever something
+				 * happens that invalidates information in
+				 * DLine structures;  if a redisplay
+				 * is in progress, it will see this and
+				 * abort the redisplay.  This is needed
+				 * because, for example, an embedded window
+				 * could change its size when it is first
+				 * displayed, invalidating the DLine that
+				 * is currently being displayed.  If redisplay
+				 * continues, it will use freed memory and
+				 * could dump core. */
+    int flags;			/* Various flag values:  see below for
+				 * definitions. */
+} TextDInfo;
+
+/*
+ * In TkTextDispChunk structures for character segments, the clientData
+ * field points to one of the following structures:
+ */
+
+typedef struct CharInfo {
+    int numChars;		/* Number of characters to display. */
+    char chars[4];		/* Characters to display.  Actual size
+				 * will be numChars, not 4.  THIS MUST BE
+				 * THE LAST FIELD IN THE STRUCTURE. */
+} CharInfo;
+
+/*
+ * Flag values for TextDInfo structures:
+ *
+ * DINFO_OUT_OF_DATE:		Non-zero means that the DLine structures
+ *				for this window are partially or completely
+ *				out of date and need to be recomputed.
+ * REDRAW_PENDING:		Means that a when-idle handler has been
+ *				scheduled to update the display.
+ * REDRAW_BORDERS:		Means window border or pad area has
+ *				potentially been damaged and must be redrawn.
+ * REPICK_NEEDED:		1 means that the widget has been modified
+ *				in a way that could change the current
+ *				character (a different character might be
+ *				under the mouse cursor now).  Need to
+ *				recompute the current character before
+ *				the next redisplay.
+ */
+
+#define DINFO_OUT_OF_DATE	1
+#define REDRAW_PENDING		2
+#define REDRAW_BORDERS		4
+#define REPICK_NEEDED		8
+
+/*
+ * The following counters keep statistics about redisplay that can be
+ * checked to see how clever this code is at reducing redisplays.
+ */
+
+static int numRedisplays;	/* Number of calls to DisplayText. */
+static int linesRedrawn;	/* Number of calls to DisplayDLine. */
+static int numCopies;		/* Number of calls to XCopyArea to copy part
+				 * of the screen. */
+
+/*
+ * Forward declarations for procedures defined later in this file:
+ */
+
+static void		AdjustForTab _ANSI_ARGS_((TkText *textPtr,
+			    TkTextTabArray *tabArrayPtr, int index,
+			    TkTextDispChunk *chunkPtr));
+static void		CharBboxProc _ANSI_ARGS_((TkTextDispChunk *chunkPtr,
+			    int index, int y, int lineHeight, int baseline,
+			    int *xPtr, int *yPtr, int *widthPtr,
+			    int *heightPtr));
+static void		CharDisplayProc _ANSI_ARGS_((TkTextDispChunk *chunkPtr,
+			    int x, int y, int height, int baseline,
+			    Display *display, Drawable dst, int screenY));
+static int		CharMeasureProc _ANSI_ARGS_((TkTextDispChunk *chunkPtr,
+			    int x));
+static void		CharUndisplayProc _ANSI_ARGS_((TkText *textPtr,
+			    TkTextDispChunk *chunkPtr));
+static void		DisplayDLine _ANSI_ARGS_((TkText *textPtr,
+			    DLine *dlPtr, DLine *prevPtr, Pixmap pixmap));
+static void		DisplayLineBackground _ANSI_ARGS_((TkText *textPtr,
+			    DLine *dlPtr, DLine *prevPtr, Pixmap pixmap));
+static void		DisplayText _ANSI_ARGS_((ClientData clientData));
+static DLine *		FindDLine _ANSI_ARGS_((DLine *dlPtr,
+			    TkTextIndex *indexPtr));
+static void		FreeDLines _ANSI_ARGS_((TkText *textPtr,
+			    DLine *firstPtr, DLine *lastPtr, int unlink));
+static void		FreeStyle _ANSI_ARGS_((TkText *textPtr,
+			    TextStyle *stylePtr));
+static TextStyle *	GetStyle _ANSI_ARGS_((TkText *textPtr,
+			    TkTextIndex *indexPtr));
+static void		GetXView _ANSI_ARGS_((Tcl_Interp *interp,
+			    TkText *textPtr, int report));
+static void		GetYView _ANSI_ARGS_((Tcl_Interp *interp,
+			    TkText *textPtr, int report));
+static DLine *		LayoutDLine _ANSI_ARGS_((TkText *textPtr,
+			    TkTextIndex *indexPtr));
+static int		MeasureChars _ANSI_ARGS_((Tk_Font tkfont,
+			    CONST char *source, int maxChars, int startX,
+			    int maxX, int tabOrigin, int *nextXPtr));
+static void		MeasureUp _ANSI_ARGS_((TkText *textPtr,
+			    TkTextIndex *srcPtr, int distance,
+			    TkTextIndex *dstPtr));
+static int		NextTabStop _ANSI_ARGS_((Tk_Font tkfont, int x,
+			    int tabOrigin));
+static void		UpdateDisplayInfo _ANSI_ARGS_((TkText *textPtr));
+static void		ScrollByLines _ANSI_ARGS_((TkText *textPtr,
+			    int offset));
+static int		SizeOfTab _ANSI_ARGS_((TkText *textPtr,
+			    TkTextTabArray *tabArrayPtr, int index, int x,
+			    int maxX));
+static void		TextInvalidateRegion _ANSI_ARGS_((TkText *textPtr,
+			    TkRegion region));
+
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkTextCreateDInfo --
+ *
+ *	This procedure is called when a new text widget is created.
+ *	Its job is to set up display-related information for the widget.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	A TextDInfo data structure is allocated and initialized and attached
+ *	to textPtr.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TkTextCreateDInfo(textPtr)
+    TkText *textPtr;		/* Overall information for text widget. */
+{
+    register TextDInfo *dInfoPtr;
+    XGCValues gcValues;
+
+    dInfoPtr = (TextDInfo *) ckalloc(sizeof(TextDInfo));
+    Tcl_InitHashTable(&dInfoPtr->styleTable, sizeof(StyleValues)/sizeof(int));
+    dInfoPtr->dLinePtr = NULL;
+    dInfoPtr->copyGC = None;
+    gcValues.graphics_exposures = True;
+    dInfoPtr->scrollGC = Tk_GetGC(textPtr->tkwin, GCGraphicsExposures,
+	    &gcValues);
+    dInfoPtr->topOfEof = 0;
+    dInfoPtr->newCharOffset = 0;
+    dInfoPtr->curPixelOffset = 0;
+    dInfoPtr->maxLength = 0;
+    dInfoPtr->xScrollFirst = -1;
+    dInfoPtr->xScrollLast = -1;
+    dInfoPtr->yScrollFirst = -1;
+    dInfoPtr->yScrollLast = -1;
+    dInfoPtr->scanMarkChar = 0;
+    dInfoPtr->scanMarkX = 0;
+    dInfoPtr->scanTotalScroll = 0;
+    dInfoPtr->scanMarkY = 0;
+    dInfoPtr->dLinesInvalidated = 0;
+    dInfoPtr->flags = DINFO_OUT_OF_DATE;
+    textPtr->dInfoPtr = dInfoPtr;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkTextFreeDInfo --
+ *
+ *	This procedure is called to free up all of the private display
+ *	information kept by this file for a text widget.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Lots of resources get freed.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TkTextFreeDInfo(textPtr)
+    TkText *textPtr;		/* Overall information for text widget. */
+{
+    register TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+
+    /*
+     * Be careful to free up styleTable *after* freeing up all the
+     * DLines, so that the hash table is still intact to free up the
+     * style-related information from the lines.  Once the lines are
+     * all free then styleTable will be empty.
+     */
+
+    FreeDLines(textPtr, dInfoPtr->dLinePtr, (DLine *) NULL, 1);
+    Tcl_DeleteHashTable(&dInfoPtr->styleTable);
+    if (dInfoPtr->copyGC != None) {
+	Tk_FreeGC(textPtr->display, dInfoPtr->copyGC);
+    }
+    Tk_FreeGC(textPtr->display, dInfoPtr->scrollGC);
+    if (dInfoPtr->flags & REDRAW_PENDING) {
+	Tcl_CancelIdleCall(DisplayText, (ClientData) textPtr);
+    }
+    ckfree((char *) dInfoPtr);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * GetStyle --
+ *
+ *	This procedure creates all the information needed to display
+ *	text at a particular location.
+ *
+ * Results:
+ *	The return value is a pointer to a TextStyle structure that
+ *	corresponds to *sValuePtr.
+ *
+ * Side effects:
+ *	A new entry may be created in the style table for the widget.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static TextStyle *
+GetStyle(textPtr, indexPtr)
+    TkText *textPtr;		/* Overall information about text widget. */
+    TkTextIndex *indexPtr;	/* The character in the text for which
+				 * display information is wanted. */
+{
+    TkTextTag **tagPtrs;
+    register TkTextTag *tagPtr;
+    StyleValues styleValues;
+    TextStyle *stylePtr;
+    Tcl_HashEntry *hPtr;
+    int numTags, new, i;
+    XGCValues gcValues;
+    unsigned long mask;
+
+    /*
+     * The variables below keep track of the highest-priority specification
+     * that has occurred for each of the various fields of the StyleValues.
+     */
+
+    int borderPrio, borderWidthPrio, reliefPrio, bgStipplePrio;
+    int fgPrio, fontPrio, fgStipplePrio;
+    int underlinePrio, justifyPrio, offsetPrio;
+    int lMargin1Prio, lMargin2Prio, rMarginPrio;
+    int spacing1Prio, spacing2Prio, spacing3Prio;
+    int overstrikePrio, tabPrio, wrapPrio;
+
+    /*
+     * Find out what tags are present for the character, then compute
+     * a StyleValues structure corresponding to those tags (scan
+     * through all of the tags, saving information for the highest-
+     * priority tag).
+     */
+
+    tagPtrs = TkBTreeGetTags(indexPtr, &numTags);
+    borderPrio = borderWidthPrio = reliefPrio = bgStipplePrio = -1;
+    fgPrio = fontPrio = fgStipplePrio = -1;
+    underlinePrio = justifyPrio = offsetPrio = -1;
+    lMargin1Prio = lMargin2Prio = rMarginPrio = -1;
+    spacing1Prio = spacing2Prio = spacing3Prio = -1;
+    overstrikePrio = tabPrio = wrapPrio = -1;
+    memset((VOID *) &styleValues, 0, sizeof(StyleValues));
+    styleValues.relief = TK_RELIEF_FLAT;
+    styleValues.fgColor = textPtr->fgColor;
+    styleValues.tkfont = textPtr->tkfont;
+    styleValues.justify = TK_JUSTIFY_LEFT;
+    styleValues.spacing1 = textPtr->spacing1;
+    styleValues.spacing2 = textPtr->spacing2;
+    styleValues.spacing3 = textPtr->spacing3;
+    styleValues.tabArrayPtr = textPtr->tabArrayPtr;
+    styleValues.wrapMode = textPtr->wrapMode;
+    for (i = 0 ; i < numTags; i++) {
+	tagPtr = tagPtrs[i];
+
+	/*
+	 * On Windows and Mac, we need to skip the selection tag if
+	 * we don't have focus.
+	 */
+
+#ifndef ALWAYS_SHOW_SELECTION
+	if ((tagPtr == textPtr->selTagPtr) && !(textPtr->flags & GOT_FOCUS)) {
+	    continue;
+	}
+#endif
+
+	if ((tagPtr->border != NULL) && (tagPtr->priority > borderPrio)) {
+	    styleValues.border = tagPtr->border;
+	    borderPrio = tagPtr->priority;
+	}
+	if ((tagPtr->bdString != NULL)
+		&& (tagPtr->priority > borderWidthPrio)) {
+	    styleValues.borderWidth = tagPtr->borderWidth;
+	    borderWidthPrio = tagPtr->priority;
+	}
+	if ((tagPtr->reliefString != NULL)
+		&& (tagPtr->priority > reliefPrio)) {
+	    if (styleValues.border == NULL) {
+		styleValues.border = textPtr->border;
+	    }
+	    styleValues.relief = tagPtr->relief;
+	    reliefPrio = tagPtr->priority;
+	}
+	if ((tagPtr->bgStipple != None)
+		&& (tagPtr->priority > bgStipplePrio)) {
+	    styleValues.bgStipple = tagPtr->bgStipple;
+	    bgStipplePrio = tagPtr->priority;
+	}
+	if ((tagPtr->fgColor != None) && (tagPtr->priority > fgPrio)) {
+	    styleValues.fgColor = tagPtr->fgColor;
+	    fgPrio = tagPtr->priority;
+	}
+	if ((tagPtr->tkfont != None) && (tagPtr->priority > fontPrio)) {
+	    styleValues.tkfont = tagPtr->tkfont;
+	    fontPrio = tagPtr->priority;
+	}
+	if ((tagPtr->fgStipple != None)
+		&& (tagPtr->priority > fgStipplePrio)) {
+	    styleValues.fgStipple = tagPtr->fgStipple;
+	    fgStipplePrio = tagPtr->priority;
+	}
+	if ((tagPtr->justifyString != NULL)
+		&& (tagPtr->priority > justifyPrio)) {
+	    styleValues.justify = tagPtr->justify;
+	    justifyPrio = tagPtr->priority;
+	}
+	if ((tagPtr->lMargin1String != NULL)
+		&& (tagPtr->priority > lMargin1Prio)) {
+	    styleValues.lMargin1 = tagPtr->lMargin1;
+	    lMargin1Prio = tagPtr->priority;
+	}
+	if ((tagPtr->lMargin2String != NULL)
+		&& (tagPtr->priority > lMargin2Prio)) {
+	    styleValues.lMargin2 = tagPtr->lMargin2;
+	    lMargin2Prio = tagPtr->priority;
+	}
+	if ((tagPtr->offsetString != NULL)
+		&& (tagPtr->priority > offsetPrio)) {
+	    styleValues.offset = tagPtr->offset;
+	    offsetPrio = tagPtr->priority;
+	}
+	if ((tagPtr->overstrikeString != NULL)
+		&& (tagPtr->priority > overstrikePrio)) {
+	    styleValues.overstrike = tagPtr->overstrike;
+	    overstrikePrio = tagPtr->priority;
+	}
+	if ((tagPtr->rMarginString != NULL)
+		&& (tagPtr->priority > rMarginPrio)) {
+	    styleValues.rMargin = tagPtr->rMargin;
+	    rMarginPrio = tagPtr->priority;
+	}
+	if ((tagPtr->spacing1String != NULL)
+		&& (tagPtr->priority > spacing1Prio)) {
+	    styleValues.spacing1 = tagPtr->spacing1;
+	    spacing1Prio = tagPtr->priority;
+	}
+	if ((tagPtr->spacing2String != NULL)
+		&& (tagPtr->priority > spacing2Prio)) {
+	    styleValues.spacing2 = tagPtr->spacing2;
+	    spacing2Prio = tagPtr->priority;
+	}
+	if ((tagPtr->spacing3String != NULL)
+		&& (tagPtr->priority > spacing3Prio)) {
+	    styleValues.spacing3 = tagPtr->spacing3;
+	    spacing3Prio = tagPtr->priority;
+	}
+	if ((tagPtr->tabString != NULL)
+		&& (tagPtr->priority > tabPrio)) {
+	    styleValues.tabArrayPtr = tagPtr->tabArrayPtr;
+	    tabPrio = tagPtr->priority;
+	}
+	if ((tagPtr->underlineString != NULL)
+		&& (tagPtr->priority > underlinePrio)) {
+	    styleValues.underline = tagPtr->underline;
+	    underlinePrio = tagPtr->priority;
+	}
+	if ((tagPtr->wrapMode != NULL)
+		&& (tagPtr->priority > wrapPrio)) {
+	    styleValues.wrapMode = tagPtr->wrapMode;
+	    wrapPrio = tagPtr->priority;
+	}
+    }
+    if (tagPtrs != NULL) {
+	ckfree((char *) tagPtrs);
+    }
+
+    /*
+     * Use an existing style if there's one around that matches.
+     */
+
+    hPtr = Tcl_CreateHashEntry(&textPtr->dInfoPtr->styleTable,
+	    (char *) &styleValues, &new);
+    if (!new) {
+	stylePtr = (TextStyle *) Tcl_GetHashValue(hPtr);
+	stylePtr->refCount++;
+	return stylePtr;
+    }
+
+    /*
+     * No existing style matched.  Make a new one.
+     */
+
+    stylePtr = (TextStyle *) ckalloc(sizeof(TextStyle));
+    stylePtr->refCount = 1;
+    if (styleValues.border != NULL) {
+	gcValues.foreground = Tk_3DBorderColor(styleValues.border)->pixel;
+	mask = GCForeground;
+	if (styleValues.bgStipple != None) {
+	    gcValues.stipple = styleValues.bgStipple;
+	    gcValues.fill_style = FillStippled;
+	    mask |= GCStipple|GCFillStyle;
+	}
+	stylePtr->bgGC = Tk_GetGC(textPtr->tkwin, mask, &gcValues);
+    } else {
+	stylePtr->bgGC = None;
+    }
+    mask = GCForeground|GCFont;
+    gcValues.foreground = styleValues.fgColor->pixel;
+    gcValues.font = Tk_FontId(styleValues.tkfont);
+    if (styleValues.fgStipple != None) {
+	gcValues.stipple = styleValues.fgStipple;
+	gcValues.fill_style = FillStippled;
+	mask |= GCStipple|GCFillStyle;
+    }
+    stylePtr->fgGC = Tk_GetGC(textPtr->tkwin, mask, &gcValues);
+    stylePtr->sValuePtr = (StyleValues *)
+	    Tcl_GetHashKey(&textPtr->dInfoPtr->styleTable, hPtr);
+    stylePtr->hPtr = hPtr;
+    Tcl_SetHashValue(hPtr, stylePtr);
+    return stylePtr;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FreeStyle --
+ *
+ *	This procedure is called when a TextStyle structure is no longer
+ *	needed.  It decrements the reference count and frees up the
+ *	space for the style structure if the reference count is 0.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The storage and other resources associated with the style
+ *	are freed up if no-one's still using it.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+FreeStyle(textPtr, stylePtr)
+    TkText *textPtr;			/* Information about overall widget. */
+    register TextStyle *stylePtr;	/* Information about style to free. */
+
+{
+    stylePtr->refCount--;
+    if (stylePtr->refCount == 0) {
+	if (stylePtr->bgGC != None) {
+	    Tk_FreeGC(textPtr->display, stylePtr->bgGC);
+	}
+	Tk_FreeGC(textPtr->display, stylePtr->fgGC);
+	Tcl_DeleteHashEntry(stylePtr->hPtr);
+	ckfree((char *) stylePtr);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * LayoutDLine --
+ *
+ *	This procedure generates a single DLine structure for a display
+ *	line whose leftmost character is given by indexPtr.
+ *	
+ * Results:
+ *	The return value is a pointer to a DLine structure desribing the
+ *	display line.  All fields are filled in and correct except for
+ *	y and nextPtr.
+ *
+ * Side effects:
+ *	Storage is allocated for the new DLine.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static DLine *
+LayoutDLine(textPtr, indexPtr)
+    TkText *textPtr;		/* Overall information about text widget. */
+    TkTextIndex *indexPtr;	/* Beginning of display line.  May not
+				 * necessarily point to a character segment. */
+{
+    register DLine *dlPtr;		/* New display line. */
+    TkTextSegment *segPtr;		/* Current segment in text. */
+    TkTextDispChunk *lastChunkPtr;	/* Last chunk allocated so far
+					 * for line. */
+    TkTextDispChunk *chunkPtr;		/* Current chunk. */
+    TkTextIndex curIndex;
+    TkTextDispChunk *breakChunkPtr;	/* Chunk containing best word break
+					 * point, if any. */
+    TkTextIndex breakIndex;		/* Index of first character in
+					 * breakChunkPtr. */
+    int breakCharOffset;		/* Character within breakChunkPtr just
+					 * to right of best break point. */
+    int noCharsYet;			/* Non-zero means that no characters
+					 * have been placed on the line yet. */
+    int justify;			/* How to justify line: taken from
+					 * style for first character in line. */
+    int jIndent;			/* Additional indentation (beyond
+					 * margins) due to justification. */
+    int rMargin;			/* Right margin width for line. */
+    Tk_Uid wrapMode;			/* Wrap mode to use for this line. */
+    int x = 0, maxX = 0;		/* Initializations needed only to
+					 * stop compiler warnings. */
+    int wholeLine;			/* Non-zero means this display line
+					 * runs to the end of the text line. */
+    int tabIndex;			/* Index of the current tab stop. */
+    int gotTab;				/* Non-zero means the current chunk
+					 * contains a tab. */
+    TkTextDispChunk *tabChunkPtr;	/* Pointer to the chunk containing
+					 * the previous tab stop. */
+    int maxChars;			/* Maximum number of characters to
+					 * include in this chunk. */
+    TkTextTabArray *tabArrayPtr;	/* Tab stops for line;  taken from
+					 * style for first character on line. */
+    int tabSize;			/* Number of pixels consumed by current
+					 * tab stop. */
+    TkTextDispChunk *lastCharChunkPtr;	/* Pointer to last chunk in display
+					 * lines with numChars > 0.  Used to
+					 * drop 0-sized chunks from the end
+					 * of the line. */
+    int offset, ascent, descent, code;
+    StyleValues *sValuePtr;
+
+    /*
+     * Create and initialize a new DLine structure.
