398 lines
11 KiB
C
398 lines
11 KiB
C
/*
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* tkColor.c --
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*
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* This file maintains a database of color values for the Tk
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* toolkit, in order to avoid round-trips to the server to
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* map color names to pixel values.
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*
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* Copyright (c) 1990-1994 The Regents of the University of California.
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* Copyright (c) 1994-1995 Sun Microsystems, Inc.
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*
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* See the file "license.terms" for information on usage and redistribution
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* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
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*
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* SCCS: @(#) tkColor.c 1.44 96/11/04 13:55:25
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*/
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#include <tkColor.h>
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/*
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* A two-level data structure is used to manage the color database.
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* The top level consists of one entry for each color name that is
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* currently active, and the bottom level contains one entry for each
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* pixel value that is still in use. The distinction between
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* levels is necessary because the same pixel may have several
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* different names. There are two hash tables, one used to index into
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* each of the data structures. The name hash table is used when
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* allocating colors, and the pixel hash table is used when freeing
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* colors.
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*/
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/*
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* Hash table for name -> TkColor mapping, and key structure used to
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* index into that table:
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*/
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static Tcl_HashTable nameTable;
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typedef struct {
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Tk_Uid name; /* Name of desired color. */
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Colormap colormap; /* Colormap from which color will be
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* allocated. */
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Display *display; /* Display for colormap. */
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} NameKey;
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/*
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* Hash table for value -> TkColor mapping, and key structure used to
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* index into that table:
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*/
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static Tcl_HashTable valueTable;
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typedef struct {
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int red, green, blue; /* Values for desired color. */
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Colormap colormap; /* Colormap from which color will be
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* allocated. */
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Display *display; /* Display for colormap. */
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} ValueKey;
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static int initialized = 0; /* 0 means static structures haven't been
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* initialized yet. */
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/*
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* Forward declarations for procedures defined in this file:
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*/
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static void ColorInit _ANSI_ARGS_((void));
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/*
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*----------------------------------------------------------------------
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*
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* Tk_GetColor --
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*
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* Given a string name for a color, map the name to a corresponding
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* XColor structure.
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*
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* Results:
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* The return value is a pointer to an XColor structure that
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* indicates the red, blue, and green intensities for the color
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* given by "name", and also specifies a pixel value to use to
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* draw in that color. If an error occurs, NULL is returned and
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* an error message will be left in interp->result.
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*
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* Side effects:
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* The color is added to an internal database with a reference count.
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* For each call to this procedure, there should eventually be a call
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* to Tk_FreeColor so that the database is cleaned up when colors
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* aren't in use anymore.
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*
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*----------------------------------------------------------------------
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*/
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XColor *
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Tk_GetColor(interp, tkwin, name)
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Tcl_Interp *interp; /* Place to leave error message if
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* color can't be found. */
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Tk_Window tkwin; /* Window in which color will be used. */
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Tk_Uid name; /* Name of color to allocated (in form
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* suitable for passing to XParseColor). */
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{
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NameKey nameKey;
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Tcl_HashEntry *nameHashPtr;
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int new;
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TkColor *tkColPtr;
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Display *display = Tk_Display(tkwin);
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if (!initialized) {
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ColorInit();
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}
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/*
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* First, check to see if there's already a mapping for this color
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* name.
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*/
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nameKey.name = name;
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nameKey.colormap = Tk_Colormap(tkwin);
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nameKey.display = display;
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nameHashPtr = Tcl_CreateHashEntry(&nameTable, (char *) &nameKey, &new);
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if (!new) {
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tkColPtr = (TkColor *) Tcl_GetHashValue(nameHashPtr);
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tkColPtr->refCount++;
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return &tkColPtr->color;
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}
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/*
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* The name isn't currently known. Map from the name to a pixel
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* value.
