Initial revision

1 files changed, 363 insertions, 0 deletions

diff --git a/generic/tkGC.c b/generic/tkGC.c
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+++ b/generic/tkGC.c
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+/* 
+ * tkGC.c --
+ *
+ *	This file maintains a database of read-only graphics contexts 
+ *	for the Tk toolkit, in order to allow GC's to be shared.
+ *
+ * Copyright (c) 1990-1994 The Regents of the University of California.
+ * Copyright (c) 1994 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: @(#) tkGC.c 1.18 96/02/15 18:53:32
+ */
+
+#include "tkPort.h"
+#include "tk.h"
+
+/*
+ * One of the following data structures exists for each GC that is
+ * currently active.  The structure is indexed with two hash tables,
+ * one based on the values in the graphics context and the other
+ * based on the display and GC identifier.
+ */
+
+typedef struct {
+    GC gc;			/* Graphics context. */
+    Display *display;		/* Display to which gc belongs. */
+    int refCount;		/* Number of active uses of gc. */
+    Tcl_HashEntry *valueHashPtr;/* Entry in valueTable (needed when deleting
+				 * this structure). */
+} TkGC;
+
+/*
+ * Hash table to map from a GC's values to a TkGC structure describing
+ * a GC with those values (used by Tk_GetGC).
+ */
+
+static Tcl_HashTable valueTable;
+typedef struct {
+    XGCValues values;		/* Desired values for GC. */
+    Display *display;		/* Display for which GC is valid. */
+    int screenNum;		/* screen number of display */
+    int depth;			/* and depth for which GC is valid. */
+} ValueKey;
+
+/*
+ * Hash table for <display + GC> -> TkGC mapping. This table is used by
+ * Tk_FreeGC.
+ */
+
+static Tcl_HashTable idTable;
+typedef struct {
+    Display *display;		/* Display for which GC was allocated. */
+    GC gc;			/* X's identifier for GC. */
+} IdKey;
+
+static int initialized = 0;	/* 0 means static structures haven't been
+				 * initialized yet. */
+
+/*
+ * Forward declarations for procedures defined in this file:
+ */
+
+static void		GCInit _ANSI_ARGS_((void));
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tk_GetGC --
+ *
+ *	Given a desired set of values for a graphics context, find
+ *	a read-only graphics context with the desired values.
+ *
+ * Results:
+ *	The return value is the X identifer for the desired graphics
+ *	context.  The caller should never modify this GC, and should
+ *	call Tk_FreeGC when the GC is no longer needed.
+ *
+ * Side effects:
+ *	The GC is added to an internal database with a reference count.
+ *	For each call to this procedure, there should eventually be a call
+ *	to Tk_FreeGC, so that the database can be cleaned up when GC's
+ *	aren't needed anymore.
+ *
+ *----------------------------------------------------------------------
+ */
+
+GC
+Tk_GetGC(tkwin, valueMask, valuePtr)
+    Tk_Window tkwin;		/* Window in which GC will be used. */
+    register unsigned long valueMask;
+				/* 1 bits correspond to values specified
+				 * in *valuesPtr;  other values are set
+				 * from defaults. */
+    register XGCValues *valuePtr;
+				/* Values are specified here for bits set
+				 * in valueMask. */
+{
+    ValueKey valueKey;
+    IdKey idKey;
+    Tcl_HashEntry *valueHashPtr, *idHashPtr;
+    register TkGC *gcPtr;
+    int new;
+    Drawable d, freeDrawable;
+
+    if (!initialized) {
+	GCInit();
+    }
+
+    /*
+     * Must zero valueKey at start to clear out pad bytes that may be
+     * part of structure on some systems.
+     */
+
+    memset((VOID *) &valueKey, 0, sizeof(valueKey));
+
+    /*
+     * First, check to see if there's already a GC that will work
+     * for this request (exact matches only, sorry).