+     */
+
+    dlPtr = (DLine *) ckalloc(sizeof(DLine));
+    dlPtr->index = *indexPtr;
+    dlPtr->count = 0;
+    dlPtr->y = 0;
+    dlPtr->oldY = -1;
+    dlPtr->height = 0;
+    dlPtr->baseline = 0;
+    dlPtr->chunkPtr = NULL;
+    dlPtr->nextPtr = NULL;
+    dlPtr->flags = NEW_LAYOUT;
+
+    /*
+     * Each iteration of the loop below creates one TkTextDispChunk for
+     * the new display line.  The line will always have at least one
+     * chunk (for the newline character at the end, if there's nothing
+     * else available).
+     */
+
+    curIndex = *indexPtr;
+    lastChunkPtr = NULL;
+    chunkPtr = NULL;
+    noCharsYet = 1;
+    breakChunkPtr = NULL;
+    breakCharOffset = 0;
+    justify = TK_JUSTIFY_LEFT;
+    tabIndex = -1;
+    tabChunkPtr = NULL;
+    tabArrayPtr = NULL;
+    rMargin = 0;
+    wrapMode = tkTextCharUid;
+    tabSize = 0;
+    lastCharChunkPtr = NULL;
+
+    /*
+     * Find the first segment to consider for the line.  Can't call
+     * TkTextIndexToSeg for this because it won't return a segment
+     * with zero size (such as the insertion cursor's mark).
+     */
+
+    for (offset = curIndex.charIndex, segPtr = curIndex.linePtr->segPtr;
+	    (offset > 0) && (offset >= segPtr->size);
+	    offset -= segPtr->size, segPtr = segPtr->nextPtr) {
+	/* Empty loop body. */
+    }
+
+    while (segPtr != NULL) {
+	if (segPtr->typePtr->layoutProc == NULL) {
+	    segPtr = segPtr->nextPtr;
+	    offset = 0;
+	    continue;
+	}
+	if (chunkPtr == NULL) {
+	    chunkPtr = (TkTextDispChunk *) ckalloc(sizeof(TkTextDispChunk));
+	    chunkPtr->nextPtr = NULL;
+	}
+	chunkPtr->stylePtr = GetStyle(textPtr, &curIndex);
+
+	/*
+	 * Save style information such as justification and indentation,
+	 * up until the first character is encountered, then retain that
+	 * information for the rest of the line.
+	 */
+
+	if (noCharsYet) {
+	    tabArrayPtr = chunkPtr->stylePtr->sValuePtr->tabArrayPtr;
+	    justify = chunkPtr->stylePtr->sValuePtr->justify;
+	    rMargin = chunkPtr->stylePtr->sValuePtr->rMargin;
+	    wrapMode = chunkPtr->stylePtr->sValuePtr->wrapMode;
+	    x = ((curIndex.charIndex == 0)
+		    ? chunkPtr->stylePtr->sValuePtr->lMargin1
+		    : chunkPtr->stylePtr->sValuePtr->lMargin2);
+	    if (wrapMode == tkTextNoneUid) {
+		maxX = INT_MAX;
+	    } else {
+		maxX = textPtr->dInfoPtr->maxX - textPtr->dInfoPtr->x
+			- rMargin;
+		if (maxX < x) {
+		    maxX = x;
+		}
+	    }
+	}
+
+	/*
+	 * See if there is a tab in the current chunk; if so, only
+	 * layout characters up to (and including) the tab.
+	 */
+
+	gotTab = 0;
+	maxChars = segPtr->size - offset;
+	if (justify == TK_JUSTIFY_LEFT) {
+	    if (segPtr->typePtr == &tkTextCharType) {
+		char *p;
+
+		for (p = segPtr->body.chars  + offset; *p != 0; p++) {
+		    if (*p == '\t') {
+			maxChars = (p + 1 - segPtr->body.chars) - offset;
+			gotTab = 1;
+			break;
+		    }
+		}
+	    }
+	}
+
+	chunkPtr->x = x;
+	code = (*segPtr->typePtr->layoutProc)(textPtr, &curIndex, segPtr,
+		offset, maxX-tabSize, maxChars, noCharsYet, wrapMode,
+		chunkPtr);
+	if (code <= 0) {
+	    FreeStyle(textPtr, chunkPtr->stylePtr);
+	    if (code < 0) {
+		/*
+		 * This segment doesn't wish to display itself (e.g. most
+		 * marks).
+		 */
+
+		segPtr = segPtr->nextPtr;
+		offset = 0;
+		continue;
+	    }
+
+	    /*
+	     * No characters from this segment fit in the window: this
+	     * means we're at the end of the display line.
+	     */
+
+	    if (chunkPtr != NULL) {
+		ckfree((char *) chunkPtr);
+	    }
+	    break;
+	}
+	if (chunkPtr->numChars > 0) {
+	    noCharsYet = 0;
+	    lastCharChunkPtr = chunkPtr;
+	}
+	if (lastChunkPtr == NULL) {
+	    dlPtr->chunkPtr = chunkPtr;
+	} else {
+	    lastChunkPtr->nextPtr = chunkPtr;
+	}
+	lastChunkPtr = chunkPtr;
+	x += chunkPtr->width;
+	if (chunkPtr->breakIndex > 0) {
+	    breakCharOffset = chunkPtr->breakIndex;
+	    breakIndex = curIndex;
+	    breakChunkPtr = chunkPtr;
+	}
+	if (chunkPtr->numChars != maxChars) {
+	    break;
+	}
+
+	/*
+	 * If we're at a new tab, adjust the layout for all the chunks
+	 * pertaining to the previous tab.  Also adjust the amount of
+	 * space left in the line to account for space that will be eaten
+	 * up by the tab.
+	 */
+
+	if (gotTab) {
+	    if (tabIndex >= 0) {
+		AdjustForTab(textPtr, tabArrayPtr, tabIndex, tabChunkPtr);
+		x = chunkPtr->x + chunkPtr->width;
+	    }
+	    tabIndex++;
+	    tabChunkPtr = chunkPtr;
+	    tabSize = SizeOfTab(textPtr, tabArrayPtr, tabIndex, x, maxX);
+	    if (tabSize >= (maxX - x)) {
+		break;
+	    }
+	}
+	curIndex.charIndex += chunkPtr->numChars;
+	offset += chunkPtr->numChars;
+	if (offset >= segPtr->size) {
+	    offset = 0;
+	    segPtr = segPtr->nextPtr;
+	}
+	chunkPtr = NULL;
+    }
+    if (noCharsYet) {
+	panic("LayoutDLine couldn't place any characters on a line");
+    }
+    wholeLine = (segPtr == NULL);
+
+    /*
+     * We're at the end of the display line.  Throw away everything
+     * after the most recent word break, if there is one;  this may
+     * potentially require the last chunk to be layed out again.
+     */
+
+    if (breakChunkPtr == NULL) {
+	/*
+	 * This code makes sure that we don't accidentally display
+	 * chunks with no characters at the end of the line (such as
+	 * the insertion cursor).  These chunks belong on the next
+	 * line.  So, throw away everything after the last chunk that
+	 * has characters in it.
+	 */
+
+	breakChunkPtr = lastCharChunkPtr;
+	breakCharOffset = breakChunkPtr->numChars;
+    }
+    if ((breakChunkPtr != NULL) && ((lastChunkPtr != breakChunkPtr)
+	    || (breakCharOffset != lastChunkPtr->numChars))) {
+	while (1) {
+	    chunkPtr = breakChunkPtr->nextPtr;
+	    if (chunkPtr == NULL) {
+		break;
+	    }
+	    FreeStyle(textPtr, chunkPtr->stylePtr);
+	    breakChunkPtr->nextPtr = chunkPtr->nextPtr;
+	    (*chunkPtr->undisplayProc)(textPtr, chunkPtr);
+	    ckfree((char *) chunkPtr);
+	}
+	if (breakCharOffset != breakChunkPtr->numChars) {
+	    (*breakChunkPtr->undisplayProc)(textPtr, breakChunkPtr);
+	    segPtr = TkTextIndexToSeg(&breakIndex, &offset);
+	    (*segPtr->typePtr->layoutProc)(textPtr, &breakIndex,
+		    segPtr, offset, maxX, breakCharOffset, 0, 
+		    wrapMode, breakChunkPtr);
+	}
+	lastChunkPtr = breakChunkPtr;
+	wholeLine = 0;
+    }
+
+    /*
+     * Make tab adjustments for the last tab stop, if there is one.
+     */
+
+    if ((tabIndex >= 0) && (tabChunkPtr != NULL)) {
+	AdjustForTab(textPtr, tabArrayPtr, tabIndex, tabChunkPtr);
+    }
+
+    /*
+     * Make one more pass over the line to recompute various things
+     * like its height, length, and total number of characters.  Also
+     * modify the x-locations of chunks to reflect justification.
+     * If we're not wrapping, I'm not sure what is the best way to
+     * handle left and center justification:  should the total length,
+     * for purposes of justification, be (a) the window width, (b)
+     * the length of the longest line in the window, or (c) the length
+     * of the longest line in the text?  (c) isn't available, (b) seems
+     * weird, since it can change with vertical scrolling, so (a) is
+     * what is implemented below.
+     */
+
+    if (wrapMode == tkTextNoneUid) {
+	maxX = textPtr->dInfoPtr->maxX - textPtr->dInfoPtr->x - rMargin;
+    }
+    dlPtr->length = lastChunkPtr->x + lastChunkPtr->width;
+    if (justify == TK_JUSTIFY_LEFT) {
+	jIndent = 0;
+    } else if (justify == TK_JUSTIFY_RIGHT) {
+	jIndent = maxX - dlPtr->length;
+    } else {
+	jIndent = (maxX - dlPtr->length)/2;
+    }
+    ascent = descent = 0;
+    for (chunkPtr = dlPtr->chunkPtr; chunkPtr != NULL;
+	    chunkPtr = chunkPtr->nextPtr) {
+	chunkPtr->x += jIndent;
+	dlPtr->count += chunkPtr->numChars;
+	if (chunkPtr->minAscent > ascent) {
+	    ascent = chunkPtr->minAscent;
+	}
+	if (chunkPtr->minDescent > descent) {
+	    descent = chunkPtr->minDescent;
+	}
+	if (chunkPtr->minHeight > dlPtr->height) {
+	    dlPtr->height = chunkPtr->minHeight;
+	}
+	sValuePtr = chunkPtr->stylePtr->sValuePtr;
+	if ((sValuePtr->borderWidth > 0)
+		&& (sValuePtr->relief != TK_RELIEF_FLAT)) {
+	    dlPtr->flags |= HAS_3D_BORDER;
+	}
+    }
+    if (dlPtr->height < (ascent + descent)) {
+	dlPtr->height = ascent + descent;
+	dlPtr->baseline = ascent;
+    } else {
+	dlPtr->baseline = ascent + (dlPtr->height - ascent - descent)/2;
+    }
+    sValuePtr = dlPtr->chunkPtr->stylePtr->sValuePtr;
+    if (dlPtr->index.charIndex == 0) {
+	dlPtr->spaceAbove = sValuePtr->spacing1;
+    } else {
+	dlPtr->spaceAbove = sValuePtr->spacing2 - sValuePtr->spacing2/2;
+    }
+    if (wholeLine) {
+	dlPtr->spaceBelow = sValuePtr->spacing3;
+    } else {
+	dlPtr->spaceBelow = sValuePtr->spacing2/2;
+    }
+    dlPtr->height += dlPtr->spaceAbove + dlPtr->spaceBelow;
+    dlPtr->baseline += dlPtr->spaceAbove;
+
+    /*
+     * Recompute line length:  may have changed because of justification.
+     */
+
+    dlPtr->length = lastChunkPtr->x + lastChunkPtr->width;
+    return dlPtr;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * UpdateDisplayInfo --
+ *
+ *	This procedure is invoked to recompute some or all of the
+ *	DLine structures for a text widget.  At the time it is called
+ *	the DLine structures still left in the widget are guaranteed
+ *	to be correct except that (a) the y-coordinates aren't
+ *	necessarily correct, (b) there may be missing structures
+ *	(the DLine structures get removed as soon as they are potentially
+ *	out-of-date), and (c) DLine structures that don't start at the
+ *	beginning of a line may be incorrect if previous information in
+ *	the same line changed size in a way that moved a line boundary
+ *	(DLines for any info that changed will have been deleted, but
+ *	not DLines for unchanged info in the same text line).
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Upon return, the DLine information for textPtr correctly reflects
+ *	the positions where characters will be displayed.  However, this
+ *	procedure doesn't actually bring the display up-to-date.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+UpdateDisplayInfo(textPtr)
+    TkText *textPtr;			/* Text widget to update. */
+{
+    register TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+    register DLine *dlPtr, *prevPtr;
+    TkTextIndex index;
+    TkTextLine *lastLinePtr;
+    int y, maxY, pixelOffset, maxOffset;
+
+    if (!(dInfoPtr->flags & DINFO_OUT_OF_DATE)) {
+	return;
+    }
+    dInfoPtr->flags &= ~DINFO_OUT_OF_DATE;
+
+    /*
+     * Delete any DLines that are now above the top of the window.
+     */
+
+    index = textPtr->topIndex;
+    dlPtr = FindDLine(dInfoPtr->dLinePtr, &index);
+    if ((dlPtr != NULL) && (dlPtr != dInfoPtr->dLinePtr)) {
+	FreeDLines(textPtr, dInfoPtr->dLinePtr, dlPtr, 1);
+    }
+
+    /*
+     *--------------------------------------------------------------
+     * Scan through the contents of the window from top to bottom,
+     * recomputing information for lines that are missing.
+     *--------------------------------------------------------------
+     */
+
+    lastLinePtr = TkBTreeFindLine(textPtr->tree,
+	    TkBTreeNumLines(textPtr->tree));
+    dlPtr = dInfoPtr->dLinePtr;
+    prevPtr = NULL;
+    y = dInfoPtr->y;
+    maxY = dInfoPtr->maxY;
+    while (1) {
+	register DLine *newPtr;
+
+	if (index.linePtr == lastLinePtr) {
+	    break;
+	}
+
+	/*
+	 * There are three possibilities right now:
+	 * (a) the next DLine (dlPtr) corresponds exactly to the next
+	 *     information we want to display: just use it as-is.
+	 * (b) the next DLine corresponds to a different line, or to
+	 *     a segment that will be coming later in the same line:
+	 *     leave this DLine alone in the hopes that we'll be able
+	 *     to use it later, then create a new DLine in front of
+	 *     it.
+	 * (c) the next DLine corresponds to a segment in the line we
+	 *     want, but it's a segment that has already been processed
+	 *     or will never be processed.  Delete the DLine and try
+	 *     again.
+	 *
+	 * One other twist on all this.  It's possible for 3D borders
+	 * to interact between lines (see DisplayLineBackground) so if
+	 * a line is relayed out and has styles with 3D borders, its
+	 * neighbors have to be redrawn if they have 3D borders too,
+	 * since the interactions could have changed (the neighbors
+	 * don't have to be relayed out, just redrawn).
+	 */
+
+	if ((dlPtr == NULL) || (dlPtr->index.linePtr != index.linePtr)) {
+	    /*
+	     * Case (b) -- must make new DLine.
+	     */
+
+	    makeNewDLine:
+	    if (tkTextDebug) {
+		char string[TK_POS_CHARS];
+
+		/*
+		 * Debugging is enabled, so keep a log of all the lines
+		 * that were re-layed out.  The test suite uses this
+		 * information.
+		 */
+
+		TkTextPrintIndex(&index, string);
+		Tcl_SetVar2(textPtr->interp, "tk_textRelayout", (char *) NULL,
+			string,
+			TCL_GLOBAL_ONLY|TCL_APPEND_VALUE|TCL_LIST_ELEMENT);
+	    }
+	    newPtr = LayoutDLine(textPtr, &index);
+	    if (prevPtr == NULL) {
+		dInfoPtr->dLinePtr = newPtr;
+	    } else {
+		prevPtr->nextPtr = newPtr;
+		if (prevPtr->flags & HAS_3D_BORDER) {
+		    prevPtr->oldY = -1;
+		}
+	    }
+	    newPtr->nextPtr = dlPtr;
+	    dlPtr = newPtr;
+	} else {
+	    /*
+	     * DlPtr refers to the line we want.  Next check the
+	     * index within the line.
+	     */
+
+	    if (index.charIndex == dlPtr->index.charIndex) {
+		/*
+		 * Case (a) -- can use existing display line as-is.
+		 */
+
+		if ((dlPtr->flags & HAS_3D_BORDER) && (prevPtr != NULL)
+			&& (prevPtr->flags & (NEW_LAYOUT))) {
+		    dlPtr->oldY = -1;
+		}
+		goto lineOK;
+	    }
+	    if (index.charIndex < dlPtr->index.charIndex) {
+		goto makeNewDLine;
+	    }
+
+	    /*
+	     * Case (c) -- dlPtr is useless.  Discard it and start
+	     * again with the next display line.
+	     */
+
+	    newPtr = dlPtr->nextPtr;
+	    FreeDLines(textPtr, dlPtr, newPtr, 0);
+	    dlPtr = newPtr;
+	    if (prevPtr != NULL) {
+		prevPtr->nextPtr = newPtr;
+	    } else {
+		dInfoPtr->dLinePtr = newPtr;
+	    }
+	    continue;
+	}
+
+	/*
+	 * Advance to the start of the next line.
+	 */
+
+	lineOK:
+	dlPtr->y = y;
+	y += dlPtr->height;
+	TkTextIndexForwChars(&index, dlPtr->count, &index);
+	prevPtr = dlPtr;
+	dlPtr = dlPtr->nextPtr;
+
+	/*
+	 * If we switched text lines, delete any DLines left for the
+	 * old text line.
+	 */
+
+	if (index.linePtr != prevPtr->index.linePtr) {
+	    register DLine *nextPtr;
+
+	    nextPtr = dlPtr;
+	    while ((nextPtr != NULL)
+		    && (nextPtr->index.linePtr == prevPtr->index.linePtr)) {
+		nextPtr = nextPtr->nextPtr;
+	    }
+	    if (nextPtr != dlPtr) {
+		FreeDLines(textPtr, dlPtr, nextPtr, 0);
+		prevPtr->nextPtr = nextPtr;
+		dlPtr = nextPtr;
+	    }
+	}
+
+	/*
+	 * It's important to have the following check here rather than in
+	 * the while statement for the loop, so that there's always at least
+	 * one DLine generated, regardless of how small the window is.  This
+	 * keeps a lot of other code from breaking.
+	 */
+
+	if (y >= maxY) {
+	    break;
+	}
+    }
+
+    /*
+     * Delete any DLine structures that don't fit on the screen.
+     */
+
+    FreeDLines(textPtr, dlPtr, (DLine *) NULL, 1);
+
+    /*
+     *--------------------------------------------------------------
+     * If there is extra space at the bottom of the window (because
+     * we've hit the end of the text), then bring in more lines at
+     * the top of the window, if there are any, to fill in the view.
+     *--------------------------------------------------------------
+     */
+
+    if (y < maxY) {
+	int lineNum, spaceLeft, charsToCount;
+	DLine *lowestPtr;
+
+	/*
+	 * Layout an entire text line (potentially > 1 display line),
+	 * then link in as many display lines as fit without moving
+	 * the bottom line out of the window.  Repeat this until
+	 * all the extra space has been used up or we've reached the
+	 * beginning of the text.
+	 */
+
+	spaceLeft = maxY - y;
+	lineNum = TkBTreeLineIndex(dInfoPtr->dLinePtr->index.linePtr);
+	charsToCount = dInfoPtr->dLinePtr->index.charIndex;
+	if (charsToCount == 0) {
+	    charsToCount = INT_MAX;
+	    lineNum--;
+	}
+	for ( ; (lineNum >= 0) && (spaceLeft > 0); lineNum--) {
+	    index.linePtr = TkBTreeFindLine(textPtr->tree, lineNum);
+	    index.charIndex = 0;
+	    lowestPtr = NULL;
+	    do {
+		dlPtr = LayoutDLine(textPtr, &index);
+		dlPtr->nextPtr = lowestPtr;
+		lowestPtr = dlPtr;
+		TkTextIndexForwChars(&index, dlPtr->count, &index);
+		charsToCount -= dlPtr->count;
+	    } while ((charsToCount > 0)
+		    && (index.linePtr == lowestPtr->index.linePtr));
+
+	    /*
+	     * Scan through the display lines from the bottom one up to
+	     * the top one.
