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/*
* tkVisual.c --
*
* This file contains library procedures for allocating and freeing
* visuals and colormaps. This code is based on a prototype
* implementation by Paul Mackerras.
*
* Copyright (c) 1994 The Regents of the University of California.
* Copyright (c) 1994-1997 Sun Microsystems, Inc.
*
* See the file "license.terms" for information on usage and redistribution of
* this file, and for a DISCLAIMER OF ALL WARRANTIES.
*/
#include "tkInt.h"
/*
* The table below maps from symbolic names for visual classes to the
* associated X class symbols.
*/
typedef struct VisualDictionary {
const char *name; /* Textual name of class. */
int minLength; /* Minimum # characters that must be specified
* for an unambiguous match. */
int class; /* X symbol for class. */
} VisualDictionary;
static const VisualDictionary visualNames[] = {
{"best", 1, 0},
{"directcolor", 2, DirectColor},
{"grayscale", 1, GrayScale},
{"greyscale", 1, GrayScale},
{"pseudocolor", 1, PseudoColor},
{"staticcolor", 7, StaticColor},
{"staticgray", 7, StaticGray},
{"staticgrey", 7, StaticGray},
{"truecolor", 1, TrueColor},
{NULL, 0, 0},
};
/*
* One of the following structures exists for each distinct non-default
* colormap allocated for a display by Tk_GetColormap.
*/
struct TkColormap {
Colormap colormap; /* X's identifier for the colormap. */
Visual *visual; /* Visual for which colormap was allocated. */
int refCount; /* How many uses of the colormap are still
* outstanding (calls to Tk_GetColormap minus
* calls to Tk_FreeColormap). */
int shareable; /* 0 means this colormap was allocated by a
* call to Tk_GetColormap with "new", implying
* that the window wants it all for itself. 1
* means that the colormap was allocated as a
* default for a particular visual, so it can
* be shared. */
struct TkColormap *nextPtr; /* Next in list of colormaps for this display,
* or NULL for end of list. */
};
/*
*----------------------------------------------------------------------
*
* Tk_GetVisual --
*
* Given a string identifying a particular kind of visual, this procedure
* returns a visual and depth that matches the specification.
*
* Results:
* The return value is normally a pointer to a visual. If an error
* occurred in looking up the visual, NULL is returned and an error
* message is left in the interp's result. The depth of the visual is
* returned to *depthPtr under normal returns. If colormapPtr is
* non-NULL, then this procedure also finds a suitable colormap for use
* with the visual in tkwin, and it returns that colormap in *colormapPtr
* unless an error occurs.
*
* Side effects:
* A new colormap may be allocated.
*
*----------------------------------------------------------------------
*/
Visual *
Tk_GetVisual(
Tcl_Interp *interp, /* Interpreter to use for error reporting. */
Tk_Window tkwin, /* Window in which visual will be used. */
const char *string, /* String describing visual. See manual entry
* for details. */
int *depthPtr, /* The depth of the returned visual is stored
* here. */
Colormap *colormapPtr) /* If non-NULL, then a suitable colormap for
* visual is placed here. This colormap must
* eventually be freed by calling
* Tk_FreeColormap. */
{
Tk_Window tkwin2;
XVisualInfo template, *visInfoList, *bestPtr;
long mask;
Visual *visual;
ptrdiff_t length;
int c, numVisuals, prio, bestPrio, i;
const char *p;
const VisualDictionary *dictPtr;
TkColormap *cmapPtr;
TkDisplay *dispPtr = ((TkWindow *) tkwin)->dispPtr;
/*
* Parse string and set up a template for use in searching for an
* appropriate visual.
*/
c = string[0];
if (c == '.') {
/*
* The string must be a window name. If the window is on the same
* screen as tkwin, then just use its visual. Otherwise use the
* information about the visual as a template for the search.
*/
tkwin2 = Tk_NameToWindow(interp, string, tkwin);
if (tkwin2 == NULL) {
return NULL;
}
visual = Tk_Visual(tkwin2);
if (Tk_Screen(tkwin) == Tk_Screen(tkwin2)) {
*depthPtr = Tk_Depth(tkwin2);
if (colormapPtr != NULL) {
/*
* Use the colormap from the other window too (but be sure to
* increment its reference count if it's one of the ones
* allocated here).
