archie/tk3.6/tkColor.c

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2024-05-27 16:13:40 +02:00
/*
* tkColor.c --
*
* This file maintains a database of color values for the Tk
* toolkit, in order to avoid round-trips to the server to
* map color names to pixel values.
*
* Copyright (c) 1990-1993 The Regents of the University of California.
* All rights reserved.
*
* Permission is hereby granted, without written agreement and without
* license or royalty fees, to use, copy, modify, and distribute this
* software and its documentation for any purpose, provided that the
* above copyright notice and the following two paragraphs appear in
* all copies of this software.
*
* IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
* OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF
* CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*/
#ifndef lint
static char rcsid[] = "$Header: /user6/ouster/wish/RCS/tkColor.c,v 1.24 93/06/16 17:15:38 ouster Exp $ SPRITE (Berkeley)";
#endif /* not lint */
#include "tkConfig.h"
#include "tk.h"
#include "tkInt.h"
/*
* A two-level data structure is used to manage the color database.
* The top level consists of one entry for each color name that is
* currently active, and the bottom level contains one entry for each
* pixel value that is still in use. The distinction between
* levels is necessary because the same pixel may have several
* different names. There are two hash tables, one used to index into
* each of the data structures. The name hash table is used when
* allocating colors, and the pixel hash table is used when freeing
* colors.
*/
/*
* One of the following data structures is used to keep track of
* each color that this module has allocated from the X display
* server. These entries are indexed by two hash tables defined
* below: nameTable and valueTable.
*/
#define COLOR_MAGIC ((unsigned int) 0xc6140277)
typedef struct TkColor {
XColor color; /* Information about this color. */
unsigned int magic; /* Used for quick integrity check on this
* structure. Must always have the
* value COLOR_MAGIC. */
Screen *screen; /* Screen where this color is valid. Used
* to delete it. */
Colormap colormap; /* Colormap from which this entry was
* allocated. */
Visual *visual; /* Visual associated with colormap. */
int refCount; /* Number of uses of this structure. */
Tcl_HashTable *tablePtr; /* Hash table that indexes this structure
* (needed when deleting structure). */
Tcl_HashEntry *hashPtr; /* Pointer to hash table entry for this
* structure. (for use in deleting entry). */
} TkColor;
/*
* Hash table for name -> TkColor mapping, and key structure used to
* index into that table:
*/
static Tcl_HashTable nameTable;
typedef struct {
Tk_Uid name; /* Name of desired color. */
Colormap colormap; /* Colormap from which color will be
* allocated. */
Display *display; /* Display for colormap. */
} NameKey;
/*
* Hash table for value -> TkColor mapping, and key structure used to
* index into that table:
*/
static Tcl_HashTable valueTable;
typedef struct {
int red, green, blue; /* Values for desired color. */
Colormap colormap; /* Colormap from which color will be
* allocated. */
Display *display; /* Display for colormap. */
} ValueKey;
static int initialized = 0; /* 0 means static structures haven't been
* initialized yet. */
/*
* Forward declarations for procedures defined in this file:
*/
static void ColorInit _ANSI_ARGS_((void));
/*
*----------------------------------------------------------------------
*
* Tk_GetColor --
*
* Given a string name for a color, map the name to a corresponding
* XColor structure.
*
* Results:
* The return value is a pointer to an XColor structure that
* indicates the red, blue, and green intensities for the color
* given by "name", and also specifies a pixel value to use to
* draw in that color in window "tkwin". If an error occurs,
* then NULL is returned and an error message will be left in
* interp->result.
*
* Side effects:
* The color is added to an internal database with a reference count.
* For each call to this procedure, there should eventually be a call
* to Tk_FreeColor, so that the database is cleaned up when colors
* aren't in use anymore.