+	     */
+
+	    while (lowestPtr != NULL) {
+		dlPtr = lowestPtr;
+		spaceLeft -= dlPtr->height;
+		if (spaceLeft < 0) {
+		    break;
+		}
+		lowestPtr = dlPtr->nextPtr;
+		dlPtr->nextPtr = dInfoPtr->dLinePtr;
+		dInfoPtr->dLinePtr = dlPtr;
+		if (tkTextDebug) {
+		    char string[TK_POS_CHARS];
+
+		    TkTextPrintIndex(&dlPtr->index, string);
+		    Tcl_SetVar2(textPtr->interp, "tk_textRelayout",
+			    (char *) NULL, string,
+			    TCL_GLOBAL_ONLY|TCL_APPEND_VALUE|TCL_LIST_ELEMENT);
+		}
+	    }
+	    FreeDLines(textPtr, lowestPtr, (DLine *) NULL, 0);
+	    charsToCount = INT_MAX;
+	}
+
+	/*
+	 * Now we're all done except that the y-coordinates in all the
+	 * DLines are wrong and the top index for the text is wrong.
+	 * Update them.
+	 */
+
+	textPtr->topIndex = dInfoPtr->dLinePtr->index;
+	y = dInfoPtr->y;
+	for (dlPtr = dInfoPtr->dLinePtr; dlPtr != NULL;
+		dlPtr = dlPtr->nextPtr) {
+	    if (y > dInfoPtr->maxY) {
+		panic("Added too many new lines in UpdateDisplayInfo");
+	    }
+	    dlPtr->y = y;
+	    y += dlPtr->height; 
+	}
+    }
+
+    /*
+     *--------------------------------------------------------------
+     * If the old top or bottom line has scrolled elsewhere on the
+     * screen, we may not be able to re-use its old contents by
+     * copying bits (e.g., a beveled edge that was drawn when it was
+     * at the top or bottom won't be drawn when the line is in the
+     * middle and its neighbor has a matching background).  Similarly,
+     * if the new top or bottom line came from somewhere else on the
+     * screen, we may not be able to copy the old bits.
+     *--------------------------------------------------------------
+     */
+
+    dlPtr = dInfoPtr->dLinePtr;
+    if ((dlPtr->flags & HAS_3D_BORDER) && !(dlPtr->flags & TOP_LINE)) {
+	dlPtr->oldY = -1;
+    }
+    while (1) {
+	if ((dlPtr->flags & TOP_LINE) && (dlPtr != dInfoPtr->dLinePtr)
+		&& (dlPtr->flags & HAS_3D_BORDER)) {
+	    dlPtr->oldY = -1;
+	}
+	if ((dlPtr->flags & BOTTOM_LINE) && (dlPtr->nextPtr != NULL)
+		&& (dlPtr->flags & HAS_3D_BORDER)) {
+	    dlPtr->oldY = -1;
+	}
+	if (dlPtr->nextPtr == NULL) {
+	    if ((dlPtr->flags & HAS_3D_BORDER)
+		    && !(dlPtr->flags & BOTTOM_LINE)) {
+		dlPtr->oldY = -1;
+	    }
+	    dlPtr->flags &= ~TOP_LINE;
+	    dlPtr->flags |= BOTTOM_LINE;
+	    break;
+	}
+	dlPtr->flags &= ~(TOP_LINE|BOTTOM_LINE);
+	dlPtr = dlPtr->nextPtr;
+    }
+    dInfoPtr->dLinePtr->flags |= TOP_LINE;
+
+    /*
+     * Arrange for scrollbars to be updated.
+     */
+
+    textPtr->flags |= UPDATE_SCROLLBARS;
+
+    /*
+     *--------------------------------------------------------------
+     * Deal with horizontal scrolling:
+     * 1. If there's empty space to the right of the longest line,
+     *    shift the screen to the right to fill in the empty space.
+     * 2. If the desired horizontal scroll position has changed,
+     *    force a full redisplay of all the lines in the widget.
+     * 3. If the wrap mode isn't "none" then re-scroll to the base
+     *    position.
+     *--------------------------------------------------------------
+     */
+
+    dInfoPtr->maxLength = 0;
+    for (dlPtr = dInfoPtr->dLinePtr; dlPtr != NULL;
+	    dlPtr = dlPtr->nextPtr) {
+	if (dlPtr->length > dInfoPtr->maxLength) {
+	    dInfoPtr->maxLength = dlPtr->length;
+	}
+    }
+    maxOffset = (dInfoPtr->maxLength - (dInfoPtr->maxX - dInfoPtr->x)
+	    + textPtr->charWidth - 1)/textPtr->charWidth;
+    if (dInfoPtr->newCharOffset > maxOffset) {
+	dInfoPtr->newCharOffset = maxOffset;
+    }
+    if (dInfoPtr->newCharOffset < 0) {
+	dInfoPtr->newCharOffset = 0;
+    }
+    pixelOffset = dInfoPtr->newCharOffset * textPtr->charWidth;
+    if (pixelOffset != dInfoPtr->curPixelOffset) {
+	dInfoPtr->curPixelOffset = pixelOffset;
+	for (dlPtr = dInfoPtr->dLinePtr; dlPtr != NULL;
+		dlPtr = dlPtr->nextPtr) {
+	    dlPtr->oldY = -1;
+	}
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FreeDLines --
+ *
+ *	This procedure is called to free up all of the resources
+ *	associated with one or more DLine structures.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Memory gets freed and various other resources are released.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+FreeDLines(textPtr, firstPtr, lastPtr, unlink)
+    TkText *textPtr;			/* Information about overall text
+					 * widget. */
+    register DLine *firstPtr;		/* Pointer to first DLine to free up. */
+    DLine *lastPtr;			/* Pointer to DLine just after last
+					 * one to free (NULL means everything
+					 * starting with firstPtr). */
+    int unlink;				/* 1 means DLines are currently linked
+					 * into the list rooted at
+					 * textPtr->dInfoPtr->dLinePtr and
+					 * they have to be unlinked.  0 means
+					 * just free without unlinking. */
+{
+    register TkTextDispChunk *chunkPtr, *nextChunkPtr;
+    register DLine *nextDLinePtr;
+
+    if (unlink) {
+	if (textPtr->dInfoPtr->dLinePtr == firstPtr) {
+	    textPtr->dInfoPtr->dLinePtr = lastPtr;
+	} else {
+	    register DLine *prevPtr;
+	    for (prevPtr = textPtr->dInfoPtr->dLinePtr;
+		    prevPtr->nextPtr != firstPtr; prevPtr = prevPtr->nextPtr) {
+		/* Empty loop body. */
+	    }
+	    prevPtr->nextPtr = lastPtr;
+	}
+    }
+    while (firstPtr != lastPtr) {
+	nextDLinePtr = firstPtr->nextPtr;
+	for (chunkPtr = firstPtr->chunkPtr; chunkPtr != NULL;
+		chunkPtr = nextChunkPtr) {
+	    if (chunkPtr->undisplayProc != NULL) {
+		(*chunkPtr->undisplayProc)(textPtr, chunkPtr);
+	    }
+	    FreeStyle(textPtr, chunkPtr->stylePtr);
+	    nextChunkPtr = chunkPtr->nextPtr;
+	    ckfree((char *) chunkPtr);
+	}
+	ckfree((char *) firstPtr);
+	firstPtr = nextDLinePtr;
+    }
+    textPtr->dInfoPtr->dLinesInvalidated = 1;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * DisplayDLine --
+ *
+ *	This procedure is invoked to draw a single line on the
+ *	screen.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The line given by dlPtr is drawn at its correct position in
+ *	textPtr's window.  Note that this is one *display* line, not
+ *	one *text* line.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+DisplayDLine(textPtr, dlPtr, prevPtr, pixmap)
+    TkText *textPtr;		/* Text widget in which to draw line. */
+    register DLine *dlPtr;	/* Information about line to draw. */
+    DLine *prevPtr;		/* Line just before one to draw, or NULL
+				 * if dlPtr is the top line. */
+    Pixmap pixmap;		/* Pixmap to use for double-buffering.
+				 * Caller must make sure it's large enough
+				 * to hold line. */
+{
+    register TkTextDispChunk *chunkPtr;
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+    Display *display;
+    int height, x;
+
+    /*
+     * First, clear the area of the line to the background color for the
+     * text widget.
+     */
+
+    display = Tk_Display(textPtr->tkwin);
+    Tk_Fill3DRectangle(textPtr->tkwin, pixmap, textPtr->border, 0, 0,
+	    Tk_Width(textPtr->tkwin), dlPtr->height, 0, TK_RELIEF_FLAT);
+
+    /*
+     * Next, draw background information for the whole line.
+     */
+
+    DisplayLineBackground(textPtr, dlPtr, prevPtr, pixmap);
+
+    /*
+     * Make another pass through all of the chunks to redraw the
+     * insertion cursor, if it is visible on this line.  Must do
+     * it here rather than in the foreground pass below because
+     * otherwise a wide insertion cursor will obscure the character
+     * to its left.
+     */
+
+    if (textPtr->state == tkNormalUid) {
+	for (chunkPtr = dlPtr->chunkPtr; (chunkPtr != NULL);
+		chunkPtr = chunkPtr->nextPtr) {
+	    x = chunkPtr->x + dInfoPtr->x - dInfoPtr->curPixelOffset;
+	    if (chunkPtr->displayProc == TkTextInsertDisplayProc) {
+		(*chunkPtr->displayProc)(chunkPtr, x, dlPtr->spaceAbove,
+			dlPtr->height - dlPtr->spaceAbove - dlPtr->spaceBelow,
+			dlPtr->baseline - dlPtr->spaceAbove, display, pixmap,
+			dlPtr->y + dlPtr->spaceAbove);
+	    }
+	}
+    }
+
+    /*
+     * Make yet another pass through all of the chunks to redraw all of
+     * foreground information.  Note:  we have to call the displayProc
+     * even for chunks that are off-screen.  This is needed, for
+     * example, so that embedded windows can be unmapped in this case.
+     * Conve
+     */
+
+    for (chunkPtr = dlPtr->chunkPtr; (chunkPtr != NULL);
+	    chunkPtr = chunkPtr->nextPtr) {
+	if (chunkPtr->displayProc == TkTextInsertDisplayProc) {
+	    /*
+	     * Already displayed the insertion cursor above.  Don't
+	     * do it again here.
+	     */
+
+	    continue;
+	}
+	x = chunkPtr->x + dInfoPtr->x - dInfoPtr->curPixelOffset;
+	if ((x + chunkPtr->width <= 0) || (x >= dInfoPtr->maxX)) {
+	    /*
+	     * Note:  we have to call the displayProc even for chunks
+	     * that are off-screen.  This is needed, for example, so
+	     * that embedded windows can be unmapped in this case.
+	     * Display the chunk at a coordinate that can be clearly
+	     * identified by the displayProc as being off-screen to
+	     * the left (the displayProc may not be able to tell if
+	     * something is off to the right).
+	     */
+
+	    (*chunkPtr->displayProc)(chunkPtr, -chunkPtr->width,
+		    dlPtr->spaceAbove,
+		    dlPtr->height - dlPtr->spaceAbove - dlPtr->spaceBelow,
+		    dlPtr->baseline - dlPtr->spaceAbove, display, pixmap,
+		    dlPtr->y + dlPtr->spaceAbove);
+	} else {
+	    (*chunkPtr->displayProc)(chunkPtr, x, dlPtr->spaceAbove,
+		    dlPtr->height - dlPtr->spaceAbove - dlPtr->spaceBelow,
+		    dlPtr->baseline - dlPtr->spaceAbove, display, pixmap,
+		    dlPtr->y + dlPtr->spaceAbove);
+	}
+	if (dInfoPtr->dLinesInvalidated) {
+	    return;
+	}
+    }
+
+    /*
+     * Copy the pixmap onto the screen.  If this is the last line on
+     * the screen then copy a piece of the line, so that it doesn't
+     * overflow into the border area.  Another special trick:  copy the
+     * padding area to the left of the line;  this is because the
+     * insertion cursor sometimes overflows onto that area and we want
+     * to get as much of the cursor as possible.
+     */
+
+    height = dlPtr->height;
+    if ((height + dlPtr->y) > dInfoPtr->maxY) {
+	height = dInfoPtr->maxY - dlPtr->y;
+    }
+    XCopyArea(display, pixmap, Tk_WindowId(textPtr->tkwin), dInfoPtr->copyGC,
+	    dInfoPtr->x, 0, (unsigned) (dInfoPtr->maxX - dInfoPtr->x),
+	    (unsigned) height, dInfoPtr->x, dlPtr->y);
+    linesRedrawn++;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * DisplayLineBackground --
+ *
+ *	This procedure is called to fill in the background for
+ *	a display line.  It draws 3D borders cleverly so that
+ *	adjacent chunks with the same style (whether on the same
+ *	line or different lines) have a single 3D border around
+ *	the whole region.
+ *
+ * Results:
+ *	There is no return value.  Pixmap is filled in with background
+ *	information for dlPtr.
+ *
+ * Side effects:
+ *	None.
+ *
+ *--------------------------------------------------------------
+ */
+
+static void
+DisplayLineBackground(textPtr, dlPtr, prevPtr, pixmap)
+    TkText *textPtr;		/* Text widget containing line. */
+    register DLine *dlPtr;	/* Information about line to draw. */
+    DLine *prevPtr;		/* Line just above dlPtr, or NULL if dlPtr
+				 * is the top-most line in the window. */
+    Pixmap pixmap;		/* Pixmap to use for double-buffering.
+				 * Caller must make sure it's large enough
+				 * to hold line.  Caller must also have
+				 * filled it with the background color for
+				 * the widget. */
+{
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+    TkTextDispChunk *chunkPtr;  /* Pointer to chunk in the current line. */
+    TkTextDispChunk *chunkPtr2;	/* Pointer to chunk in the line above or
+				 * below the current one.  NULL if we're to
+				 * the left of or to the right of the chunks
+				 * in the line. */
+    TkTextDispChunk *nextPtr2;	/* Next chunk after chunkPtr2 (it's not the
+				 * same as chunkPtr2->nextPtr in the case
+				 * where chunkPtr2 is NULL because the line
+				 * is indented). */
+    int leftX;			/* The left edge of the region we're
+				 * currently working on. */
+    int leftXIn;		/* 1 means beveled edge at leftX slopes right
+				 * as it goes down, 0 means it slopes left
+				 * as it goes down. */
+    int rightX;			/* Right edge of chunkPtr. */
+    int rightX2;		/* Right edge of chunkPtr2. */
+    int matchLeft;		/* Does the style of this line match that
+				 * of its neighbor just to the left of
+				 * the current x coordinate? */
+    int matchRight;		/* Does line's style match its neighbor
+				 * just to the right of the current x-coord? */
+    int minX, maxX, xOffset;
+    StyleValues *sValuePtr;
+    Display *display;
+
+    /*
+     * Pass 1: scan through dlPtr from left to right.  For each range of
+     * chunks with the same style, draw the main background for the style
+     * plus the vertical parts of the 3D borders (the left and right
+     * edges).
+     */
+
+    display = Tk_Display(textPtr->tkwin);
+    minX = dInfoPtr->curPixelOffset;
+    xOffset = dInfoPtr->x - minX;
+    maxX = minX + dInfoPtr->maxX - dInfoPtr->x;
+    chunkPtr = dlPtr->chunkPtr;
+
+    /*
+     * Note A: in the following statement, and a few others later in
+     * this file marked with "See Note A above", the right side of the
+     * assignment was replaced with 0 on 6/18/97.  This has the effect
+     * of highlighting the empty space to the left of a line whenever
+     * the leftmost character of the line is highlighted.  This way,
+     * multi-line highlights always line up along their left edges. 
+     * However, this may look funny in the case where a single word is
+     * highlighted. To undo the change, replace "leftX = 0" with "leftX
+     * = chunkPtr->x" and "rightX2 = 0" with "rightX2 = nextPtr2->x"
+     * here and at all the marked points below.  This restores the old
+     * behavior where empty space to the left of a line is not
+     * highlighted, leaving a ragged left edge for multi-line
+     * highlights.
+     */
+
+    leftX = 0;
+    for (; leftX < maxX; chunkPtr = chunkPtr->nextPtr) {
+	if ((chunkPtr->nextPtr != NULL)
+		&& SAME_BACKGROUND(chunkPtr->nextPtr->stylePtr,
+		chunkPtr->stylePtr)) {
+	    continue;
+	}
+	sValuePtr = chunkPtr->stylePtr->sValuePtr;
+	rightX = chunkPtr->x + chunkPtr->width;
+	if ((chunkPtr->nextPtr == NULL) && (rightX < maxX)) {
+	    rightX = maxX;
+	}
+	if (chunkPtr->stylePtr->bgGC != None) {
+	    XFillRectangle(display, pixmap, chunkPtr->stylePtr->bgGC,
+		    leftX + xOffset, 0, (unsigned int) (rightX - leftX),
+		    (unsigned int) dlPtr->height);
+	    if (sValuePtr->relief != TK_RELIEF_FLAT) {
+		Tk_3DVerticalBevel(textPtr->tkwin, pixmap, sValuePtr->border,
+			leftX + xOffset, 0, sValuePtr->borderWidth,
+			dlPtr->height, 1, sValuePtr->relief);
+		Tk_3DVerticalBevel(textPtr->tkwin, pixmap, sValuePtr->border,
+			rightX - sValuePtr->borderWidth + xOffset,
+			0, sValuePtr->borderWidth, dlPtr->height, 0,
+			sValuePtr->relief);
+	    }
+	}
+	leftX = rightX;
+    }
+
+    /*
+     * Pass 2: draw the horizontal bevels along the top of the line.  To
+     * do this, scan through dlPtr from left to right while simultaneously
+     * scanning through the line just above dlPtr.  ChunkPtr2 and nextPtr2
+     * refer to two adjacent chunks in the line above.
+     */
+
+    chunkPtr = dlPtr->chunkPtr;
+    leftX = 0;				/* See Note A above. */
+    leftXIn = 1;
+    rightX = chunkPtr->x + chunkPtr->width;
+    if ((chunkPtr->nextPtr == NULL) && (rightX < maxX)) {
+	rightX = maxX;
+    }
+    chunkPtr2 = NULL;
+    if (prevPtr != NULL) {
+	/*
+	 * Find the chunk in the previous line that covers leftX.
+	 */
+
+	nextPtr2 = prevPtr->chunkPtr;
+	rightX2 = 0;			/* See Note A above. */
+	while (rightX2 <= leftX) {
+	    chunkPtr2 = nextPtr2;
+	    if (chunkPtr2 == NULL) {
+		break;
+	    }
+	    nextPtr2 = chunkPtr2->nextPtr;
+	    rightX2 = chunkPtr2->x + chunkPtr2->width;
+	    if (nextPtr2 == NULL) {
+		rightX2 = INT_MAX;
+	    }
+	}
+    } else {
+	nextPtr2 = NULL;
+	rightX2 = INT_MAX;
+    }
+
+    while (leftX < maxX) {
+	matchLeft = (chunkPtr2 != NULL)
+		&& SAME_BACKGROUND(chunkPtr2->stylePtr, chunkPtr->stylePtr);
+	sValuePtr = chunkPtr->stylePtr->sValuePtr;
+	if (rightX <= rightX2) {
+	    /*
+	     * The chunk in our line is about to end.  If its style
+	     * changes then draw the bevel for the current style.
+	     */
+
+	    if ((chunkPtr->nextPtr == NULL)
+		    || !SAME_BACKGROUND(chunkPtr->stylePtr,
+		    chunkPtr->nextPtr->stylePtr)) {
+		if (!matchLeft && (sValuePtr->relief != TK_RELIEF_FLAT)) {
+		    Tk_3DHorizontalBevel(textPtr->tkwin, pixmap,
+			    sValuePtr->border, leftX + xOffset, 0,
+			    rightX - leftX, sValuePtr->borderWidth, leftXIn,
+			    1, 1, sValuePtr->relief);
+		}
+		leftX = rightX;
+		leftXIn = 1;
+
+		/*
+		 * If the chunk in the line above is also ending at
+		 * the same point then advance to the next chunk in
+		 * that line.
+		 */
+
+		if ((rightX == rightX2) && (chunkPtr2 != NULL)) {
+		    goto nextChunk2;
+		}
+	    }
+	    chunkPtr = chunkPtr->nextPtr;
+	    if (chunkPtr == NULL) {
+		break;
+	    }
+	    rightX = chunkPtr->x + chunkPtr->width;
+	    if ((chunkPtr->nextPtr == NULL) && (rightX < maxX)) {
+		rightX = maxX;
+	    }
+	    continue;
+	}
+
+	/*
+	 * The chunk in the line above is ending at an x-position where
+	 * there is no change in the style of the current line.  If the
+	 * style above matches the current line on one side of the change
+	 * but not on the other, we have to draw an L-shaped piece of
+	 * bevel.