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*/
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tkColPtr = TkpGetColor(tkwin, name);
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if (tkColPtr == NULL) {
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if (interp != NULL) {
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if (*name == '#') {
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Tcl_AppendResult(interp, "invalid color name \"", name,
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"\"", (char *) NULL);
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} else {
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Tcl_AppendResult(interp, "unknown color name \"", name,
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"\"", (char *) NULL);
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}
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}
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Tcl_DeleteHashEntry(nameHashPtr);
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return (XColor *) NULL;
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}
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/*
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* Now create a new TkColor structure and add it to nameTable.
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*/
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tkColPtr->magic = COLOR_MAGIC;
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tkColPtr->gc = None;
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tkColPtr->screen = Tk_Screen(tkwin);
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tkColPtr->colormap = nameKey.colormap;
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tkColPtr->visual = Tk_Visual(tkwin);
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tkColPtr->refCount = 1;
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tkColPtr->tablePtr = &nameTable;
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tkColPtr->hashPtr = nameHashPtr;
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Tcl_SetHashValue(nameHashPtr, tkColPtr);
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return &tkColPtr->color;
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}
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/*
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*----------------------------------------------------------------------
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*
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* Tk_GetColorByValue --
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*
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* Given a desired set of red-green-blue intensities for a color,
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* locate a pixel value to use to draw that color in a given
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* window.
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*
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* Results:
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* The return value is a pointer to an XColor structure that
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* indicates the closest red, blue, and green intensities available
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* to those specified in colorPtr, and also specifies a pixel
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* value to use to draw in that color.
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*
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* Side effects:
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* The color is added to an internal database with a reference count.
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* For each call to this procedure, there should eventually be a call
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* to Tk_FreeColor, so that the database is cleaned up when colors
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* aren't in use anymore.
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*
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*----------------------------------------------------------------------
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*/
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XColor *
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Tk_GetColorByValue(tkwin, colorPtr)
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Tk_Window tkwin; /* Window where color will be used. */
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XColor *colorPtr; /* Red, green, and blue fields indicate
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* desired color. */
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{
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ValueKey valueKey;
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Tcl_HashEntry *valueHashPtr;
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int new;
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TkColor *tkColPtr;
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Display *display = Tk_Display(tkwin);
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if (!initialized) {
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ColorInit();
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}
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/*
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* First, check to see if there's already a mapping for this color
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* name.
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*/
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valueKey.red = colorPtr->red;
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valueKey.green = colorPtr->green;
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valueKey.blue = colorPtr->blue;
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valueKey.colormap = Tk_Colormap(tkwin);
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valueKey.display = display;
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valueHashPtr = Tcl_CreateHashEntry(&valueTable, (char *) &valueKey, &new);
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if (!new) {
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tkColPtr = (TkColor *) Tcl_GetHashValue(valueHashPtr);
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tkColPtr->refCount++;
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return &tkColPtr->color;
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}
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/*
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* The name isn't currently known. Find a pixel value for this
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* color and add a new structure to valueTable.
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*/
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tkColPtr = TkpGetColorByValue(tkwin, colorPtr);
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tkColPtr->magic = COLOR_MAGIC;
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tkColPtr->gc = None;
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tkColPtr->screen = Tk_Screen(tkwin);
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tkColPtr->colormap = valueKey.colormap;
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tkColPtr->visual = Tk_Visual(tkwin);
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tkColPtr->refCount = 1;
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tkColPtr->tablePtr = &valueTable;
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tkColPtr->hashPtr = valueHashPtr;
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Tcl_SetHashValue(valueHashPtr, tkColPtr);
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return &tkColPtr->color;
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}
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/*
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*--------------------------------------------------------------
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*
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* Tk_NameOfColor --
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*
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* Given a color, return a textual string identifying
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* the color.
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*
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* Results:
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* If colorPtr was created by Tk_GetColor, then the return
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* value is the "string" that was used to create it.
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* Otherwise the return value is a string that could have
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* been passed to Tk_GetColor to allocate that color. The
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* storage for the returned string is only guaranteed to
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* persist up until the next call to this procedure.
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*
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* Side effects:
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* None.