+     */
+
+    if (valueMask & GCFunction) {
+	valueKey.values.function = valuePtr->function;
+    } else {
+	valueKey.values.function = GXcopy;
+    }
+    if (valueMask & GCPlaneMask) {
+	valueKey.values.plane_mask = valuePtr->plane_mask;
+    } else {
+	valueKey.values.plane_mask = (unsigned) ~0;
+    }
+    if (valueMask & GCForeground) {
+	valueKey.values.foreground = valuePtr->foreground;
+    } else {
+	valueKey.values.foreground = 0;
+    }
+    if (valueMask & GCBackground) {
+	valueKey.values.background = valuePtr->background;
+    } else {
+	valueKey.values.background = 1;
+    }
+    if (valueMask & GCLineWidth) {
+	valueKey.values.line_width = valuePtr->line_width;
+    } else {
+	valueKey.values.line_width = 0;
+    }
+    if (valueMask & GCLineStyle) {
+	valueKey.values.line_style = valuePtr->line_style;
+    } else {
+	valueKey.values.line_style = LineSolid;
+    }
+    if (valueMask & GCCapStyle) {
+	valueKey.values.cap_style = valuePtr->cap_style;
+    } else {
+	valueKey.values.cap_style = CapButt;
+    }
+    if (valueMask & GCJoinStyle) {
+	valueKey.values.join_style = valuePtr->join_style;
+    } else {
+	valueKey.values.join_style = JoinMiter;
+    }
+    if (valueMask & GCFillStyle) {
+	valueKey.values.fill_style = valuePtr->fill_style;
+    } else {
+	valueKey.values.fill_style = FillSolid;
+    }
+    if (valueMask & GCFillRule) {
+	valueKey.values.fill_rule = valuePtr->fill_rule;
+    } else {
+	valueKey.values.fill_rule = EvenOddRule;
+    }
+    if (valueMask & GCArcMode) {
+	valueKey.values.arc_mode = valuePtr->arc_mode;
+    } else {
+	valueKey.values.arc_mode = ArcPieSlice;
+    }
+    if (valueMask & GCTile) {
+	valueKey.values.tile = valuePtr->tile;
+    } else {
+	valueKey.values.tile = None;
+    }
+    if (valueMask & GCStipple) {
+	valueKey.values.stipple = valuePtr->stipple;
+    } else {
+	valueKey.values.stipple = None;
+    }
+    if (valueMask & GCTileStipXOrigin) {
+	valueKey.values.ts_x_origin = valuePtr->ts_x_origin;
+    } else {
+	valueKey.values.ts_x_origin = 0;
+    }
+    if (valueMask & GCTileStipYOrigin) {
+	valueKey.values.ts_y_origin = valuePtr->ts_y_origin;
+    } else {
+	valueKey.values.ts_y_origin = 0;
+    }
+    if (valueMask & GCFont) {
+	valueKey.values.font = valuePtr->font;
+    } else {
+	valueKey.values.font = None;
+    }
+    if (valueMask & GCSubwindowMode) {
+	valueKey.values.subwindow_mode = valuePtr->subwindow_mode;
+    } else {
+	valueKey.values.subwindow_mode = ClipByChildren;
+    }
+    if (valueMask & GCGraphicsExposures) {
+	valueKey.values.graphics_exposures = valuePtr->graphics_exposures;
+    } else {
+	valueKey.values.graphics_exposures = True;
+    }
+    if (valueMask & GCClipXOrigin) {
+	valueKey.values.clip_x_origin = valuePtr->clip_x_origin;
+    } else {
+	valueKey.values.clip_x_origin = 0;
+    }
+    if (valueMask & GCClipYOrigin) {
+	valueKey.values.clip_y_origin = valuePtr->clip_y_origin;
+    } else {
+	valueKey.values.clip_y_origin = 0;
+    }
+    if (valueMask & GCClipMask) {
+	valueKey.values.clip_mask = valuePtr->clip_mask;
+    } else {
+	valueKey.values.clip_mask = None;
+    }
+    if (valueMask & GCDashOffset) {
+	valueKey.values.dash_offset = valuePtr->dash_offset;
+    } else {
+	valueKey.values.dash_offset = 0;
+    }
+    if (valueMask & GCDashList) {
+	valueKey.values.dashes = valuePtr->dashes;
+    } else {
+	valueKey.values.dashes = 4;
+    }
+    valueKey.display = Tk_Display(tkwin);
+    valueKey.screenNum = Tk_ScreenNumber(tkwin);
+    valueKey.depth = Tk_Depth(tkwin);
+    valueHashPtr = Tcl_CreateHashEntry(&valueTable, (char *) &valueKey, &new);
+    if (!new) {
+	gcPtr = (TkGC *) Tcl_GetHashValue(valueHashPtr);
+	gcPtr->refCount++;
+	return gcPtr->gc;
+    }
+
+    /*
+     * No GC is currently available for this set of values.  Allocate a
+     * new GC and add a new structure to the database.