+	 */
+
+	matchRight = (nextPtr2 != NULL)
+		&& SAME_BACKGROUND(nextPtr2->stylePtr, chunkPtr->stylePtr);
+	if (matchLeft && !matchRight) {
+	    if (sValuePtr->relief != TK_RELIEF_FLAT) {
+		Tk_3DVerticalBevel(textPtr->tkwin, pixmap, sValuePtr->border,
+			rightX2 - sValuePtr->borderWidth + xOffset, 0,
+			sValuePtr->borderWidth, sValuePtr->borderWidth, 0,
+			sValuePtr->relief);
+	    }
+	    leftX = rightX2 - sValuePtr->borderWidth;
+	    leftXIn = 0;
+	} else if (!matchLeft && matchRight
+		&& (sValuePtr->relief != TK_RELIEF_FLAT)) {
+	    Tk_3DVerticalBevel(textPtr->tkwin, pixmap, sValuePtr->border,
+		    rightX2 + xOffset, 0, sValuePtr->borderWidth,
+		    sValuePtr->borderWidth, 1, sValuePtr->relief);
+	    Tk_3DHorizontalBevel(textPtr->tkwin, pixmap, sValuePtr->border,
+		    leftX + xOffset, 0, rightX2 + sValuePtr->borderWidth -leftX,
+		    sValuePtr->borderWidth, leftXIn, 0, 1,
+		    sValuePtr->relief);
+	}
+
+	nextChunk2:
+	chunkPtr2 = nextPtr2;
+	if (chunkPtr2 == NULL) {
+	    rightX2 = INT_MAX;
+	} else {
+	    nextPtr2 = chunkPtr2->nextPtr;
+	    rightX2 = chunkPtr2->x + chunkPtr2->width;
+	    if (nextPtr2 == NULL) {
+		rightX2 = INT_MAX;
+	    }
+	}
+    }
+    /*
+     * Pass 3: draw the horizontal bevels along the bottom of the line.
+     * This uses the same approach as pass 2.
+     */
+
+    chunkPtr = dlPtr->chunkPtr;
+    leftX = 0;				/* See Note A above. */
+    leftXIn = 0;
+    rightX = chunkPtr->x + chunkPtr->width;
+    if ((chunkPtr->nextPtr == NULL) && (rightX < maxX)) {
+	rightX = maxX;
+    }
+    chunkPtr2 = NULL;
+    if (dlPtr->nextPtr != NULL) {
+	/*
+	 * Find the chunk in the previous line that covers leftX.
+	 */
+
+	nextPtr2 = dlPtr->nextPtr->chunkPtr;
+	rightX2 = 0;			/* See Note A above. */
+	while (rightX2 <= leftX) {
+	    chunkPtr2 = nextPtr2;
+	    if (chunkPtr2 == NULL) {
+		break;
+	    }
+	    nextPtr2 = chunkPtr2->nextPtr;
+	    rightX2 = chunkPtr2->x + chunkPtr2->width;
+	    if (nextPtr2 == NULL) {
+		rightX2 = INT_MAX;
+	    }
+	}
+    } else {
+	nextPtr2 = NULL;
+	rightX2 = INT_MAX;
+    }
+
+    while (leftX < maxX) {
+	matchLeft = (chunkPtr2 != NULL)
+		&& SAME_BACKGROUND(chunkPtr2->stylePtr, chunkPtr->stylePtr);
+	sValuePtr = chunkPtr->stylePtr->sValuePtr;
+	if (rightX <= rightX2) {
+	    if ((chunkPtr->nextPtr == NULL)
+		    || !SAME_BACKGROUND(chunkPtr->stylePtr,
+		    chunkPtr->nextPtr->stylePtr)) {
+		if (!matchLeft && (sValuePtr->relief != TK_RELIEF_FLAT)) {
+		    Tk_3DHorizontalBevel(textPtr->tkwin, pixmap,
+			    sValuePtr->border, leftX + xOffset,
+			    dlPtr->height - sValuePtr->borderWidth,
+			    rightX - leftX, sValuePtr->borderWidth, leftXIn,
+			    0, 0, sValuePtr->relief);
+		}
+		leftX = rightX;
+		leftXIn = 0;
+		if ((rightX == rightX2) && (chunkPtr2 != NULL)) {
+		    goto nextChunk2b;
+		}
+	    }
+	    chunkPtr = chunkPtr->nextPtr;
+	    if (chunkPtr == NULL) {
+		break;
+	    }
+	    rightX = chunkPtr->x + chunkPtr->width;
+	    if ((chunkPtr->nextPtr == NULL) && (rightX < maxX)) {
+		rightX = maxX;
+	    }
+	    continue;
+	}
+
+	matchRight = (nextPtr2 != NULL)
+		&& SAME_BACKGROUND(nextPtr2->stylePtr, chunkPtr->stylePtr);
+	if (matchLeft && !matchRight) {
+	    if (sValuePtr->relief != TK_RELIEF_FLAT) {
+		Tk_3DVerticalBevel(textPtr->tkwin, pixmap, sValuePtr->border,
+			rightX2 - sValuePtr->borderWidth + xOffset,
+			dlPtr->height - sValuePtr->borderWidth,
+			sValuePtr->borderWidth, sValuePtr->borderWidth, 0,
+			sValuePtr->relief);
+	    }
+	    leftX = rightX2 - sValuePtr->borderWidth;
+	    leftXIn = 1;
+	} else if (!matchLeft && matchRight
+		&& (sValuePtr->relief != TK_RELIEF_FLAT)) {
+	    Tk_3DVerticalBevel(textPtr->tkwin, pixmap, sValuePtr->border,
+		    rightX2 + xOffset, dlPtr->height - sValuePtr->borderWidth,
+		    sValuePtr->borderWidth, sValuePtr->borderWidth,
+		    1, sValuePtr->relief);
+	    Tk_3DHorizontalBevel(textPtr->tkwin, pixmap, sValuePtr->border,
+		    leftX + xOffset, dlPtr->height - sValuePtr->borderWidth,
+		    rightX2 + sValuePtr->borderWidth - leftX,
+		    sValuePtr->borderWidth, leftXIn, 1, 0, sValuePtr->relief);
+	}
+
+	nextChunk2b:
+	chunkPtr2 = nextPtr2;
+	if (chunkPtr2 == NULL) {
+	    rightX2 = INT_MAX;
+	} else {
+	    nextPtr2 = chunkPtr2->nextPtr;
+	    rightX2 = chunkPtr2->x + chunkPtr2->width;
+	    if (nextPtr2 == NULL) {
+		rightX2 = INT_MAX;
+	    }
+	}
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * DisplayText --
+ *
+ *	This procedure is invoked as a when-idle handler to update the
+ *	display.  It only redisplays the parts of the text widget that
+ *	are out of date.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Information is redrawn on the screen.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+DisplayText(clientData)
+    ClientData clientData;	/* Information about widget. */
+{
+    register TkText *textPtr = (TkText *) clientData;
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+    Tk_Window tkwin;
+    register DLine *dlPtr;
+    DLine *prevPtr;
+    Pixmap pixmap;
+    int maxHeight, borders;
+    int bottomY = 0;		/* Initialization needed only to stop
+				 * compiler warnings. */
+    Tcl_Interp *interp;
+
+    if (textPtr->tkwin == NULL) {
+
+	/*
+	 * The widget has been deleted.  Don't do anything.
+	 */
+
+	return;
+    }
+
+    interp = textPtr->interp;
+    Tcl_Preserve((ClientData) interp);
+
+    if (tkTextDebug) {
+	Tcl_SetVar2(interp, "tk_textRelayout", (char *) NULL, "",
+                TCL_GLOBAL_ONLY);
+    }
+
+    if (textPtr->tkwin == NULL) {
+
+	/*
+	 * The widget has been deleted.  Don't do anything.
+	 */
+
+        goto end;
+    }
+
+    if (!Tk_IsMapped(textPtr->tkwin) || (dInfoPtr->maxX <= dInfoPtr->x)
+	    || (dInfoPtr->maxY <= dInfoPtr->y)) {
+	UpdateDisplayInfo(textPtr);
+	dInfoPtr->flags &= ~REDRAW_PENDING;
+	goto doScrollbars;
+    }
+    numRedisplays++;
+    if (tkTextDebug) {
+	Tcl_SetVar2(interp, "tk_textRedraw", (char *) NULL, "",
+                TCL_GLOBAL_ONLY);
+    }
+
+    if (textPtr->tkwin == NULL) {
+
+	/*
+	 * The widget has been deleted.  Don't do anything.
+	 */
+
+	goto end;
+    }
+
+    /*
+     * Choose a new current item if that is needed (this could cause
+     * event handlers to be invoked, hence the preserve/release calls
+     * and the loop, since the handlers could conceivably necessitate
+     * yet another current item calculation).  The tkwin check is because
+     * the whole window could go away in the Tcl_Release call.
+     */
+
+    while (dInfoPtr->flags & REPICK_NEEDED) {
+	Tcl_Preserve((ClientData) textPtr);
+	dInfoPtr->flags &= ~REPICK_NEEDED;
+	TkTextPickCurrent(textPtr, &textPtr->pickEvent);
+	tkwin = textPtr->tkwin;
+	Tcl_Release((ClientData) textPtr);
+	if (tkwin == NULL) {
+	    goto end;
+	}
+    }
+
+    /*
+     * First recompute what's supposed to be displayed.
+     */
+
+    UpdateDisplayInfo(textPtr);
+    dInfoPtr->dLinesInvalidated = 0;
+
+    /*
+     * See if it's possible to bring some parts of the screen up-to-date
+     * by scrolling (copying from other parts of the screen).
+     */
+
+    for (dlPtr = dInfoPtr->dLinePtr; dlPtr != NULL; dlPtr = dlPtr->nextPtr) {
+	register DLine *dlPtr2;
+	int offset, height, y, oldY;
+	TkRegion damageRgn;
+
+	if ((dlPtr->oldY == -1) || (dlPtr->y == dlPtr->oldY)
+		|| ((dlPtr->oldY + dlPtr->height) > dInfoPtr->maxY)) {
+	    continue;
+	}
+
+	/*
+	 * This line is already drawn somewhere in the window so it only
+	 * needs to be copied to its new location.  See if there's a group
+	 * of lines that can all be copied together.
+	 */
+
+	offset = dlPtr->y - dlPtr->oldY;
+	height = dlPtr->height;
+	y = dlPtr->y;
+	for (dlPtr2 = dlPtr->nextPtr; dlPtr2 != NULL;
+		dlPtr2 = dlPtr2->nextPtr) {
+	    if ((dlPtr2->oldY == -1)
+		    || ((dlPtr2->oldY + offset) != dlPtr2->y)
+		    || ((dlPtr2->oldY + dlPtr2->height) > dInfoPtr->maxY)) {
+		break;
+	    }
+	    height += dlPtr2->height;
+	}
+
+	/*
+	 * Reduce the height of the area being copied if necessary to
+	 * avoid overwriting the border area.
+	 */
+
+	if ((y + height) > dInfoPtr->maxY) {
+	    height = dInfoPtr->maxY -y;
+	}
+	oldY = dlPtr->oldY;
+
+	/*
+	 * Update the lines we are going to scroll to show that they
+	 * have been copied.
+	 */
+
+	while (1) {
+	    dlPtr->oldY = dlPtr->y;
+	    if (dlPtr->nextPtr == dlPtr2) {
+		break;
+	    }
+	    dlPtr = dlPtr->nextPtr;
+	}
+
+	/*
+	 * Scan through the lines following the copied ones to see if
+	 * we are going to overwrite them with the copy operation.
+	 * If so, mark them for redisplay.
+	 */
+
+	for ( ; dlPtr2 != NULL; dlPtr2 = dlPtr2->nextPtr) {
+	    if ((dlPtr2->oldY != -1)
+		    && ((dlPtr2->oldY + dlPtr2->height) > y)
+		    && (dlPtr2->oldY < (y + height))) {
+		dlPtr2->oldY = -1;
+	    }
+	}
+
+	/*
+	 * Now scroll the lines.  This may generate damage which we
+	 * handle by calling TextInvalidateRegion to mark the display
+	 * blocks as stale.
+	 */
+
+	damageRgn = TkCreateRegion();
+	if (TkScrollWindow(textPtr->tkwin, dInfoPtr->scrollGC,
+		dInfoPtr->x, oldY,
+		(dInfoPtr->maxX - dInfoPtr->x), height,
+		0, y - oldY, damageRgn)) {
+	    TextInvalidateRegion(textPtr, damageRgn);
+	}
+	numCopies++;
+	TkDestroyRegion(damageRgn);
+    }
+
+    /*
+     * Clear the REDRAW_PENDING flag here.  This is actually pretty
+     * tricky.  We want to wait until *after* doing the scrolling,
+     * since that could generate more areas to redraw and don't
+     * want to reschedule a redisplay for them.  On the other hand,
+     * we can't wait until after all the redisplaying, because the
+     * act of redisplaying could actually generate more redisplays
+     * (e.g. in the case of a nested window with event bindings triggered
+     * by redisplay).
+     */
+
+    dInfoPtr->flags &= ~REDRAW_PENDING;
+
+    /*
+     * Redraw the borders if that's needed.
+     */
+
+    if (dInfoPtr->flags & REDRAW_BORDERS) {
+	if (tkTextDebug) {
+	    Tcl_SetVar2(interp, "tk_textRedraw", (char *) NULL, "borders",
+		    TCL_GLOBAL_ONLY|TCL_APPEND_VALUE|TCL_LIST_ELEMENT);
+	}
+
+        if (textPtr->tkwin == NULL) {
+
+	    /*
+             * The widget has been deleted.  Don't do anything.
+             */
+
+            goto end;
+        }
+
+	Tk_Draw3DRectangle(textPtr->tkwin, Tk_WindowId(textPtr->tkwin),
+		textPtr->border, textPtr->highlightWidth,
+		textPtr->highlightWidth,
+		Tk_Width(textPtr->tkwin) - 2*textPtr->highlightWidth,
+		Tk_Height(textPtr->tkwin) - 2*textPtr->highlightWidth,
+		textPtr->borderWidth, textPtr->relief);
+	if (textPtr->highlightWidth != 0) {
+	    GC gc;
+    
+	    if (textPtr->flags & GOT_FOCUS) {
+		gc = Tk_GCForColor(textPtr->highlightColorPtr,
+			Tk_WindowId(textPtr->tkwin));
+	    } else {
+		gc = Tk_GCForColor(textPtr->highlightBgColorPtr,
+			Tk_WindowId(textPtr->tkwin));
+	    }
+	    Tk_DrawFocusHighlight(textPtr->tkwin, gc, textPtr->highlightWidth,
+		    Tk_WindowId(textPtr->tkwin));
+	}
+	borders = textPtr->borderWidth + textPtr->highlightWidth;
+	if (textPtr->padY > 0) {
+	    Tk_Fill3DRectangle(textPtr->tkwin, Tk_WindowId(textPtr->tkwin),
+		    textPtr->border, borders, borders,
+		    Tk_Width(textPtr->tkwin) - 2*borders, textPtr->padY,
+		    0, TK_RELIEF_FLAT);
+	    Tk_Fill3DRectangle(textPtr->tkwin, Tk_WindowId(textPtr->tkwin),
+		    textPtr->border, borders,
+		    Tk_Height(textPtr->tkwin) - borders - textPtr->padY,
+		    Tk_Width(textPtr->tkwin) - 2*borders,
+		    textPtr->padY, 0, TK_RELIEF_FLAT);
+	}
+	if (textPtr->padX > 0) {
+	    Tk_Fill3DRectangle(textPtr->tkwin, Tk_WindowId(textPtr->tkwin),
+		    textPtr->border, borders, borders + textPtr->padY,
+		    textPtr->padX,
+		    Tk_Height(textPtr->tkwin) - 2*borders -2*textPtr->padY,
+		    0, TK_RELIEF_FLAT);
+	    Tk_Fill3DRectangle(textPtr->tkwin, Tk_WindowId(textPtr->tkwin),
+		    textPtr->border,
+		    Tk_Width(textPtr->tkwin) - borders - textPtr->padX,
+		    borders + textPtr->padY, textPtr->padX,
+		    Tk_Height(textPtr->tkwin) - 2*borders -2*textPtr->padY,
+		    0, TK_RELIEF_FLAT);
+	}
+	dInfoPtr->flags &= ~REDRAW_BORDERS;
+    }
+
+    /*
+     * Now we have to redraw the lines that couldn't be updated by
+     * scrolling.  First, compute the height of the largest line and
+     * allocate an off-screen pixmap to use for double-buffered
+     * displays.
+     */
+
+    maxHeight = -1;
+    for (dlPtr = dInfoPtr->dLinePtr; dlPtr != NULL;
+	    dlPtr = dlPtr->nextPtr) {
+	if ((dlPtr->height > maxHeight) && (dlPtr->oldY != dlPtr->y)) {
+	    maxHeight = dlPtr->height;
+	}
+	bottomY = dlPtr->y + dlPtr->height;
+    }
+    if (maxHeight > dInfoPtr->maxY) {
+	maxHeight = dInfoPtr->maxY;
+    }
+    if (maxHeight > 0) {
+	pixmap = Tk_GetPixmap(Tk_Display(textPtr->tkwin),
+		Tk_WindowId(textPtr->tkwin), Tk_Width(textPtr->tkwin),
+		maxHeight, Tk_Depth(textPtr->tkwin));
+	for (prevPtr = NULL, dlPtr = textPtr->dInfoPtr->dLinePtr;
+		(dlPtr != NULL) && (dlPtr->y < dInfoPtr->maxY);
+		prevPtr = dlPtr, dlPtr = dlPtr->nextPtr) {
+	    if (dlPtr->oldY != dlPtr->y) {
+		if (tkTextDebug) {
+		    char string[TK_POS_CHARS];
+		    TkTextPrintIndex(&dlPtr->index, string);
+		    Tcl_SetVar2(textPtr->interp, "tk_textRedraw",
+			    (char *) NULL, string,
+			    TCL_GLOBAL_ONLY|TCL_APPEND_VALUE|TCL_LIST_ELEMENT);
+		}
+		DisplayDLine(textPtr, dlPtr, prevPtr, pixmap);
+		if (dInfoPtr->dLinesInvalidated) {
+		    Tk_FreePixmap(Tk_Display(textPtr->tkwin), pixmap);
+		    return;
+		}
+		dlPtr->oldY = dlPtr->y;
+		dlPtr->flags &= ~NEW_LAYOUT;
+	    }
+	}
+	Tk_FreePixmap(Tk_Display(textPtr->tkwin), pixmap);
+    }
+
+    /*
+     * See if we need to refresh the part of the window below the
+     * last line of text (if there is any such area).  Refresh the
+     * padding area on the left too, since the insertion cursor might
+     * have been displayed there previously).
+     */
+
+    if (dInfoPtr->topOfEof > dInfoPtr->maxY) {
+	dInfoPtr->topOfEof = dInfoPtr->maxY;
+    }
+    if (bottomY < dInfoPtr->topOfEof) {
+	if (tkTextDebug) {
+	    Tcl_SetVar2(textPtr->interp, "tk_textRedraw",
+		    (char *) NULL, "eof",
+		    TCL_GLOBAL_ONLY|TCL_APPEND_VALUE|TCL_LIST_ELEMENT);
+	}
+
+        if (textPtr->tkwin == NULL) {
+
+	    /*
+             * The widget has been deleted.  Don't do anything.
+             */
+
+            goto end;
+        }
+
+	Tk_Fill3DRectangle(textPtr->tkwin, Tk_WindowId(textPtr->tkwin),
+		textPtr->border, dInfoPtr->x - textPtr->padX, bottomY,
+		dInfoPtr->maxX - (dInfoPtr->x - textPtr->padX),
+		dInfoPtr->topOfEof-bottomY, 0, TK_RELIEF_FLAT);
+    }
+    dInfoPtr->topOfEof = bottomY;
+
+    doScrollbars:
+
+    /*
+     * Update the vertical scrollbar, if there is one.  Note:  it's
+     * important to clear REDRAW_PENDING here, just in case the
+     * scroll procedure does something that requires redisplay.
+     */
+    
+    if (textPtr->flags & UPDATE_SCROLLBARS) {
+	textPtr->flags &= ~UPDATE_SCROLLBARS;
+	if (textPtr->yScrollCmd != NULL) {
+	    GetYView(textPtr->interp, textPtr, 1);
+	}
+
+        if (textPtr->tkwin == NULL) {
+
+	    /*
+             * The widget has been deleted.  Don't do anything.
+             */
+
+            goto end;
+        }
+
+	/*
+	 * Update the horizontal scrollbar, if any.
+	 */
+
+	if (textPtr->xScrollCmd != NULL) {
+	    GetXView(textPtr->interp, textPtr, 1);
+	}
+    }
+
+end:
+    Tcl_Release((ClientData) interp);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkTextEventuallyRepick --
+ *
+ *	This procedure is invoked whenever something happens that
+ *	could change the current character or the tags associated
+ *	with it.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	A repick is scheduled as an idle handler.
+ *
+ *----------------------------------------------------------------------
+ */
+
+	/* ARGSUSED */
+void
+TkTextEventuallyRepick(textPtr)
+    TkText *textPtr;		/* Widget record for text widget. */
+{
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+
+    dInfoPtr->flags |= REPICK_NEEDED;
+    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
+	dInfoPtr->flags |= REDRAW_PENDING;
+	Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkTextRedrawRegion --
+ *
+ *	This procedure is invoked to schedule a redisplay for a given
+ *	region of a text widget.  The redisplay itself may not occur
+ *	immediately:  it's scheduled as a when-idle handler.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Information will eventually be redrawn on the screen.