*
*----------------------------------------------------------------------
*/
XColor *
Tk_GetColor(interp, tkwin, colormap, name)
Tcl_Interp *interp; /* Place to leave error message if
* color can't be found. */
Tk_Window tkwin; /* Window in which color will be used. */
Colormap colormap; /* Map from which to allocate color. None
* means use current colormap for tkwin. */
Tk_Uid name; /* Name of color to allocated (in form
* suitable for passing to XParseColor). */
{
NameKey nameKey;
Tcl_HashEntry *nameHashPtr;
int new;
TkColor *tkColPtr;
XColor color;
if (!initialized) {
ColorInit();
}
/*
* First, check to see if there's already a mapping for this color
* name.
*/
nameKey.name = name;
if (colormap == None) {
colormap = Tk_Colormap(tkwin);
}
nameKey.colormap = colormap;
nameKey.display = Tk_Display(tkwin);
nameHashPtr = Tcl_CreateHashEntry(&nameTable, (char *) &nameKey, &new);
if (!new) {
tkColPtr = (TkColor *) Tcl_GetHashValue(nameHashPtr);
tkColPtr->refCount++;
return &tkColPtr->color;
}
/*
* The name isn't currently known. Map from the name to a pixel
* value. There are several tricks here:
*
* 1. Call XAllocNamedColor rather than XParseColor for non-# names:
* this saves a server round-trip for those names.
* 2. If the display is supposed to be treated as mono, then look
* up the color value and translate to mono.
* 3. If a color allocation fails, then reset the display's color model
* to mono, generate an error message, and retry with the mono
* approach.
*/
if (*name != '#') {
XColor screen;
if (Tk_GetColorModel(tkwin) != TK_COLOR) {
if (XLookupColor(Tk_Display(tkwin), colormap, name, &color,
&screen) == 0) {
badColorName:
Tcl_AppendResult(interp, "unknown color name \"",
name, "\"", (char *) NULL);
Tcl_DeleteHashEntry(nameHashPtr);
return (XColor *) NULL;
}
goto useMonoApproximation;
}
if (XAllocNamedColor(Tk_Display(tkwin), colormap, name,
&screen, &color) == 0) {
char message[120];
/*
* Couldn't allocate the color. Try translating the name to
* a color value, to see whether the problem is a bad color
* name or a full colormap. If the colormap is full, then
* put the display into mono mode and
*/
if (XLookupColor(Tk_Display(tkwin), colormap, name, &color,
&screen) == 0) {
goto badColorName;
}
outOfColors:
Tk_SetColorModel(tkwin, TK_MONO);
Tcl_AppendResult(interp, "no more colors left in colormap; ",
"changing screen's color model to monochrome",
(char *) NULL);
sprintf(message, "\n (while allocating color \"%.50s\")", name);
Tcl_AddErrorInfo(interp, message);
Tk_BackgroundError(interp);
goto useMonoApproximation;
}
} else {
if (XParseColor(Tk_Display(tkwin), colormap, name, &color) == 0) {
Tcl_AppendResult(interp, "invalid color name \"", name,
"\"", (char *) NULL);
Tcl_DeleteHashEntry(nameHashPtr);
return (XColor *) NULL;
}
if (Tk_GetColorModel(tkwin) != TK_COLOR) {
useMonoApproximation:
if ((((int) color.red) + ((int) color.green) + ((int) color.blue))
> (3*65535)/2) {
color.pixel = WhitePixelOfScreen(Tk_Screen(tkwin));
} else {
color.pixel = BlackPixelOfScreen(Tk_Screen(tkwin));
}
} else if (XAllocColor(Tk_Display(tkwin), colormap, &color) == 0) {
goto outOfColors;
}
}
/*
* Now create a new TkColor structure and add it to nameTable.
