Initial revision

FossilOrigin-Name: 2bf55ca9aa942b581137b9f474da5ad9c1480de4

1 files changed, 3791 insertions, 0 deletions

diff --git a/generic/tkCanvas.c b/generic/tkCanvas.c
new file mode 100644
index 0000000..b093226
--- /dev/null
+++ b/generic/tkCanvas.c
@@ -0,0 +1,3791 @@
+/* 
+ * tkCanvas.c --
+ *
+ *	This module implements canvas widgets for the Tk toolkit.
+ *	A canvas displays a background and a collection of graphical
+ *	objects such as rectangles, lines, and texts.
+ *
+ * Copyright (c) 1991-1994 The Regents of the University of California.
+ * Copyright (c) 1994-1995 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: @(#) tkCanvas.c 1.126 97/07/31 09:05:52
+ */
+
+#include "default.h"
+#include "tkInt.h"
+#include "tkPort.h"
+#include "tkCanvas.h"
+
+/*
+ * See tkCanvas.h for key data structures used to implement canvases.
+ */
+
+/*
+ * The structure defined below is used to keep track of a tag search
+ * in progress.  Only the "prevPtr" field should be accessed by anyone
+ * other than StartTagSearch and NextItem.
+ */
+
+typedef struct TagSearch {
+    TkCanvas *canvasPtr;	/* Canvas widget being searched. */
+    Tk_Uid tag;			/* Tag to search for.   0 means return
+				 * all items. */
+    Tk_Item *prevPtr;		/* Item just before last one found (or NULL
+				 * if last one found was first in the item
+				 * list of canvasPtr). */
+    Tk_Item *currentPtr;	/* Pointer to last item returned. */
+    int searchOver;		/* Non-zero means NextItem should always
+				 * return NULL. */
+} TagSearch;
+
+/*
+ * Information used for argv parsing.
+ */
+
+static Tk_ConfigSpec configSpecs[] = {
+    {TK_CONFIG_BORDER, "-background", "background", "Background",
+	DEF_CANVAS_BG_COLOR, Tk_Offset(TkCanvas, bgBorder),
+	TK_CONFIG_COLOR_ONLY},
+    {TK_CONFIG_BORDER, "-background", "background", "Background",
+	DEF_CANVAS_BG_MONO, Tk_Offset(TkCanvas, bgBorder),
+	TK_CONFIG_MONO_ONLY},
+    {TK_CONFIG_SYNONYM, "-bd", "borderWidth", (char *) NULL,
+	(char *) NULL, 0, 0},
+    {TK_CONFIG_SYNONYM, "-bg", "background", (char *) NULL,
+	(char *) NULL, 0, 0},
+    {TK_CONFIG_PIXELS, "-borderwidth", "borderWidth", "BorderWidth",
+	DEF_CANVAS_BORDER_WIDTH, Tk_Offset(TkCanvas, borderWidth), 0},
+    {TK_CONFIG_DOUBLE, "-closeenough", "closeEnough", "CloseEnough",
+	DEF_CANVAS_CLOSE_ENOUGH, Tk_Offset(TkCanvas, closeEnough), 0},
+    {TK_CONFIG_BOOLEAN, "-confine", "confine", "Confine",
+	DEF_CANVAS_CONFINE, Tk_Offset(TkCanvas, confine), 0},
+    {TK_CONFIG_ACTIVE_CURSOR, "-cursor", "cursor", "Cursor",
+	DEF_CANVAS_CURSOR, Tk_Offset(TkCanvas, cursor), TK_CONFIG_NULL_OK},
+    {TK_CONFIG_PIXELS, "-height", "height", "Height",
+	DEF_CANVAS_HEIGHT, Tk_Offset(TkCanvas, height), 0},
+    {TK_CONFIG_COLOR, "-highlightbackground", "highlightBackground",
+	"HighlightBackground", DEF_CANVAS_HIGHLIGHT_BG,
+	Tk_Offset(TkCanvas, highlightBgColorPtr), 0},
+    {TK_CONFIG_COLOR, "-highlightcolor", "highlightColor", "HighlightColor",
+	DEF_CANVAS_HIGHLIGHT, Tk_Offset(TkCanvas, highlightColorPtr), 0},
+    {TK_CONFIG_PIXELS, "-highlightthickness", "highlightThickness",
+	"HighlightThickness",
+	DEF_CANVAS_HIGHLIGHT_WIDTH, Tk_Offset(TkCanvas, highlightWidth), 0},
+    {TK_CONFIG_BORDER, "-insertbackground", "insertBackground", "Foreground",
+	DEF_CANVAS_INSERT_BG, Tk_Offset(TkCanvas, textInfo.insertBorder), 0},
+    {TK_CONFIG_PIXELS, "-insertborderwidth", "insertBorderWidth", "BorderWidth",
+	DEF_CANVAS_INSERT_BD_COLOR,
+	Tk_Offset(TkCanvas, textInfo.insertBorderWidth), TK_CONFIG_COLOR_ONLY},
+    {TK_CONFIG_PIXELS, "-insertborderwidth", "insertBorderWidth", "BorderWidth",
+	DEF_CANVAS_INSERT_BD_MONO,
+	Tk_Offset(TkCanvas, textInfo.insertBorderWidth), TK_CONFIG_MONO_ONLY},
+    {TK_CONFIG_INT, "-insertofftime", "insertOffTime", "OffTime",
+	DEF_CANVAS_INSERT_OFF_TIME, Tk_Offset(TkCanvas, insertOffTime), 0},
+    {TK_CONFIG_INT, "-insertontime", "insertOnTime", "OnTime",
+	DEF_CANVAS_INSERT_ON_TIME, Tk_Offset(TkCanvas, insertOnTime), 0},
+    {TK_CONFIG_PIXELS, "-insertwidth", "insertWidth", "InsertWidth",
+	DEF_CANVAS_INSERT_WIDTH, Tk_Offset(TkCanvas, textInfo.insertWidth), 0},
+    {TK_CONFIG_RELIEF, "-relief", "relief", "Relief",
+	DEF_CANVAS_RELIEF, Tk_Offset(TkCanvas, relief), 0},
+    {TK_CONFIG_STRING, "-scrollregion", "scrollRegion", "ScrollRegion",
+	DEF_CANVAS_SCROLL_REGION, Tk_Offset(TkCanvas, regionString),
+	TK_CONFIG_NULL_OK},
+    {TK_CONFIG_BORDER, "-selectbackground", "selectBackground", "Foreground",
+	DEF_CANVAS_SELECT_COLOR, Tk_Offset(TkCanvas, textInfo.selBorder),
+	TK_CONFIG_COLOR_ONLY},
+    {TK_CONFIG_BORDER, "-selectbackground", "selectBackground", "Foreground",
+	DEF_CANVAS_SELECT_MONO, Tk_Offset(TkCanvas, textInfo.selBorder),
+	TK_CONFIG_MONO_ONLY},
+    {TK_CONFIG_PIXELS, "-selectborderwidth", "selectBorderWidth", "BorderWidth",
+	DEF_CANVAS_SELECT_BD_COLOR,
+	Tk_Offset(TkCanvas, textInfo.selBorderWidth), TK_CONFIG_COLOR_ONLY},
+    {TK_CONFIG_PIXELS, "-selectborderwidth", "selectBorderWidth", "BorderWidth",
+	DEF_CANVAS_SELECT_BD_MONO, Tk_Offset(TkCanvas, textInfo.selBorderWidth),
+	TK_CONFIG_MONO_ONLY},
+    {TK_CONFIG_COLOR, "-selectforeground", "selectForeground", "Background",
+	DEF_CANVAS_SELECT_FG_COLOR, Tk_Offset(TkCanvas, textInfo.selFgColorPtr),
+	TK_CONFIG_COLOR_ONLY},
+    {TK_CONFIG_COLOR, "-selectforeground", "selectForeground", "Background",
+	DEF_CANVAS_SELECT_FG_MONO, Tk_Offset(TkCanvas, textInfo.selFgColorPtr),
+	TK_CONFIG_MONO_ONLY},
+    {TK_CONFIG_STRING, "-takefocus", "takeFocus", "TakeFocus",
+	DEF_CANVAS_TAKE_FOCUS, Tk_Offset(TkCanvas, takeFocus),
+	TK_CONFIG_NULL_OK},
+    {TK_CONFIG_PIXELS, "-width", "width", "Width",
+	DEF_CANVAS_WIDTH, Tk_Offset(TkCanvas, width), 0},
+    {TK_CONFIG_STRING, "-xscrollcommand", "xScrollCommand", "ScrollCommand",
+	DEF_CANVAS_X_SCROLL_CMD, Tk_Offset(TkCanvas, xScrollCmd),
+	TK_CONFIG_NULL_OK},
+    {TK_CONFIG_PIXELS, "-xscrollincrement", "xScrollIncrement",
+	"ScrollIncrement",
+	DEF_CANVAS_X_SCROLL_INCREMENT, Tk_Offset(TkCanvas, xScrollIncrement),
+	0},
+    {TK_CONFIG_STRING, "-yscrollcommand", "yScrollCommand", "ScrollCommand",
+	DEF_CANVAS_Y_SCROLL_CMD, Tk_Offset(TkCanvas, yScrollCmd),
+	TK_CONFIG_NULL_OK},
+    {TK_CONFIG_PIXELS, "-yscrollincrement", "yScrollIncrement",
+	"ScrollIncrement",
+	DEF_CANVAS_Y_SCROLL_INCREMENT, Tk_Offset(TkCanvas, yScrollIncrement),
+	0},
+    {TK_CONFIG_END, (char *) NULL, (char *) NULL, (char *) NULL,
+	(char *) NULL, 0, 0}
+};
+
+/*
+ * List of all the item types known at present:
+ */
+
+static Tk_ItemType *typeList = NULL;	/* NULL means initialization hasn't
+					 * been done yet. */
+
+/*
+ * Standard item types provided by Tk:
+ */
+
+extern Tk_ItemType tkArcType, tkBitmapType, tkImageType, tkLineType;
+extern Tk_ItemType tkOvalType, tkPolygonType;
+extern Tk_ItemType tkRectangleType, tkTextType, tkWindowType;
+
+/*
+ * Various Tk_Uid's used by this module (set up during initialization):
+ */
+
+static Tk_Uid allUid = NULL;
+static Tk_Uid currentUid = NULL;
+
+/*
+ * Statistics counters:
+ */
+
+static int numIdSearches;
+static int numSlowSearches;
+
+/*
+ * Prototypes for procedures defined later in this file:
+ */
+
+static void		CanvasBindProc _ANSI_ARGS_((ClientData clientData,
+			    XEvent *eventPtr));
+static void		CanvasBlinkProc _ANSI_ARGS_((ClientData clientData));
+static void		CanvasCmdDeletedProc _ANSI_ARGS_((
+			    ClientData clientData));
+static void		CanvasDoEvent _ANSI_ARGS_((TkCanvas *canvasPtr,
+			    XEvent *eventPtr));
+static void		CanvasEventProc _ANSI_ARGS_((ClientData clientData,
+			    XEvent *eventPtr));
+static int		CanvasFetchSelection _ANSI_ARGS_((
+			    ClientData clientData, int offset,
+			    char *buffer, int maxBytes));
+static Tk_Item *	CanvasFindClosest _ANSI_ARGS_((TkCanvas *canvasPtr,
+			    double coords[2]));
+static void		CanvasFocusProc _ANSI_ARGS_((TkCanvas *canvasPtr,
+			    int gotFocus));
+static void		CanvasLostSelection _ANSI_ARGS_((
+			    ClientData clientData));
+static void		CanvasSelectTo _ANSI_ARGS_((TkCanvas *canvasPtr,
+			    Tk_Item *itemPtr, int index));
+static void		CanvasSetOrigin _ANSI_ARGS_((TkCanvas *canvasPtr,
+			    int xOrigin, int yOrigin));
+static void		CanvasUpdateScrollbars _ANSI_ARGS_((
+			    TkCanvas *canvasPtr));
+static int		CanvasWidgetCmd _ANSI_ARGS_((ClientData clientData,
+			    Tcl_Interp *interp, int argc, char **argv));
+static void		CanvasWorldChanged _ANSI_ARGS_((
+			    ClientData instanceData));
+static int		ConfigureCanvas _ANSI_ARGS_((Tcl_Interp *interp,
+			    TkCanvas *canvasPtr, int argc, char **argv,
+			    int flags));
+static void		DestroyCanvas _ANSI_ARGS_((char *memPtr));
+static void		DisplayCanvas _ANSI_ARGS_((ClientData clientData));
+static void		DoItem _ANSI_ARGS_((Tcl_Interp *interp,
+			    Tk_Item *itemPtr, Tk_Uid tag));
+static int		FindItems _ANSI_ARGS_((Tcl_Interp *interp,
+			    TkCanvas *canvasPtr, int argc, char **argv,
+			    char *newTag, char *cmdName, char *option));
+static int		FindArea _ANSI_ARGS_((Tcl_Interp *interp,
+			    TkCanvas *canvasPtr, char **argv, Tk_Uid uid,
+			    int enclosed));
+static double		GridAlign _ANSI_ARGS_((double coord, double spacing));
+static void		InitCanvas _ANSI_ARGS_((void));
+static Tk_Item *	NextItem _ANSI_ARGS_((TagSearch *searchPtr));
+static void		PickCurrentItem _ANSI_ARGS_((TkCanvas *canvasPtr,
+			    XEvent *eventPtr));
+static void		PrintScrollFractions _ANSI_ARGS_((int screen1,
+			    int screen2, int object1, int object2,
+			    char *string));
+static void		RelinkItems _ANSI_ARGS_((TkCanvas *canvasPtr,
+			    char *tag, Tk_Item *prevPtr));
+static Tk_Item *	StartTagSearch _ANSI_ARGS_((TkCanvas *canvasPtr,
+			    char *tag, TagSearch *searchPtr));
+
+/*
+ * The structure below defines canvas class behavior by means of procedures
+ * that can be invoked from generic window code.
+ */
+
+static TkClassProcs canvasClass = {
+    NULL,			/* createProc. */
+    CanvasWorldChanged,		/* geometryProc. */
+    NULL			/* modalProc. */
+};
+
+
+/*
+ *--------------------------------------------------------------
+ *
+ * Tk_CanvasCmd --
+ *
+ *	This procedure is invoked to process the "canvas" Tcl
+ *	command.  See the user documentation for details on what
+ *	it does.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	See the user documentation.
+ *
+ *--------------------------------------------------------------
+ */
+
+int
+Tk_CanvasCmd(clientData, interp, argc, argv)
+    ClientData clientData;		/* Main window associated with
+				 * interpreter. */
+    Tcl_Interp *interp;		/* Current interpreter. */
+    int argc;			/* Number of arguments. */
+    char **argv;		/* Argument strings. */
+{
+    Tk_Window tkwin = (Tk_Window) clientData;
+    TkCanvas *canvasPtr;
+    Tk_Window new;
+
+    if (typeList == NULL) {
+	InitCanvas();
+    }
+
+    if (argc < 2) {
+	Tcl_AppendResult(interp, "wrong # args: should be \"",
+		argv[0], " pathName ?options?\"", (char *) NULL);
+	return TCL_ERROR;
+    }
+
+    new = Tk_CreateWindowFromPath(interp, tkwin, argv[1], (char *) NULL);
+    if (new == NULL) {
+	return TCL_ERROR;
+    }
+
+    /*
+     * Initialize fields that won't be initialized by ConfigureCanvas,
+     * or which ConfigureCanvas expects to have reasonable values
+     * (e.g. resource pointers).
