/*
* 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 "tkInt.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));
}