*/
*colormapPtr = Tk_Colormap(tkwin2);
for (cmapPtr = dispPtr->cmapPtr; cmapPtr != NULL;
cmapPtr = cmapPtr->nextPtr) {
if (cmapPtr->colormap == *colormapPtr) {
cmapPtr->refCount += 1;
break;
}
}
}
return visual;
}
template.depth = Tk_Depth(tkwin2);
template.class = visual->class;
template.red_mask = visual->red_mask;
template.green_mask = visual->green_mask;
template.blue_mask = visual->blue_mask;
template.colormap_size = visual->map_entries;
template.bits_per_rgb = visual->bits_per_rgb;
mask = VisualDepthMask|VisualClassMask|VisualRedMaskMask
|VisualGreenMaskMask|VisualBlueMaskMask|VisualColormapSizeMask
|VisualBitsPerRGBMask;
} else if ((c == 0) || ((c == 'd') && (string[1] != 0)
&& (strncmp(string, "default", strlen(string)) == 0))) {
/*
* Use the default visual for the window's screen.
*/
if (colormapPtr != NULL) {
*colormapPtr = DefaultColormapOfScreen(Tk_Screen(tkwin));
}
*depthPtr = DefaultDepthOfScreen(Tk_Screen(tkwin));
return DefaultVisualOfScreen(Tk_Screen(tkwin));
} else if (isdigit(UCHAR(c))) {
int visualId;
/*
* This is a visual ID.
*/
if (Tcl_GetInt(interp, string, &visualId) == TCL_ERROR) {
Tcl_SetObjResult(interp, Tcl_ObjPrintf(
"bad X identifier for visual: \"%s\"", string));
Tcl_SetErrorCode(interp, "TK", "VALUE", "VISUALID", NULL);
return NULL;
}
template.visualid = visualId;
mask = VisualIDMask;
} else {
/*
* Parse the string into a class name (or "best") optionally followed
* by whitespace and a depth.
*/
for (p = string; *p != 0; p++) {
if (isspace(UCHAR(*p)) || isdigit(UCHAR(*p))) {
break;
}
}
length = p - string;
template.class = -1;
for (dictPtr = visualNames; dictPtr->name != NULL; dictPtr++) {
if ((dictPtr->name[0] == c) && (length >= dictPtr->minLength)
&& (strncmp(string, dictPtr->name,
(size_t) length) == 0)) {
template.class = dictPtr->class;
break;
}
}
if (template.class == -1) {
Tcl_Obj *msgObj = Tcl_ObjPrintf(
"unknown or ambiguous visual name \"%s\": class must be ",
string);
for (dictPtr = visualNames; dictPtr->name != NULL; dictPtr++) {
Tcl_AppendPrintfToObj(msgObj, "%s, ", dictPtr->name);
}
Tcl_AppendToObj(msgObj, "or default", -1);
Tcl_SetObjResult(interp, msgObj);
Tcl_SetErrorCode(interp, "TK", "LOOKUP", "VISUAL", string, NULL);
return NULL;
}
while (isspace(UCHAR(*p))) {
p++;
}
if (*p == 0) {
template.depth = 10000;
} else if (Tcl_GetInt(interp, p, &template.depth) != TCL_OK) {
return NULL;
}
if (c == 'b') {
mask = 0;
} else {
mask = VisualClassMask;
}
}
/*
* Find all visuals that match the template we've just created, and return
* an error if there are none that match.
*/
template.screen = Tk_ScreenNumber(tkwin);
mask |= VisualScreenMask;
visInfoList = XGetVisualInfo(Tk_Display(tkwin), mask, &template,
&numVisuals);
if (visInfoList == NULL) {
Tcl_SetObjResult(interp, Tcl_NewStringObj(
"couldn't find an appropriate visual", -1));
Tcl_SetErrorCode(interp, "TK", "VISUAL", "INAPPROPRIATE", NULL);
return NULL;
}
/*
* Search through the visuals that were returned to find the best one.
* The choice is based on the following criteria, in decreasing order of
* importance:
*
* 1. Depth: choose a visual with exactly the desired depth, else one with
* more bits than requested but as few bits as possible, else one with
* fewer bits but as many as possible.
* 2. Class: some visual classes are more desirable than others; pick the
* visual with the most desirable class.