+     */
+
+    canvasPtr = (TkCanvas *) ckalloc(sizeof(TkCanvas));
+    canvasPtr->tkwin = new;
+    canvasPtr->display = Tk_Display(new);
+    canvasPtr->interp = interp;
+    canvasPtr->widgetCmd = Tcl_CreateCommand(interp,
+	    Tk_PathName(canvasPtr->tkwin), CanvasWidgetCmd,
+	    (ClientData) canvasPtr, CanvasCmdDeletedProc);
+    canvasPtr->firstItemPtr = NULL;
+    canvasPtr->lastItemPtr = NULL;
+    canvasPtr->borderWidth = 0;
+    canvasPtr->bgBorder = NULL;
+    canvasPtr->relief = TK_RELIEF_FLAT;
+    canvasPtr->highlightWidth = 0;
+    canvasPtr->highlightBgColorPtr = NULL;
+    canvasPtr->highlightColorPtr = NULL;
+    canvasPtr->inset = 0;
+    canvasPtr->pixmapGC = None;
+    canvasPtr->width = None;
+    canvasPtr->height = None;
+    canvasPtr->confine = 0;
+    canvasPtr->textInfo.selBorder = NULL;
+    canvasPtr->textInfo.selBorderWidth = 0;
+    canvasPtr->textInfo.selFgColorPtr = NULL;
+    canvasPtr->textInfo.selItemPtr = NULL;
+    canvasPtr->textInfo.selectFirst = -1;
+    canvasPtr->textInfo.selectLast = -1;
+    canvasPtr->textInfo.anchorItemPtr = NULL;
+    canvasPtr->textInfo.selectAnchor = 0;
+    canvasPtr->textInfo.insertBorder = NULL;
+    canvasPtr->textInfo.insertWidth = 0;
+    canvasPtr->textInfo.insertBorderWidth = 0;
+    canvasPtr->textInfo.focusItemPtr = NULL;
+    canvasPtr->textInfo.gotFocus = 0;
+    canvasPtr->textInfo.cursorOn = 0;
+    canvasPtr->insertOnTime = 0;
+    canvasPtr->insertOffTime = 0;
+    canvasPtr->insertBlinkHandler = (Tcl_TimerToken) NULL;
+    canvasPtr->xOrigin = canvasPtr->yOrigin = 0;
+    canvasPtr->drawableXOrigin = canvasPtr->drawableYOrigin = 0;
+    canvasPtr->bindingTable = NULL;
+    canvasPtr->currentItemPtr = NULL;
+    canvasPtr->newCurrentPtr = NULL;
+    canvasPtr->closeEnough = 0.0;
+    canvasPtr->pickEvent.type = LeaveNotify;
+    canvasPtr->pickEvent.xcrossing.x = 0;
+    canvasPtr->pickEvent.xcrossing.y = 0;
+    canvasPtr->state = 0;
+    canvasPtr->xScrollCmd = NULL;
+    canvasPtr->yScrollCmd = NULL;
+    canvasPtr->scrollX1 = 0;
+    canvasPtr->scrollY1 = 0;
+    canvasPtr->scrollX2 = 0;
+    canvasPtr->scrollY2 = 0;
+    canvasPtr->regionString = NULL;
+    canvasPtr->xScrollIncrement = 0;
+    canvasPtr->yScrollIncrement = 0;
+    canvasPtr->scanX = 0;
+    canvasPtr->scanXOrigin = 0;
+    canvasPtr->scanY = 0;
+    canvasPtr->scanYOrigin = 0;
+    canvasPtr->hotPtr = NULL;
+    canvasPtr->hotPrevPtr = NULL;
+    canvasPtr->cursor = None;
+    canvasPtr->takeFocus = NULL;
+    canvasPtr->pixelsPerMM = WidthOfScreen(Tk_Screen(new));
+    canvasPtr->pixelsPerMM /= WidthMMOfScreen(Tk_Screen(new));
+    canvasPtr->flags = 0;
+    canvasPtr->nextId = 1;
+    canvasPtr->psInfoPtr = NULL;
+
+    Tk_SetClass(canvasPtr->tkwin, "Canvas");
+    TkSetClassProcs(canvasPtr->tkwin, &canvasClass, (ClientData) canvasPtr);
+    Tk_CreateEventHandler(canvasPtr->tkwin,
+	    ExposureMask|StructureNotifyMask|FocusChangeMask,
+	    CanvasEventProc, (ClientData) canvasPtr);
+    Tk_CreateEventHandler(canvasPtr->tkwin, KeyPressMask|KeyReleaseMask
+	    |ButtonPressMask|ButtonReleaseMask|EnterWindowMask
+	    |LeaveWindowMask|PointerMotionMask|VirtualEventMask,
+	    CanvasBindProc, (ClientData) canvasPtr);
+    Tk_CreateSelHandler(canvasPtr->tkwin, XA_PRIMARY, XA_STRING,
+	    CanvasFetchSelection, (ClientData) canvasPtr, XA_STRING);
+    if (ConfigureCanvas(interp, canvasPtr, argc-2, argv+2, 0) != TCL_OK) {
+	goto error;
+    }
+
+    interp->result = Tk_PathName(canvasPtr->tkwin);
+    return TCL_OK;
+
+    error:
+    Tk_DestroyWindow(canvasPtr->tkwin);
+    return TCL_ERROR;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * CanvasWidgetCmd --
+ *
+ *	This procedure is invoked to process the Tcl command
+ *	that corresponds to a widget managed by this module.
+ *	See the user documentation for details on what it does.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	See the user documentation.
+ *
+ *--------------------------------------------------------------
+ */
+
+static int
+CanvasWidgetCmd(clientData, interp, argc, argv)
+    ClientData clientData;		/* Information about canvas
+					 * widget. */
+    Tcl_Interp *interp;			/* Current interpreter. */
+    int argc;				/* Number of arguments. */
+    char **argv;			/* Argument strings. */
+{
+    TkCanvas *canvasPtr = (TkCanvas *) clientData;
+    size_t length;
+    int c, result;
+    Tk_Item *itemPtr = NULL;		/* Initialization needed only to
+					 * prevent compiler warning. */
+    TagSearch search;
+
+    if (argc < 2) {
+	Tcl_AppendResult(interp, "wrong # args: should be \"",
+		argv[0], " option ?arg arg ...?\"", (char *) NULL);
+	return TCL_ERROR;
+    }
+    Tcl_Preserve((ClientData) canvasPtr);
+    result = TCL_OK;
+    c = argv[1][0];
+    length = strlen(argv[1]);
+    if ((c == 'a') && (strncmp(argv[1], "addtag", length) == 0)) {
+	if (argc < 4) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " addtags tag searchCommand ?arg arg ...?\"",
+		    (char *) NULL);
+	    goto error;
+	}
+	result = FindItems(interp, canvasPtr, argc-3, argv+3, argv[2], argv[0],
+		" addtag tag");
+    } else if ((c == 'b') && (strncmp(argv[1], "bbox", length) == 0)
+	    && (length >= 2)) {
+	int i, gotAny;
+	int x1 = 0, y1 = 0, x2 = 0, y2 = 0;	/* Initializations needed
+						 * only to prevent compiler
+						 * warnings. */
+
+	if (argc < 3) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " bbox tagOrId ?tagOrId ...?\"",
+		    (char *) NULL);
+	    goto error;
+	}
+	gotAny = 0;
+	for (i = 2; i < argc; i++) {
+	    for (itemPtr = StartTagSearch(canvasPtr, argv[i], &search);
+		    itemPtr != NULL; itemPtr = NextItem(&search)) {
+		if ((itemPtr->x1 >= itemPtr->x2)
+			|| (itemPtr->y1 >= itemPtr->y2)) {
+		    continue;
+		}
+		if (!gotAny) {
+		    x1 = itemPtr->x1;
+		    y1 = itemPtr->y1;
+		    x2 = itemPtr->x2;
+		    y2 = itemPtr->y2;
+		    gotAny = 1;
+		} else {
+		    if (itemPtr->x1 < x1) {
+			x1 = itemPtr->x1;
+		    }
+		    if (itemPtr->y1 < y1) {
+			y1 = itemPtr->y1;
+		    }
+		    if (itemPtr->x2 > x2) {
+			x2 = itemPtr->x2;
+		    }
+		    if (itemPtr->y2 > y2) {
+			y2 = itemPtr->y2;
+		    }
+		}
+	    }
+	}
+	if (gotAny) {
+	    sprintf(interp->result, "%d %d %d %d", x1, y1, x2, y2);
+	}
+    } else if ((c == 'b') && (strncmp(argv[1], "bind", length) == 0)
+	    && (length >= 2)) {
+	ClientData object;
+
+	if ((argc < 3) || (argc > 5)) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " bind tagOrId ?sequence? ?command?\"",
+		    (char *) NULL);
+	    goto error;
+	}
+
+	/*
+	 * Figure out what object to use for the binding (individual
+	 * item vs. tag).
+	 */
+
+	object = 0;
+	if (isdigit(UCHAR(argv[2][0]))) {
+	    int id;
+	    char *end;
+
+	    id = strtoul(argv[2], &end, 0);
+	    if (*end != 0) {
+		goto bindByTag;
+	    }
+	    for (itemPtr = canvasPtr->firstItemPtr; itemPtr != NULL;
+		    itemPtr = itemPtr->nextPtr) {
+		if (itemPtr->id == id) {
+		    object = (ClientData) itemPtr;
+		    break;
+		}
+	    }
+	    if (object == 0) {
+		Tcl_AppendResult(interp, "item \"", argv[2],
+			"\" doesn't exist", (char *) NULL);
+		goto error;
+	    }
+	} else {
+	    bindByTag:
+	    object = (ClientData) Tk_GetUid(argv[2]);
+	}
+
+	/*
+	 * Make a binding table if the canvas doesn't already have
+	 * one.
+	 */
+
+	if (canvasPtr->bindingTable == NULL) {
+	    canvasPtr->bindingTable = Tk_CreateBindingTable(interp);
+	}
+
+	if (argc == 5) {
+	    int append = 0;
+	    unsigned long mask;
+
+	    if (argv[4][0] == 0) {
+		result = Tk_DeleteBinding(interp, canvasPtr->bindingTable,
+			object, argv[3]);
+		goto done;
+	    }
+	    if (argv[4][0] == '+') {
+		argv[4]++;
+		append = 1;
+	    }
+	    mask = Tk_CreateBinding(interp, canvasPtr->bindingTable,
+		    object, argv[3], argv[4], append);
+	    if (mask == 0) {
+		goto error;
+	    }
+	    if (mask & (unsigned) ~(ButtonMotionMask|Button1MotionMask
+		    |Button2MotionMask|Button3MotionMask|Button4MotionMask
+		    |Button5MotionMask|ButtonPressMask|ButtonReleaseMask
+		    |EnterWindowMask|LeaveWindowMask|KeyPressMask
+		    |KeyReleaseMask|PointerMotionMask|VirtualEventMask)) {
+		Tk_DeleteBinding(interp, canvasPtr->bindingTable,
+			object, argv[3]);
+		Tcl_ResetResult(interp);
+		Tcl_AppendResult(interp, "requested illegal events; ",
+			"only key, button, motion, enter, leave, and virtual ",
+			"events may be used", (char *) NULL);
+		goto error;
+	    }
+	} else if (argc == 4) {
+	    char *command;
+    
+	    command = Tk_GetBinding(interp, canvasPtr->bindingTable,
+		    object, argv[3]);
+	    if (command == NULL) {
+		goto error;
+	    }
+	    interp->result = command;
+	} else {
+	    Tk_GetAllBindings(interp, canvasPtr->bindingTable, object);
+	}
+    } else if ((c == 'c') && (strcmp(argv[1], "canvasx") == 0)) {
+	int x;
+	double grid;
+
+	if ((argc < 3) || (argc > 4)) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " canvasx screenx ?gridspacing?\"",
+		    (char *) NULL);
+	    goto error;
+	}
+	if (Tk_GetPixels(interp, canvasPtr->tkwin, argv[2], &x) != TCL_OK) {
+	    goto error;
+	}
+	if (argc == 4) {
+	    if (Tk_CanvasGetCoord(interp, (Tk_Canvas) canvasPtr, argv[3],
+		    &grid) != TCL_OK) {
+		goto error;
+	    }
+	} else {
+	    grid = 0.0;
+	}
+	x += canvasPtr->xOrigin;
+	Tcl_PrintDouble(interp, GridAlign((double) x, grid), interp->result);
+    } else if ((c == 'c') && (strcmp(argv[1], "canvasy") == 0)) {
+	int y;
+	double grid;
+
+	if ((argc < 3) || (argc > 4)) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " canvasy screeny ?gridspacing?\"",
+		    (char *) NULL);
+	    goto error;
+	}
+	if (Tk_GetPixels(interp, canvasPtr->tkwin, argv[2], &y) != TCL_OK) {
+	    goto error;
+	}
+	if (argc == 4) {
+	    if (Tk_CanvasGetCoord(interp, (Tk_Canvas) canvasPtr,
+		    argv[3], &grid) != TCL_OK) {
+		goto error;
+	    }
+	} else {
+	    grid = 0.0;
+	}
+	y += canvasPtr->yOrigin;
+	Tcl_PrintDouble(interp, GridAlign((double) y, grid), interp->result);
+    } else if ((c == 'c') && (strncmp(argv[1], "cget", length) == 0)
+	    && (length >= 2)) {
+	if (argc != 3) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " cget option\"",
+		    (char *) NULL);
+	    goto error;
+	}
+	result = Tk_ConfigureValue(interp, canvasPtr->tkwin, configSpecs,
+		(char *) canvasPtr, argv[2], 0);
+    } else if ((c == 'c') && (strncmp(argv[1], "configure", length) == 0)
+	    && (length >= 3)) {
+	if (argc == 2) {
+	    result = Tk_ConfigureInfo(interp, canvasPtr->tkwin, configSpecs,
+		    (char *) canvasPtr, (char *) NULL, 0);
+	} else if (argc == 3) {
+	    result = Tk_ConfigureInfo(interp, canvasPtr->tkwin, configSpecs,
+		    (char *) canvasPtr, argv[2], 0);
+	} else {
+	    result = ConfigureCanvas(interp, canvasPtr, argc-2, argv+2,
+		    TK_CONFIG_ARGV_ONLY);
+	}
+    } else if ((c == 'c') && (strncmp(argv[1], "coords", length) == 0)
+	    && (length >= 3)) {
+	if (argc < 3) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " coords tagOrId ?x y x y ...?\"",
+		    (char *) NULL);
+	    goto error;
+	}
+	itemPtr = StartTagSearch(canvasPtr, argv[2], &search);
+	if (itemPtr != NULL) {
+	    if (argc != 3) {
+		Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+			itemPtr->x1, itemPtr->y1, itemPtr->x2, itemPtr->y2);
+	    }
+	    if (itemPtr->typePtr->coordProc != NULL) {
+		result = (*itemPtr->typePtr->coordProc)(interp,
+			(Tk_Canvas) canvasPtr, itemPtr, argc-3, argv+3);
+	    }
+	    if (argc != 3) {
+		Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+			itemPtr->x1, itemPtr->y1, itemPtr->x2, itemPtr->y2);
+	    }
+	}
+    } else if ((c == 'c') && (strncmp(argv[1], "create", length) == 0)
+	    && (length >= 2)) {
+	Tk_ItemType *typePtr;
+	Tk_ItemType *matchPtr = NULL;
+	Tk_Item *itemPtr;
+
+	if (argc < 3) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " create type ?arg arg ...?\"", (char *) NULL);
+	    goto error;
+	}
+	c = argv[2][0];
+	length = strlen(argv[2]);
+	for (typePtr = typeList; typePtr != NULL; typePtr = typePtr->nextPtr) {
+	    if ((c == typePtr->name[0])
+		    && (strncmp(argv[2], typePtr->name, length) == 0)) {
+		if (matchPtr != NULL) {
+		    badType:
+		    Tcl_AppendResult(interp,
+			    "unknown or ambiguous item type \"",
+			    argv[2], "\"", (char *) NULL);
+		    goto error;
+		}
+		matchPtr = typePtr;
+	    }
+	}
+	if (matchPtr == NULL) {
+	    goto badType;
+	}
+	typePtr = matchPtr;
+	itemPtr = (Tk_Item *) ckalloc((unsigned) typePtr->itemSize);
+	itemPtr->id = canvasPtr->nextId;
+	canvasPtr->nextId++;
+	itemPtr->tagPtr = itemPtr->staticTagSpace;
+	itemPtr->tagSpace = TK_TAG_SPACE;
+	itemPtr->numTags = 0;
+	itemPtr->typePtr = typePtr;
+	if ((*typePtr->createProc)(interp, (Tk_Canvas) canvasPtr,
+		itemPtr, argc-3, argv+3) != TCL_OK) {
+	    ckfree((char *) itemPtr);
+	    goto error;
+	}
+	itemPtr->nextPtr = NULL;
+	canvasPtr->hotPtr = itemPtr;
+	canvasPtr->hotPrevPtr = canvasPtr->lastItemPtr;
+	if (canvasPtr->lastItemPtr == NULL) {
+	    canvasPtr->firstItemPtr = itemPtr;
+	} else {
+	    canvasPtr->lastItemPtr->nextPtr = itemPtr;
+	}
+	canvasPtr->lastItemPtr = itemPtr;
+	Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+		itemPtr->x1, itemPtr->y1, itemPtr->x2, itemPtr->y2);
+	canvasPtr->flags |= REPICK_NEEDED;
+	sprintf(interp->result, "%d", itemPtr->id);
+    } else if ((c == 'd') && (strncmp(argv[1], "dchars", length) == 0)
+	    && (length >= 2)) {
+	int first, last;
+
+	if ((argc != 4) && (argc != 5)) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " dchars tagOrId first ?last?\"",
+		    (char *) NULL);
+	    goto error;
+	}
+	for (itemPtr = StartTagSearch(canvasPtr, argv[2], &search);
+		itemPtr != NULL; itemPtr = NextItem(&search)) {
+	    if ((itemPtr->typePtr->indexProc == NULL)
+		    || (itemPtr->typePtr->dCharsProc == NULL)) {
+		continue;
+	    }
+	    if ((*itemPtr->typePtr->indexProc)(interp, (Tk_Canvas) canvasPtr,
+		    itemPtr, argv[3], &first) != TCL_OK) {
+		goto error;
+	    }
+	    if (argc == 5) {
+		if ((*itemPtr->typePtr->indexProc)(interp,
+			(Tk_Canvas) canvasPtr, itemPtr, argv[4], &last)
+			!= TCL_OK) {
+		    goto error;
+		}
+	    } else {
+		last = first;
+	    }
+
+	    /*
+	     * Redraw both item's old and new areas:  it's possible
+	     * that a delete could result in a new area larger than
+	     * the old area.