+ *
+ *----------------------------------------------------------------------
+ */
+
+	/* ARGSUSED */
+void
+TkTextRedrawRegion(textPtr, x, y, width, height)
+    TkText *textPtr;		/* Widget record for text widget. */
+    int x, y;			/* Coordinates of upper-left corner of area
+				 * to be redrawn, in pixels relative to
+				 * textPtr's window. */
+    int width, height;		/* Width and height of area to be redrawn. */
+{
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+    TkRegion damageRgn = TkCreateRegion();
+    XRectangle rect;
+
+    rect.x = x;
+    rect.y = y;
+    rect.width = width;
+    rect.height = height;
+    TkUnionRectWithRegion(&rect, damageRgn, damageRgn);
+
+    TextInvalidateRegion(textPtr, damageRgn);
+
+    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
+	dInfoPtr->flags |= REDRAW_PENDING;
+	Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
+    }
+    TkDestroyRegion(damageRgn);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TextInvalidateRegion --
+ *
+ *	Mark a region of text as invalid.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Updates the display information for the text widget.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+TextInvalidateRegion(textPtr, region)
+    TkText *textPtr;		/* Widget record for text widget. */
+    TkRegion region;		/* Region of area to redraw. */
+{
+    register DLine *dlPtr;
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+    int maxY, inset;
+    XRectangle rect;
+
+    /*
+     * Find all lines that overlap the given region and mark them for
+     * redisplay.
+     */
+
+    TkClipBox(region, &rect);
+    maxY = rect.y + rect.height;
+    for (dlPtr = dInfoPtr->dLinePtr; dlPtr != NULL;
+	    dlPtr = dlPtr->nextPtr) {
+	if ((dlPtr->oldY != -1) && (TkRectInRegion(region, rect.x, dlPtr->y,
+		rect.width, (unsigned int) dlPtr->height) != RectangleOut)) {
+	    dlPtr->oldY = -1;
+	}
+    }
+    if (dInfoPtr->topOfEof < maxY) {
+	dInfoPtr->topOfEof = maxY;
+    }
+
+    /*
+     * Schedule the redisplay operation if there isn't one already
+     * scheduled.
+     */
+
+    inset = textPtr->borderWidth + textPtr->highlightWidth;
+    if ((rect.x < (inset + textPtr->padX))
+	    || (rect.y < (inset + textPtr->padY))
+	    || ((int) (rect.x + rect.width) > (Tk_Width(textPtr->tkwin)
+		    - inset - textPtr->padX))
+	    || (maxY > (Tk_Height(textPtr->tkwin) - inset - textPtr->padY))) {
+	dInfoPtr->flags |= REDRAW_BORDERS;
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkTextChanged --
+ *
+ *	This procedure is invoked when info in a text widget is about
+ *	to be modified in a way that changes how it is displayed (e.g.
+ *	characters were inserted or deleted, or tag information was
+ *	changed).  This procedure must be called *before* a change is
+ *	made, so that indexes in the display information are still
+ *	valid.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The range of character between index1Ptr (inclusive) and
+ *	index2Ptr (exclusive) will be redisplayed at some point in the
+ *	future (the actual redisplay is scheduled as a when-idle handler).
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TkTextChanged(textPtr, index1Ptr, index2Ptr)
+    TkText *textPtr;		/* Widget record for text widget. */
+    TkTextIndex *index1Ptr;	/* Index of first character to redisplay. */
+    TkTextIndex *index2Ptr;	/* Index of character just after last one
+				 * to redisplay. */
+{
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+    DLine *firstPtr, *lastPtr;
+    TkTextIndex rounded;
+
+    /*
+     * Schedule both a redisplay and a recomputation of display information.
+     * It's done here rather than the end of the procedure for two reasons:
+     *
+     * 1. If there are no display lines to update we'll want to return
+     *    immediately, well before the end of the procedure.
+     * 2. It's important to arrange for the redisplay BEFORE calling
+     *    FreeDLines.  The reason for this is subtle and has to do with
+     *    embedded windows.  The chunk delete procedure for an embedded
+     *    window will schedule an idle handler to unmap the window.
+     *    However, we want the idle handler for redisplay to be called
+     *    first, so that it can put the embedded window back on the screen
+     *    again (if appropriate).  This will prevent the window from ever
+     *    being unmapped, and thereby avoid flashing.
+     */
+
+    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
+	Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
+    }
+    dInfoPtr->flags |= REDRAW_PENDING|DINFO_OUT_OF_DATE|REPICK_NEEDED;
+
+    /*
+     * Find the DLines corresponding to index1Ptr and index2Ptr.  There
+     * is one tricky thing here, which is that we have to relayout in
+     * units of whole text lines:  round index1Ptr back to the beginning
+     * of its text line, and include all the display lines after index2,
+     * up to the end of its text line.  This is necessary because the
+     * indices stored in the display lines will no longer be valid.  It's
+     * also needed because any edit could change the way lines wrap.
+     */
+
+    rounded = *index1Ptr;
+    rounded.charIndex = 0;
+    firstPtr = FindDLine(dInfoPtr->dLinePtr, &rounded);
+    if (firstPtr == NULL) {
+	return;
+    }
+    lastPtr = FindDLine(dInfoPtr->dLinePtr, index2Ptr);
+    while ((lastPtr != NULL)
+	    && (lastPtr->index.linePtr == index2Ptr->linePtr)) {
+	lastPtr = lastPtr->nextPtr;
+    }
+
+    /*
+     * Delete all the DLines from firstPtr up to but not including lastPtr.
+     */
+
+    FreeDLines(textPtr, firstPtr, lastPtr, 1);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkTextRedrawTag --
+ *
+ *	This procedure is invoked to request a redraw of all characters
+ *	in a given range that have a particular tag on or off.  It's
+ *	called, for example, when tag options change.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Information on the screen may be redrawn, and the layout of
+ *	the screen may change.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TkTextRedrawTag(textPtr, index1Ptr, index2Ptr, tagPtr, withTag)
+    TkText *textPtr;		/* Widget record for text widget. */
+    TkTextIndex *index1Ptr;	/* First character in range to consider
+				 * for redisplay.  NULL means start at
+				 * beginning of text. */
+    TkTextIndex *index2Ptr;	/* Character just after last one to consider
+				 * for redisplay.  NULL means process all
+				 * the characters in the text. */
+    TkTextTag *tagPtr;		/* Information about tag. */
+    int withTag;		/* 1 means redraw characters that have the
+				 * tag, 0 means redraw those without. */
+{
+    register DLine *dlPtr;
+    DLine *endPtr;
+    int tagOn;
+    TkTextSearch search;
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+    TkTextIndex *curIndexPtr;
+    TkTextIndex endOfText, *endIndexPtr;
+
+    /*
+     * Round up the starting position if it's before the first line
+     * visible on the screen (we only care about what's on the screen).
+     */
+
+    dlPtr = dInfoPtr->dLinePtr;
+    if (dlPtr == NULL) {
+	return;
+    }
+    if ((index1Ptr == NULL) || (TkTextIndexCmp(&dlPtr->index, index1Ptr) > 0)) {
+	index1Ptr = &dlPtr->index;
+    }
+
+    /*
+     * Set the stopping position if it wasn't specified.
+     */
+
+    if (index2Ptr == NULL) {
+	index2Ptr = TkTextMakeIndex(textPtr->tree,
+		TkBTreeNumLines(textPtr->tree), 0, &endOfText);
+    }
+
+    /* 
+     * Initialize a search through all transitions on the tag, starting
+     * with the first transition where the tag's current state is different
+     * from what it will eventually be.
+     */
+
+    TkBTreeStartSearch(index1Ptr, index2Ptr, tagPtr, &search);
+    /*
+     * Make our own curIndex because at this point search.curIndex
+     * may not equal index1Ptr->curIndex in the case the first tag toggle
+     * comes after index1Ptr (See the use of FindTagStart in TkBTreeStartSearch)
+     */
+    curIndexPtr = index1Ptr;
+    tagOn = TkBTreeCharTagged(index1Ptr, tagPtr);
+    if (tagOn != withTag) {
+	if (!TkBTreeNextTag(&search)) {
+	    return;
+	}
+	curIndexPtr = &search.curIndex;
+    }
+
+    /*
+     * Schedule a redisplay and layout recalculation if they aren't
+     * already pending.  This has to be done before calling FreeDLines,
+     * for the reason given in TkTextChanged.
+     */
+
+    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
+	Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
+    }
+    dInfoPtr->flags |= REDRAW_PENDING|DINFO_OUT_OF_DATE|REPICK_NEEDED;
+
+    /*
+     * Each loop through the loop below is for one range of characters
+     * where the tag's current state is different than its eventual
+     * state.  At the top of the loop, search contains information about
+     * the first character in the range.
+     */
+
+    while (1) {
+	/*
+	 * Find the first DLine structure in the range.  Note: if the
+	 * desired character isn't the first in its text line, then look
+	 * for the character just before it instead.  This is needed to
+	 * handle the case where the first character of a wrapped
+	 * display line just got smaller, so that it now fits on the
+	 * line before:  need to relayout the line containing the
+	 * previous character.
+	 */
+
+	if (curIndexPtr->charIndex == 0) {
+	    dlPtr = FindDLine(dlPtr, curIndexPtr);
+	} else {
+	    TkTextIndex tmp;
+
+	    tmp = *curIndexPtr;
+	    tmp.charIndex -= 1;
+	    dlPtr = FindDLine(dlPtr, &tmp);
+	}
+	if (dlPtr == NULL) {
+	    break;
+	}
+
+	/*
+	 * Find the first DLine structure that's past the end of the range.
+	 */
+
+	if (!TkBTreeNextTag(&search)) {
+	    endIndexPtr = index2Ptr;
+	} else {
+	    curIndexPtr = &search.curIndex;
+	    endIndexPtr = curIndexPtr;
+	}
+	endPtr = FindDLine(dlPtr, endIndexPtr);
+	if ((endPtr != NULL) && (endPtr->index.linePtr == endIndexPtr->linePtr)
+		&& (endPtr->index.charIndex < endIndexPtr->charIndex)) {
+	    endPtr = endPtr->nextPtr;
+	}
+
+	/*
+	 * Delete all of the display lines in the range, so that they'll
+	 * be re-layed out and redrawn.
+	 */
+
+	FreeDLines(textPtr, dlPtr, endPtr, 1);
+	dlPtr = endPtr;
+
+	/*
+	 * Find the first text line in the next range.
+	 */
+
+	if (!TkBTreeNextTag(&search)) {
+	    break;
+	}
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkTextRelayoutWindow --
+ *
+ *	This procedure is called when something has happened that
+ *	invalidates the whole layout of characters on the screen, such
+ *	as a change in a configuration option for the overall text
+ *	widget or a change in the window size.  It causes all display
+ *	information to be recomputed and the window to be redrawn.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	All the display information will be recomputed for the window
+ *	and the window will be redrawn.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TkTextRelayoutWindow(textPtr)
+    TkText *textPtr;		/* Widget record for text widget. */
+{
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+    GC new;
+    XGCValues gcValues;
+
+    /*
+     * Schedule the window redisplay.  See TkTextChanged for the
+     * reason why this has to be done before any calls to FreeDLines.
+     */
+
+    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
+	Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
+    }
+    dInfoPtr->flags |= REDRAW_PENDING|REDRAW_BORDERS|DINFO_OUT_OF_DATE
+	    |REPICK_NEEDED;
+
+    /*
+     * (Re-)create the graphics context for drawing the traversal
+     * highlight.
+     */
+
+    gcValues.graphics_exposures = False;
+    new = Tk_GetGC(textPtr->tkwin, GCGraphicsExposures, &gcValues);
+    if (dInfoPtr->copyGC != None) {
+	Tk_FreeGC(textPtr->display, dInfoPtr->copyGC);
+    }
+    dInfoPtr->copyGC = new;
+
+    /*
+     * Throw away all the current layout information.
+     */
+
+    FreeDLines(textPtr, dInfoPtr->dLinePtr, (DLine *) NULL, 1);
+    dInfoPtr->dLinePtr = NULL;
+
+    /*
+     * Recompute some overall things for the layout.  Even if the
+     * window gets very small, pretend that there's at least one
+     * pixel of drawing space in it.
+     */
+
+    if (textPtr->highlightWidth < 0) {
+	textPtr->highlightWidth = 0;
+    }
+    dInfoPtr->x = textPtr->highlightWidth + textPtr->borderWidth
+	    + textPtr->padX;
+    dInfoPtr->y = textPtr->highlightWidth + textPtr->borderWidth
+	    + textPtr->padY;
+    dInfoPtr->maxX = Tk_Width(textPtr->tkwin) - textPtr->highlightWidth
+	    - textPtr->borderWidth - textPtr->padX;
+    if (dInfoPtr->maxX <= dInfoPtr->x) {
+	dInfoPtr->maxX = dInfoPtr->x + 1;
+    }
+    dInfoPtr->maxY = Tk_Height(textPtr->tkwin) - textPtr->highlightWidth
+	    - textPtr->borderWidth - textPtr->padY;
+    if (dInfoPtr->maxY <= dInfoPtr->y) {
+	dInfoPtr->maxY = dInfoPtr->y + 1;
+    }
+    dInfoPtr->topOfEof = dInfoPtr->maxY;
+
+    /*
+     * If the upper-left character isn't the first in a line, recompute
+     * it.  This is necessary because a change in the window's size
+     * or options could change the way lines wrap.
+     */
+
+    if (textPtr->topIndex.charIndex != 0) {
+	MeasureUp(textPtr, &textPtr->topIndex, 0, &textPtr->topIndex);
+    }
+
+    /*
+     * Invalidate cached scrollbar positions, so that scrollbars
+     * sliders will be udpated.
+     */
+
+    dInfoPtr->xScrollFirst = dInfoPtr->xScrollLast = -1;
+    dInfoPtr->yScrollFirst = dInfoPtr->yScrollLast = -1;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkTextSetYView --
+ *
+ *	This procedure is called to specify what lines are to be
+ *	displayed in a text widget.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The display will (eventually) be updated so that the position
+ *	given by "indexPtr" is visible on the screen at the position
+ *	determined by "pickPlace".
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TkTextSetYView(textPtr, indexPtr, pickPlace)
+    TkText *textPtr;		/* Widget record for text widget. */
+    TkTextIndex *indexPtr;	/* Position that is to appear somewhere
+				 * in the view. */
+    int pickPlace;		/* 0 means topLine must appear at top of
+				 * screen.  1 means we get to pick where it
+				 * appears:  minimize screen motion or else
+				 * display line at center of screen. */
+{
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+    register DLine *dlPtr;
+    int bottomY, close, lineIndex;
+    TkTextIndex tmpIndex, rounded;
+    Tk_FontMetrics fm;
+
+    /*
+     * If the specified position is the extra line at the end of the
+     * text, round it back to the last real line.
+     */
+
+    lineIndex = TkBTreeLineIndex(indexPtr->linePtr);
+    if (lineIndex == TkBTreeNumLines(indexPtr->tree)) {
+	TkTextIndexBackChars(indexPtr, 1, &rounded);
+	indexPtr = &rounded;
+    }
+
+    if (!pickPlace) {
+	/*
+	 * The specified position must go at the top of the screen.
+	 * Just leave all the DLine's alone: we may be able to reuse
+	 * some of the information that's currently on the screen
+	 * without redisplaying it all.
+	 */
+
+	if (indexPtr->charIndex == 0) {
+	    textPtr->topIndex = *indexPtr;
+	} else {
+	    MeasureUp(textPtr, indexPtr, 0, &textPtr->topIndex);
+	}
+	goto scheduleUpdate;
+    }
+
+    /*
+     * We have to pick where to display the index.  First, bring
+     * the display information up to date and see if the index will be
+     * completely visible in the current screen configuration.  If so
+     * then there's nothing to do.
+     */
+
+    if (dInfoPtr->flags & DINFO_OUT_OF_DATE) {
+	UpdateDisplayInfo(textPtr);
+    }
+    dlPtr = FindDLine(dInfoPtr->dLinePtr, indexPtr);
+    if (dlPtr != NULL) {
+	if ((dlPtr->y + dlPtr->height) > dInfoPtr->maxY) {
+	    /*
+	     * Part of the line hangs off the bottom of the screen;
+	     * pretend the whole line is off-screen.
+	     */
+
+	    dlPtr = NULL;
+	} else if ((dlPtr->index.linePtr == indexPtr->linePtr)
+		&& (dlPtr->index.charIndex <= indexPtr->charIndex)) {
+	    return;
+	}
+    }
+
+    /*
+     * The desired line isn't already on-screen.  Figure out what
+     * it means to be "close" to the top or bottom of the screen.
+     * Close means within 1/3 of the screen height or within three
+     * lines, whichever is greater.  Add one extra line also, to
+     * account for the way MeasureUp rounds.
+     */
+
+    Tk_GetFontMetrics(textPtr->tkfont, &fm);
+    bottomY = (dInfoPtr->y + dInfoPtr->maxY + fm.linespace)/2;
+    close = (dInfoPtr->maxY - dInfoPtr->y)/3;
+    if (close < 3*fm.linespace) {
+	close = 3*fm.linespace;
+    }
+    close += fm.linespace;
+    if (dlPtr != NULL) {
+	/*
+	 * The desired line is above the top of screen.  If it is
+	 * "close" to the top of the window then make it the top
+	 * line on the screen.
+	 */
+
+	MeasureUp(textPtr, &textPtr->topIndex, close, &tmpIndex);
+	if (TkTextIndexCmp(&tmpIndex, indexPtr) <= 0) {
+	    MeasureUp(textPtr, indexPtr, 0, &textPtr->topIndex);
+	    goto scheduleUpdate;
+	}
+    } else {
+	/*
+	 * The desired line is below the bottom of the screen.  If it is
+	 * "close" to the bottom of the screen then position it at the
+	 * bottom of the screen.
+	 */
+
+	MeasureUp(textPtr, indexPtr, close, &tmpIndex);
+	if (FindDLine(dInfoPtr->dLinePtr, &tmpIndex) != NULL) {
+	    bottomY = dInfoPtr->maxY - dInfoPtr->y;
+	}
+    }
+
+    /*
+     * Our job now is to arrange the display so that indexPtr appears
+     * as low on the screen as possible but with its bottom no lower
+     * than bottomY.  BottomY is the bottom of the window if the
+     * desired line is just below the current screen, otherwise it
+     * is a half-line lower than the center of the window.
+     */
+
+    MeasureUp(textPtr, indexPtr, bottomY, &textPtr->topIndex);
+
+    scheduleUpdate:
+    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
+	Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
+    }
+    dInfoPtr->flags |= REDRAW_PENDING|DINFO_OUT_OF_DATE|REPICK_NEEDED;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * MeasureUp --
+ *
+ *	Given one index, find the index of the first character
+ *	on the highest display line that would be displayed no more
+ *	than "distance" pixels above the given index.
+ *
+ * Results:
+ *	*dstPtr is filled in with the index of the first character
+ *	on a display line.  The display line is found by measuring
+ *	up "distance" pixels above the pixel just below an imaginary
+ *	display line that contains srcPtr.  If the display line
+ *	that covers this coordinate actually extends above the 
+ *	coordinate, then return the index of the next lower line
+ *	instead (i.e. the returned index will be completely visible
+ *	at or below the given y-coordinate).
+ *
+ * Side effects:
+ *	None.
+ *
+ *--------------------------------------------------------------
+ */
+
+static void
+MeasureUp(textPtr, srcPtr, distance, dstPtr)
+    TkText *textPtr;		/* Text widget in which to measure. */
+    TkTextIndex *srcPtr;	/* Index of character from which to start
+				 * measuring. */
+    int distance;		/* Vertical distance in pixels measured
+				 * from the pixel just below the lowest
+				 * one in srcPtr's line. */
+    TkTextIndex *dstPtr;	/* Index to fill in with result. */
+{
+    int lineNum;		/* Number of current line. */
+    int charsToCount;		/* Maximum number of characters to measure
+				 * in current line. */
+    TkTextIndex bestIndex;	/* Best candidate seen so far for result. */
+    TkTextIndex index;
+    DLine *dlPtr, *lowestPtr;
+    int noBestYet;		/* 1 means bestIndex hasn't been set. */
+
+    noBestYet = 1;
+    charsToCount = srcPtr->charIndex + 1;
+    index.tree = srcPtr->tree;
+    for (lineNum = TkBTreeLineIndex(srcPtr->linePtr); lineNum >= 0;
+	    lineNum--) {
+	/*
+	 * Layout an entire text line (potentially > 1 display line).
+	 * For the first line, which contains srcPtr, only layout the
+	 * part up through srcPtr (charsToCount is non-infinite to
+	 * accomplish this).  Make a list of all the display lines
+	 * in backwards order (the lowest DLine on the screen is first
+	 * in the list).
+	 */
+
+	index.linePtr = TkBTreeFindLine(srcPtr->tree, lineNum);
+	index.charIndex = 0;
+	lowestPtr = NULL;
+	do {
+	    dlPtr = LayoutDLine(textPtr, &index);
+	    dlPtr->nextPtr = lowestPtr;
+	    lowestPtr = dlPtr;
+	    TkTextIndexForwChars(&index, dlPtr->count, &index);
+	    charsToCount -= dlPtr->count;
+	} while ((charsToCount > 0) && (index.linePtr == dlPtr->index.linePtr));
+
+	/*
+	 * Scan through the display lines to see if we've covered enough
+	 * vertical distance.  If so, save the starting index for the
+	 * line at the desired location.