* 3. Default: the default visual for the screen gets preference over
* other visuals, all else being equal.
*/
bestPrio = 0;
bestPtr = NULL;
for (i = 0; i < numVisuals; i++) {
switch (visInfoList[i].class) {
case DirectColor:
prio = 5; break;
case GrayScale:
prio = 1; break;
case PseudoColor:
prio = 7; break;
case StaticColor:
prio = 3; break;
case StaticGray:
prio = 1; break;
case TrueColor:
prio = 5; break;
default:
prio = 0; break;
}
if (visInfoList[i].visual
== DefaultVisualOfScreen(Tk_Screen(tkwin))) {
prio++;
}
if (bestPtr == NULL) {
goto newBest;
}
if (visInfoList[i].depth < bestPtr->depth) {
if (visInfoList[i].depth >= template.depth) {
goto newBest;
}
} else if (visInfoList[i].depth > bestPtr->depth) {
if (bestPtr->depth < template.depth) {
goto newBest;
}
} else {
if (prio > bestPrio) {
goto newBest;
}
}
continue;
newBest:
bestPtr = &visInfoList[i];
bestPrio = prio;
}
CLANG_ASSERT(bestPtr);
*depthPtr = bestPtr->depth;
visual = bestPtr->visual;
XFree((char *) visInfoList);
/*
* If we need to find a colormap for this visual, do it now. If the visual
* is the default visual for the screen, then use the default colormap.
* Otherwise search for an existing colormap that's shareable. If all else
* fails, create a new colormap.
*/
if (colormapPtr != NULL) {
if (visual == DefaultVisualOfScreen(Tk_Screen(tkwin))) {
*colormapPtr = DefaultColormapOfScreen(Tk_Screen(tkwin));
} else {
for (cmapPtr = dispPtr->cmapPtr; cmapPtr != NULL;
cmapPtr = cmapPtr->nextPtr) {
if (cmapPtr->shareable && (cmapPtr->visual == visual)) {
*colormapPtr = cmapPtr->colormap;
cmapPtr->refCount += 1;
goto done;
}
}
cmapPtr = ckalloc(sizeof(TkColormap));
cmapPtr->colormap = XCreateColormap(Tk_Display(tkwin),
RootWindowOfScreen(Tk_Screen(tkwin)), visual,
AllocNone);
cmapPtr->visual = visual;
cmapPtr->refCount = 1;
cmapPtr->shareable = 1;
cmapPtr->nextPtr = dispPtr->cmapPtr;
dispPtr->cmapPtr = cmapPtr;
*colormapPtr = cmapPtr->colormap;
}
}
done:
return visual;
}
/*
*----------------------------------------------------------------------
*
* Tk_GetColormap --
*
* Given a string identifying a colormap, this procedure finds an
* appropriate colormap.
*
* Results:
* The return value is normally the X resource identifier for the
* colormap. If an error occurs, None is returned and an error message is
* placed in the interp's result.
*
* Side effects:
* A reference count is incremented for the colormap, so Tk_FreeColormap
* must eventually be called exactly once for each call to
* Tk_GetColormap.
*
*----------------------------------------------------------------------
*/
Colormap
Tk_GetColormap(
Tcl_Interp *interp, /* Interpreter to use for error reporting. */
Tk_Window tkwin, /* Window where colormap will be used. */
const char *string) /* String that identifies colormap: either
* "new" or the name of another window. */
{
Colormap colormap;
TkColormap *cmapPtr;
TkDisplay *dispPtr = ((TkWindow *) tkwin)->dispPtr;
Tk_Window other;
/*
* Allocate a new colormap, if that's what is wanted.
*/
if (strcmp(string, "new") == 0) {
cmapPtr = ckalloc(sizeof(TkColormap));
cmapPtr->colormap = XCreateColormap(Tk_Display(tkwin),
RootWindowOfScreen(Tk_Screen(tkwin)), Tk_Visual(tkwin),
AllocNone);
cmapPtr->visual = Tk_Visual(tkwin);
cmapPtr->refCount = 1;
cmapPtr->shareable = 0;
cmapPtr->nextPtr = dispPtr->cmapPtr;
dispPtr->cmapPtr = cmapPtr;
return cmapPtr->colormap;
}
/*
* Use a colormap from an existing window. It must have the same visual as
* tkwin (which means, among other things, that the other window must be
* on the same screen).