+	     */
+
+	    Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+		    itemPtr->x1, itemPtr->y1, itemPtr->x2, itemPtr->y2);
+	    (*itemPtr->typePtr->dCharsProc)((Tk_Canvas) canvasPtr,
+		    itemPtr, first, last);
+	    Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+		    itemPtr->x1, itemPtr->y1, itemPtr->x2, itemPtr->y2);
+	}
+    } else if ((c == 'd') && (strncmp(argv[1], "delete", length) == 0)
+	    && (length >= 2)) {
+	int i;
+
+	for (i = 2; i < argc; i++) {
+	    for (itemPtr = StartTagSearch(canvasPtr, argv[i], &search);
+		itemPtr != NULL; itemPtr = NextItem(&search)) {
+		Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+			itemPtr->x1, itemPtr->y1, itemPtr->x2, itemPtr->y2);
+		if (canvasPtr->bindingTable != NULL) {
+		    Tk_DeleteAllBindings(canvasPtr->bindingTable,
+			    (ClientData) itemPtr);
+		}
+		(*itemPtr->typePtr->deleteProc)((Tk_Canvas) canvasPtr, itemPtr,
+			canvasPtr->display);
+		if (itemPtr->tagPtr != itemPtr->staticTagSpace) {
+		    ckfree((char *) itemPtr->tagPtr);
+		}
+		if (search.prevPtr == NULL) {
+		    canvasPtr->firstItemPtr = itemPtr->nextPtr;
+		    if (canvasPtr->firstItemPtr == NULL) {
+			canvasPtr->lastItemPtr = NULL;
+		    }
+		} else {
+		    search.prevPtr->nextPtr = itemPtr->nextPtr;
+		}
+		if (canvasPtr->lastItemPtr == itemPtr) {
+		    canvasPtr->lastItemPtr = search.prevPtr;
+		}
+		ckfree((char *) itemPtr);
+		if (itemPtr == canvasPtr->currentItemPtr) {
+		    canvasPtr->currentItemPtr = NULL;
+		    canvasPtr->flags |= REPICK_NEEDED;
+		}
+		if (itemPtr == canvasPtr->newCurrentPtr) {
+		    canvasPtr->newCurrentPtr = NULL;
+		    canvasPtr->flags |= REPICK_NEEDED;
+		}
+		if (itemPtr == canvasPtr->textInfo.focusItemPtr) {
+		    canvasPtr->textInfo.focusItemPtr = NULL;
+		}
+		if (itemPtr == canvasPtr->textInfo.selItemPtr) {
+		    canvasPtr->textInfo.selItemPtr = NULL;
+		}
+		if ((itemPtr == canvasPtr->hotPtr)
+			|| (itemPtr == canvasPtr->hotPrevPtr)) {
+		    canvasPtr->hotPtr = NULL;
+		}
+	    }
+	}
+    } else if ((c == 'd') && (strncmp(argv[1], "dtag", length) == 0)
+	    && (length >= 2)) {
+	Tk_Uid tag;
+	int i;
+
+	if ((argc != 3) && (argc != 4)) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " dtag tagOrId ?tagToDelete?\"",
+		    (char *) NULL);
+	    goto error;
+	}
+	if (argc == 4) {
+	    tag = Tk_GetUid(argv[3]);
+	} else {
+	    tag = Tk_GetUid(argv[2]);
+	}
+	for (itemPtr = StartTagSearch(canvasPtr, argv[2], &search);
+		itemPtr != NULL; itemPtr = NextItem(&search)) {
+	    for (i = itemPtr->numTags-1; i >= 0; i--) {
+		if (itemPtr->tagPtr[i] == tag) {
+		    itemPtr->tagPtr[i] = itemPtr->tagPtr[itemPtr->numTags-1];
+		    itemPtr->numTags--;
+		}
+	    }
+	}
+    } else if ((c == 'f') && (strncmp(argv[1], "find", length) == 0)
+	    && (length >= 2)) {
+	if (argc < 3) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " find searchCommand ?arg arg ...?\"",
+		    (char *) NULL);
+	    goto error;
+	}
+	result = FindItems(interp, canvasPtr, argc-2, argv+2, (char *) NULL,
+		argv[0]," find");
+    } else if ((c == 'f') && (strncmp(argv[1], "focus", length) == 0)
+	    && (length >= 2)) {
+	if (argc > 3) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " focus ?tagOrId?\"",
+		    (char *) NULL);
+	    goto error;
+	}
+	itemPtr = canvasPtr->textInfo.focusItemPtr;
+	if (argc == 2) {
+	    if (itemPtr != NULL) {
+		sprintf(interp->result, "%d", itemPtr->id);
+	    }
+	    goto done;
+	}
+	if ((itemPtr != NULL) && (canvasPtr->textInfo.gotFocus)) {
+	    Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+		    itemPtr->x1, itemPtr->y1, itemPtr->x2, itemPtr->y2);
+	}
+	if (argv[2][0] == 0) {
+	    canvasPtr->textInfo.focusItemPtr = NULL;
+	    goto done;
+	}
+	for (itemPtr = StartTagSearch(canvasPtr, argv[2], &search);
+		itemPtr != NULL; itemPtr = NextItem(&search)) {
+	    if (itemPtr->typePtr->icursorProc != NULL) {
+		break;
+	    }
+	}
+	if (itemPtr == NULL) {
+	    goto done;
+	}
+	canvasPtr->textInfo.focusItemPtr = itemPtr;
+	if (canvasPtr->textInfo.gotFocus) {
+	    Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+		    itemPtr->x1, itemPtr->y1, itemPtr->x2, itemPtr->y2);
+	}
+    } else if ((c == 'g') && (strncmp(argv[1], "gettags", length) == 0)) {
+	if (argc != 3) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " gettags tagOrId\"", (char *) NULL);
+	    goto error;
+	}
+	itemPtr = StartTagSearch(canvasPtr, argv[2], &search);
+	if (itemPtr != NULL) {
+	    int i;
+	    for (i = 0; i < itemPtr->numTags; i++) {
+		Tcl_AppendElement(interp, (char *) itemPtr->tagPtr[i]);
+	    }
+	}
+    } else if ((c == 'i') && (strncmp(argv[1], "icursor", length) == 0)
+	    && (length >= 2)) {
+	int index;
+
+	if (argc != 4) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " icursor tagOrId index\"",
+		    (char *) NULL);
+	    goto error;
+	}
+	for (itemPtr = StartTagSearch(canvasPtr, argv[2], &search);
+		itemPtr != NULL; itemPtr = NextItem(&search)) {
+	    if ((itemPtr->typePtr->indexProc == NULL)
+		    || (itemPtr->typePtr->icursorProc == NULL)) {
+		goto done;
+	    }
+	    if ((*itemPtr->typePtr->indexProc)(interp, (Tk_Canvas) canvasPtr,
+		    itemPtr, argv[3], &index) != TCL_OK) {
+		goto error;
+	    }
+	    (*itemPtr->typePtr->icursorProc)((Tk_Canvas) canvasPtr, itemPtr,
+		    index);
+	    if ((itemPtr == canvasPtr->textInfo.focusItemPtr)
+		    && (canvasPtr->textInfo.cursorOn)) {
+		Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+			itemPtr->x1, itemPtr->y1, itemPtr->x2, itemPtr->y2);
+	    }
+	}
+    } else if ((c == 'i') && (strncmp(argv[1], "index", length) == 0)
+	    && (length >= 3)) {
+	int index;
+
+	if (argc != 4) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " index tagOrId string\"",
+		    (char *) NULL);
+	    goto error;
+	}
+	for (itemPtr = StartTagSearch(canvasPtr, argv[2], &search);
+		itemPtr != NULL; itemPtr = NextItem(&search)) {
+	    if (itemPtr->typePtr->indexProc != NULL) {
+		break;
+	    }
+	}
+	if (itemPtr == NULL) {
+	    Tcl_AppendResult(interp, "can't find an indexable item \"",
+		    argv[2], "\"", (char *) NULL);
+	    goto error;
+	}
+	if ((*itemPtr->typePtr->indexProc)(interp, (Tk_Canvas) canvasPtr,
+		itemPtr, argv[3], &index) != TCL_OK) {
+	    goto error;
+	}
+	sprintf(interp->result, "%d", index);
+    } else if ((c == 'i') && (strncmp(argv[1], "insert", length) == 0)
+	    && (length >= 3)) {
+	int beforeThis;
+
+	if (argc != 5) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " insert tagOrId beforeThis string\"",
+		    (char *) NULL);
+	    goto error;
+	}
+	for (itemPtr = StartTagSearch(canvasPtr, argv[2], &search);
+		itemPtr != NULL; itemPtr = NextItem(&search)) {
+	    if ((itemPtr->typePtr->indexProc == NULL)
+		    || (itemPtr->typePtr->insertProc == NULL)) {
+		continue;
+	    }
+	    if ((*itemPtr->typePtr->indexProc)(interp, (Tk_Canvas) canvasPtr,
+		    itemPtr, argv[3], &beforeThis) != TCL_OK) {
+		goto error;
+	    }
+
+	    /*
+	     * Redraw both item's old and new areas:  it's possible
+	     * that an insertion could result in a new area either
+	     * larger or smaller than the old area.
+	     */
+
+	    Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+		    itemPtr->x1, itemPtr->y1, itemPtr->x2, itemPtr->y2);
+	    (*itemPtr->typePtr->insertProc)((Tk_Canvas) canvasPtr,
+		    itemPtr, beforeThis, argv[4]);
+	    Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr, itemPtr->x1,
+		    itemPtr->y1, itemPtr->x2, itemPtr->y2);
+	}
+    } else if ((c == 'i') && (strncmp(argv[1], "itemcget", length) == 0)
+	    && (length >= 6)) {
+	if (argc != 4) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " itemcget tagOrId option\"",
+		    (char *) NULL);
+	    return TCL_ERROR;
+	}
+	itemPtr = StartTagSearch(canvasPtr, argv[2], &search);
+	if (itemPtr != NULL) {
+	    result = Tk_ConfigureValue(canvasPtr->interp, canvasPtr->tkwin,
+		    itemPtr->typePtr->configSpecs, (char *) itemPtr,
+		    argv[3], 0);
+	}
+    } else if ((c == 'i') && (strncmp(argv[1], "itemconfigure", length) == 0)
+	    && (length >= 6)) {
+	if (argc < 3) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " itemconfigure tagOrId ?option value ...?\"",
+		    (char *) NULL);
+	    goto error;
+	}
+	for (itemPtr = StartTagSearch(canvasPtr, argv[2], &search);
+		itemPtr != NULL; itemPtr = NextItem(&search)) {
+	    if (argc == 3) {
+		result = Tk_ConfigureInfo(canvasPtr->interp, canvasPtr->tkwin,
+			itemPtr->typePtr->configSpecs, (char *) itemPtr,
+			(char *) NULL, 0);
+	    } else if (argc == 4) {
+		result = Tk_ConfigureInfo(canvasPtr->interp, canvasPtr->tkwin,
+			itemPtr->typePtr->configSpecs, (char *) itemPtr,
+			argv[3], 0);
+	    } else {
+		Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+			itemPtr->x1, itemPtr->y1, itemPtr->x2, itemPtr->y2);
+		result = (*itemPtr->typePtr->configProc)(interp,
+			(Tk_Canvas) canvasPtr, itemPtr, argc-3, argv+3,
+			TK_CONFIG_ARGV_ONLY);
+		Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+			itemPtr->x1, itemPtr->y1, itemPtr->x2, itemPtr->y2);
+		canvasPtr->flags |= REPICK_NEEDED;
+	    }
+	    if ((result != TCL_OK) || (argc < 5)) {
+		break;
+	    }
+	}
+    } else if ((c == 'l') && (strncmp(argv[1], "lower", length) == 0)) {
+	Tk_Item *prevPtr;
+
+	if ((argc != 3) && (argc != 4)) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " lower tagOrId ?belowThis?\"",
+		    (char *) NULL);
+	    goto error;
+	}
+
+	/*
+	 * First find the item just after which we'll insert the
+	 * named items.
+	 */
+
+	if (argc == 3) {
+	    prevPtr = NULL;
+	} else {
+	    prevPtr = StartTagSearch(canvasPtr, argv[3], &search);
+	    if (prevPtr != NULL) {
+		prevPtr = search.prevPtr;
+	    } else {
+		Tcl_AppendResult(interp, "tag \"", argv[3],
+			"\" doesn't match any items", (char *) NULL);
+		goto error;
+	    }
+	}
+	RelinkItems(canvasPtr, argv[2], prevPtr);
+    } else if ((c == 'm') && (strncmp(argv[1], "move", length) == 0)) {
+	double xAmount, yAmount;
+
+	if (argc != 5) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " move tagOrId xAmount yAmount\"",
+		    (char *) NULL);
+	    goto error;
+	}
+	if ((Tk_CanvasGetCoord(interp, (Tk_Canvas) canvasPtr, argv[3],
+		&xAmount) != TCL_OK) || (Tk_CanvasGetCoord(interp,
+		(Tk_Canvas) canvasPtr, argv[4], &yAmount) != TCL_OK)) {
+	    goto error;
+	}
+	for (itemPtr = StartTagSearch(canvasPtr, argv[2], &search);
+		itemPtr != NULL; itemPtr = NextItem(&search)) {
+	    Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+		    itemPtr->x1, itemPtr->y1, itemPtr->x2, itemPtr->y2);
+	    (void) (*itemPtr->typePtr->translateProc)((Tk_Canvas) canvasPtr,
+		    itemPtr,  xAmount, yAmount);
+	    Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+		    itemPtr->x1, itemPtr->y1, itemPtr->x2, itemPtr->y2);
+	    canvasPtr->flags |= REPICK_NEEDED;
+	}
+    } else if ((c == 'p') && (strncmp(argv[1], "postscript", length) == 0)) {
+	result = TkCanvPostscriptCmd(canvasPtr, interp, argc, argv);
+    } else if ((c == 'r') && (strncmp(argv[1], "raise", length) == 0)) {
+	Tk_Item *prevPtr;
+
+	if ((argc != 3) && (argc != 4)) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " raise tagOrId ?aboveThis?\"",
+		    (char *) NULL);
+	    goto error;
+	}
+
+	/*
+	 * First find the item just after which we'll insert the
+	 * named items.
+	 */
+
+	if (argc == 3) {
+	    prevPtr = canvasPtr->lastItemPtr;
+	} else {
+	    prevPtr = NULL;
+	    for (itemPtr = StartTagSearch(canvasPtr, argv[3], &search);
+		    itemPtr != NULL; itemPtr = NextItem(&search)) {
+		prevPtr = itemPtr;
+	    }
+	    if (prevPtr == NULL) {
+		Tcl_AppendResult(interp, "tagOrId \"", argv[3],
+			"\" doesn't match any items", (char *) NULL);
+		goto error;
+	    }
+	}
+	RelinkItems(canvasPtr, argv[2], prevPtr);
+    } else if ((c == 's') && (strncmp(argv[1], "scale", length) == 0)
+	    && (length >= 3)) {
+	double xOrigin, yOrigin, xScale, yScale;
+
+	if (argc != 7) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " scale tagOrId xOrigin yOrigin xScale yScale\"",
+		    (char *) NULL);
+	    goto error;
+	}
+	if ((Tk_CanvasGetCoord(interp, (Tk_Canvas) canvasPtr,
+		    argv[3], &xOrigin) != TCL_OK)
+		|| (Tk_CanvasGetCoord(interp, (Tk_Canvas) canvasPtr,
+		    argv[4], &yOrigin) != TCL_OK)
+		|| (Tcl_GetDouble(interp, argv[5], &xScale) != TCL_OK)
+		|| (Tcl_GetDouble(interp, argv[6], &yScale) != TCL_OK)) {
+	    goto error;
+	}
+	if ((xScale == 0.0) || (yScale == 0.0)) {
+	    interp->result = "scale factor cannot be zero";
+	    goto error;
+	}
+	for (itemPtr = StartTagSearch(canvasPtr, argv[2], &search);
+		itemPtr != NULL; itemPtr = NextItem(&search)) {
+	    Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+		    itemPtr->x1, itemPtr->y1, itemPtr->x2, itemPtr->y2);
+	    (void) (*itemPtr->typePtr->scaleProc)((Tk_Canvas) canvasPtr,
+		    itemPtr, xOrigin, yOrigin, xScale, yScale);
+	    Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+		    itemPtr->x1, itemPtr->y1, itemPtr->x2, itemPtr->y2);
+	    canvasPtr->flags |= REPICK_NEEDED;
+	}
+    } else if ((c == 's') && (strncmp(argv[1], "scan", length) == 0)
+	    && (length >= 3)) {
+	int x, y;
+
+	if (argc != 5) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " scan mark|dragto x y\"", (char *) NULL);
+	    goto error;
+	}
+	if ((Tcl_GetInt(interp, argv[3], &x) != TCL_OK)
+		|| (Tcl_GetInt(interp, argv[4], &y) != TCL_OK)){
+	    goto error;
+	}
+	if ((argv[2][0] == 'm')
+		&& (strncmp(argv[2], "mark", strlen(argv[2])) == 0)) {
+	    canvasPtr->scanX = x;
+	    canvasPtr->scanXOrigin = canvasPtr->xOrigin;
+	    canvasPtr->scanY = y;
+	    canvasPtr->scanYOrigin = canvasPtr->yOrigin;
+	} else if ((argv[2][0] == 'd')
+		&& (strncmp(argv[2], "dragto", strlen(argv[2])) == 0)) {
+	    int newXOrigin, newYOrigin, tmp;
+
+	    /*
+	     * Compute a new view origin for the canvas, amplifying the
+	     * mouse motion.
