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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));
+}