+	 */
+
+	for (dlPtr = lowestPtr; dlPtr != NULL; dlPtr = dlPtr->nextPtr) {
+	    distance -= dlPtr->height;
+	    if (distance < 0) {
+		*dstPtr = (noBestYet) ? dlPtr->index : bestIndex;
+		break;
+	    }
+	    bestIndex = dlPtr->index;
+	    noBestYet = 0;
+	}
+
+	/*
+	 * Discard the display lines, then either return or prepare
+	 * for the next display line to lay out.
+	 */
+
+	FreeDLines(textPtr, lowestPtr, (DLine *) NULL, 0);
+	if (distance < 0) {
+	    return;
+	}
+	charsToCount = INT_MAX;		/* Consider all chars. in next line. */
+    }
+
+    /*
+     * Ran off the beginning of the text.  Return the first character
+     * in the text.
+     */
+
+    TkTextMakeIndex(textPtr->tree, 0, 0, dstPtr);
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * TkTextSeeCmd --
+ *
+ *	This procedure is invoked to process the "see" option for
+ *	the widget command for text widgets. See the user documentation
+ *	for details on what it does.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	See the user documentation.
+ *
+ *--------------------------------------------------------------
+ */
+
+int
+TkTextSeeCmd(textPtr, interp, argc, argv)
+    TkText *textPtr;		/* Information about text widget. */
+    Tcl_Interp *interp;		/* Current interpreter. */
+    int argc;			/* Number of arguments. */
+    char **argv;		/* Argument strings.  Someone else has already
+				 * parsed this command enough to know that
+				 * argv[1] is "see". */
+{
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+    TkTextIndex index;
+    int x, y, width, height, lineWidth, charCount, oneThird, delta;
+    DLine *dlPtr;
+    TkTextDispChunk *chunkPtr;
+
+    if (argc != 3) {
+	Tcl_AppendResult(interp, "wrong # args: should be \"",
+		argv[0], " see index\"", (char *) NULL);
+	return TCL_ERROR;
+    }
+    if (TkTextGetIndex(interp, textPtr, argv[2], &index) != TCL_OK) {
+	return TCL_ERROR;
+    }
+
+    /*
+     * If the specified position is the extra line at the end of the
+     * text, round it back to the last real line.
+     */
+
+    if (TkBTreeLineIndex(index.linePtr) == TkBTreeNumLines(index.tree)) {
+	TkTextIndexBackChars(&index, 1, &index);
+    }
+
+    /*
+     * First get the desired position into the vertical range of the window.
+     */
+
+    TkTextSetYView(textPtr, &index, 1);
+
+    /*
+     * Now make sure that the character is in view horizontally.
+     */
+
+    if (dInfoPtr->flags & DINFO_OUT_OF_DATE) {
+	UpdateDisplayInfo(textPtr);
+    }
+    lineWidth = dInfoPtr->maxX - dInfoPtr->x;
+    if (dInfoPtr->maxLength < lineWidth) {
+	return TCL_OK;
+    }
+
+    /*
+     * Find the chunk that contains the desired index.
+     */
+
+    dlPtr = FindDLine(dInfoPtr->dLinePtr, &index);
+    charCount = index.charIndex - dlPtr->index.charIndex;
+    for (chunkPtr = dlPtr->chunkPtr; ; chunkPtr = chunkPtr->nextPtr) {
+	if (charCount < chunkPtr->numChars) {
+	    break;
+	}
+	charCount -= chunkPtr->numChars;
+    }
+
+    /*
+     * Call a chunk-specific procedure to find the horizontal range of
+     * the character within the chunk.
+     */
+
+    (*chunkPtr->bboxProc)(chunkPtr, charCount, dlPtr->y + dlPtr->spaceAbove,
+	    dlPtr->height - dlPtr->spaceAbove - dlPtr->spaceBelow,
+	    dlPtr->baseline - dlPtr->spaceAbove, &x, &y, &width,
+	    &height);
+    delta = x - dInfoPtr->curPixelOffset;
+    oneThird = lineWidth/3;
+    if (delta < 0) {
+	if (delta < -oneThird) {
+	    dInfoPtr->newCharOffset = (x - lineWidth/2)/textPtr->charWidth;
+	} else {
+	    dInfoPtr->newCharOffset -= ((-delta) + textPtr->charWidth - 1)
+		/ textPtr->charWidth;
+	}
+    } else {
+	delta -= (lineWidth - width);
+	if (delta > 0) {
+	    if (delta > oneThird) {
+		dInfoPtr->newCharOffset = (x - lineWidth/2)/textPtr->charWidth;
+	    } else {
+		dInfoPtr->newCharOffset += (delta + textPtr->charWidth - 1)
+		    / textPtr->charWidth;
+	    }
+	} else {
+	    return TCL_OK;
+	}
+    }
+    dInfoPtr->flags |= DINFO_OUT_OF_DATE;
+    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
+	dInfoPtr->flags |= REDRAW_PENDING;
+	Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
+    }
+    return TCL_OK;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * TkTextXviewCmd --
+ *
+ *	This procedure is invoked to process the "xview" option for
+ *	the widget command for text widgets. See the user documentation
+ *	for details on what it does.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	See the user documentation.
+ *
+ *--------------------------------------------------------------
+ */
+
+int
+TkTextXviewCmd(textPtr, interp, argc, argv)
+    TkText *textPtr;		/* Information about text widget. */
+    Tcl_Interp *interp;		/* Current interpreter. */
+    int argc;			/* Number of arguments. */
+    char **argv;		/* Argument strings.  Someone else has already
+				 * parsed this command enough to know that
+				 * argv[1] is "xview". */
+{
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+    int type, charsPerPage, count, newOffset;
+    double fraction;
+
+    if (dInfoPtr->flags & DINFO_OUT_OF_DATE) {
+	UpdateDisplayInfo(textPtr);
+    }
+
+    if (argc == 2) {
+	GetXView(interp, textPtr, 0);
+	return TCL_OK;
+    }
+
+    newOffset = dInfoPtr->newCharOffset;
+    type = Tk_GetScrollInfo(interp, argc, argv, &fraction, &count);
+    switch (type) {
+	case TK_SCROLL_ERROR:
+	    return TCL_ERROR;
+	case TK_SCROLL_MOVETO:
+	    if (fraction > 1.0) {
+		fraction = 1.0;
+	    }
+	    if (fraction < 0) {
+		fraction = 0;
+	    }
+	    newOffset = (int) (((fraction * dInfoPtr->maxLength) / textPtr->charWidth)
+		    + 0.5);
+	    break;
+	case TK_SCROLL_PAGES:
+	    charsPerPage = ((dInfoPtr->maxX - dInfoPtr->x) / textPtr->charWidth)
+		    - 2;
+	    if (charsPerPage < 1) {
+		charsPerPage = 1;
+	    }
+	    newOffset += charsPerPage*count;
+	    break;
+	case TK_SCROLL_UNITS:
+	    newOffset += count;
+	    break;
+    }
+
+    dInfoPtr->newCharOffset = newOffset;
+    dInfoPtr->flags |= DINFO_OUT_OF_DATE;
+    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
+	dInfoPtr->flags |= REDRAW_PENDING;
+	Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
+    }
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * ScrollByLines --
+ *
+ *	This procedure is called to scroll a text widget up or down
+ *	by a given number of lines.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The view in textPtr's window changes to reflect the value
+ *	of "offset".
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+ScrollByLines(textPtr, offset)
+    TkText *textPtr;		/* Widget to scroll. */
+    int offset;			/* Amount by which to scroll, in *screen*
+				 * lines.  Positive means that information
+				 * later in text becomes visible, negative
+				 * means that information earlier in the
+				 * text becomes visible. */
+{
+    int i, charsToCount, lineNum;
+    TkTextIndex new, index;
+    TkTextLine *lastLinePtr;
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+    DLine *dlPtr, *lowestPtr;
+
+    if (offset < 0) {
+	/*
+	 * Must scroll up (to show earlier information in the text).
+	 * The code below is similar to that in MeasureUp, except that
+	 * it counts lines instead of pixels.
+	 */
+
+	charsToCount = textPtr->topIndex.charIndex + 1;
+	index.tree = textPtr->tree;
+	offset--;			/* Skip line containing topIndex. */
+	for (lineNum = TkBTreeLineIndex(textPtr->topIndex.linePtr);
+		lineNum >= 0; lineNum--) {
+	    index.linePtr = TkBTreeFindLine(textPtr->tree, lineNum);
+	    index.charIndex = 0;
+	    lowestPtr = NULL;
+	    do {
+		dlPtr = LayoutDLine(textPtr, &index);
+		dlPtr->nextPtr = lowestPtr;
+		lowestPtr = dlPtr;
+		TkTextIndexForwChars(&index, dlPtr->count, &index);
+		charsToCount -= dlPtr->count;
+	    } while ((charsToCount > 0)
+		    && (index.linePtr == dlPtr->index.linePtr));
+
+	    for (dlPtr = lowestPtr; dlPtr != NULL; dlPtr = dlPtr->nextPtr) {
+		offset++;
+		if (offset == 0) {
+		    textPtr->topIndex = dlPtr->index;
+		    break;
+		}
+	    }
+    
+	    /*
+	     * Discard the display lines, then either return or prepare
+	     * for the next display line to lay out.
+	     */
+    
+	    FreeDLines(textPtr, lowestPtr, (DLine *) NULL, 0);
+	    if (offset >= 0) {
+		goto scheduleUpdate;
+	    }
+	    charsToCount = INT_MAX;
+	}
+    
+	/*
+	 * Ran off the beginning of the text.  Return the first character
+	 * in the text.
+	 */
+
+	TkTextMakeIndex(textPtr->tree, 0, 0, &textPtr->topIndex);
+    } else {
+	/*
+	 * Scrolling down, to show later information in the text.
+	 * Just count lines from the current top of the window.
+	 */
+
+	lastLinePtr = TkBTreeFindLine(textPtr->tree,
+		TkBTreeNumLines(textPtr->tree));
+	for (i = 0; i < offset; i++) {
+	    dlPtr = LayoutDLine(textPtr, &textPtr->topIndex);
+	    dlPtr->nextPtr = NULL;
+	    TkTextIndexForwChars(&textPtr->topIndex, dlPtr->count, &new);
+	    FreeDLines(textPtr, dlPtr, (DLine *) NULL, 0);
+	    if (new.linePtr == lastLinePtr) {
+		break;
+	    }
+	    textPtr->topIndex = new;
+	}
+    }
+
+    scheduleUpdate:
+    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
+	Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
+    }
+    dInfoPtr->flags |= REDRAW_PENDING|DINFO_OUT_OF_DATE|REPICK_NEEDED;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * TkTextYviewCmd --
+ *
+ *	This procedure is invoked to process the "yview" option for
+ *	the widget command for text widgets. See the user documentation
+ *	for details on what it does.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	See the user documentation.
+ *
+ *--------------------------------------------------------------
+ */
+
+int
+TkTextYviewCmd(textPtr, interp, argc, argv)
+    TkText *textPtr;		/* Information about text widget. */
+    Tcl_Interp *interp;		/* Current interpreter. */
+    int argc;			/* Number of arguments. */
+    char **argv;		/* Argument strings.  Someone else has already
+				 * parsed this command enough to know that
+				 * argv[1] is "yview". */
+{
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+    int pickPlace, lineNum, type, charsInLine;
+    Tk_FontMetrics fm;
+    int pixels, count;
+    size_t switchLength;
+    double fraction;
+    TkTextIndex index, new;
+    TkTextLine *lastLinePtr;
+    DLine *dlPtr;
+
+    if (dInfoPtr->flags & DINFO_OUT_OF_DATE) {
+	UpdateDisplayInfo(textPtr);
+    }
+
+    if (argc == 2) {
+	GetYView(interp, textPtr, 0);
+	return TCL_OK;
+    }
+
+    /*
+     * Next, handle the old syntax: "pathName yview ?-pickplace? where"
+     */
+
+    pickPlace = 0;
+    if (argv[2][0] == '-') {
+	switchLength = strlen(argv[2]);
+	if ((switchLength >= 2)
+		&& (strncmp(argv[2], "-pickplace", switchLength) == 0)) {
+	    pickPlace = 1;
+	    if (argc != 4) {
+		Tcl_AppendResult(interp, "wrong # args: should be \"",
+			argv[0], " yview -pickplace lineNum|index\"",
+			(char *) NULL);
+		return TCL_ERROR;
+	    }
+	}
+    }
+    if ((argc == 3) || pickPlace) {
+	if (Tcl_GetInt(interp, argv[2+pickPlace], &lineNum) == TCL_OK) {
+	    TkTextMakeIndex(textPtr->tree, lineNum, 0, &index);
+	    TkTextSetYView(textPtr, &index, 0);
+	    return TCL_OK;
+	}
+    
+	/*
+	 * The argument must be a regular text index.
+	 */
+    
+	Tcl_ResetResult(interp);
+	if (TkTextGetIndex(interp, textPtr, argv[2+pickPlace],
+		&index) != TCL_OK) {
+	    return TCL_ERROR;
+	}
+	TkTextSetYView(textPtr, &index, pickPlace);
+	return TCL_OK;
+    }
+
+    /*
+     * New syntax: dispatch based on argv[2].
+     */
+
+    type = Tk_GetScrollInfo(interp, argc, argv, &fraction, &count);
+    switch (type) {
+	case TK_SCROLL_ERROR:
+	    return TCL_ERROR;
+	case TK_SCROLL_MOVETO:
+	    if (fraction > 1.0) {
+		fraction = 1.0;
+	    }
+	    if (fraction < 0) {
+		fraction = 0;
+	    }
+	    fraction *= TkBTreeNumLines(textPtr->tree);
+	    lineNum = (int) fraction;
+	    TkTextMakeIndex(textPtr->tree, lineNum, 0, &index);
+	    charsInLine = TkBTreeCharsInLine(index.linePtr);
+	    index.charIndex = (int)((charsInLine * (fraction-lineNum)) + 0.5);
+	    if (index.charIndex >= charsInLine) {
+		TkTextMakeIndex(textPtr->tree, lineNum+1, 0, &index);
+	    }
+	    TkTextSetYView(textPtr, &index, 0);
+	    break;
+	case TK_SCROLL_PAGES:
+	    /*
+	     * Scroll up or down by screenfuls.  Actually, use the
+	     * window height minus two lines, so that there's some
+	     * overlap between adjacent pages.
+	     */
+
+	    Tk_GetFontMetrics(textPtr->tkfont, &fm);
+	    if (count < 0) {
+		pixels = (dInfoPtr->maxY - 2*fm.linespace - dInfoPtr->y)*(-count)
+			+ fm.linespace;
+		MeasureUp(textPtr, &textPtr->topIndex, pixels, &new);
+		if (TkTextIndexCmp(&textPtr->topIndex, &new) == 0) {
+		    /*
+		     * A page of scrolling ended up being less than one line.
+		     * Scroll one line anyway.
+		     */
+
+		    count = -1;
+		    goto scrollByLines;
+		}
+		textPtr->topIndex = new;
+	    } else {
+		/*
+		 * Scrolling down by pages.  Layout lines starting at the
+		 * top index and count through the desired vertical distance.
+		 */
+
+		pixels = (dInfoPtr->maxY - 2*fm.linespace - dInfoPtr->y)*count;
+		lastLinePtr = TkBTreeFindLine(textPtr->tree,
+			TkBTreeNumLines(textPtr->tree));
+		do {
+		    dlPtr = LayoutDLine(textPtr, &textPtr->topIndex);
+		    dlPtr->nextPtr = NULL;
+		    TkTextIndexForwChars(&textPtr->topIndex, dlPtr->count,
+			    &new);
+		    pixels -= dlPtr->height;
+		    FreeDLines(textPtr, dlPtr, (DLine *) NULL, 0);
+		    if (new.linePtr == lastLinePtr) {
+			break;
+		    }
+		    textPtr->topIndex = new;
+		} while (pixels > 0);
+	    }
+	    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
+		Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
+	    }
+	    dInfoPtr->flags |= REDRAW_PENDING|DINFO_OUT_OF_DATE|REPICK_NEEDED;
+	    break;
+	case TK_SCROLL_UNITS:
+	    scrollByLines:
+	    ScrollByLines(textPtr, count);
+	    break;
+    }
+    return TCL_OK;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * TkTextScanCmd --
+ *
+ *	This procedure is invoked to process the "scan" option for
+ *	the widget command for text widgets. See the user documentation
+ *	for details on what it does.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	See the user documentation.
+ *
+ *--------------------------------------------------------------
+ */
+
+int
+TkTextScanCmd(textPtr, interp, argc, argv)
+    register TkText *textPtr;	/* Information about text widget. */
+    Tcl_Interp *interp;		/* Current interpreter. */
+    int argc;			/* Number of arguments. */
+    char **argv;		/* Argument strings.  Someone else has already
+				 * parsed this command enough to know that
+				 * argv[1] is "scan". */
+{
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+    TkTextIndex index;
+    int c, x, y, totalScroll, newChar, maxChar;
+    Tk_FontMetrics fm;
+    size_t length;
+
+    if (argc != 5) {
+	Tcl_AppendResult(interp, "wrong # args: should be \"",
+		argv[0], " scan mark|dragto x y\"", (char *) NULL);
+	return TCL_ERROR;
+    }
+    if (Tcl_GetInt(interp, argv[3], &x) != TCL_OK) {
+	return TCL_ERROR;
+    }
+    if (Tcl_GetInt(interp, argv[4], &y) != TCL_OK) {
+	return TCL_ERROR;
+    }
+    c = argv[2][0];
+    length = strlen(argv[2]);
+    if ((c == 'd') && (strncmp(argv[2], "dragto", length) == 0)) {
+	/*
+	 * Amplify the difference between the current position and the
+	 * mark position to compute how much the view should shift, then
+	 * update the mark position to correspond to the new view.  If we
+	 * run off the edge of the text, reset the mark point so that the
+	 * current position continues to correspond to the edge of the
+	 * window.  This means that the picture will start dragging as
+	 * soon as the mouse reverses direction (without this reset, might
+	 * have to slide mouse a long ways back before the picture starts
+	 * moving again).
+	 */
+
+	newChar = dInfoPtr->scanMarkChar + (10*(dInfoPtr->scanMarkX - x))
+		/ (textPtr->charWidth);
+	maxChar = 1 + (dInfoPtr->maxLength - (dInfoPtr->maxX - dInfoPtr->x)
+		+ textPtr->charWidth - 1)/textPtr->charWidth;
+	if (newChar < 0) {
+	    dInfoPtr->scanMarkChar = newChar = 0;
+	    dInfoPtr->scanMarkX = x;
+	} else if (newChar > maxChar) {
+	    dInfoPtr->scanMarkChar = newChar = maxChar;
+	    dInfoPtr->scanMarkX = x;
+	}
+	dInfoPtr->newCharOffset = newChar;
+
+	Tk_GetFontMetrics(textPtr->tkfont, &fm);
+	totalScroll = (10*(dInfoPtr->scanMarkY - y)) / fm.linespace;
+	if (totalScroll != dInfoPtr->scanTotalScroll) {
+	    index = textPtr->topIndex;
+	    ScrollByLines(textPtr, totalScroll-dInfoPtr->scanTotalScroll);
+	    dInfoPtr->scanTotalScroll = totalScroll;
+	    if ((index.linePtr == textPtr->topIndex.linePtr) &&
+		    (index.charIndex == textPtr->topIndex.charIndex)) {
+		dInfoPtr->scanTotalScroll = 0;
+		dInfoPtr->scanMarkY = y;
+	    }
+	}
+    } else if ((c == 'm') && (strncmp(argv[2], "mark", length) == 0)) {
+	dInfoPtr->scanMarkChar = dInfoPtr->newCharOffset;
+	dInfoPtr->scanMarkX = x;
+	dInfoPtr->scanTotalScroll = 0;
+	dInfoPtr->scanMarkY = y;
+    } else {
+	Tcl_AppendResult(interp, "bad scan option \"", argv[2],
+		"\": must be mark or dragto", (char *) NULL);
+	return TCL_ERROR;
+    }
+    dInfoPtr->flags |= DINFO_OUT_OF_DATE;
+    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
+	dInfoPtr->flags |= REDRAW_PENDING;
+	Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
+    }
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * GetXView --
+ *
+ *	This procedure computes the fractions that indicate what's
+ *	visible in a text window and, optionally, evaluates a
+ *	Tcl script to report them to the text's associated scrollbar.
+ *
+ * Results:
+ *	If report is zero, then interp->result is filled in with
+ *	two real numbers separated by a space, giving the position of
+ *	the left and right edges of the window as fractions from 0 to
+ *	1, where 0 means the left edge of the text and 1 means the right
+ *	edge.  If report is non-zero, then interp->result isn't modified
+ *	directly, but instead a script is evaluated in interp to report
+ *	the new horizontal scroll position to the scrollbar (if the scroll
+ *	position hasn't changed then no script is invoked).