+	     */
+
+	    tmp = canvasPtr->scanXOrigin - 10*(x - canvasPtr->scanX)
+		    - canvasPtr->scrollX1;
+	    newXOrigin = canvasPtr->scrollX1 + tmp;
+	    tmp = canvasPtr->scanYOrigin - 10*(y - canvasPtr->scanY)
+		    - canvasPtr->scrollY1;
+	    newYOrigin = canvasPtr->scrollY1 + tmp;
+	    CanvasSetOrigin(canvasPtr, newXOrigin, newYOrigin);
+	} else {
+	    Tcl_AppendResult(interp, "bad scan option \"", argv[2],
+		    "\": must be mark or dragto", (char *) NULL);
+	    goto error;
+	}
+    } else if ((c == 's') && (strncmp(argv[1], "select", length) == 0)
+	    && (length >= 2)) {
+	int index;
+
+	if (argc < 3) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " select option ?tagOrId? ?arg?\"", (char *) NULL);
+	    goto error;
+	}
+	if (argc >= 4) {
+	    for (itemPtr = StartTagSearch(canvasPtr, argv[3], &search);
+		    itemPtr != NULL; itemPtr = NextItem(&search)) {
+		if ((itemPtr->typePtr->indexProc != NULL)
+			&& (itemPtr->typePtr->selectionProc != NULL)){
+		    break;
+		}
+	    }
+	    if (itemPtr == NULL) {
+		Tcl_AppendResult(interp,
+			"can't find an indexable and selectable item \"",
+			argv[3], "\"", (char *) NULL);
+		goto error;
+	    }
+	}
+	if (argc == 5) {
+	    if ((*itemPtr->typePtr->indexProc)(interp, (Tk_Canvas) canvasPtr,
+		    itemPtr, argv[4], &index) != TCL_OK) {
+		goto error;
+	    }
+	}
+	length = strlen(argv[2]);
+	c = argv[2][0];
+	if ((c == 'a') && (strncmp(argv[2], "adjust", length) == 0)) {
+	    if (argc != 5) {
+		Tcl_AppendResult(interp, "wrong # args: should be \"",
+			argv[0], " select adjust tagOrId index\"",
+			(char *) NULL);
+		goto error;
+	    }
+	    if (canvasPtr->textInfo.selItemPtr == itemPtr) {
+		if (index < (canvasPtr->textInfo.selectFirst
+			+ canvasPtr->textInfo.selectLast)/2) {
+		    canvasPtr->textInfo.selectAnchor =
+			    canvasPtr->textInfo.selectLast + 1;
+		} else {
+		    canvasPtr->textInfo.selectAnchor =
+			    canvasPtr->textInfo.selectFirst;
+		}
+	    }
+	    CanvasSelectTo(canvasPtr, itemPtr, index);
+	} else if ((c == 'c') && (argv[2] != NULL)
+		&& (strncmp(argv[2], "clear", length) == 0)) {
+	    if (argc != 3) {
+		Tcl_AppendResult(interp, "wrong # args: should be \"",
+			argv[0], " select clear\"", (char *) NULL);
+		goto error;
+	    }
+	    if (canvasPtr->textInfo.selItemPtr != NULL) {
+		Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+			canvasPtr->textInfo.selItemPtr->x1,
+			canvasPtr->textInfo.selItemPtr->y1,
+			canvasPtr->textInfo.selItemPtr->x2,
+			canvasPtr->textInfo.selItemPtr->y2);
+		canvasPtr->textInfo.selItemPtr = NULL;
+	    }
+	    goto done;
+	} else if ((c == 'f') && (strncmp(argv[2], "from", length) == 0)) {
+	    if (argc != 5) {
+		Tcl_AppendResult(interp, "wrong # args: should be \"",
+			argv[0], " select from tagOrId index\"",
+			(char *) NULL);
+		goto error;
+	    }
+	    canvasPtr->textInfo.anchorItemPtr = itemPtr;
+	    canvasPtr->textInfo.selectAnchor = index;
+	} else if ((c == 'i') && (strncmp(argv[2], "item", length) == 0)) {
+	    if (argc != 3) {
+		Tcl_AppendResult(interp, "wrong # args: should be \"",
+			argv[0], " select item\"", (char *) NULL);
+		goto error;
+	    }
+	    if (canvasPtr->textInfo.selItemPtr != NULL) {
+		sprintf(interp->result, "%d",
+			canvasPtr->textInfo.selItemPtr->id);
+	    }
+	} else if ((c == 't') && (strncmp(argv[2], "to", length) == 0)) {
+	    if (argc != 5) {
+		Tcl_AppendResult(interp, "wrong # args: should be \"",
+			argv[0], " select to tagOrId index\"",
+			(char *) NULL);
+		goto error;
+	    }
+	    CanvasSelectTo(canvasPtr, itemPtr, index);
+	} else {
+	    Tcl_AppendResult(interp, "bad select option \"", argv[2],
+		    "\": must be adjust, clear, from, item, or to",
+		    (char *) NULL);
+	    goto error;
+	}
+    } else if ((c == 't') && (strncmp(argv[1], "type", length) == 0)) {
+	if (argc != 3) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " type tag\"", (char *) NULL);
+	    goto error;
+	}
+	itemPtr = StartTagSearch(canvasPtr, argv[2], &search);
+	if (itemPtr != NULL) {
+	    interp->result = itemPtr->typePtr->name;
+	}
+    } else if ((c == 'x') && (strncmp(argv[1], "xview", length) == 0)) {
+	int count, type;
+	int newX = 0;		/* Initialization needed only to prevent
+				 * gcc warnings. */
+	double fraction;
+
+	if (argc == 2) {
+	    PrintScrollFractions(canvasPtr->xOrigin + canvasPtr->inset,
+		    canvasPtr->xOrigin + Tk_Width(canvasPtr->tkwin)
+		    - canvasPtr->inset, canvasPtr->scrollX1,
+		    canvasPtr->scrollX2, interp->result);
+	} else {
+	    type = Tk_GetScrollInfo(interp, argc, argv, &fraction, &count);
+	    switch (type) {
+		case TK_SCROLL_ERROR:
+		    goto error;
+		case TK_SCROLL_MOVETO:
+		    newX = canvasPtr->scrollX1 - canvasPtr->inset
+			    + (int) (fraction * (canvasPtr->scrollX2
+			    - canvasPtr->scrollX1) + 0.5);
+		    break;
+		case TK_SCROLL_PAGES:
+		    newX = (int) (canvasPtr->xOrigin + count * .9
+			    * (Tk_Width(canvasPtr->tkwin) - 2*canvasPtr->inset));
+		    break;
+		case TK_SCROLL_UNITS:
+		    if (canvasPtr->xScrollIncrement > 0) {
+			newX = canvasPtr->xOrigin
+				+ count*canvasPtr->xScrollIncrement;
+		    } else {
+			newX = (int) (canvasPtr->xOrigin + count * .1
+				* (Tk_Width(canvasPtr->tkwin)
+				- 2*canvasPtr->inset));
+		    }
+		    break;
+	    }
+	    CanvasSetOrigin(canvasPtr, newX, canvasPtr->yOrigin);
+	}
+    } else if ((c == 'y') && (strncmp(argv[1], "yview", length) == 0)) {
+	int count, type;
+	int newY = 0;		/* Initialization needed only to prevent
+				 * gcc warnings. */
+	double fraction;
+
+	if (argc == 2) {
+	    PrintScrollFractions(canvasPtr->yOrigin + canvasPtr->inset,
+		    canvasPtr->yOrigin + Tk_Height(canvasPtr->tkwin)
+		    - canvasPtr->inset, canvasPtr->scrollY1,
+		    canvasPtr->scrollY2, interp->result);
+	} else {
+	    type = Tk_GetScrollInfo(interp, argc, argv, &fraction, &count);
+	    switch (type) {
+		case TK_SCROLL_ERROR:
+		    goto error;
+		case TK_SCROLL_MOVETO:
+		    newY = canvasPtr->scrollY1 - canvasPtr->inset
+			    + (int) (fraction*(canvasPtr->scrollY2
+			    - canvasPtr->scrollY1) + 0.5);
+		    break;
+		case TK_SCROLL_PAGES:
+		    newY = (int) (canvasPtr->yOrigin + count * .9
+			    * (Tk_Height(canvasPtr->tkwin)
+			    - 2*canvasPtr->inset));
+		    break;
+		case TK_SCROLL_UNITS:
+		    if (canvasPtr->yScrollIncrement > 0) {
+			newY = canvasPtr->yOrigin
+				+ count*canvasPtr->yScrollIncrement;
+		    } else {
+			newY = (int) (canvasPtr->yOrigin + count * .1
+				* (Tk_Height(canvasPtr->tkwin)
+				- 2*canvasPtr->inset));
+		    }
+		    break;
+	    }
+	    CanvasSetOrigin(canvasPtr, canvasPtr->xOrigin, newY);
+	}
+    } else {
+	Tcl_AppendResult(interp, "bad option \"", argv[1],
+		"\": must be addtag, bbox, bind, ",
+		"canvasx, canvasy, cget, configure, coords, create, ",
+		"dchars, delete, dtag, find, focus, ",
+		"gettags, icursor, index, insert, itemcget, itemconfigure, ",
+		"lower, move, postscript, raise, scale, scan, ",
+		"select, type, xview, or yview",
+		(char *) NULL);  
+	goto error;
+    }
+    done:
+    Tcl_Release((ClientData) canvasPtr);
+    return result;
+
+    error:
+    Tcl_Release((ClientData) canvasPtr);
+    return TCL_ERROR;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * DestroyCanvas --
+ *
+ *	This procedure is invoked by Tcl_EventuallyFree or Tcl_Release
+ *	to clean up the internal structure of a canvas at a safe time
+ *	(when no-one is using it anymore).
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Everything associated with the canvas is freed up.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+DestroyCanvas(memPtr)
+    char *memPtr;		/* Info about canvas widget. */
+{
+    TkCanvas *canvasPtr = (TkCanvas *) memPtr;
+    Tk_Item *itemPtr;
+
+    /*
+     * Free up all of the items in the canvas.
+     */
+
+    for (itemPtr = canvasPtr->firstItemPtr; itemPtr != NULL;
+	    itemPtr = canvasPtr->firstItemPtr) {
+	canvasPtr->firstItemPtr = itemPtr->nextPtr;
+	(*itemPtr->typePtr->deleteProc)((Tk_Canvas) canvasPtr, itemPtr,
+		canvasPtr->display);
+	if (itemPtr->tagPtr != itemPtr->staticTagSpace) {
+	    ckfree((char *) itemPtr->tagPtr);
+	}
+	ckfree((char *) itemPtr);
+    }
+
+    /*
+     * Free up all the stuff that requires special handling,
+     * then let Tk_FreeOptions handle all the standard option-related
+     * stuff.
+     */
+
+    if (canvasPtr->pixmapGC != None) {
+	Tk_FreeGC(canvasPtr->display, canvasPtr->pixmapGC);
+    }
+    Tcl_DeleteTimerHandler(canvasPtr->insertBlinkHandler);
+    if (canvasPtr->bindingTable != NULL) {
+	Tk_DeleteBindingTable(canvasPtr->bindingTable);
+    }
+    Tk_FreeOptions(configSpecs, (char *) canvasPtr, canvasPtr->display, 0);
+    ckfree((char *) canvasPtr);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * ConfigureCanvas --
+ *
+ *	This procedure is called to process an argv/argc list, plus
+ *	the Tk option database, in order to configure (or
+ *	reconfigure) a canvas widget.
+ *
+ * Results:
+ *	The return value is a standard Tcl result.  If TCL_ERROR is
+ *	returned, then interp->result contains an error message.
+ *
+ * Side effects:
+ *	Configuration information, such as colors, border width,
+ *	etc. get set for canvasPtr;  old resources get freed,
+ *	if there were any.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+ConfigureCanvas(interp, canvasPtr, argc, argv, flags)
+    Tcl_Interp *interp;		/* Used for error reporting. */
+    TkCanvas *canvasPtr;	/* Information about widget;  may or may
+				 * not already have values for some fields. */
+    int argc;			/* Number of valid entries in argv. */
+    char **argv;		/* Arguments. */
+    int flags;			/* Flags to pass to Tk_ConfigureWidget. */
+{
+    XGCValues gcValues;
+    GC new;
+
+    if (Tk_ConfigureWidget(interp, canvasPtr->tkwin, configSpecs,
+	    argc, argv, (char *) canvasPtr, flags) != TCL_OK) {
+	return TCL_ERROR;
+    }
+
+    /*
+     * A few options need special processing, such as setting the
+     * background from a 3-D border and creating a GC for copying
+     * bits to the screen.
+     */
+
+    Tk_SetBackgroundFromBorder(canvasPtr->tkwin, canvasPtr->bgBorder);
+
+    if (canvasPtr->highlightWidth < 0) {
+	canvasPtr->highlightWidth = 0;
+    }
+    canvasPtr->inset = canvasPtr->borderWidth + canvasPtr->highlightWidth;
+
+    gcValues.function = GXcopy;
+    gcValues.foreground = Tk_3DBorderColor(canvasPtr->bgBorder)->pixel;
+    gcValues.graphics_exposures = False;
+    new = Tk_GetGC(canvasPtr->tkwin,
+	    GCFunction|GCForeground|GCGraphicsExposures, &gcValues);
+    if (canvasPtr->pixmapGC != None) {
+	Tk_FreeGC(canvasPtr->display, canvasPtr->pixmapGC);
+    }
+    canvasPtr->pixmapGC = new;
+
+    /*
+     * Reset the desired dimensions for the window.
+     */
+
+    Tk_GeometryRequest(canvasPtr->tkwin, canvasPtr->width + 2*canvasPtr->inset,
+	    canvasPtr->height + 2*canvasPtr->inset);
+
+    /*
+     * Restart the cursor timing sequence in case the on-time or off-time
+     * just changed.
+     */
+
+    if (canvasPtr->textInfo.gotFocus) {
+	CanvasFocusProc(canvasPtr, 1);
+    }
+
+    /*
+     * Recompute the scroll region.
+     */
+
+    canvasPtr->scrollX1 = 0;
+    canvasPtr->scrollY1 = 0;
+    canvasPtr->scrollX2 = 0;
+    canvasPtr->scrollY2 = 0;
+    if (canvasPtr->regionString != NULL) {
+	int argc2;
+	char **argv2;
+
+	if (Tcl_SplitList(canvasPtr->interp, canvasPtr->regionString,
+		&argc2, &argv2) != TCL_OK) {
+	    return TCL_ERROR;
+	}
+	if (argc2 != 4) {
+	    Tcl_AppendResult(interp, "bad scrollRegion \"",
+		    canvasPtr->regionString, "\"", (char *) NULL);
+	    badRegion:
+	    ckfree(canvasPtr->regionString);
+	    ckfree((char *) argv2);
+	    canvasPtr->regionString = NULL;
+	    return TCL_ERROR;
+	}
+	if ((Tk_GetPixels(canvasPtr->interp, canvasPtr->tkwin,
+		    argv2[0], &canvasPtr->scrollX1) != TCL_OK)
+		|| (Tk_GetPixels(canvasPtr->interp, canvasPtr->tkwin,
+		    argv2[1], &canvasPtr->scrollY1) != TCL_OK)
+		|| (Tk_GetPixels(canvasPtr->interp, canvasPtr->tkwin,
+		    argv2[2], &canvasPtr->scrollX2) != TCL_OK)
+		|| (Tk_GetPixels(canvasPtr->interp, canvasPtr->tkwin,
+		    argv2[3], &canvasPtr->scrollY2) != TCL_OK)) {
+	    goto badRegion;
+	}
+	ckfree((char *) argv2);
+    }
+
+    /*
+     * Reset the canvas's origin (this is a no-op unless confine
+     * mode has just been turned on or the scroll region has changed).
+     */
+
+    CanvasSetOrigin(canvasPtr, canvasPtr->xOrigin, canvasPtr->yOrigin);
+    canvasPtr->flags |= UPDATE_SCROLLBARS|REDRAW_BORDERS;
+    Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+	    canvasPtr->xOrigin, canvasPtr->yOrigin,
+	    canvasPtr->xOrigin + Tk_Width(canvasPtr->tkwin),
+	    canvasPtr->yOrigin + Tk_Height(canvasPtr->tkwin));
+    return TCL_OK;
+}
+
+/*
+ *---------------------------------------------------------------------------
+ *
+ * CanvasWorldChanged --
+ *
+ *      This procedure is called when the world has changed in some
+ *      way and the widget needs to recompute all its graphics contexts
+ *	and determine its new geometry.
+ *
+ * Results:
+ *      None.
+ *
+ * Side effects:
+ *	Configures all items in the canvas with a empty argc/argv, for
+ *	the side effect of causing all the items to recompute their
+ *	geometry and to be redisplayed.
+ *
+ *---------------------------------------------------------------------------
+ */
+ 
+static void
+CanvasWorldChanged(instanceData)
+    ClientData instanceData;	/* Information about widget. */
+{
+    TkCanvas *canvasPtr;
+    Tk_Item *itemPtr;
+    int result;
+
+    canvasPtr = (TkCanvas *) instanceData;
+    itemPtr = canvasPtr->firstItemPtr;
+    for ( ; itemPtr != NULL; itemPtr = itemPtr->nextPtr) {
+	result = (*itemPtr->typePtr->configProc)(canvasPtr->interp,
+		(Tk_Canvas) canvasPtr, itemPtr, 0, NULL,
+		TK_CONFIG_ARGV_ONLY);
+	if (result != TCL_OK) {
+	    Tcl_ResetResult(canvasPtr->interp);
+	}
+    }
+    canvasPtr->flags |= REPICK_NEEDED;
+    Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+	    canvasPtr->xOrigin, canvasPtr->yOrigin,
+	    canvasPtr->xOrigin + Tk_Width(canvasPtr->tkwin),
+	    canvasPtr->yOrigin + Tk_Height(canvasPtr->tkwin));
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * DisplayCanvas --
+ *
+ *	This procedure redraws the contents of a canvas window.
+ *	It is invoked as a do-when-idle handler, so it only runs
+ *	when there's nothing else for the application to do.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Information appears on the screen.
+ *
+ *--------------------------------------------------------------
+ */
+
+static void
+DisplayCanvas(clientData)
+    ClientData clientData;	/* Information about widget. */
+{
+    TkCanvas *canvasPtr = (TkCanvas *) clientData;
+    Tk_Window tkwin = canvasPtr->tkwin;
+    Tk_Item *itemPtr;
+    Pixmap pixmap;
+    int screenX1, screenX2, screenY1, screenY2, width, height;
+
+    if (canvasPtr->tkwin == NULL) {
+	return;
+    }
+    if (!Tk_IsMapped(tkwin)) {
+	goto done;
+    }
+
+    /*
+     * Choose a new current item if that is needed (this could cause
+     * event handlers to be invoked).
+     */
+
+    while (canvasPtr->flags & REPICK_NEEDED) {
+	Tcl_Preserve((ClientData) canvasPtr);
+	canvasPtr->flags &= ~REPICK_NEEDED;
+	PickCurrentItem(canvasPtr, &canvasPtr->pickEvent);
+	tkwin = canvasPtr->tkwin;
+	Tcl_Release((ClientData) canvasPtr);
+	if (tkwin == NULL) {
+	    return;
+	}
+    }
+
+    /*
+     * Compute the intersection between the area that needs redrawing
+     * and the area that's visible on the screen.
+     */
+
+    if ((canvasPtr->redrawX1 < canvasPtr->redrawX2)
+	    && (canvasPtr->redrawY1 < canvasPtr->redrawY2)) {
+	screenX1 = canvasPtr->xOrigin + canvasPtr->inset;
+	screenY1 = canvasPtr->yOrigin + canvasPtr->inset;
+	screenX2 = canvasPtr->xOrigin + Tk_Width(tkwin) - canvasPtr->inset;
+	screenY2 = canvasPtr->yOrigin + Tk_Height(tkwin) - canvasPtr->inset;
+	if (canvasPtr->redrawX1 > screenX1) {
+	    screenX1 = canvasPtr->redrawX1;
+	}
+	if (canvasPtr->redrawY1 > screenY1) {
+	    screenY1 = canvasPtr->redrawY1;
+	}
+	if (canvasPtr->redrawX2 < screenX2) {
+	    screenX2 = canvasPtr->redrawX2;
+	}
+	if (canvasPtr->redrawY2 < screenY2) {
+	    screenY2 = canvasPtr->redrawY2;
+	}
+	if ((screenX1 >= screenX2) || (screenY1 >= screenY2)) {
+	    goto borders;
+	}
+    
+	/*
+	 * Redrawing is done in a temporary pixmap that is allocated
+	 * here and freed at the end of the procedure.  All drawing
+	 * is done to the pixmap, and the pixmap is copied to the
+	 * screen at the end of the procedure. The temporary pixmap
+	 * serves two purposes:
+	 *
+	 * 1. It provides a smoother visual effect (no clearing and
+	 *    gradual redraw will be visible to users).