*/
tkColPtr = (TkColor *) ckalloc(sizeof(TkColor));
tkColPtr->color = color;
tkColPtr->magic = COLOR_MAGIC;
tkColPtr->screen = Tk_Screen(tkwin);
tkColPtr->colormap = colormap;
tkColPtr->visual = Tk_Visual(tkwin);
tkColPtr->refCount = 1;
tkColPtr->tablePtr = &nameTable;
tkColPtr->hashPtr = nameHashPtr;
Tcl_SetHashValue(nameHashPtr, tkColPtr);
return &tkColPtr->color;
}
/*
*----------------------------------------------------------------------
*
* Tk_GetColorByValue --
*
* Given a desired set of red-green-blue intensities for a color,
* locate a pixel value to use to draw that color in a given
* window.
*
* Results:
* The return value is a pointer to an XColor structure that
* indicates the closest red, blue, and green intensities available
* to those specified in colorPtr, and also specifies a pixel
* value to use to draw in that color in window "tkwin". If an
* error occurs, then NULL is returned and an error message will
* be left in interp->result.
*
* Side effects:
* The color is added to an internal database with a reference count.
* For each call to this procedure, there should eventually be a call
* to Tk_FreeColor, so that the database is cleaned up when colors
* aren't in use anymore.
*
*----------------------------------------------------------------------
*/
XColor *
Tk_GetColorByValue(interp, tkwin, colormap, colorPtr)
Tcl_Interp *interp; /* Place to leave error message if
* color can't be found. */
Tk_Window tkwin; /* Window in which color will be used. */
Colormap colormap; /* Map from which to allocate color. None
* means use current colormap for tkwin. */
XColor *colorPtr; /* Red, green, and blue fields indicate
* desired color. */
{
ValueKey valueKey;
Tcl_HashEntry *valueHashPtr;
int new;
TkColor *tkColPtr;
if (!initialized) {
ColorInit();
}
/*
* First, check to see if there's already a mapping for this color
* name.
*/
valueKey.red = colorPtr->red;
valueKey.green = colorPtr->green;
valueKey.blue = colorPtr->blue;
if (colormap == None) {
colormap = Tk_Colormap(tkwin);
}
valueKey.colormap = colormap;
valueKey.display = Tk_Display(tkwin);
valueHashPtr = Tcl_CreateHashEntry(&valueTable, (char *) &valueKey, &new);
if (!new) {
tkColPtr = (TkColor *) Tcl_GetHashValue(valueHashPtr);
tkColPtr->refCount++;
return &tkColPtr->color;
}
/*
* The name isn't currently known. Find a pixel value for this
* color and add a new structure to valueTable.
*/
tkColPtr = (TkColor *) ckalloc(sizeof(TkColor));
tkColPtr->color.red = valueKey.red;
tkColPtr->color.green = valueKey.green;
tkColPtr->color.blue = valueKey.blue;
if (Tk_GetColorModel(tkwin) != TK_COLOR) {
useMonoApproximation:
if ((((int) tkColPtr->color.red) + ((int) tkColPtr->color.green)
+ ((int) tkColPtr->color.blue)) > (3*65535)/2) {
tkColPtr->color.pixel = WhitePixelOfScreen(Tk_Screen(tkwin));
} else {
tkColPtr->color.pixel = BlackPixelOfScreen(Tk_Screen(tkwin));
}
} else {
if (XAllocColor(Tk_Display(tkwin), colormap, &tkColPtr->color) == 0) {
Tk_SetColorModel(tkwin, TK_MONO);
Tcl_AppendResult(interp, "no more colors left in colormap; ",
"changing screen's color model to monochrome",
(char *) NULL);
Tcl_AddErrorInfo(interp,
"\n (while allocating color in Tk_GetColorByValue)");
Tk_BackgroundError(interp);
goto useMonoApproximation;
}
}
tkColPtr->magic = COLOR_MAGIC;
tkColPtr->screen = Tk_Screen(tkwin);
tkColPtr->colormap = colormap;
tkColPtr->visual = Tk_Visual(tkwin);
tkColPtr->refCount = 1;
tkColPtr->tablePtr = &valueTable;
tkColPtr->hashPtr = valueHashPtr;
Tcl_SetHashValue(valueHashPtr, tkColPtr);
return &tkColPtr->color;
}
/*
*--------------------------------------------------------------
*
* Tk_NameOfColor --
*
* Given a color, return a textual string identifying
* the color.