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+GetXView(interp, textPtr, report)
+    Tcl_Interp *interp;			/* If "report" is FALSE, string
+					 * describing visible range gets
+					 * stored in interp->result. */
+    TkText *textPtr;			/* Information about text widget. */
+    int report;				/* Non-zero means report info to
+					 * scrollbar if it has changed. */
+{
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+    char buffer[200];
+    double first, last;
+    int code;
+
+    if (dInfoPtr->maxLength > 0) {
+	first = ((double) dInfoPtr->curPixelOffset)
+		/ dInfoPtr->maxLength;
+	last = first + ((double) (dInfoPtr->maxX - dInfoPtr->x))
+		/ dInfoPtr->maxLength;
+	if (last > 1.0) {
+	    last = 1.0;
+	}
+    } else {
+	first = 0;
+	last = 1.0;
+    }
+    if (!report) {
+	sprintf(interp->result, "%g %g", first, last);
+	return;
+    }
+    if ((first == dInfoPtr->xScrollFirst) && (last == dInfoPtr->xScrollLast)) {
+	return;
+    }
+    dInfoPtr->xScrollFirst = first;
+    dInfoPtr->xScrollLast = last;
+    sprintf(buffer, " %g %g", first, last);
+    code = Tcl_VarEval(interp, textPtr->xScrollCmd,
+	    buffer, (char *) NULL);
+    if (code != TCL_OK) {
+	Tcl_AddErrorInfo(interp,
+		"\n    (horizontal scrolling command executed by text)");
+	Tcl_BackgroundError(interp);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * GetYView --
+ *
+ *	This procedure computes the fractions that indicate what's
+ *	visible in a text window and, optionally, evaluates a
+ *	Tcl script to report them to the text's associated scrollbar.
+ *
+ * Results:
+ *	If report is zero, then interp->result is filled in with
+ *	two real numbers separated by a space, giving the position of
+ *	the top and bottom of the window as fractions from 0 to 1, where
+ *	0 means the beginning of the text and 1 means the end.  If
+ *	report is non-zero, then interp->result isn't modified directly,
+ *	but a script is evaluated in interp to report the new scroll
+ *	position to the scrollbar (if the scroll position hasn't changed
+ *	then no script is invoked).
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+GetYView(interp, textPtr, report)
+    Tcl_Interp *interp;			/* If "report" is FALSE, string
+					 * describing visible range gets
+					 * stored in interp->result. */
+    TkText *textPtr;			/* Information about text widget. */
+    int report;				/* Non-zero means report info to
+					 * scrollbar if it has changed. */
+{
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+    char buffer[200];
+    double first, last;
+    DLine *dlPtr;
+    int totalLines, code, count;
+
+    dlPtr = dInfoPtr->dLinePtr;
+    totalLines = TkBTreeNumLines(textPtr->tree);
+    first = ((double) TkBTreeLineIndex(dlPtr->index.linePtr))
+	    + ((double) dlPtr->index.charIndex)
+	    / (TkBTreeCharsInLine(dlPtr->index.linePtr));
+    first /= totalLines;
+    while (1) {
+	if ((dlPtr->y + dlPtr->height) > dInfoPtr->maxY) {
+	    /*
+	     * The last line is only partially visible, so don't
+	     * count its characters in what's visible.
+	     */
+	    count = 0;
+	    break;
+	}
+	if (dlPtr->nextPtr == NULL) {
+	    count = dlPtr->count;
+	    break;
+	}
+	dlPtr = dlPtr->nextPtr;
+    }
+    last = ((double) TkBTreeLineIndex(dlPtr->index.linePtr))
+	    + ((double) (dlPtr->index.charIndex + count))
+	    / (TkBTreeCharsInLine(dlPtr->index.linePtr));
+    last /= totalLines;
+    if (!report) {
+	sprintf(interp->result, "%g %g", first, last);
+	return;
+    }
+    if ((first == dInfoPtr->yScrollFirst) && (last == dInfoPtr->yScrollLast)) {
+	return;
+    }
+    dInfoPtr->yScrollFirst = first;
+    dInfoPtr->yScrollLast = last;
+    sprintf(buffer, " %g %g", first, last);
+    code = Tcl_VarEval(interp, textPtr->yScrollCmd,
+	    buffer, (char *) NULL);
+    if (code != TCL_OK) {
+	Tcl_AddErrorInfo(interp,
+		"\n    (vertical scrolling command executed by text)");
+	Tcl_BackgroundError(interp);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FindDLine --
+ *
+ *	This procedure is called to find the DLine corresponding to a
+ *	given text index.
+ *
+ * Results:
+ *	The return value is a pointer to the first DLine found in the
+ *	list headed by dlPtr that displays information at or after the
+ *	specified position.  If there is no such line in the list then
+ *	NULL is returned.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static DLine *
+FindDLine(dlPtr, indexPtr)
+    register DLine *dlPtr;	/* Pointer to first in list of DLines
+				 * to search. */
+    TkTextIndex *indexPtr;	/* Index of desired character. */
+{
+    TkTextLine *linePtr;
+
+    if (dlPtr == NULL) {
+	return NULL;
+    }
+    if (TkBTreeLineIndex(indexPtr->linePtr)
+	    < TkBTreeLineIndex(dlPtr->index.linePtr)) {
+	/*
+	 * The first display line is already past the desired line.
+	 */
+	return dlPtr;
+    }
+
+    /*
+     * Find the first display line that covers the desired text line.
+     */
+
+    linePtr = dlPtr->index.linePtr;
+    while (linePtr != indexPtr->linePtr) {
+	while (dlPtr->index.linePtr == linePtr) {
+	    dlPtr = dlPtr->nextPtr;
+	    if (dlPtr == NULL) {
+		return NULL;
+	    }
+	}
+	linePtr = TkBTreeNextLine(linePtr);
+	if (linePtr == NULL) {
+	    panic("FindDLine reached end of text");
+	}
+    }
+    if (indexPtr->linePtr != dlPtr->index.linePtr) {
+	return dlPtr;
+    }
+
+    /*
+     * Now get to the right position within the text line.
+     */
+
+    while (indexPtr->charIndex >= (dlPtr->index.charIndex + dlPtr->count)) {
+	dlPtr = dlPtr->nextPtr;
+	if ((dlPtr == NULL) || (dlPtr->index.linePtr != indexPtr->linePtr)) {
+	    break;
+	}
+    }
+    return dlPtr;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkTextPixelIndex --
+ *
+ *	Given an (x,y) coordinate on the screen, find the location of
+ *	the character closest to that location.
+ *
+ * Results:
+ *	The index at *indexPtr is modified to refer to the character
+ *	on the display that is closest to (x,y).
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TkTextPixelIndex(textPtr, x, y, indexPtr)
+    TkText *textPtr;		/* Widget record for text widget. */
+    int x, y;			/* Pixel coordinates of point in widget's
+				 * window. */
+    TkTextIndex *indexPtr;	/* This index gets filled in with the
+				 * index of the character nearest to (x,y). */
+{
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+    register DLine *dlPtr;
+    register TkTextDispChunk *chunkPtr;
+
+    /*
+     * Make sure that all of the layout information about what's
+     * displayed where on the screen is up-to-date.
+     */
+
+    if (dInfoPtr->flags & DINFO_OUT_OF_DATE) {
+	UpdateDisplayInfo(textPtr);
+    }
+
+    /*
+     * If the coordinates are above the top of the window, then adjust
+     * them to refer to the upper-right corner of the window.  If they're
+     * off to one side or the other, then adjust to the closest side.
+     */
+
+    if (y < dInfoPtr->y) {
+	y = dInfoPtr->y;
+	x = dInfoPtr->x;
+    }
+    if (x >= dInfoPtr->maxX) {
+	x = dInfoPtr->maxX - 1;
+    }
+    if (x < dInfoPtr->x) {
+	x = dInfoPtr->x;
+    }
+
+    /*
+     * Find the display line containing the desired y-coordinate.
+     */
+
+    for (dlPtr = dInfoPtr->dLinePtr; y >= (dlPtr->y + dlPtr->height);
+	    dlPtr = dlPtr->nextPtr) {
+	if (dlPtr->nextPtr == NULL) {
+	    /*
+	     * Y-coordinate is off the bottom of the displayed text.
+	     * Use the last character on the last line.
+	     */
+
+	    x = dInfoPtr->maxX - 1;
+	    break;
+	}
+    }
+
+    /*
+     * Scan through the line's chunks to find the one that contains
+     * the desired x-coordinate.  Before doing this, translate the
+     * x-coordinate from the coordinate system of the window to the
+     * coordinate system of the line (to take account of x-scrolling).
+     */
+
+    *indexPtr = dlPtr->index;
+    x = x - dInfoPtr->x + dInfoPtr->curPixelOffset;
+    for (chunkPtr = dlPtr->chunkPtr; x >= (chunkPtr->x + chunkPtr->width);
+	    indexPtr->charIndex += chunkPtr->numChars,
+	    chunkPtr = chunkPtr->nextPtr) {
+	if (chunkPtr->nextPtr == NULL) {
+	    indexPtr->charIndex += chunkPtr->numChars - 1;
+	    return;
+	}
+    }
+
+    /*
+     * If the chunk has more than one character in it, ask it which
+     * character is at the desired location.
+     */
+
+    if (chunkPtr->numChars > 1) {
+	indexPtr->charIndex += (*chunkPtr->measureProc)(chunkPtr, x);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkTextCharBbox --
+ *
+ *	Given an index, find the bounding box of the screen area
+ *	occupied by that character.
+ *
+ * Results:
+ *	Zero is returned if the character is on the screen.  -1
+ *	means the character isn't on the screen.  If the return value
+ *	is 0, then the bounding box of the part of the character that's
+ *	visible on the screen is returned to *xPtr, *yPtr, *widthPtr,
+ *	and *heightPtr.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TkTextCharBbox(textPtr, indexPtr, xPtr, yPtr, widthPtr, heightPtr)
+    TkText *textPtr;		/* Widget record for text widget. */
+    TkTextIndex *indexPtr;	/* Index of character whose bounding
+				 * box is desired. */
+    int *xPtr, *yPtr;		/* Filled with character's upper-left
+				 * coordinate. */
+    int *widthPtr, *heightPtr;	/* Filled in with character's dimensions. */
+{
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+    DLine *dlPtr;
+    register TkTextDispChunk *chunkPtr;
+    int index;
+
+    /*
+     * Make sure that all of the screen layout information is up to date.
+     */
+
+    if (dInfoPtr->flags & DINFO_OUT_OF_DATE) {
+	UpdateDisplayInfo(textPtr);
+    }
+
+    /*
+     * Find the display line containing the desired index.
+     */
+
+    dlPtr = FindDLine(dInfoPtr->dLinePtr, indexPtr);
+    if ((dlPtr == NULL) || (TkTextIndexCmp(&dlPtr->index, indexPtr) > 0)) {
+	return -1;
+    }
+
+    /*
+     * Find the chunk within the line that contains the desired
+     * index.
+     */
+
+    index = indexPtr->charIndex - dlPtr->index.charIndex;
+    for (chunkPtr = dlPtr->chunkPtr; ; chunkPtr = chunkPtr->nextPtr) {
+	if (chunkPtr == NULL) {
+	    return -1;
+	}
+	if (index < chunkPtr->numChars) {
+	    break;
+	}
+	index -= chunkPtr->numChars;
+    }
+
+    /*
+     * Call a chunk-specific procedure to find the horizontal range of
+     * the character within the chunk, then fill in the vertical range.
+     * The x-coordinate returned by bboxProc is a coordinate within a
+     * line, not a coordinate on the screen.  Translate it to reflect
+     * horizontal scrolling.
+     */
+
+    (*chunkPtr->bboxProc)(chunkPtr, index, dlPtr->y + dlPtr->spaceAbove,
+	    dlPtr->height - dlPtr->spaceAbove - dlPtr->spaceBelow,
+	    dlPtr->baseline - dlPtr->spaceAbove, xPtr, yPtr, widthPtr,
+	    heightPtr);
+    *xPtr = *xPtr + dInfoPtr->x - dInfoPtr->curPixelOffset;
+    if ((index == (chunkPtr->numChars-1)) && (chunkPtr->nextPtr == NULL)) {
+	/*
+	 * Last character in display line.  Give it all the space up to
+	 * the line.
+	 */
+
+	if (*xPtr > dInfoPtr->maxX) {
+	    *xPtr = dInfoPtr->maxX;
+	}
+	*widthPtr = dInfoPtr->maxX - *xPtr;
+    }
+    if ((*xPtr + *widthPtr) <= dInfoPtr->x) {
+	return -1;
+    }
+    if ((*xPtr + *widthPtr) > dInfoPtr->maxX) {
+	*widthPtr = dInfoPtr->maxX - *xPtr;
+	if (*widthPtr <= 0) {
+	    return -1;
+	}
+    }
+    if ((*yPtr + *heightPtr) > dInfoPtr->maxY) {
+	*heightPtr = dInfoPtr->maxY - *yPtr;
+	if (*heightPtr <= 0) {
+	    return -1;
+	}
+    }
+    return 0;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkTextDLineInfo --
+ *
+ *	Given an index, return information about the display line
+ *	containing that character.
+ *
+ * Results:
+ *	Zero is returned if the character is on the screen.  -1
+ *	means the character isn't on the screen.  If the return value
+ *	is 0, then information is returned in the variables pointed
+ *	to by xPtr, yPtr, widthPtr, heightPtr, and basePtr.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TkTextDLineInfo(textPtr, indexPtr, xPtr, yPtr, widthPtr, heightPtr, basePtr)
+    TkText *textPtr;		/* Widget record for text widget. */
+    TkTextIndex *indexPtr;	/* Index of character whose bounding
+				 * box is desired. */
+    int *xPtr, *yPtr;		/* Filled with line's upper-left
+				 * coordinate. */
+    int *widthPtr, *heightPtr;	/* Filled in with line's dimensions. */
+    int *basePtr;		/* Filled in with the baseline position,
+				 * measured as an offset down from *yPtr. */
+{
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+    DLine *dlPtr;
+
+    /*
+     * Make sure that all of the screen layout information is up to date.
+     */
+
+    if (dInfoPtr->flags & DINFO_OUT_OF_DATE) {
+	UpdateDisplayInfo(textPtr);
+    }
+
+    /*
+     * Find the display line containing the desired index.
+     */
+
+    dlPtr = FindDLine(dInfoPtr->dLinePtr, indexPtr);
+    if ((dlPtr == NULL) || (TkTextIndexCmp(&dlPtr->index, indexPtr) > 0)) {
+	return -1;
+    }
+
+    *xPtr = dInfoPtr->x - dInfoPtr->curPixelOffset + dlPtr->chunkPtr->x;
+    *widthPtr = dlPtr->length - dlPtr->chunkPtr->x;
+    *yPtr = dlPtr->y;
+    if ((dlPtr->y + dlPtr->height) > dInfoPtr->maxY) {
+	*heightPtr = dInfoPtr->maxY - dlPtr->y;
+    } else {
+	*heightPtr = dlPtr->height;
+    }
+    *basePtr = dlPtr->baseline;
+    return 0;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * TkTextCharLayoutProc --
+ *
+ *	This procedure is the "layoutProc" for character segments.
+ *
+ * Results:
+ *	If there is something to display for the chunk then a
+ *	non-zero value is returned and the fields of chunkPtr
+ *	will be filled in (see the declaration of TkTextDispChunk
+ *	in tkText.h for details).  If zero is returned it means
+ *	that no characters from this chunk fit in the window.
+ *	If -1 is returned it means that this segment just doesn't
+ *	need to be displayed (never happens for text).
+ *
+ * Side effects:
+ *	Memory is allocated to hold additional information about
+ *	the chunk.
+ *
+ *--------------------------------------------------------------
+ */
+
+int
+TkTextCharLayoutProc(textPtr, indexPtr, segPtr, offset, maxX, maxChars,
+	noCharsYet, wrapMode, chunkPtr)
+    TkText *textPtr;		/* Text widget being layed out. */
+    TkTextIndex *indexPtr;	/* Index of first character to lay out
+				 * (corresponds to segPtr and offset). */
+    TkTextSegment *segPtr;	/* Segment being layed out. */
+    int offset;			/* Offset within segment of first character
+				 * to consider. */
+    int maxX;			/* Chunk must not occupy pixels at this
+				 * position or higher. */
+    int maxChars;		/* Chunk must not include more than this
+				 * many characters. */
+    int noCharsYet;		/* Non-zero means no characters have been
+				 * assigned to this display line yet. */
+    Tk_Uid wrapMode;		/* How to handle line wrapping: tkTextCharUid,
+				 * tkTextNoneUid, or tkTextWordUid. */
+    register TkTextDispChunk *chunkPtr;
+				/* Structure to fill in with information
+				 * about this chunk.  The x field has already
+				 * been set by the caller. */
+{
+    Tk_Font tkfont;
+    int nextX, charsThatFit, count;
+    CharInfo *ciPtr;
+    char *p;
+    TkTextSegment *nextPtr;
+    Tk_FontMetrics fm;
+
+    /*
+     * Figure out how many characters will fit in the space we've got.
+     * Include the next character, even though it won't fit completely,
+     * if any of the following is true:
+     *   (a) the chunk contains no characters and the display line contains
+     *	     no characters yet (i.e. the line isn't wide enough to hold
+     *	     even a single character).
+     *   (b) at least one pixel of the character is visible, we haven't
+     *	     already exceeded the character limit, and the next character
+     *	     is a white space character.
+     */
+
+    p = segPtr->body.chars + offset;
+    tkfont = chunkPtr->stylePtr->sValuePtr->tkfont;
+    charsThatFit = MeasureChars(tkfont, p, maxChars, chunkPtr->x, maxX, 0,
+	    &nextX);
+    if (charsThatFit < maxChars) {
+	if ((charsThatFit == 0) && noCharsYet) {
+	    charsThatFit = 1;
+	    MeasureChars(tkfont, p, 1, chunkPtr->x, INT_MAX, 0, &nextX);
+	}
+	if ((nextX < maxX) && ((p[charsThatFit] == ' ')
+		|| (p[charsThatFit] == '\t'))) {
+	    /*
+	     * Space characters are funny, in that they are considered
+	     * to fit if there is at least one pixel of space left on the
+	     * line.  Just give the space character whatever space is left.
+	     */
+
+	    nextX = maxX;
+	    charsThatFit++;
+	}
+	if (p[charsThatFit] == '\n') {
+	    /*
+	     * A newline character takes up no space, so if the previous
+	     * character fits then so does the newline.
+	     */
+
+	    charsThatFit++;
+	}
+	if (charsThatFit == 0) {
+	    return 0;
+	}
+    }
+	
+    Tk_GetFontMetrics(tkfont, &fm);
+
+    /*
+     * Fill in the chunk structure and allocate and initialize a
+     * CharInfo structure.  If the last character is a newline
+     * then don't bother to display it.
+     */
+
+    chunkPtr->displayProc = CharDisplayProc;
+    chunkPtr->undisplayProc = CharUndisplayProc;
+    chunkPtr->measureProc = CharMeasureProc;
+    chunkPtr->bboxProc = CharBboxProc;
+    chunkPtr->numChars = charsThatFit;
+    chunkPtr->minAscent = fm.ascent + chunkPtr->stylePtr->sValuePtr->offset;
+    chunkPtr->minDescent = fm.descent - chunkPtr->stylePtr->sValuePtr->offset;
+    chunkPtr->minHeight = 0;
+    chunkPtr->width = nextX - chunkPtr->x;
+    chunkPtr->breakIndex = -1;
+    ciPtr = (CharInfo *) ckalloc((unsigned)
+	    (sizeof(CharInfo) - 3 + charsThatFit));
+    chunkPtr->clientData = (ClientData) ciPtr;
+    ciPtr->numChars = charsThatFit;
+    strncpy(ciPtr->chars, p, (size_t) charsThatFit);
+    if (p[charsThatFit-1] == '\n') {
+	ciPtr->numChars--;
+    }
+
+    /*
+     * Compute a break location.  If we're in word wrap mode, a
+     * break can occur after any space character, or at the end of
+     * the chunk if the next segment (ignoring those with zero size)
+     * is not a character segment.
+     */
+
+    if (wrapMode != tkTextWordUid) {
+	chunkPtr->breakIndex = chunkPtr->numChars;
+    } else {
+	for (count = charsThatFit, p += charsThatFit-1; count > 0;
+		count--, p--) {
+	    if (isspace(UCHAR(*p))) {
+		chunkPtr->breakIndex = count;
+		break;
+	    }
+	}
+	if ((charsThatFit+offset) == segPtr->size) {
+	    for (nextPtr = segPtr->nextPtr; nextPtr != NULL;
+		    nextPtr = nextPtr->nextPtr) {
+		if (nextPtr->size != 0) {
+		    if (nextPtr->typePtr != &tkTextCharType) {
+			chunkPtr->breakIndex = chunkPtr->numChars;
+		    }
+		    break;
+		}
+	    }
+	}
+    }
+    return 1;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * CharDisplayProc --
+ *
+ *	This procedure is called to display a character chunk on
+ *	the screen or in an off-screen pixmap.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Graphics are drawn.