+	 * 2. It allows us to redraw only the objects that overlap
+	 *    the redraw area.  Otherwise incorrect results could
+	 *	  occur from redrawing things that stick outside of
+	 *	  the redraw area (we'd have to redraw everything in
+	 *    order to make the overlaps look right).
+	 *
+	 * Some tricky points about the pixmap:
+	 *
+	 * 1. We only allocate a large enough pixmap to hold the
+	 *    area that has to be redisplayed.  This saves time in
+	 *    in the X server for large objects that cover much
+	 *    more than the area being redisplayed:  only the area
+	 *    of the pixmap will actually have to be redrawn.
+	 * 2. Some X servers (e.g. the one for DECstations) have troubles
+	 *    with characters that overlap an edge of the pixmap (on the
+	 *    DEC servers, as of 8/18/92, such characters are drawn one
+	 *    pixel too far to the right).  To handle this problem,
+	 *    make the pixmap a bit larger than is absolutely needed
+	 *    so that for normal-sized fonts the characters that overlap
+	 *    the edge of the pixmap will be outside the area we care
+	 *    about.
+	 */
+    
+	canvasPtr->drawableXOrigin = screenX1 - 30;
+	canvasPtr->drawableYOrigin = screenY1 - 30;
+	pixmap = Tk_GetPixmap(Tk_Display(tkwin), Tk_WindowId(tkwin),
+	    (screenX2 + 30 - canvasPtr->drawableXOrigin),
+	    (screenY2 + 30 - canvasPtr->drawableYOrigin),
+	    Tk_Depth(tkwin));
+    
+	/*
+	 * Clear the area to be redrawn.
+	 */
+    
+	width = screenX2 - screenX1;
+	height = screenY2 - screenY1;
+    
+	XFillRectangle(Tk_Display(tkwin), pixmap, canvasPtr->pixmapGC,
+		screenX1 - canvasPtr->drawableXOrigin,
+		screenY1 - canvasPtr->drawableYOrigin, (unsigned int) width,
+		(unsigned int) height);
+    
+	/*
+	 * Scan through the item list, redrawing those items that need it.
+	 * An item must be redraw if either (a) it intersects the smaller
+	 * on-screen area or (b) it intersects the full canvas area and its
+	 * type requests that it be redrawn always (e.g. so subwindows can
+	 * be unmapped when they move off-screen).
+	 */
+    
+	for (itemPtr = canvasPtr->firstItemPtr; itemPtr != NULL;
+		itemPtr = itemPtr->nextPtr) {
+	    if ((itemPtr->x1 >= screenX2)
+		    || (itemPtr->y1 >= screenY2)
+		    || (itemPtr->x2 < screenX1)
+		    || (itemPtr->y2 < screenY1)) {
+		if (!itemPtr->typePtr->alwaysRedraw
+			|| (itemPtr->x1 >= canvasPtr->redrawX2)
+			|| (itemPtr->y1 >= canvasPtr->redrawY2)
+			|| (itemPtr->x2 < canvasPtr->redrawX1)
+			|| (itemPtr->y2 < canvasPtr->redrawY1)) {
+		    continue;
+		}
+	    }
+	    (*itemPtr->typePtr->displayProc)((Tk_Canvas) canvasPtr, itemPtr,
+		    canvasPtr->display, pixmap, screenX1, screenY1, width,
+		    height);
+	}
+    
+	/*
+	 * Copy from the temporary pixmap to the screen, then free up
+	 * the temporary pixmap.
+	 */
+    
+	XCopyArea(Tk_Display(tkwin), pixmap, Tk_WindowId(tkwin),
+		canvasPtr->pixmapGC,
+		screenX1 - canvasPtr->drawableXOrigin,
+		screenY1 - canvasPtr->drawableYOrigin,
+		(unsigned) (screenX2 - screenX1),
+		(unsigned) (screenY2 - screenY1),
+		screenX1 - canvasPtr->xOrigin, screenY1 - canvasPtr->yOrigin);
+	Tk_FreePixmap(Tk_Display(tkwin), pixmap);
+    }
+
+    /*
+     * Draw the window borders, if needed.
+     */
+
+    borders:
+    if (canvasPtr->flags & REDRAW_BORDERS) {
+	canvasPtr->flags &= ~REDRAW_BORDERS;
+	if (canvasPtr->borderWidth > 0) {
+	    Tk_Draw3DRectangle(tkwin, Tk_WindowId(tkwin),
+		    canvasPtr->bgBorder, canvasPtr->highlightWidth,
+		    canvasPtr->highlightWidth,
+		    Tk_Width(tkwin) - 2*canvasPtr->highlightWidth,
+		    Tk_Height(tkwin) - 2*canvasPtr->highlightWidth,
+		    canvasPtr->borderWidth, canvasPtr->relief);
+	}
+	if (canvasPtr->highlightWidth != 0) {
+	    GC gc;
+    
+	    if (canvasPtr->textInfo.gotFocus) {
+		gc = Tk_GCForColor(canvasPtr->highlightColorPtr,
+			Tk_WindowId(tkwin));
+	    } else {
+		gc = Tk_GCForColor(canvasPtr->highlightBgColorPtr,
+			Tk_WindowId(tkwin));
+	    }
+	    Tk_DrawFocusHighlight(tkwin, gc, canvasPtr->highlightWidth,
+		    Tk_WindowId(tkwin));
+	}
+    }
+
+    done:
+    canvasPtr->flags &= ~REDRAW_PENDING;
+    canvasPtr->redrawX1 = canvasPtr->redrawX2 = 0;
+    canvasPtr->redrawY1 = canvasPtr->redrawY2 = 0;
+    if (canvasPtr->flags & UPDATE_SCROLLBARS) {
+	CanvasUpdateScrollbars(canvasPtr);
+    }
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * CanvasEventProc --
+ *
+ *	This procedure is invoked by the Tk dispatcher for various
+ *	events on canvases.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	When the window gets deleted, internal structures get
+ *	cleaned up.  When it gets exposed, it is redisplayed.
+ *
+ *--------------------------------------------------------------
+ */
+
+static void
+CanvasEventProc(clientData, eventPtr)
+    ClientData clientData;	/* Information about window. */
+    XEvent *eventPtr;		/* Information about event. */
+{
+    TkCanvas *canvasPtr = (TkCanvas *) clientData;
+
+    if (eventPtr->type == Expose) {
+	int x, y;
+
+	x = eventPtr->xexpose.x + canvasPtr->xOrigin;
+	y = eventPtr->xexpose.y + canvasPtr->yOrigin;
+	Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr, x, y,
+		x + eventPtr->xexpose.width,
+		y + eventPtr->xexpose.height);
+	if ((eventPtr->xexpose.x < canvasPtr->inset)
+		|| (eventPtr->xexpose.y < canvasPtr->inset)
+		|| ((eventPtr->xexpose.x + eventPtr->xexpose.width)
+		    > (Tk_Width(canvasPtr->tkwin) - canvasPtr->inset))
+		|| ((eventPtr->xexpose.y + eventPtr->xexpose.height)
+		    > (Tk_Height(canvasPtr->tkwin) - canvasPtr->inset))) {
+	    canvasPtr->flags |= REDRAW_BORDERS;
+	}
+    } else if (eventPtr->type == DestroyNotify) {
+	if (canvasPtr->tkwin != NULL) {
+	    canvasPtr->tkwin = NULL;
+            Tcl_DeleteCommandFromToken(canvasPtr->interp,
+		    canvasPtr->widgetCmd);
+	}
+	if (canvasPtr->flags & REDRAW_PENDING) {
+	    Tcl_CancelIdleCall(DisplayCanvas, (ClientData) canvasPtr);
+	}
+	Tcl_EventuallyFree((ClientData) canvasPtr, DestroyCanvas);
+    } else if (eventPtr->type == ConfigureNotify) {
+	canvasPtr->flags |= UPDATE_SCROLLBARS;
+
+	/*
+	 * The call below is needed in order to recenter the canvas if
+	 * it's confined and its scroll region is smaller than the window.
+	 */
+
+	CanvasSetOrigin(canvasPtr, canvasPtr->xOrigin, canvasPtr->yOrigin);
+	Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr, canvasPtr->xOrigin,
+		canvasPtr->yOrigin,
+		canvasPtr->xOrigin + Tk_Width(canvasPtr->tkwin),
+		canvasPtr->yOrigin + Tk_Height(canvasPtr->tkwin));
+	canvasPtr->flags |= REDRAW_BORDERS;
+    } else if (eventPtr->type == FocusIn) {
+	if (eventPtr->xfocus.detail != NotifyInferior) {
+	    CanvasFocusProc(canvasPtr, 1);
+	}
+    } else if (eventPtr->type == FocusOut) {
+	if (eventPtr->xfocus.detail != NotifyInferior) {
+	    CanvasFocusProc(canvasPtr, 0);
+	}
+    } else if (eventPtr->type == UnmapNotify) {
+	Tk_Item *itemPtr;
+
+	/*
+	 * Special hack:  if the canvas is unmapped, then must notify
+	 * all items with "alwaysRedraw" set, so that they know that
+	 * they are no longer displayed.
+	 */
+
+	for (itemPtr = canvasPtr->firstItemPtr; itemPtr != NULL;
+		itemPtr = itemPtr->nextPtr) {
+	    if (itemPtr->typePtr->alwaysRedraw) {
+		(*itemPtr->typePtr->displayProc)((Tk_Canvas) canvasPtr,
+			itemPtr, canvasPtr->display, None, 0, 0, 0, 0);
+	    }
+	}
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * CanvasCmdDeletedProc --
+ *
+ *	This procedure is invoked when a widget command is deleted.  If
+ *	the widget isn't already in the process of being destroyed,
+ *	this command destroys it.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The widget is destroyed.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+CanvasCmdDeletedProc(clientData)
+    ClientData clientData;	/* Pointer to widget record for widget. */
+{
+    TkCanvas *canvasPtr = (TkCanvas *) clientData;
+    Tk_Window tkwin = canvasPtr->tkwin;
+
+    /*
+     * This procedure could be invoked either because the window was
+     * destroyed and the command was then deleted (in which case tkwin
+     * is NULL) or because the command was deleted, and then this procedure
+     * destroys the widget.
+     */
+
+    if (tkwin != NULL) {
+	canvasPtr->tkwin = NULL;
+	Tk_DestroyWindow(tkwin);
+    }
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * Tk_CanvasEventuallyRedraw --
+ *
+ *	Arrange for part or all of a canvas widget to redrawn at
+ *	some convenient time in the future.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The screen will eventually be refreshed.
+ *
+ *--------------------------------------------------------------
+ */
+
+void
+Tk_CanvasEventuallyRedraw(canvas, x1, y1, x2, y2)
+    Tk_Canvas canvas;		/* Information about widget. */
+    int x1, y1;			/* Upper left corner of area to redraw.
+				 * Pixels on edge are redrawn. */
+    int x2, y2;			/* Lower right corner of area to redraw.
+				 * Pixels on edge are not redrawn. */
+{
+    TkCanvas *canvasPtr = (TkCanvas *) canvas;
+    if ((x1 == x2) || (y1 == y2)) {
+	return;
+    }
+    if (canvasPtr->flags & REDRAW_PENDING) {
+	if (x1 <= canvasPtr->redrawX1) {
+	    canvasPtr->redrawX1 = x1;
+	}
+	if (y1 <= canvasPtr->redrawY1) {
+	    canvasPtr->redrawY1 = y1;
+	}
+	if (x2 >= canvasPtr->redrawX2) {
+	    canvasPtr->redrawX2 = x2;
+	}
+	if (y2 >= canvasPtr->redrawY2) {
+	    canvasPtr->redrawY2 = y2;
+	}
+    } else {
+	canvasPtr->redrawX1 = x1;
+	canvasPtr->redrawY1 = y1;
+	canvasPtr->redrawX2 = x2;
+	canvasPtr->redrawY2 = y2;
+	Tcl_DoWhenIdle(DisplayCanvas, (ClientData) canvasPtr);
+	canvasPtr->flags |= REDRAW_PENDING;
+    }
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * Tk_CreateItemType --
+ *
+ *	This procedure may be invoked to add a new kind of canvas
+ *	element to the core item types supported by Tk.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	From now on, the new item type will be useable in canvas
+ *	widgets (e.g. typePtr->name can be used as the item type
+ *	in "create" widget commands).  If there was already a
+ *	type with the same name as in typePtr, it is replaced with
+ *	the new type.
+ *
+ *--------------------------------------------------------------
+ */
+
+void
+Tk_CreateItemType(typePtr)
+    Tk_ItemType *typePtr;		/* Information about item type;
+					 * storage must be statically
+					 * allocated (must live forever). */
+{
+    Tk_ItemType *typePtr2, *prevPtr;
+
+    if (typeList == NULL) {
+	InitCanvas();
+    }
+
+    /*
+     * If there's already an item type with the given name, remove it.
+     */
+
+    for (typePtr2 = typeList, prevPtr = NULL; typePtr2 != NULL;
+	    prevPtr = typePtr2, typePtr2 = typePtr2->nextPtr) {
+	if (strcmp(typePtr2->name, typePtr->name) == 0) {
+	    if (prevPtr == NULL) {
+		typeList = typePtr2->nextPtr;
+	    } else {
+		prevPtr->nextPtr = typePtr2->nextPtr;
+	    }
+	    break;
+	}
+    }
+    typePtr->nextPtr = typeList;
+    typeList = typePtr;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tk_GetItemTypes --
+ *
+ *	This procedure returns a pointer to the list of all item
+ *	types.
+ *
+ * Results:
+ *	The return value is a pointer to the first in the list
+ *	of item types currently supported by canvases.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tk_ItemType *
+Tk_GetItemTypes()
+{
+    if (typeList == NULL) {
+	InitCanvas();
+    }
+    return typeList;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * InitCanvas --
+ *
+ *	This procedure is invoked to perform once-only-ever
+ *	initialization for the module, such as setting up
+ *	the type table.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	None.
+ *
+ *--------------------------------------------------------------
+ */
+
+static void
+InitCanvas()
+{
+    if (typeList != NULL) {
+	return;
+    }
+    typeList = &tkRectangleType;
+    tkRectangleType.nextPtr = &tkTextType;
+    tkTextType.nextPtr = &tkLineType;
+    tkLineType.nextPtr = &tkPolygonType;
+    tkPolygonType.nextPtr = &tkImageType;
+    tkImageType.nextPtr = &tkOvalType;
+    tkOvalType.nextPtr = &tkBitmapType;
+    tkBitmapType.nextPtr = &tkArcType;
+    tkArcType.nextPtr = &tkWindowType;
+    tkWindowType.nextPtr = NULL;
+    allUid = Tk_GetUid("all");
+    currentUid = Tk_GetUid("current");
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * StartTagSearch --
+ *
+ *	This procedure is called to initiate an enumeration of
+ *	all items in a given canvas that contain a given tag.
+ *
+ * Results:
+ *	The return value is a pointer to the first item in
+ *	canvasPtr that matches tag, or NULL if there is no
+ *	such item.  The information at *searchPtr is initialized
+ *	such that successive calls to NextItem will return
+ *	successive items that match tag.
+ *
+ * Side effects:
+ *	SearchPtr is linked into a list of searches in progress
+ *	on canvasPtr, so that elements can safely be deleted
+ *	while the search is in progress.  EndTagSearch must be
+ *	called at the end of the search to unlink searchPtr from
+ *	this list.
+ *
+ *--------------------------------------------------------------
+ */
+
+static Tk_Item *
+StartTagSearch(canvasPtr, tag, searchPtr)
+    TkCanvas *canvasPtr;		/* Canvas whose items are to be
+					 * searched. */
+    char *tag;				/* String giving tag value. */
+    TagSearch *searchPtr;		/* Record describing tag search;
+					 * will be initialized here. */
+{
+    int id;
+    Tk_Item *itemPtr, *prevPtr;
+    Tk_Uid *tagPtr;
+    Tk_Uid uid;
+    int count;
+
+    /*
+     * Initialize the search.
+     */
+
+    searchPtr->canvasPtr = canvasPtr;
+    searchPtr->searchOver = 0;
+
+    /*
+     * Find the first matching item in one of several ways. If the tag
+     * is a number then it selects the single item with the matching
+     * identifier.  In this case see if the item being requested is the
+     * hot item, in which case the search can be skipped.
+     */
+
+    if (isdigit(UCHAR(*tag))) {
+	char *end;
+
+	numIdSearches++;
+	id = strtoul(tag, &end, 0);
+	if (*end == 0) {
+	    itemPtr = canvasPtr->hotPtr;
+	    prevPtr = canvasPtr->hotPrevPtr;
+	    if ((itemPtr == NULL) || (itemPtr->id != id) || (prevPtr == NULL)
+		    || (prevPtr->nextPtr != itemPtr)) {
+		numSlowSearches++;
+		for (prevPtr = NULL, itemPtr = canvasPtr->firstItemPtr;
+			itemPtr != NULL;
+			prevPtr = itemPtr, itemPtr = itemPtr->nextPtr) {
+		    if (itemPtr->id == id) {
+			break;
+		    }
+		}
+	    }
+	    searchPtr->prevPtr = prevPtr;
+	    searchPtr->searchOver = 1;
+	    canvasPtr->hotPtr = itemPtr;
+	    canvasPtr->hotPrevPtr = prevPtr;
+	    return itemPtr;
+	}
+    }
+
+    searchPtr->tag = uid = Tk_GetUid(tag);
+    if (uid == allUid) {
+
+	/*
+	 * All items match.
+	 */
+
+	searchPtr->tag = NULL;
+	searchPtr->prevPtr = NULL;
+	searchPtr->currentPtr = canvasPtr->firstItemPtr;
+	return canvasPtr->firstItemPtr;
+    }
+
+    /*
+     * None of the above.  Search for an item with a matching tag.