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*
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*--------------------------------------------------------------
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*/
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char *
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Tk_NameOfColor(colorPtr)
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XColor *colorPtr; /* Color whose name is desired. */
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{
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register TkColor *tkColPtr = (TkColor *) colorPtr;
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static char string[20];
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if ((tkColPtr->magic == COLOR_MAGIC)
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&& (tkColPtr->tablePtr == &nameTable)) {
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return ((NameKey *) tkColPtr->hashPtr->key.words)->name;
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}
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sprintf(string, "#%04x%04x%04x", colorPtr->red, colorPtr->green,
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colorPtr->blue);
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return string;
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}
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/*
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*----------------------------------------------------------------------
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*
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* Tk_GCForColor --
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*
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* Given a color allocated from this module, this procedure
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* returns a GC that can be used for simple drawing with that
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* color.
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*
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* Results:
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* The return value is a GC with color set as its foreground
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* color and all other fields defaulted. This GC is only valid
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* as long as the color exists; it is freed automatically when
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* the last reference to the color is freed.
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*
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* Side effects:
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* None.
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*
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*----------------------------------------------------------------------
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*/
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GC
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Tk_GCForColor(colorPtr, drawable)
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XColor *colorPtr; /* Color for which a GC is desired. Must
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* have been allocated by Tk_GetColor or
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* Tk_GetColorByName. */
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Drawable drawable; /* Drawable in which the color will be
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* used (must have same screen and depth
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* as the one for which the color was
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* allocated). */
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{
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TkColor *tkColPtr = (TkColor *) colorPtr;
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XGCValues gcValues;
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/*
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* Do a quick sanity check to make sure this color was really
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* allocated by Tk_GetColor.
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*/
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if (tkColPtr->magic != COLOR_MAGIC) {
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panic("Tk_GCForColor called with bogus color");
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}
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if (tkColPtr->gc == None) {
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gcValues.foreground = tkColPtr->color.pixel;
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tkColPtr->gc = XCreateGC(DisplayOfScreen(tkColPtr->screen),
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drawable, GCForeground, &gcValues);
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}
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return tkColPtr->gc;
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}
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/*
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*----------------------------------------------------------------------
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*
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* Tk_FreeColor --
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*
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* This procedure is called to release a color allocated by
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* Tk_GetColor.
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*
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* Results:
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* None.
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*
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* Side effects:
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* The reference count associated with colorPtr is deleted, and
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* the color is released to X if there are no remaining uses
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* for it.
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*
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*----------------------------------------------------------------------
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*/
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void
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Tk_FreeColor(colorPtr)
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XColor *colorPtr; /* Color to be released. Must have been
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* allocated by Tk_GetColor or
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* Tk_GetColorByValue. */
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{
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register TkColor *tkColPtr = (TkColor *) colorPtr;
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Screen *screen = tkColPtr->screen;
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/*
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* Do a quick sanity check to make sure this color was really
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* allocated by Tk_GetColor.
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*/
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if (tkColPtr->magic != COLOR_MAGIC) {
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panic("Tk_FreeColor called with bogus color");
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}
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tkColPtr->refCount--;
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if (tkColPtr->refCount == 0) {
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if (tkColPtr->gc != None) {
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XFreeGC(DisplayOfScreen(screen), tkColPtr->gc);
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tkColPtr->gc = None;
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}
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TkpFreeColor(tkColPtr);
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Tcl_DeleteHashEntry(tkColPtr->hashPtr);
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tkColPtr->magic = 0;
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ckfree((char *) tkColPtr);
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}
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}
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/*
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*----------------------------------------------------------------------
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*
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* ColorInit --
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*
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* Initialize the structure used for color management.
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*
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* Results:
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* None.
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*
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* Side effects:
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* Read the code.
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*
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*----------------------------------------------------------------------
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*/
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static void
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ColorInit()
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{
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initialized = 1;
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Tcl_InitHashTable(&nameTable, sizeof(NameKey)/sizeof(int));
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Tcl_InitHashTable(&valueTable, sizeof(ValueKey)/sizeof(int));
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}
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