+ *
+ *--------------------------------------------------------------
+ */
+
+static void
+CharDisplayProc(chunkPtr, x, y, height, baseline, display, dst, screenY)
+    TkTextDispChunk *chunkPtr;		/* Chunk that is to be drawn. */
+    int x;				/* X-position in dst at which to
+					 * draw this chunk (may differ from
+					 * the x-position in the chunk because
+					 * of scrolling). */
+    int y;				/* Y-position at which to draw this
+					 * chunk in dst. */
+    int height;				/* Total height of line. */
+    int baseline;			/* Offset of baseline from y. */
+    Display *display;			/* Display to use for drawing. */
+    Drawable dst;			/* Pixmap or window in which to draw
+					 * chunk. */
+    int screenY;			/* Y-coordinate in text window that
+					 * corresponds to y. */
+{
+    CharInfo *ciPtr = (CharInfo *) chunkPtr->clientData;
+    TextStyle *stylePtr;
+    StyleValues *sValuePtr;
+    int offsetChars, offsetX;
+
+    if ((x + chunkPtr->width) <= 0) {
+	/*
+	 * The chunk is off-screen.
+	 */
+
+	return;
+    }
+
+    stylePtr = chunkPtr->stylePtr;
+    sValuePtr = stylePtr->sValuePtr;
+
+    /*
+     * If the text sticks out way to the left of the window, skip
+     * over the characters that aren't in the visible part of the
+     * window.  This is essential if x is very negative (such as
+     * less than 32K);  otherwise overflow problems will occur
+     * in servers that use 16-bit arithmetic, like X.
+     */
+
+    offsetX = x;
+    offsetChars = 0;
+    if (x < 0) {
+	offsetChars = MeasureChars(sValuePtr->tkfont, ciPtr->chars,
+	    ciPtr->numChars, x, 0, x - chunkPtr->x, &offsetX);
+    }
+
+    /*
+     * Draw the text, underline, and overstrike for this chunk.
+     */
+
+    if (ciPtr->numChars > offsetChars) {
+	int numChars = ciPtr->numChars - offsetChars;
+	char *string = ciPtr->chars + offsetChars;
+
+	if ((numChars > 0) && (string[numChars - 1] == '\t')) {
+	    numChars--;
+	}
+	Tk_DrawChars(display, dst, stylePtr->fgGC, sValuePtr->tkfont, string,
+		numChars, offsetX, y + baseline - sValuePtr->offset);
+	if (sValuePtr->underline) {
+	    Tk_UnderlineChars(display, dst, stylePtr->fgGC, sValuePtr->tkfont,
+		    ciPtr->chars + offsetChars, offsetX,
+		    y + baseline - sValuePtr->offset,
+		    0, numChars);
+
+	}
+	if (sValuePtr->overstrike) {
+	    Tk_FontMetrics fm;
+	    
+	    Tk_GetFontMetrics(sValuePtr->tkfont, &fm);
+	    Tk_UnderlineChars(display, dst, stylePtr->fgGC, sValuePtr->tkfont,
+		    ciPtr->chars + offsetChars, offsetX,
+		    y + baseline - sValuePtr->offset
+			    - fm.descent - (fm.ascent * 3) / 10,
+		    0, numChars);
+	}
+    }
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * CharUndisplayProc --
+ *
+ *	This procedure is called when a character chunk is no
+ *	longer going to be displayed.  It frees up resources
+ *	that were allocated to display the chunk.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Memory and other resources get freed.
+ *
+ *--------------------------------------------------------------
+ */
+
+static void
+CharUndisplayProc(textPtr, chunkPtr)
+    TkText *textPtr;			/* Overall information about text
+					 * widget. */
+    TkTextDispChunk *chunkPtr;		/* Chunk that is about to be freed. */
+{
+    CharInfo *ciPtr = (CharInfo *) chunkPtr->clientData;
+
+    ckfree((char *) ciPtr);
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * CharMeasureProc --
+ *
+ *	This procedure is called to determine which character in
+ *	a character chunk lies over a given x-coordinate.
+ *
+ * Results:
+ *	The return value is the index *within the chunk* of the
+ *	character that covers the position given by "x".
+ *
+ * Side effects:
+ *	None.
+ *
+ *--------------------------------------------------------------
+ */
+
+static int
+CharMeasureProc(chunkPtr, x)
+    TkTextDispChunk *chunkPtr;		/* Chunk containing desired coord. */
+    int x;				/* X-coordinate, in same coordinate
+					 * system as chunkPtr->x. */
+{
+    CharInfo *ciPtr = (CharInfo *) chunkPtr->clientData;
+    int endX;
+
+    return MeasureChars(chunkPtr->stylePtr->sValuePtr->tkfont, ciPtr->chars,
+	    chunkPtr->numChars-1, chunkPtr->x, x, 0, &endX);
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * CharBboxProc --
+ *
+ *	This procedure is called to compute the bounding box of
+ *	the area occupied by a single character.
+ *
+ * Results:
+ *	There is no return value.  *xPtr and *yPtr are filled in
+ *	with the coordinates of the upper left corner of the
+ *	character, and *widthPtr and *heightPtr are filled in with
+ *	the dimensions of the character in pixels.  Note:  not all
+ *	of the returned bbox is necessarily visible on the screen
+ *	(the rightmost part might be off-screen to the right,
+ *	and the bottommost part might be off-screen to the bottom).
+ *
+ * Side effects:
+ *	None.
+ *
+ *--------------------------------------------------------------
+ */
+
+static void
+CharBboxProc(chunkPtr, index, y, lineHeight, baseline, xPtr, yPtr,
+	widthPtr, heightPtr)
+    TkTextDispChunk *chunkPtr;		/* Chunk containing desired char. */
+    int index;				/* Index of desired character within
+					 * the chunk. */
+    int y;				/* Topmost pixel in area allocated
+					 * for this line. */
+    int lineHeight;			/* Height of line, in pixels. */
+    int baseline;			/* Location of line's baseline, in
+					 * pixels measured down from y. */
+    int *xPtr, *yPtr;			/* Gets filled in with coords of
+					 * character's upper-left pixel. 
+					 * X-coord is in same coordinate
+					 * system as chunkPtr->x. */
+    int *widthPtr;			/* Gets filled in with width of
+					 * character, in pixels. */
+    int *heightPtr;			/* Gets filled in with height of
+					 * character, in pixels. */
+{
+    CharInfo *ciPtr = (CharInfo *) chunkPtr->clientData;
+    int maxX;
+
+    maxX = chunkPtr->width + chunkPtr->x;
+    MeasureChars(chunkPtr->stylePtr->sValuePtr->tkfont, ciPtr->chars, index,
+	    chunkPtr->x, 1000000, 0, xPtr);
+
+    if (index == ciPtr->numChars) {
+	/*
+	 * This situation only happens if the last character in a line
+	 * is a space character, in which case it absorbs all of the
+	 * extra space in the line (see TkTextCharLayoutProc).
+	 */
+
+	*widthPtr = maxX - *xPtr;
+    } else if ((ciPtr->chars[index] == '\t')
+	    && (index == (ciPtr->numChars-1))) {
+	/*
+	 * The desired character is a tab character that terminates a
+	 * chunk;  give it all the space left in the chunk.
+	 */
+
+	*widthPtr = maxX - *xPtr;
+    } else {
+	MeasureChars(chunkPtr->stylePtr->sValuePtr->tkfont, 
+		ciPtr->chars + index, 1, *xPtr, 1000000, 0, widthPtr);
+	if (*widthPtr > maxX) {
+	    *widthPtr = maxX - *xPtr;
+	} else {
+	    *widthPtr -= *xPtr;
+	}
+    }
+    *yPtr = y + baseline - chunkPtr->minAscent;
+    *heightPtr = chunkPtr->minAscent + chunkPtr->minDescent;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * AdjustForTab --
+ *
+ *	This procedure is called to move a series of chunks right
+ *	in order to align them with a tab stop.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The width of chunkPtr gets adjusted so that it absorbs the
+ *	extra space due to the tab.  The x locations in all the chunks
+ *	after chunkPtr are adjusted rightward to align with the tab
+ *	stop given by tabArrayPtr and index.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+AdjustForTab(textPtr, tabArrayPtr, index, chunkPtr)
+    TkText *textPtr;			/* Information about the text widget as
+					 * a whole. */
+    TkTextTabArray *tabArrayPtr;	/* Information about the tab stops
+					 * that apply to this line.  May be
+					 * NULL to indicate default tabbing
+					 * (every 8 chars). */
+    int index;				/* Index of current tab stop. */
+    TkTextDispChunk *chunkPtr;		/* Chunk whose last character is
+					 * the tab;  the following chunks
+					 * contain information to be shifted
+					 * right. */
+
+{
+    int x, desired, delta, width, decimal, i, gotDigit;
+    TkTextDispChunk *chunkPtr2, *decimalChunkPtr;
+    CharInfo *ciPtr;
+    int tabX, prev, spaceWidth;
+    char *p;
+    TkTextTabAlign alignment;
+
+    if (chunkPtr->nextPtr == NULL) {
+	/*
+	 * Nothing after the actual tab;  just return.
+	 */
+
+	return;
+    }
+
+    /*
+     * If no tab information has been given, do the usual thing:
+     * round up to the next boundary of 8 average-sized characters.
+     */
+
+    x = chunkPtr->nextPtr->x;
+    if ((tabArrayPtr == NULL) || (tabArrayPtr->numTabs == 0)) {
+	/*
+	 * No tab information has been given, so use the default
+	 * interpretation of tabs.
+	 */
+
+	desired = NextTabStop(textPtr->tkfont, x, 0);
+	goto update;
+    }
+
+    if (index < tabArrayPtr->numTabs) {
+	alignment = tabArrayPtr->tabs[index].alignment;
+	tabX = tabArrayPtr->tabs[index].location;
+    } else {
+	/*
+	 * Ran out of tab stops;  compute a tab position by extrapolating
+	 * from the last two tab positions.
+	 */
+
+	if (tabArrayPtr->numTabs > 1) {
+	    prev = tabArrayPtr->tabs[tabArrayPtr->numTabs-2].location;
+	} else {
+	    prev = 0;
+	}
+	alignment = tabArrayPtr->tabs[tabArrayPtr->numTabs-1].alignment;
+	tabX = tabArrayPtr->tabs[tabArrayPtr->numTabs-1].location
+		+ (index + 1 - tabArrayPtr->numTabs)
+		* (tabArrayPtr->tabs[tabArrayPtr->numTabs-1].location - prev);
+    }
+
+    if (alignment == LEFT) {
+	desired = tabX;
+	goto update;
+    }
+
+    if ((alignment == CENTER) || (alignment == RIGHT)) {
+	/*
+	 * Compute the width of all the information in the tab group,
+	 * then use it to pick a desired location.
+	 */
+
+	width = 0;
+	for (chunkPtr2 = chunkPtr->nextPtr; chunkPtr2 != NULL;
+		chunkPtr2 = chunkPtr2->nextPtr) {
+	    width += chunkPtr2->width;
+	}
+	if (alignment == CENTER) {
+	    desired = tabX - width/2;
+	} else {
+	    desired = tabX - width;
+	}
+	goto update;
+    }
+
+    /*
+     * Must be numeric alignment.  Search through the text to be
+     * tabbed, looking for the last , or . before the first character
+     * that isn't a number, comma, period, or sign.
+     */
+
+    decimalChunkPtr = NULL;
+    decimal = gotDigit = 0;
+    for (chunkPtr2 = chunkPtr->nextPtr; chunkPtr2 != NULL;
+	    chunkPtr2 = chunkPtr2->nextPtr) {
+	if (chunkPtr2->displayProc != CharDisplayProc) {
+	    continue;
+	}
+	ciPtr = (CharInfo *) chunkPtr2->clientData;
+	for (p = ciPtr->chars, i = 0; i < ciPtr->numChars; p++, i++) {
+	    if (isdigit(UCHAR(*p))) {
+		gotDigit = 1;
+	    } else if ((*p == '.') || (*p == ',')) {
+		decimal = p-ciPtr->chars;
+		decimalChunkPtr = chunkPtr2;
+	    } else if (gotDigit) {
+		if (decimalChunkPtr == NULL) {
+		    decimal = p-ciPtr->chars;
+		    decimalChunkPtr = chunkPtr2;
+		}
+		goto endOfNumber;
+	    }
+	}
+    }
+    endOfNumber:
+    if (decimalChunkPtr != NULL) {
+	int curX;
+
+	ciPtr = (CharInfo *) decimalChunkPtr->clientData;
+	MeasureChars(decimalChunkPtr->stylePtr->sValuePtr->tkfont,
+		ciPtr->chars, decimal, decimalChunkPtr->x, 1000000, 0, &curX);
+	desired = tabX - (curX - x);
+	goto update;
+    } else {
+	/*
+	 * There wasn't a decimal point.  Right justify the text.
+	 */
+    
+	width = 0;
+	for (chunkPtr2 = chunkPtr->nextPtr; chunkPtr2 != NULL;
+		chunkPtr2 = chunkPtr2->nextPtr) {
+	    width += chunkPtr2->width;
+	}
+	desired = tabX - width;
+    }
+
+    /*
+     * Shift all of the chunks to the right so that the left edge is
+     * at the desired location, then expand the chunk containing the
+     * tab.  Be sure that the tab occupies at least the width of a
+     * space character.
+     */
+
+    update:
+    delta = desired - x;
+    MeasureChars(textPtr->tkfont, " ", 1, 0, INT_MAX, 0, &spaceWidth);
+    if (delta < spaceWidth) {
+	delta = spaceWidth;
+    }
+    for (chunkPtr2 = chunkPtr->nextPtr; chunkPtr2 != NULL;
+	    chunkPtr2 = chunkPtr2->nextPtr) {
+	chunkPtr2->x += delta;
+    }
+    chunkPtr->width += delta;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * SizeOfTab --
+ *
+ *	This returns an estimate of the amount of white space that will
+ *	be consumed by a tab.
+ *
+ * Results:
+ *	The return value is the minimum number of pixels that will
+ *	be occupied by the index'th tab of tabArrayPtr, assuming that
+ *	the current position on the line is x and the end of the
+ *	line is maxX.  For numeric tabs, this is a conservative
+ *	estimate.  The return value is always >= 0.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+SizeOfTab(textPtr, tabArrayPtr, index, x, maxX)
+    TkText *textPtr;			/* Information about the text widget as
+					 * a whole. */
+    TkTextTabArray *tabArrayPtr;	/* Information about the tab stops
+					 * that apply to this line.  NULL
+					 * means use default tabbing (every
+					 * 8 chars.) */
+    int index;				/* Index of current tab stop. */
+    int x;				/* Current x-location in line. Only
+					 * used if tabArrayPtr == NULL. */
+    int maxX;				/* X-location of pixel just past the
+					 * right edge of the line. */
+{
+    int tabX, prev, result, spaceWidth;
+    TkTextTabAlign alignment;
+
+    if ((tabArrayPtr == NULL) || (tabArrayPtr->numTabs == 0)) {
+	tabX = NextTabStop(textPtr->tkfont, x, 0);
+	return tabX - x;
+    }
+    if (index < tabArrayPtr->numTabs) {
+	tabX = tabArrayPtr->tabs[index].location;
+	alignment = tabArrayPtr->tabs[index].alignment;
+    } else {
+	/*
+	 * Ran out of tab stops;  compute a tab position by extrapolating
+	 * from the last two tab positions.
+	 */
+
+	if (tabArrayPtr->numTabs > 1) {
+	    prev = tabArrayPtr->tabs[tabArrayPtr->numTabs-2].location;
+	} else {
+	    prev = 0;
+	}
+	tabX = tabArrayPtr->tabs[tabArrayPtr->numTabs-1].location
+		+ (index + 1 - tabArrayPtr->numTabs)
+		* (tabArrayPtr->tabs[tabArrayPtr->numTabs-1].location - prev);
+	alignment = tabArrayPtr->tabs[tabArrayPtr->numTabs-1].alignment;
+    }
+    if (alignment == CENTER) {
+	/*
+	 * Be very careful in the arithmetic below, because maxX may
+	 * be the largest positive number:  watch out for integer
+	 * overflow.
+	 */
+
+	if ((maxX-tabX) < (tabX - x)) {
+	    result = (maxX - x) - 2*(maxX - tabX);
+	} else {
+	    result = 0;
+	}
+	goto done;
+    }
+    if (alignment == RIGHT) {
+	result = 0;
+	goto done;
+    }
+
+    /*
+     * Note: this treats NUMERIC alignment the same as LEFT
+     * alignment, which is somewhat conservative.  However, it's
+     * pretty tricky at this point to figure out exactly where
+     * the damn decimal point will be.
+     */
+
+    if (tabX > x) {
+	result = tabX - x;
+    } else {
+	result = 0;
+    }
+
+    done:
+    MeasureChars(textPtr->tkfont, " ", 1, 0, INT_MAX, 0, &spaceWidth);
+    if (result < spaceWidth) {
+	result = spaceWidth;
+    }
+    return result;
+}
+
+/*
+ *---------------------------------------------------------------------------
+ *
+ * NextTabStop --
+ *
+ *	Given the current position, determine where the next default
+ *	tab stop would be located.  This procedure is called when the
+ *	current chunk in the text has no tabs defined and so the default
+ *	tab spacing for the font should be used.
+ *
+ * Results:
+ *	The location in pixels of the next tab stop.
+ *
+ * Side effects:
+ *	None.
+ *
+ *---------------------------------------------------------------------------
+ */
+
+static int
+NextTabStop(tkfont, x, tabOrigin)
+    Tk_Font tkfont;		/* Font in which chunk that contains tab
+				 * stop will be drawn. */
+    int x;			/* X-position in pixels where last
+				 * character was drawn.  The next tab stop
+				 * occurs somewhere after this location. */
+    int tabOrigin;		/* The origin for tab stops.  May be
+				 * non-zero if text has been scrolled. */
+{
+    int tabWidth, rem;
+    
+    tabWidth = Tk_TextWidth(tkfont, "0", 1) * 8;
+    if (tabWidth == 0) {
+	tabWidth = 1;
+    }
+
+    x += tabWidth;
+    rem = (x - tabOrigin) % tabWidth;
+    if (rem < 0) {
+	rem += tabWidth;
+    }
+    x -= rem;
+    return x;
+}
+
+/*
+ *---------------------------------------------------------------------------
+ *
+ *  MeasureChars --
+ *
+ *	Determine the number of characters from the string that will fit
+ *	in the given horizontal span.  The measurement is done under the
+ *	assumption that Tk_DisplayChars will be used to actually display
+ *	the characters.
+ *
+ *	If tabs are encountered in the string, they will be expanded
+ *	to the next tab stop, unless the TK_IGNORE_TABS flag is specified.
+ *
+ *	If a newline is encountered in the string, the line will be
+ *	broken at that point, unless the TK_NEWSLINES_NOT_SPECIAL flag
+ *	is specified.  
+ *
+ * Results:
+ *	The return value is the number of characters from source
+ *	that fit in the span given by startX and maxX.  *nextXPtr
+ *	is filled in with the x-coordinate at which the first
+ *	character that didn't fit would be drawn, if it were to
+ *	be drawn.
+ *
+ * Side effects:
+ *	None.
+ *
+ *--------------------------------------------------------------
+ */
+
+static int
+MeasureChars(tkfont, source, maxChars, startX, maxX, tabOrigin, nextXPtr)
+    Tk_Font tkfont;		/* Font in which to draw characters. */
+    CONST char *source;		/* Characters to be displayed.  Need not
+				 * be NULL-terminated. */
+    int maxChars;		/* Maximum # of characters to consider from
+				 * source. */
+    int startX;			/* X-position at which first character will
+				 * be drawn. */
+    int maxX;			/* Don't consider any character that would
+				 * cross this x-position. */
+    int tabOrigin;		/* X-location that serves as "origin" for
+				 * tab stops. */
+    int *nextXPtr;		/* Return x-position of terminating
+				 * character here. */
+{
+    int curX, width, ch;
+    CONST char *special, *end, *start;
+
+    ch = 0;			/* lint. */
+    curX = startX;
+    special = source;
+    end = source + maxChars;
+    for (start = source; start < end; ) {
+	if (start >= special) {
+	    /*
+	     * Find the next special character in the string.
+	     */
+
+	    for (special = start; special < end; special++) {
+		ch = *special;
+		if ((ch == '\t') || (ch == '\n')) {
+		    break;
+		}
+	    }
+	}
+
+	/*
+	 * Special points at the next special character (or the end of the
+	 * string).  Process characters between start and special.
+	 */
+
+	if (curX >= maxX) {
+	    break;
+	}
+	start += Tk_MeasureChars(tkfont, start, special - start, maxX - curX,
+		0, &width);
+	curX += width;
+	if (start < special) {
+	    /*
+	     * No more chars fit in line.
+	     */
+
+	    break;
+	}
+	if (special < end) {
+	    if (ch == '\t') {
+		start++;
+	    } else {
+		break;
+	    }
+	}
+    }
+
+    *nextXPtr = curX;
+    return start - source;
+}