+     */
+
+    for (prevPtr = NULL, itemPtr = canvasPtr->firstItemPtr; itemPtr != NULL;
+	    prevPtr = itemPtr, itemPtr = itemPtr->nextPtr) {
+	for (tagPtr = itemPtr->tagPtr, count = itemPtr->numTags;
+		count > 0; tagPtr++, count--) {
+	    if (*tagPtr == uid) {
+		searchPtr->prevPtr = prevPtr;
+		searchPtr->currentPtr = itemPtr;
+		return itemPtr;
+	    }
+	}
+    }
+    searchPtr->prevPtr = prevPtr;
+    searchPtr->searchOver = 1;
+    return NULL;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * NextItem --
+ *
+ *	This procedure returns successive items that match a given
+ *	tag;  it should be called only after StartTagSearch has been
+ *	used to begin a search.
+ *
+ * Results:
+ *	The return value is a pointer to the next item that matches
+ *	the tag specified to StartTagSearch, or NULL if no such
+ *	item exists.  *SearchPtr is updated so that the next call
+ *	to this procedure will return the next item.
+ *
+ * Side effects:
+ *	None.
+ *
+ *--------------------------------------------------------------
+ */
+
+static Tk_Item *
+NextItem(searchPtr)
+    TagSearch *searchPtr;		/* Record describing search in
+					 * progress. */
+{
+    Tk_Item *itemPtr, *prevPtr;
+    int count;
+    Tk_Uid uid;
+    Tk_Uid *tagPtr;
+
+    /*
+     * Find next item in list (this may not actually be a suitable
+     * one to return), and return if there are no items left.
+     */
+
+    prevPtr = searchPtr->prevPtr;
+    if (prevPtr == NULL) {
+	itemPtr = searchPtr->canvasPtr->firstItemPtr;
+    } else {
+	itemPtr = prevPtr->nextPtr;
+    }
+    if ((itemPtr == NULL) || (searchPtr->searchOver)) {
+	searchPtr->searchOver = 1;
+	return NULL;
+    }
+    if (itemPtr != searchPtr->currentPtr) {
+	/*
+	 * The structure of the list has changed.  Probably the
+	 * previously-returned item was removed from the list.
+	 * In this case, don't advance prevPtr;  just return
+	 * its new successor (i.e. do nothing here).
+	 */
+    } else {
+	prevPtr = itemPtr;
+	itemPtr = prevPtr->nextPtr;
+    }
+
+    /*
+     * Handle special case of "all" search by returning next item.
+     */
+
+    uid = searchPtr->tag;
+    if (uid == NULL) {
+	searchPtr->prevPtr = prevPtr;
+	searchPtr->currentPtr = itemPtr;
+	return itemPtr;
+    }
+
+    /*
+     * Look for an item with a particular tag.
+     */
+
+    for ( ; itemPtr != NULL; prevPtr = itemPtr, itemPtr = itemPtr->nextPtr) {
+	for (tagPtr = itemPtr->tagPtr, count = itemPtr->numTags;
+		count > 0; tagPtr++, count--) {
+	    if (*tagPtr == uid) {
+		searchPtr->prevPtr = prevPtr;
+		searchPtr->currentPtr = itemPtr;
+		return itemPtr;
+	    }
+	}
+    }
+    searchPtr->prevPtr = prevPtr;
+    searchPtr->searchOver = 1;
+    return NULL;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * DoItem --
+ *
+ *	This is a utility procedure called by FindItems.  It
+ *	either adds itemPtr's id to the result forming in interp,
+ *	or it adds a new tag to itemPtr, depending on the value
+ *	of tag.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	If tag is NULL then itemPtr's id is added as a list element
+ *	to interp->result;  otherwise tag is added to itemPtr's
+ *	list of tags.
+ *
+ *--------------------------------------------------------------
+ */
+
+static void
+DoItem(interp, itemPtr, tag)
+    Tcl_Interp *interp;			/* Interpreter in which to (possibly)
+					 * record item id. */
+    Tk_Item *itemPtr;			/* Item to (possibly) modify. */
+    Tk_Uid tag;				/* Tag to add to those already
+					 * present for item, or NULL. */
+{
+    Tk_Uid *tagPtr;
+    int count;
+
+    /*
+     * Handle the "add-to-result" case and return, if appropriate.
+     */
+
+    if (tag == NULL) {
+	char msg[30];
+	sprintf(msg, "%d", itemPtr->id);
+	Tcl_AppendElement(interp, msg);
+	return;
+    }
+
+    for (tagPtr = itemPtr->tagPtr, count = itemPtr->numTags;
+	    count > 0; tagPtr++, count--) {
+	if (tag == *tagPtr) {
+	    return;
+	}
+    }
+
+    /*
+     * Grow the tag space if there's no more room left in the current
+     * block.
+     */
+
+    if (itemPtr->tagSpace == itemPtr->numTags) {
+	Tk_Uid *newTagPtr;
+
+	itemPtr->tagSpace += 5;
+	newTagPtr = (Tk_Uid *) ckalloc((unsigned)
+		(itemPtr->tagSpace * sizeof(Tk_Uid)));
+	memcpy((VOID *) newTagPtr, (VOID *) itemPtr->tagPtr,
+		(itemPtr->numTags * sizeof(Tk_Uid)));
+	if (itemPtr->tagPtr != itemPtr->staticTagSpace) {
+	    ckfree((char *) itemPtr->tagPtr);
+	}
+	itemPtr->tagPtr = newTagPtr;
+	tagPtr = &itemPtr->tagPtr[itemPtr->numTags];
+    }
+
+    /*
+     * Add in the new tag.
+     */
+
+    *tagPtr = tag;
+    itemPtr->numTags++;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * FindItems --
+ *
+ *	This procedure does all the work of implementing the
+ *	"find" and "addtag" options of the canvas widget command,
+ *	which locate items that have certain features (location,
+ *	tags, position in display list, etc.).
+ *
+ * Results:
+ *	A standard Tcl return value.  If newTag is NULL, then a
+ *	list of ids from all the items that match argc/argv is
+ *	returned in interp->result.  If newTag is NULL, then
+ *	the normal interp->result is an empty string.  If an error
+ *	occurs, then interp->result will hold an error message.
+ *
+ * Side effects:
+ *	If newTag is non-NULL, then all the items that match the
+ *	information in argc/argv have that tag added to their
+ *	lists of tags.
+ *
+ *--------------------------------------------------------------
+ */
+
+static int
+FindItems(interp, canvasPtr, argc, argv, newTag, cmdName, option)
+    Tcl_Interp *interp;			/* Interpreter for error reporting. */
+    TkCanvas *canvasPtr;		/* Canvas whose items are to be
+					 * searched. */
+    int argc;				/* Number of entries in argv.  Must be
+					 * greater than zero. */
+    char **argv;			/* Arguments that describe what items
+					 * to search for (see user doc on
+					 * "find" and "addtag" options). */
+    char *newTag;			/* If non-NULL, gives new tag to set
+					 * on all found items;  if NULL, then
+					 * ids of found items are returned
+					 * in interp->result. */
+    char *cmdName;			/* Name of original Tcl command, for
+					 * use in error messages. */
+    char *option;			/* For error messages:  gives option
+					 * from Tcl command and other stuff
+					 * up to what's in argc/argv. */
+{
+    int c;
+    size_t length;
+    TagSearch search;
+    Tk_Item *itemPtr;
+    Tk_Uid uid;
+
+    if (newTag != NULL) {
+	uid = Tk_GetUid(newTag);
+    } else {
+	uid = NULL;
+    }
+    c = argv[0][0];
+    length = strlen(argv[0]);
+    if ((c == 'a') && (strncmp(argv[0], "above", length) == 0)
+	    && (length >= 2)) {
+	Tk_Item *lastPtr = NULL;
+	if (argc != 2) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    cmdName, option, " above tagOrId", (char *) NULL);
+	    return TCL_ERROR;
+	}
+	for (itemPtr = StartTagSearch(canvasPtr, argv[1], &search);
+		itemPtr != NULL; itemPtr = NextItem(&search)) {
+	    lastPtr = itemPtr;
+	}
+	if ((lastPtr != NULL) && (lastPtr->nextPtr != NULL)) {
+	    DoItem(interp, lastPtr->nextPtr, uid);
+	}
+    } else if ((c == 'a') && (strncmp(argv[0], "all", length) == 0)
+	    && (length >= 2)) {
+	if (argc != 1) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    cmdName, option, " all", (char *) NULL);
+	    return TCL_ERROR;
+	}
+
+	for (itemPtr = canvasPtr->firstItemPtr; itemPtr != NULL;
+		itemPtr = itemPtr->nextPtr) {
+	    DoItem(interp, itemPtr, uid);
+	}
+    } else if ((c == 'b') && (strncmp(argv[0], "below", length) == 0)) {
+	if (argc != 2) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    cmdName, option, " below tagOrId", (char *) NULL);
+	    return TCL_ERROR;
+	}
+	(void) StartTagSearch(canvasPtr, argv[1], &search);
+	if (search.prevPtr != NULL) {
+	    DoItem(interp, search.prevPtr, uid);
+	}
+    } else if ((c == 'c') && (strncmp(argv[0], "closest", length) == 0)) {
+	double closestDist;
+	Tk_Item *startPtr, *closestPtr;
+	double coords[2], halo;
+	int x1, y1, x2, y2;
+
+	if ((argc < 3) || (argc > 5)) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    cmdName, option, " closest x y ?halo? ?start?",
+		    (char *) NULL);
+	    return TCL_ERROR;
+	}
+	if ((Tk_CanvasGetCoord(interp, (Tk_Canvas) canvasPtr, argv[1],
+		&coords[0]) != TCL_OK) || (Tk_CanvasGetCoord(interp,
+		(Tk_Canvas) canvasPtr, argv[2], &coords[1]) != TCL_OK)) {
+	    return TCL_ERROR;
+	}
+	if (argc > 3) {
+	    if (Tk_CanvasGetCoord(interp, (Tk_Canvas) canvasPtr, argv[3],
+		    &halo) != TCL_OK) {
+		return TCL_ERROR;
+	    }
+	    if (halo < 0.0) {
+		Tcl_AppendResult(interp, "can't have negative halo value \"",
+			argv[3], "\"", (char *) NULL);
+		return TCL_ERROR;
+	    }
+	} else {
+	    halo = 0.0;
+	}
+
+	/*
+	 * Find the item at which to start the search.
+	 */
+
+	startPtr = canvasPtr->firstItemPtr;
+	if (argc == 5) {
+	    itemPtr = StartTagSearch(canvasPtr, argv[4], &search);
+	    if (itemPtr != NULL) {
+		startPtr = itemPtr;
+	    }
+	}
+
+	/*
+	 * The code below is optimized so that it can eliminate most
+	 * items without having to call their item-specific procedures.
+	 * This is done by keeping a bounding box (x1, y1, x2, y2) that
+	 * an item's bbox must overlap if the item is to have any
+	 * chance of being closer than the closest so far.
+	 */
+
+	itemPtr = startPtr;
+	if (itemPtr == NULL) {
+	    return TCL_OK;
+	}
+	closestDist = (*itemPtr->typePtr->pointProc)((Tk_Canvas) canvasPtr,
+		itemPtr, coords) - halo;
+	if (closestDist < 0.0) {
+	    closestDist = 0.0;
+	}
+	while (1) {
+	    double newDist;
+
+	    /*
+	     * Update the bounding box using itemPtr, which is the
+	     * new closest item.
+	     */
+
+	    x1 = (int) (coords[0] - closestDist - halo - 1);
+	    y1 = (int) (coords[1] - closestDist - halo - 1);
+	    x2 = (int) (coords[0] + closestDist + halo + 1);
+	    y2 = (int) (coords[1] + closestDist + halo + 1);
+	    closestPtr = itemPtr;
+
+	    /*
+	     * Search for an item that beats the current closest one.
+	     * Work circularly through the canvas's item list until
+	     * getting back to the starting item.
+	     */
+
+	    while (1) {
+		itemPtr = itemPtr->nextPtr;
+		if (itemPtr == NULL) {
+		    itemPtr = canvasPtr->firstItemPtr;
+		}
+		if (itemPtr == startPtr) {
+		    DoItem(interp, closestPtr, uid);
+		    return TCL_OK;
+		}
+		if ((itemPtr->x1 >= x2) || (itemPtr->x2 <= x1)
+			|| (itemPtr->y1 >= y2) || (itemPtr->y2 <= y1)) {
+		    continue;
+		}
+		newDist = (*itemPtr->typePtr->pointProc)((Tk_Canvas) canvasPtr,
+			itemPtr, coords) - halo;
+		if (newDist < 0.0) {
+		    newDist = 0.0;
+		}
+		if (newDist <= closestDist) {
+		    closestDist = newDist;
+		    break;
+		}
+	    }
+	}
+    } else if ((c == 'e') && (strncmp(argv[0], "enclosed", length) == 0)) {
+	if (argc != 5) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    cmdName, option, " enclosed x1 y1 x2 y2", (char *) NULL);
+	    return TCL_ERROR;
+	}
+	return FindArea(interp, canvasPtr, argv+1, uid, 1);
+    } else if ((c == 'o') && (strncmp(argv[0], "overlapping", length) == 0)) {
+	if (argc != 5) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    cmdName, option, " overlapping x1 y1 x2 y2",
+		    (char *) NULL);
+	    return TCL_ERROR;
+	}
+	return FindArea(interp, canvasPtr, argv+1, uid, 0);
+    } else if ((c == 'w') && (strncmp(argv[0], "withtag", length) == 0)) {
+		if (argc != 2) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    cmdName, option, " withtag tagOrId", (char *) NULL);
+	    return TCL_ERROR;
+	}
+	for (itemPtr = StartTagSearch(canvasPtr, argv[1], &search);
+		itemPtr != NULL; itemPtr = NextItem(&search)) {
+	    DoItem(interp, itemPtr, uid);
+	}
+    } else  {
+	Tcl_AppendResult(interp, "bad search command \"", argv[0],
+		"\": must be above, all, below, closest, enclosed, ",
+		"overlapping, or withtag", (char *) NULL);
+	return TCL_ERROR;
+    }
+    return TCL_OK;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * FindArea --
+ *
+ *	This procedure implements area searches for the "find"
+ *	and "addtag" options.
+ *
+ * Results:
+ *	A standard Tcl return value.  If newTag is NULL, then a
+ *	list of ids from all the items overlapping or enclosed
+ *	by the rectangle given by argc is returned in interp->result.
+ *	If newTag is NULL, then the normal interp->result is an
+ *	empty string.  If an error occurs, then interp->result will
+ *	hold an error message.
+ *
+ * Side effects:
+ *	If uid is non-NULL, then all the items overlapping
+ *	or enclosed by the area in argv have that tag added to
+ *	their lists of tags.
+ *
+ *--------------------------------------------------------------
+ */
+
+static int
+FindArea(interp, canvasPtr, argv, uid, enclosed)
+    Tcl_Interp *interp;			/* Interpreter for error reporting
+					 * and result storing. */
+    TkCanvas *canvasPtr;		/* Canvas whose items are to be
+					 * searched. */
+    char **argv;			/* Array of four arguments that
+					 * give the coordinates of the
+					 * rectangular area to search. */
+    Tk_Uid uid;				/* If non-NULL, gives new tag to set
+					 * on all found items;  if NULL, then
+					 * ids of found items are returned
+					 * in interp->result. */
+    int enclosed;			/* 0 means overlapping or enclosed
+					 * items are OK, 1 means only enclosed
+					 * items are OK. */
+{
+    double rect[4], tmp;
+    int x1, y1, x2, y2;
+    Tk_Item *itemPtr;
+
+    if ((Tk_CanvasGetCoord(interp, (Tk_Canvas) canvasPtr, argv[0],
+		&rect[0]) != TCL_OK)
+	    || (Tk_CanvasGetCoord(interp, (Tk_Canvas) canvasPtr, argv[1],
+		&rect[1]) != TCL_OK)
+	    || (Tk_CanvasGetCoord(interp, (Tk_Canvas) canvasPtr, argv[2],
+		&rect[2]) != TCL_OK)
+	    || (Tk_CanvasGetCoord(interp, (Tk_Canvas) canvasPtr, argv[3],
+		&rect[3]) != TCL_OK)) {
+	return TCL_ERROR;
+    }
+    if (rect[0] > rect[2]) {
+	tmp = rect[0]; rect[0] = rect[2]; rect[2] = tmp;
+    }
+    if (rect[1] > rect[3]) {
+	tmp = rect[1]; rect[1] = rect[3]; rect[3] = tmp;
+    }
+
+    /*
+     * Use an integer bounding box for a quick test, to avoid
+     * calling item-specific code except for items that are close.
+     */
+
+    x1 = (int) (rect[0]-1.0);
+    y1 = (int) (rect[1]-1.0);
+    x2 = (int) (rect[2]+1.0);
+    y2 = (int) (rect[3]+1.0);
+    for (itemPtr = canvasPtr->firstItemPtr; itemPtr != NULL;
+	    itemPtr = itemPtr->nextPtr) {
+	if ((itemPtr->x1 >= x2) || (itemPtr->x2 <= x1)
+		|| (itemPtr->y1 >= y2) || (itemPtr->y2 <= y1)) {
+	    continue;
+	}
+	if ((*itemPtr->typePtr->areaProc)((Tk_Canvas) canvasPtr, itemPtr, rect)
+		>= enclosed) {
+	    DoItem(interp, itemPtr, uid);
+	}
+    }
+    return TCL_OK;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * RelinkItems --
+ *
+ *	Move one or more items to a different place in the
+ *	display order for a canvas.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The items identified by "tag" are moved so that they
+ *	are all together in the display list and immediately
+ *	after prevPtr.  The order of the moved items relative
+ *	to each other is not changed.