*
* Results:
* If colorPtr was created by Tk_GetColor, then the return
* value is the "string" that was used to create it.
* Otherwise the return value is a string that could have
* been passed to Tk_GetColor to allocate that color. The
* storage for the returned string is only guaranteed to
* persist up until the next call to this procedure.
*
* Side effects:
* None.
*
*--------------------------------------------------------------
*/
char *
Tk_NameOfColor(colorPtr)
XColor *colorPtr; /* Color whose name is desired. */
{
register TkColor *tkColPtr = (TkColor *) colorPtr;
static char string[20];
if ((tkColPtr->magic == COLOR_MAGIC)
&& (tkColPtr->tablePtr == &nameTable)) {
return ((NameKey *) tkColPtr->hashPtr->key.words)->name;
}
sprintf(string, "#%4x%4x%4x", colorPtr->red, colorPtr->green,
colorPtr->blue);
return string;
}
/*
*----------------------------------------------------------------------
*
* Tk_FreeColor --
*
* This procedure is called to release a color allocated by
* Tk_GetColor.
*
* Results:
* None.
*
* Side effects:
* The reference count associated with colorPtr is deleted, and
* the color is released to X if there are no remaining uses
* for it.
*
*----------------------------------------------------------------------
*/
void
Tk_FreeColor(colorPtr)
XColor *colorPtr; /* Color to be released. Must have been
* allocated by Tk_GetColor or
* Tk_GetColorByValue. */
{
register TkColor *tkColPtr = (TkColor *) colorPtr;
Visual *visual;
Screen *screen = tkColPtr->screen;
/*
* Do a quick sanity check to make sure this color was really
* allocated by Tk_GetColor.
*/
if (tkColPtr->magic != COLOR_MAGIC) {
panic("Tk_FreeColor called with bogus color");
}
tkColPtr->refCount--;
if (tkColPtr->refCount == 0) {
/*
* Careful! Don't free black or white, since this will
* make some servers very unhappy. Also, there is a bug in
* some servers (such Sun's X11/NeWS server) where reference
* counting is performed incorrectly, so that if a color is
* allocated twice in different places and then freed twice,
* the second free generates an error (this bug existed as of
* 10/1/92). To get around this problem, ignore errors that
* occur during the free operation.
*/
visual = tkColPtr->visual;
if ((visual->class != StaticGray) && (visual->class != StaticColor)
&& (tkColPtr->color.pixel != BlackPixelOfScreen(screen))
&& (tkColPtr->color.pixel != WhitePixelOfScreen(screen))) {
Tk_ErrorHandler handler;
handler = Tk_CreateErrorHandler(DisplayOfScreen(screen),
-1, -1, -1, (Tk_ErrorProc *) NULL, (ClientData) NULL);
XFreeColors(DisplayOfScreen(screen), tkColPtr->colormap,
&tkColPtr->color.pixel, 1, 0L);
Tk_DeleteErrorHandler(handler);
}
Tcl_DeleteHashEntry(tkColPtr->hashPtr);
tkColPtr->magic = 0;
ckfree((char *) tkColPtr);
}
}
/*
*----------------------------------------------------------------------
*
* ColorInit --
*
* Initialize the structure used for color management.
*
* Results:
* None.
*
* Side effects:
* Read the code.
*
*----------------------------------------------------------------------
*/
static void
ColorInit()
{
initialized = 1;
Tcl_InitHashTable(&nameTable, sizeof(NameKey)/sizeof(int));
Tcl_InitHashTable(&valueTable, sizeof(ValueKey)/sizeof(int));
}