*/
other = Tk_NameToWindow(interp, string, tkwin);
if (other == NULL) {
return None;
}
if (Tk_Screen(other) != Tk_Screen(tkwin)) {
Tcl_SetObjResult(interp, Tcl_ObjPrintf(
"can't use colormap for %s: not on same screen", string));
Tcl_SetErrorCode(interp, "TK", "COLORMAP", "SCREEN", NULL);
return None;
}
if (Tk_Visual(other) != Tk_Visual(tkwin)) {
Tcl_SetObjResult(interp, Tcl_ObjPrintf(
"can't use colormap for %s: incompatible visuals", string));
Tcl_SetErrorCode(interp, "TK", "COLORMAP", "INCOMPATIBLE", NULL);
return None;
}
colormap = Tk_Colormap(other);
/*
* If the colormap was a special one allocated by code in this file,
* increment its reference count.
*/
for (cmapPtr = dispPtr->cmapPtr; cmapPtr != NULL;
cmapPtr = cmapPtr->nextPtr) {
if (cmapPtr->colormap == colormap) {
cmapPtr->refCount += 1;
}
}
return colormap;
}
/*
*----------------------------------------------------------------------
*
* Tk_FreeColormap --
*
* This procedure is called to release a colormap that was previously
* allocated by Tk_GetColormap.
*
* Results:
* None.
*
* Side effects:
* The colormap's reference count is decremented. If this was the last
* reference to the colormap, then the colormap is freed.
*
*----------------------------------------------------------------------
*/
void
Tk_FreeColormap(
Display *display, /* Display for which colormap was
* allocated. */
Colormap colormap) /* Colormap that is no longer needed. Must
* have been returned by previous call to
* Tk_GetColormap, or preserved by a previous
* call to Tk_PreserveColormap. */
{
TkDisplay *dispPtr;
TkColormap *cmapPtr, *prevPtr;
/*
* Find Tk's information about the display, then see if this colormap is a
* non-default one (if it's a default one, there won't be an entry for it
* in the display's list).
*/
dispPtr = TkGetDisplay(display);
if (dispPtr == NULL) {
Tcl_Panic("unknown display passed to Tk_FreeColormap");
}
for (prevPtr = NULL, cmapPtr = dispPtr->cmapPtr; cmapPtr != NULL;
prevPtr = cmapPtr, cmapPtr = cmapPtr->nextPtr) {
if (cmapPtr->colormap == colormap) {
cmapPtr->refCount -= 1;
if (cmapPtr->refCount == 0) {
XFreeColormap(display, colormap);
if (prevPtr == NULL) {
dispPtr->cmapPtr = cmapPtr->nextPtr;
} else {
prevPtr->nextPtr = cmapPtr->nextPtr;
}
ckfree(cmapPtr);
}
return;
}
}
}
/*
*----------------------------------------------------------------------
*
* Tk_PreserveColormap --
*
* This procedure is called to indicate to Tk that the specified colormap
* is being referenced from another location and should not be freed
* until all extra references are eliminated. The colormap must have been
* returned by Tk_GetColormap.
*
* Results:
* None.
*
* Side effects:
* The colormap's reference count is incremented, so Tk_FreeColormap must
* eventually be called exactly once for each call to
* Tk_PreserveColormap.
*
*----------------------------------------------------------------------
*/
void
Tk_PreserveColormap(
Display *display, /* Display for which colormap was
* allocated. */
Colormap colormap) /* Colormap that should be preserved. */
{
TkDisplay *dispPtr;
TkColormap *cmapPtr;
/*
* Find Tk's information about the display, then see if this colormap is a
* non-default one (if it's a default one, there won't be an entry for it
* in the display's list).
*/
dispPtr = TkGetDisplay(display);
if (dispPtr == NULL) {
Tcl_Panic("unknown display passed to Tk_PreserveColormap");
}
for (cmapPtr = dispPtr->cmapPtr; cmapPtr != NULL;
cmapPtr = cmapPtr->nextPtr) {
if (cmapPtr->colormap == colormap) {
cmapPtr->refCount += 1;
return;
}
}
}
/*
* Local Variables:
* mode: c
* c-basic-offset: 4
* fill-column: 78
* End:
*/
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