+ *
+ *--------------------------------------------------------------
+ */
+
+static void
+RelinkItems(canvasPtr, tag, prevPtr)
+    TkCanvas *canvasPtr;	/* Canvas to be modified. */
+    char *tag;			/* Tag identifying items to be moved
+				 * in the redisplay list. */
+    Tk_Item *prevPtr;		/* Reposition the items so that they
+				 * go just after this item (NULL means
+				 * put at beginning of list). */
+{
+    Tk_Item *itemPtr;
+    TagSearch search;
+    Tk_Item *firstMovePtr, *lastMovePtr;
+
+    /*
+     * Find all of the items to be moved and remove them from
+     * the list, making an auxiliary list running from firstMovePtr
+     * to lastMovePtr.  Record their areas for redisplay.
+     */
+
+    firstMovePtr = lastMovePtr = NULL;
+    for (itemPtr = StartTagSearch(canvasPtr, tag, &search);
+	    itemPtr != NULL; itemPtr = NextItem(&search)) {
+	if (itemPtr == prevPtr) {
+	    /*
+	     * Item after which insertion is to occur is being
+	     * moved!  Switch to insert after its predecessor.
+	     */
+
+	    prevPtr = search.prevPtr;
+	}
+	if (search.prevPtr == NULL) {
+	    canvasPtr->firstItemPtr = itemPtr->nextPtr;
+	} else {
+	    search.prevPtr->nextPtr = itemPtr->nextPtr;
+	}
+	if (canvasPtr->lastItemPtr == itemPtr) {
+	    canvasPtr->lastItemPtr = search.prevPtr;
+	}
+	if (firstMovePtr == NULL) {
+	    firstMovePtr = itemPtr;
+	} else {
+	    lastMovePtr->nextPtr = itemPtr;
+	}
+	lastMovePtr = itemPtr;
+	Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr, itemPtr->x1, itemPtr->y1,
+		itemPtr->x2, itemPtr->y2);
+	canvasPtr->flags |= REPICK_NEEDED;
+    }
+
+    /*
+     * Insert the list of to-be-moved items back into the canvas's
+     * at the desired position.
+     */
+
+    if (firstMovePtr == NULL) {
+	return;
+    }
+    if (prevPtr == NULL) {
+	lastMovePtr->nextPtr = canvasPtr->firstItemPtr;
+	canvasPtr->firstItemPtr = firstMovePtr;
+    } else {
+	lastMovePtr->nextPtr = prevPtr->nextPtr;
+	prevPtr->nextPtr = firstMovePtr;
+    }
+    if (canvasPtr->lastItemPtr == prevPtr) {
+	canvasPtr->lastItemPtr = lastMovePtr;
+    }
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * CanvasBindProc --
+ *
+ *	This procedure is invoked by the Tk dispatcher to handle
+ *	events associated with bindings on items.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Depends on the command invoked as part of the binding
+ *	(if there was any).
+ *
+ *--------------------------------------------------------------
+ */
+
+static void
+CanvasBindProc(clientData, eventPtr)
+    ClientData clientData;		/* Pointer to canvas structure. */
+    XEvent *eventPtr;			/* Pointer to X event that just
+					 * happened. */
+{
+    TkCanvas *canvasPtr = (TkCanvas *) clientData;
+
+    Tcl_Preserve((ClientData) canvasPtr);
+
+    /*
+     * This code below keeps track of the current modifier state in
+     * canvasPtr>state.  This information is used to defer repicks of
+     * the current item while buttons are down.
+     */
+
+    if ((eventPtr->type == ButtonPress) || (eventPtr->type == ButtonRelease)) {
+	int mask;
+
+	switch (eventPtr->xbutton.button) {
+	    case Button1:
+		mask = Button1Mask;
+		break;
+	    case Button2:
+		mask = Button2Mask;
+		break;
+	    case Button3:
+		mask = Button3Mask;
+		break;
+	    case Button4:
+		mask = Button4Mask;
+		break;
+	    case Button5:
+		mask = Button5Mask;
+		break;
+	    default:
+		mask = 0;
+		break;
+	}
+
+	/*
+	 * For button press events, repick the current item using the
+	 * button state before the event, then process the event.  For
+	 * button release events, first process the event, then repick
+	 * the current item using the button state *after* the event
+	 * (the button has logically gone up before we change the
+	 * current item).
+	 */
+
+	if (eventPtr->type == ButtonPress) {
+	    /*
+	     * On a button press, first repick the current item using
+	     * the button state before the event, the process the event.
+	     */
+
+	    canvasPtr->state = eventPtr->xbutton.state;
+	    PickCurrentItem(canvasPtr, eventPtr);
+	    canvasPtr->state ^= mask;
+	    CanvasDoEvent(canvasPtr, eventPtr);
+	} else {
+	    /*
+	     * Button release: first process the event, with the button
+	     * still considered to be down.  Then repick the current
+	     * item under the assumption that the button is no longer down.
+	     */
+
+	    canvasPtr->state = eventPtr->xbutton.state;
+	    CanvasDoEvent(canvasPtr, eventPtr);
+	    eventPtr->xbutton.state ^= mask;
+	    canvasPtr->state = eventPtr->xbutton.state;
+	    PickCurrentItem(canvasPtr, eventPtr);
+	    eventPtr->xbutton.state ^= mask;
+	}
+	goto done;
+    } else if ((eventPtr->type == EnterNotify)
+	    || (eventPtr->type == LeaveNotify)) {
+	canvasPtr->state = eventPtr->xcrossing.state;
+	PickCurrentItem(canvasPtr, eventPtr);
+	goto done;
+    } else if (eventPtr->type == MotionNotify) {
+	canvasPtr->state = eventPtr->xmotion.state;
+	PickCurrentItem(canvasPtr, eventPtr);
+    }
+    CanvasDoEvent(canvasPtr, eventPtr);
+
+    done:
+    Tcl_Release((ClientData) canvasPtr);
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * PickCurrentItem --
+ *
+ *	Find the topmost item in a canvas that contains a given
+ *	location and mark the the current item.  If the current
+ *	item has changed, generate a fake exit event on the old
+ *	current item and a fake enter event on the new current
+ *	item.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The current item for canvasPtr may change.  If it does,
+ *	then the commands associated with item entry and exit
+ *	could do just about anything.  A binding script could
+ *	delete the canvas, so callers should protect themselves
+ *	with Tcl_Preserve and Tcl_Release.
+ *
+ *--------------------------------------------------------------
+ */
+
+static void
+PickCurrentItem(canvasPtr, eventPtr)
+    TkCanvas *canvasPtr;		/* Canvas widget in which to select
+					 * current item. */
+    XEvent *eventPtr;			/* Event describing location of
+					 * mouse cursor.  Must be EnterWindow,
+					 * LeaveWindow, ButtonRelease, or
+					 * MotionNotify. */
+{
+    double coords[2];
+    int buttonDown;
+
+    /*
+     * Check whether or not a button is down.  If so, we'll log entry
+     * and exit into and out of the current item, but not entry into
+     * any other item.  This implements a form of grabbing equivalent
+     * to what the X server does for windows.
+     */
+
+    buttonDown = canvasPtr->state
+	    & (Button1Mask|Button2Mask|Button3Mask|Button4Mask|Button5Mask);
+    if (!buttonDown) {
+	canvasPtr->flags &= ~LEFT_GRABBED_ITEM;
+    }
+
+    /*
+     * Save information about this event in the canvas.  The event in
+     * the canvas is used for two purposes:
+     *
+     * 1. Event bindings: if the current item changes, fake events are
+     *    generated to allow item-enter and item-leave bindings to trigger.
+     * 2. Reselection: if the current item gets deleted, can use the
+     *    saved event to find a new current item.
+     * Translate MotionNotify events into EnterNotify events, since that's
+     * what gets reported to item handlers.
+     */
+
+    if (eventPtr != &canvasPtr->pickEvent) {
+	if ((eventPtr->type == MotionNotify)
+		|| (eventPtr->type == ButtonRelease)) {
+	    canvasPtr->pickEvent.xcrossing.type = EnterNotify;
+	    canvasPtr->pickEvent.xcrossing.serial = eventPtr->xmotion.serial;
+	    canvasPtr->pickEvent.xcrossing.send_event
+		    = eventPtr->xmotion.send_event;
+	    canvasPtr->pickEvent.xcrossing.display = eventPtr->xmotion.display;
+	    canvasPtr->pickEvent.xcrossing.window = eventPtr->xmotion.window;
+	    canvasPtr->pickEvent.xcrossing.root = eventPtr->xmotion.root;
+	    canvasPtr->pickEvent.xcrossing.subwindow = None;
+	    canvasPtr->pickEvent.xcrossing.time = eventPtr->xmotion.time;
+	    canvasPtr->pickEvent.xcrossing.x = eventPtr->xmotion.x;
+	    canvasPtr->pickEvent.xcrossing.y = eventPtr->xmotion.y;
+	    canvasPtr->pickEvent.xcrossing.x_root = eventPtr->xmotion.x_root;
+	    canvasPtr->pickEvent.xcrossing.y_root = eventPtr->xmotion.y_root;
+	    canvasPtr->pickEvent.xcrossing.mode = NotifyNormal;
+	    canvasPtr->pickEvent.xcrossing.detail = NotifyNonlinear;
+	    canvasPtr->pickEvent.xcrossing.same_screen
+		    = eventPtr->xmotion.same_screen;
+	    canvasPtr->pickEvent.xcrossing.focus = False;
+	    canvasPtr->pickEvent.xcrossing.state = eventPtr->xmotion.state;
+	} else  {
+	    canvasPtr->pickEvent = *eventPtr;
+	}
+    }
+
+    /*
+     * If this is a recursive call (there's already a partially completed
+     * call pending on the stack;  it's in the middle of processing a
+     * Leave event handler for the old current item) then just return;
+     * the pending call will do everything that's needed.
+     */
+
+    if (canvasPtr->flags & REPICK_IN_PROGRESS) {
+	return;
+    }
+
+    /*
+     * A LeaveNotify event automatically means that there's no current
+     * object, so the check for closest item can be skipped.
+     */
+
+    coords[0] = canvasPtr->pickEvent.xcrossing.x + canvasPtr->xOrigin;
+    coords[1] = canvasPtr->pickEvent.xcrossing.y + canvasPtr->yOrigin;
+    if (canvasPtr->pickEvent.type != LeaveNotify) {
+	canvasPtr->newCurrentPtr = CanvasFindClosest(canvasPtr, coords);
+    } else {
+	canvasPtr->newCurrentPtr = NULL;
+    }
+
+    if ((canvasPtr->newCurrentPtr == canvasPtr->currentItemPtr)
+	    && !(canvasPtr->flags & LEFT_GRABBED_ITEM)) {
+	/*
+	 * Nothing to do:  the current item hasn't changed.
+	 */
+
+	return;
+    }
+
+    /*
+     * Simulate a LeaveNotify event on the previous current item and
+     * an EnterNotify event on the new current item.  Remove the "current"
+     * tag from the previous current item and place it on the new current
+     * item.
+     */
+
+    if ((canvasPtr->newCurrentPtr != canvasPtr->currentItemPtr)
+	    && (canvasPtr->currentItemPtr != NULL)
+	    && !(canvasPtr->flags & LEFT_GRABBED_ITEM)) {
+	XEvent event;
+	Tk_Item *itemPtr = canvasPtr->currentItemPtr;
+	int i;
+
+	event = canvasPtr->pickEvent;
+	event.type = LeaveNotify;
+
+	/*
+	 * If the event's detail happens to be NotifyInferior the
+	 * binding mechanism will discard the event.  To be consistent,
+	 * always use NotifyAncestor.
+	 */
+
+	event.xcrossing.detail = NotifyAncestor;
+	canvasPtr->flags |= REPICK_IN_PROGRESS;
+	CanvasDoEvent(canvasPtr, &event);
+	canvasPtr->flags &= ~REPICK_IN_PROGRESS;
+
+	/*
+	 * The check below is needed because there could be an event
+	 * handler for <LeaveNotify> that deletes the current item.
+	 */
+
+	if ((itemPtr == canvasPtr->currentItemPtr) && !buttonDown) {
+	    for (i = itemPtr->numTags-1; i >= 0; i--) {
+		if (itemPtr->tagPtr[i] == currentUid) {
+		    itemPtr->tagPtr[i] = itemPtr->tagPtr[itemPtr->numTags-1];
+		    itemPtr->numTags--;
+		    break;
+		}
+	    }
+	}
+    
+	/*
+	 * Note:  during CanvasDoEvent above, it's possible that
+	 * canvasPtr->newCurrentPtr got reset to NULL because the
+	 * item was deleted.
+	 */
+    }
+    if ((canvasPtr->newCurrentPtr != canvasPtr->currentItemPtr) && buttonDown) {
+	canvasPtr->flags |= LEFT_GRABBED_ITEM;
+	return;
+    }
+
+    /*
+     * Special note:  it's possible that canvasPtr->newCurrentPtr ==
+     * canvasPtr->currentItemPtr here.  This can happen, for example,
+     * if LEFT_GRABBED_ITEM was set.
+     */
+
+    canvasPtr->flags &= ~LEFT_GRABBED_ITEM;
+    canvasPtr->currentItemPtr = canvasPtr->newCurrentPtr;
+    if (canvasPtr->currentItemPtr != NULL) {
+	XEvent event;
+
+	DoItem((Tcl_Interp *) NULL, canvasPtr->currentItemPtr, currentUid);
+	event = canvasPtr->pickEvent;
+	event.type = EnterNotify;
+	event.xcrossing.detail = NotifyAncestor;
+	CanvasDoEvent(canvasPtr, &event);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * CanvasFindClosest --
+ *
+ *	Given x and y coordinates, find the topmost canvas item that
+ *	is "close" to the coordinates.
+ *
+ * Results:
+ *	The return value is a pointer to the topmost item that is
+ *	close to (x,y), or NULL if no item is close.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static Tk_Item *
+CanvasFindClosest(canvasPtr, coords)
+    TkCanvas *canvasPtr;		/* Canvas widget to search. */
+    double coords[2];			/* Desired x,y position in canvas,
+					 * not screen, coordinates.) */
+{
+    Tk_Item *itemPtr;
+    Tk_Item *bestPtr;
+    int x1, y1, x2, y2;
+
+    x1 = (int) (coords[0] - canvasPtr->closeEnough);
+    y1 = (int) (coords[1] - canvasPtr->closeEnough);
+    x2 = (int) (coords[0] + canvasPtr->closeEnough);
+    y2 = (int) (coords[1] + canvasPtr->closeEnough);
+
+    bestPtr = NULL;
+    for (itemPtr = canvasPtr->firstItemPtr; itemPtr != NULL;
+	    itemPtr = itemPtr->nextPtr) {
+	if ((itemPtr->x1 > x2) || (itemPtr->x2 < x1)
+		|| (itemPtr->y1 > y2) || (itemPtr->y2 < y1)) {
+	    continue;
+	}
+	if ((*itemPtr->typePtr->pointProc)((Tk_Canvas) canvasPtr,
+		itemPtr, coords) <= canvasPtr->closeEnough) {
+	    bestPtr = itemPtr;
+	}
+    }
+    return bestPtr;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * CanvasDoEvent --
+ *
+ *	This procedure is called to invoke binding processing
+ *	for a new event that is associated with the current item
+ *	for a canvas.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Depends on the bindings for the canvas.  A binding script
+ *	could delete the canvas, so callers should protect themselves
+ *	with Tcl_Preserve and Tcl_Release.
+ *
+ *--------------------------------------------------------------
+ */
+
+static void
+CanvasDoEvent(canvasPtr, eventPtr)
+    TkCanvas *canvasPtr;		/* Canvas widget in which event
+					 * occurred. */
+    XEvent *eventPtr;			/* Real or simulated X event that
+					 * is to be processed. */
+{
+#define NUM_STATIC 3
+    ClientData staticObjects[NUM_STATIC];
+    ClientData *objectPtr;
+    int numObjects, i;
+    Tk_Item *itemPtr;
+
+    if (canvasPtr->bindingTable == NULL) {
+	return;
+    }
+
+    itemPtr = canvasPtr->currentItemPtr;
+    if ((eventPtr->type == KeyPress) || (eventPtr->type == KeyRelease)) {
+	itemPtr = canvasPtr->textInfo.focusItemPtr;
+    }
+    if (itemPtr == NULL) {
+	return;
+    }
+
+    /*
+     * Set up an array with all the relevant objects for processing
+     * this event.  The relevant objects are (a) the event's item,
+     * (b) the tags associated with the event's item, and (c) the
+     * tag "all".  If there are a lot of tags then malloc an array
+     * to hold all of the objects.
+     */
+
+    numObjects = itemPtr->numTags + 2;
+    if (numObjects <= NUM_STATIC) {
+	objectPtr = staticObjects;
+    } else {
+	objectPtr = (ClientData *) ckalloc((unsigned)
+		(numObjects * sizeof(ClientData)));
+    }
+    objectPtr[0] = (ClientData) allUid;
+    for (i = itemPtr->numTags-1; i >= 0; i--) {
+	objectPtr[i+1] = (ClientData) itemPtr->tagPtr[i];
+    }
+    objectPtr[itemPtr->numTags+1] = (ClientData) itemPtr;
+
+    /*
+     * Invoke the binding system, then free up the object array if
+     * it was malloc-ed.