+     */
+
+    gcPtr = (TkGC *) ckalloc(sizeof(TkGC));
+
+    /*
+     * Find or make a drawable to use to specify the screen and depth
+     * of the GC.  We may have to make a small pixmap, to avoid doing
+     * Tk_MakeWindowExist on the window.
+     */
+
+    freeDrawable = None;
+    if (Tk_WindowId(tkwin) != None) {
+	d = Tk_WindowId(tkwin);
+    } else if (valueKey.depth ==
+	    DefaultDepth(valueKey.display, valueKey.screenNum)) {
+	d = RootWindow(valueKey.display, valueKey.screenNum);
+    } else {
+	d = Tk_GetPixmap(valueKey.display,
+		RootWindow(valueKey.display, valueKey.screenNum),
+		1, 1, valueKey.depth);
+	freeDrawable = d;
+    }
+
+    gcPtr->gc = XCreateGC(valueKey.display, d, valueMask, &valueKey.values);
+    gcPtr->display = valueKey.display;
+    gcPtr->refCount = 1;
+    gcPtr->valueHashPtr = valueHashPtr;
+    idKey.display = valueKey.display;
+    idKey.gc = gcPtr->gc;
+    idHashPtr = Tcl_CreateHashEntry(&idTable, (char *) &idKey, &new);
+    if (!new) {
+	panic("GC already registered in Tk_GetGC");
+    }
+    Tcl_SetHashValue(valueHashPtr, gcPtr);
+    Tcl_SetHashValue(idHashPtr, gcPtr);
+    if (freeDrawable != None) {
+	Tk_FreePixmap(valueKey.display, freeDrawable);
+    }
+
+    return gcPtr->gc;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tk_FreeGC --
+ *
+ *	This procedure is called to release a graphics context allocated by
+ *	Tk_GetGC.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The reference count associated with gc is decremented, and
+ *	gc is officially deallocated if no-one is using it anymore.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tk_FreeGC(display, gc)
+    Display *display;		/* Display for which gc was allocated. */
+    GC gc;			/* Graphics context to be released. */
+{
+    IdKey idKey;
+    Tcl_HashEntry *idHashPtr;
+    register TkGC *gcPtr;
+
+    if (!initialized) {
+	panic("Tk_FreeGC called before Tk_GetGC");
+    }
+
+    idKey.display = display;
+    idKey.gc = gc;
+    idHashPtr = Tcl_FindHashEntry(&idTable, (char *) &idKey);
+    if (idHashPtr == NULL) {
+	panic("Tk_FreeGC received unknown gc argument");
+    }
+    gcPtr = (TkGC *) Tcl_GetHashValue(idHashPtr);
+    gcPtr->refCount--;
+    if (gcPtr->refCount == 0) {
+	Tk_FreeXId(gcPtr->display, (XID) XGContextFromGC(gcPtr->gc));
+	XFreeGC(gcPtr->display, gcPtr->gc);
+	Tcl_DeleteHashEntry(gcPtr->valueHashPtr);
+	Tcl_DeleteHashEntry(idHashPtr);
+	ckfree((char *) gcPtr);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * GCInit --
+ *
+ *	Initialize the structures used for GC management.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Read the code.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+GCInit()
+{
+    initialized = 1;
+    Tcl_InitHashTable(&valueTable, sizeof(ValueKey)/sizeof(int));
+    Tcl_InitHashTable(&idTable, sizeof(IdKey)/sizeof(int));
+}