+     */
+
+    if (canvasPtr->tkwin != NULL) {
+	Tk_BindEvent(canvasPtr->bindingTable, eventPtr, canvasPtr->tkwin,
+		numObjects, objectPtr);
+    }
+    if (objectPtr != staticObjects) {
+	ckfree((char *) objectPtr);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * CanvasBlinkProc --
+ *
+ *	This procedure is called as a timer handler to blink the
+ *	insertion cursor off and on.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The cursor gets turned on or off, redisplay gets invoked,
+ *	and this procedure reschedules itself.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+CanvasBlinkProc(clientData)
+    ClientData clientData;	/* Pointer to record describing entry. */
+{
+    TkCanvas *canvasPtr = (TkCanvas *) clientData;
+
+    if (!canvasPtr->textInfo.gotFocus || (canvasPtr->insertOffTime == 0)) {
+	return;
+    }
+    if (canvasPtr->textInfo.cursorOn) {
+	canvasPtr->textInfo.cursorOn = 0;
+	canvasPtr->insertBlinkHandler = Tcl_CreateTimerHandler(
+		canvasPtr->insertOffTime, CanvasBlinkProc,
+		(ClientData) canvasPtr);
+    } else {
+	canvasPtr->textInfo.cursorOn = 1;
+	canvasPtr->insertBlinkHandler = Tcl_CreateTimerHandler(
+		canvasPtr->insertOnTime, CanvasBlinkProc,
+		(ClientData) canvasPtr);
+    }
+    if (canvasPtr->textInfo.focusItemPtr != NULL) {
+	Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+		canvasPtr->textInfo.focusItemPtr->x1,
+		canvasPtr->textInfo.focusItemPtr->y1,
+		canvasPtr->textInfo.focusItemPtr->x2,
+		canvasPtr->textInfo.focusItemPtr->y2);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * CanvasFocusProc --
+ *
+ *	This procedure is called whenever a canvas gets or loses the
+ *	input focus.  It's also called whenever the window is
+ *	reconfigured while it has the focus.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The cursor gets turned on or off.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+CanvasFocusProc(canvasPtr, gotFocus)
+    TkCanvas *canvasPtr;	/* Canvas that just got or lost focus. */
+    int gotFocus;		/* 1 means window is getting focus, 0 means
+				 * it's losing it. */
+{
+    Tcl_DeleteTimerHandler(canvasPtr->insertBlinkHandler);
+    if (gotFocus) {
+	canvasPtr->textInfo.gotFocus = 1;
+	canvasPtr->textInfo.cursorOn = 1;
+	if (canvasPtr->insertOffTime != 0) {
+	    canvasPtr->insertBlinkHandler = Tcl_CreateTimerHandler(
+		    canvasPtr->insertOffTime, CanvasBlinkProc,
+		    (ClientData) canvasPtr);
+	}
+    } else {
+	canvasPtr->textInfo.gotFocus = 0;
+	canvasPtr->textInfo.cursorOn = 0;
+	canvasPtr->insertBlinkHandler = (Tcl_TimerToken) NULL;
+    }
+    if (canvasPtr->textInfo.focusItemPtr != NULL) {
+	Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+		canvasPtr->textInfo.focusItemPtr->x1,
+		canvasPtr->textInfo.focusItemPtr->y1,
+		canvasPtr->textInfo.focusItemPtr->x2,
+		canvasPtr->textInfo.focusItemPtr->y2);
+    }
+    if (canvasPtr->highlightWidth > 0) {
+	canvasPtr->flags |= REDRAW_BORDERS;
+	if (!(canvasPtr->flags & REDRAW_PENDING)) {
+	    Tcl_DoWhenIdle(DisplayCanvas, (ClientData) canvasPtr);
+	    canvasPtr->flags |= REDRAW_PENDING;
+	}
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * CanvasSelectTo --
+ *
+ *	Modify the selection by moving its un-anchored end.  This could
+ *	make the selection either larger or smaller.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The selection changes.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+CanvasSelectTo(canvasPtr, itemPtr, index)
+    TkCanvas *canvasPtr;	/* Information about widget. */
+    Tk_Item *itemPtr;		/* Item that is to hold selection. */
+    int index;			/* Index of element that is to become the
+				 * "other" end of the selection. */
+{
+    int oldFirst, oldLast;
+    Tk_Item *oldSelPtr;
+
+    oldFirst = canvasPtr->textInfo.selectFirst;
+    oldLast = canvasPtr->textInfo.selectLast;
+    oldSelPtr = canvasPtr->textInfo.selItemPtr;
+
+    /*
+     * Grab the selection if we don't own it already.
+     */
+
+    if (canvasPtr->textInfo.selItemPtr == NULL) {
+	Tk_OwnSelection(canvasPtr->tkwin, XA_PRIMARY, CanvasLostSelection,
+		(ClientData) canvasPtr);
+    } else if (canvasPtr->textInfo.selItemPtr != itemPtr) {
+	Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+		canvasPtr->textInfo.selItemPtr->x1,
+		canvasPtr->textInfo.selItemPtr->y1,
+		canvasPtr->textInfo.selItemPtr->x2,
+		canvasPtr->textInfo.selItemPtr->y2);
+    }
+    canvasPtr->textInfo.selItemPtr = itemPtr;
+
+    if (canvasPtr->textInfo.anchorItemPtr != itemPtr) {
+	canvasPtr->textInfo.anchorItemPtr = itemPtr;
+	canvasPtr->textInfo.selectAnchor = index;
+    }
+    if (canvasPtr->textInfo.selectAnchor <= index) {
+	canvasPtr->textInfo.selectFirst = canvasPtr->textInfo.selectAnchor;
+	canvasPtr->textInfo.selectLast = index;
+    } else {
+	canvasPtr->textInfo.selectFirst = index;
+	canvasPtr->textInfo.selectLast = canvasPtr->textInfo.selectAnchor - 1;
+    }
+    if ((canvasPtr->textInfo.selectFirst != oldFirst)
+	    || (canvasPtr->textInfo.selectLast != oldLast)
+	    || (itemPtr != oldSelPtr)) {
+	Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+		itemPtr->x1, itemPtr->y1, itemPtr->x2, itemPtr->y2);
+    }
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * CanvasFetchSelection --
+ *
+ *	This procedure is invoked by Tk to return part or all of
+ *	the selection, when the selection is in a canvas widget.
+ *	This procedure always returns the selection as a STRING.
+ *
+ * Results:
+ *	The return value is the number of non-NULL bytes stored
+ *	at buffer.  Buffer is filled (or partially filled) with a
+ *	NULL-terminated string containing part or all of the selection,
+ *	as given by offset and maxBytes.
+ *
+ * Side effects:
+ *	None.
+ *
+ *--------------------------------------------------------------
+ */
+
+static int
+CanvasFetchSelection(clientData, offset, buffer, maxBytes)
+    ClientData clientData;		/* Information about canvas widget. */
+    int offset;				/* Offset within selection of first
+					 * character to be returned. */
+    char *buffer;			/* Location in which to place
+					 * selection. */
+    int maxBytes;			/* Maximum number of bytes to place
+					 * at buffer, not including terminating
+					 * NULL character. */
+{
+    TkCanvas *canvasPtr = (TkCanvas *) clientData;
+
+    if (canvasPtr->textInfo.selItemPtr == NULL) {
+	return -1;
+    }
+    if (canvasPtr->textInfo.selItemPtr->typePtr->selectionProc == NULL) {
+	return -1;
+    }
+    return (*canvasPtr->textInfo.selItemPtr->typePtr->selectionProc)(
+	    (Tk_Canvas) canvasPtr, canvasPtr->textInfo.selItemPtr, offset,
+	    buffer, maxBytes);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * CanvasLostSelection --
+ *
+ *	This procedure is called back by Tk when the selection is
+ *	grabbed away from a canvas widget.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The existing selection is unhighlighted, and the window is
+ *	marked as not containing a selection.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+CanvasLostSelection(clientData)
+    ClientData clientData;		/* Information about entry widget. */
+{
+    TkCanvas *canvasPtr = (TkCanvas *) clientData;
+
+    if (canvasPtr->textInfo.selItemPtr != NULL) {
+	Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+		canvasPtr->textInfo.selItemPtr->x1,
+		canvasPtr->textInfo.selItemPtr->y1,
+		canvasPtr->textInfo.selItemPtr->x2,
+		canvasPtr->textInfo.selItemPtr->y2);
+    }
+    canvasPtr->textInfo.selItemPtr = NULL;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * GridAlign --
+ *
+ *	Given a coordinate and a grid spacing, this procedure
+ *	computes the location of the nearest grid line to the
+ *	coordinate.
+ *
+ * Results:
+ *	The return value is the location of the grid line nearest
+ *	to coord.
+ *
+ * Side effects:
+ *	None.
+ *
+ *--------------------------------------------------------------
+ */
+
+static double
+GridAlign(coord, spacing)
+    double coord;		/* Coordinate to grid-align. */
+    double spacing;		/* Spacing between grid lines.   If <= 0
+				 * then no alignment is done. */
+{
+    if (spacing <= 0.0) {
+	return coord;
+    }
+    if (coord < 0) {
+	return -((int) ((-coord)/spacing + 0.5)) * spacing;
+    }
+    return ((int) (coord/spacing + 0.5)) * spacing;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * PrintScrollFractions --
+ *
+ *	Given the range that's visible in the window and the "100%
+ *	range" for what's in the canvas, print a string containing
+ *	the scroll fractions.  This procedure is used for both x
+ *	and y scrolling.
+ *
+ * Results:
+ *	The memory pointed to by string is modified to hold
+ *	two real numbers containing the scroll fractions (between
+ *	0 and 1) corresponding to the other arguments.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+PrintScrollFractions(screen1, screen2, object1, object2, string)
+    int screen1;		/* Lowest coordinate visible in the window. */
+    int screen2;		/* Highest coordinate visible in the window. */
+    int object1;		/* Lowest coordinate in the object. */
+    int object2;		/* Highest coordinate in the object. */
+    char *string;		/* Two real numbers get printed here.  Must
+				 * have enough storage for two %g
+				 * conversions. */
+{
+    double range, f1, f2;
+
+    range = object2 - object1;
+    if (range <= 0) {
+	f1 = 0;
+	f2 = 1.0;
+    } else {
+	f1 = (screen1 - object1)/range;
+	if (f1 < 0) {
+	    f1 = 0.0;
+	}
+	f2 = (screen2 - object1)/range;
+	if (f2 > 1.0) {
+	    f2 = 1.0;
+	}
+	if (f2 < f1) {
+	    f2 = f1;
+	}
+    }
+    sprintf(string, "%g %g", f1, f2);
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * CanvasUpdateScrollbars --
+ *
+ *	This procedure is invoked whenever a canvas has changed in
+ *	a way that requires scrollbars to be redisplayed (e.g. the
+ *	view in the canvas has changed).
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	If there are scrollbars associated with the canvas, then
+ *	their scrolling commands are invoked to cause them to
+ *	redisplay.  If errors occur, additional Tcl commands may
+ *	be invoked to process the errors.
+ *
+ *--------------------------------------------------------------
+ */
+
+static void
+CanvasUpdateScrollbars(canvasPtr)
+    TkCanvas *canvasPtr;		/* Information about canvas. */
+{
+    int result;
+    char buffer[200];
+    Tcl_Interp *interp;
+    int xOrigin, yOrigin, inset, width, height, scrollX1, scrollX2,
+        scrollY1, scrollY2;
+    char *xScrollCmd, *yScrollCmd;
+
+    /*
+     * Save all the relevant values from the canvasPtr, because it might be
+     * deleted as part of either of the two calls to Tcl_VarEval below.
+     */
+    
+    interp = canvasPtr->interp;
+    Tcl_Preserve((ClientData) interp);
+    xScrollCmd = canvasPtr->xScrollCmd;
+    if (xScrollCmd != (char *) NULL) {
+        Tcl_Preserve((ClientData) xScrollCmd);
+    }
+    yScrollCmd = canvasPtr->yScrollCmd;
+    if (yScrollCmd != (char *) NULL) {
+        Tcl_Preserve((ClientData) yScrollCmd);
+    }
+    xOrigin = canvasPtr->xOrigin;
+    yOrigin = canvasPtr->yOrigin;
+    inset = canvasPtr->inset;
+    width = Tk_Width(canvasPtr->tkwin);
+    height = Tk_Height(canvasPtr->tkwin);
+    scrollX1 = canvasPtr->scrollX1;
+    scrollX2 = canvasPtr->scrollX2;
+    scrollY1 = canvasPtr->scrollY1;
+    scrollY2 = canvasPtr->scrollY2;
+    canvasPtr->flags &= ~UPDATE_SCROLLBARS;
+    if (canvasPtr->xScrollCmd != NULL) {
+	PrintScrollFractions(xOrigin + inset, xOrigin + width - inset,
+                scrollX1, scrollX2, buffer);
+	result = Tcl_VarEval(interp, xScrollCmd, " ", buffer, (char *) NULL);
+	if (result != TCL_OK) {
+	    Tcl_BackgroundError(interp);
+	}
+	Tcl_ResetResult(interp);
+        Tcl_Release((ClientData) xScrollCmd);
+    }
+
+    if (yScrollCmd != NULL) {
+	PrintScrollFractions(yOrigin + inset, yOrigin + height - inset,
+                scrollY1, scrollY2, buffer);
+	result = Tcl_VarEval(interp, yScrollCmd, " ", buffer, (char *) NULL);
+	if (result != TCL_OK) {
+	    Tcl_BackgroundError(interp);
+	}
+	Tcl_ResetResult(interp);
+        Tcl_Release((ClientData) yScrollCmd);
+    }
+    Tcl_Release((ClientData) interp);
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * CanvasSetOrigin --
+ *
+ *	This procedure is invoked to change the mapping between
+ *	canvas coordinates and screen coordinates in the canvas
+ *	window.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The canvas will be redisplayed to reflect the change in
+ *	view.  In addition, scrollbars will be updated if there
+ *	are any.
+ *
+ *--------------------------------------------------------------
+ */
+
+static void
+CanvasSetOrigin(canvasPtr, xOrigin, yOrigin)
+    TkCanvas *canvasPtr;	/* Information about canvas. */
+    int xOrigin;		/* New X origin for canvas (canvas x-coord
+				 * corresponding to left edge of canvas
+				 * window). */
+    int yOrigin;		/* New Y origin for canvas (canvas y-coord
+				 * corresponding to top edge of canvas
+				 * window). */
+{
+    int left, right, top, bottom, delta;
+
+    /*
+     * If scroll increments have been set, round the window origin
+     * to the nearest multiple of the increments.  Remember, the
+     * origin is the place just inside the borders,  not the upper
+     * left corner.
+     */
+
+    if (canvasPtr->xScrollIncrement > 0) {
+	if (xOrigin >= 0) {
+	    xOrigin += canvasPtr->xScrollIncrement/2;
+	    xOrigin -= (xOrigin + canvasPtr->inset)
+		    % canvasPtr->xScrollIncrement;
+	} else {
+	    xOrigin = (-xOrigin) + canvasPtr->xScrollIncrement/2;
+	    xOrigin = -(xOrigin - (xOrigin - canvasPtr->inset)
+		    % canvasPtr->xScrollIncrement);
+	}
+    }
+    if (canvasPtr->yScrollIncrement > 0) {
+	if (yOrigin >= 0) {
+	    yOrigin += canvasPtr->yScrollIncrement/2;
+	    yOrigin -= (yOrigin + canvasPtr->inset)
+		    % canvasPtr->yScrollIncrement;
+	} else {
+	    yOrigin = (-yOrigin) + canvasPtr->yScrollIncrement/2;
+	    yOrigin = -(yOrigin - (yOrigin - canvasPtr->inset)
+		    % canvasPtr->yScrollIncrement);
+	}
+    }
+
+    /*
+     * Adjust the origin if necessary to keep as much as possible of the
+     * canvas in the view.  The variables left, right, etc. keep track of
+     * how much extra space there is on each side of the view before it
+     * will stick out past the scroll region.  If one side sticks out past
+     * the edge of the scroll region, adjust the view to bring that side
+     * back to the edge of the scrollregion (but don't move it so much that
+     * the other side sticks out now).  If scroll increments are in effect,
+     * be sure to adjust only by full increments.
+     */
+
+    if ((canvasPtr->confine) && (canvasPtr->regionString != NULL)) {
+	left = xOrigin + canvasPtr->inset - canvasPtr->scrollX1;
+	right = canvasPtr->scrollX2
+		- (xOrigin + Tk_Width(canvasPtr->tkwin) - canvasPtr->inset);
+	top = yOrigin + canvasPtr->inset - canvasPtr->scrollY1;
+	bottom = canvasPtr->scrollY2
+		- (yOrigin + Tk_Height(canvasPtr->tkwin) - canvasPtr->inset);
+	if ((left < 0) && (right > 0)) {
+	    delta = (right > -left) ? -left : right;
+	    if (canvasPtr->xScrollIncrement > 0) {
+		delta -= delta % canvasPtr->xScrollIncrement;
+	    }
+	    xOrigin += delta;
+	} else if ((right < 0) && (left > 0)) {
+	    delta = (left > -right) ? -right : left;
+	    if (canvasPtr->xScrollIncrement > 0) {
+		delta -= delta % canvasPtr->xScrollIncrement;
+	    }
+	    xOrigin -= delta;
+	}
+	if ((top < 0) && (bottom > 0)) {
+	    delta = (bottom > -top) ? -top : bottom;
+	    if (canvasPtr->yScrollIncrement > 0) {
+		delta -= delta % canvasPtr->yScrollIncrement;
+	    }
+	    yOrigin += delta;
+	} else if ((bottom < 0) && (top > 0)) {
+	    delta = (top > -bottom) ? -bottom : top;
+	    if (canvasPtr->yScrollIncrement > 0) {
+		delta -= delta % canvasPtr->yScrollIncrement;
+	    }
+	    yOrigin -= delta;
+	}
+    }
+
+    if ((xOrigin == canvasPtr->xOrigin) && (yOrigin == canvasPtr->yOrigin)) {
+	return;
+    }
+
+    /*
+     * Tricky point: must redisplay not only everything that's visible
+     * in the window's final configuration, but also everything that was
+     * visible in the initial configuration.  This is needed because some
+     * item types, like windows, need to know when they move off-screen
+     * so they can explicitly undisplay themselves.
+     */
+
+    Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+	    canvasPtr->xOrigin, canvasPtr->yOrigin,
+	    canvasPtr->xOrigin + Tk_Width(canvasPtr->tkwin),
+	    canvasPtr->yOrigin + Tk_Height(canvasPtr->tkwin));
+    canvasPtr->xOrigin = xOrigin;
+    canvasPtr->yOrigin = yOrigin;
+    canvasPtr->flags |= UPDATE_SCROLLBARS;
+    Tk_CanvasEventuallyRedraw((Tk_Canvas) canvasPtr,
+	    canvasPtr->xOrigin, canvasPtr->yOrigin,
+	    canvasPtr->xOrigin + Tk_Width(canvasPtr->tkwin),
+	    canvasPtr->yOrigin + Tk_Height(canvasPtr->tkwin));
+}