stk/Tk/generic/tkColor.c

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/*
* 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) 1990-1994 The Regents of the University of California.
* Copyright (c) 1994-1995 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: @(#) tkColor.c 1.44 96/11/04 13:55:25
*/
#include <tkColor.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.
*/
/*
* 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. If an error occurs, 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, 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. */
Tk_Uid name; /* Name of color to allocated (in form
* suitable for passing to XParseColor). */
{
NameKey nameKey;
Tcl_HashEntry *nameHashPtr;
int new;
TkColor *tkColPtr;
Display *display = Tk_Display(tkwin);
if (!initialized) {
ColorInit();
}
/*
* First, check to see if there's already a mapping for this color
* name.
*/
nameKey.name = name;
nameKey.colormap = Tk_Colormap(tkwin);
nameKey.display = display;
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.
*/
tkColPtr = TkpGetColor(tkwin, name);
if (tkColPtr == NULL) {
if (interp != NULL) {
if (*name == '#') {
Tcl_AppendResult(interp, "invalid color name \"", name,
"\"", (char *) NULL);
} else {
Tcl_AppendResult(interp, "unknown color name \"", name,
"\"", (char *) NULL);
}
}
Tcl_DeleteHashEntry(nameHashPtr);
return (XColor *) NULL;
}
/*
* Now create a new TkColor structure and add it to nameTable.
*/
tkColPtr->magic = COLOR_MAGIC;
tkColPtr->gc = None;
tkColPtr->screen = Tk_Screen(tkwin);
tkColPtr->colormap = nameKey.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.
*
* 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(tkwin, colorPtr)
Tk_Window tkwin; /* Window where color will be used. */
XColor *colorPtr; /* Red, green, and blue fields indicate
* desired color. */
{
ValueKey valueKey;
Tcl_HashEntry *valueHashPtr;
int new;
TkColor *tkColPtr;
Display *display = Tk_Display(tkwin);
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;
valueKey.colormap = Tk_Colormap(tkwin);
valueKey.display = display;
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 = TkpGetColorByValue(tkwin, colorPtr);
tkColPtr->magic = COLOR_MAGIC;
tkColPtr->gc = None;
tkColPtr->screen = Tk_Screen(tkwin);
tkColPtr->colormap = valueKey.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, "#%04x%04x%04x", colorPtr->red, colorPtr->green,
colorPtr->blue);
return string;
}
/*
*----------------------------------------------------------------------
*
* Tk_GCForColor --
*
* Given a color allocated from this module, this procedure
* returns a GC that can be used for simple drawing with that
* color.
*
* Results:
* The return value is a GC with color set as its foreground
* color and all other fields defaulted. This GC is only valid
* as long as the color exists; it is freed automatically when
* the last reference to the color is freed.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
GC
Tk_GCForColor(colorPtr, drawable)
XColor *colorPtr; /* Color for which a GC is desired. Must
* have been allocated by Tk_GetColor or
* Tk_GetColorByName. */
Drawable drawable; /* Drawable in which the color will be
* used (must have same screen and depth
* as the one for which the color was
* allocated). */
{
TkColor *tkColPtr = (TkColor *) colorPtr;
XGCValues gcValues;
/*
* Do a quick sanity check to make sure this color was really
* allocated by Tk_GetColor.
*/
if (tkColPtr->magic != COLOR_MAGIC) {
panic("Tk_GCForColor called with bogus color");
}
if (tkColPtr->gc == None) {
gcValues.foreground = tkColPtr->color.pixel;
tkColPtr->gc = XCreateGC(DisplayOfScreen(tkColPtr->screen),
drawable, GCForeground, &gcValues);
}
return tkColPtr->gc;
}
/*
*----------------------------------------------------------------------
*
* 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;
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) {
if (tkColPtr->gc != None) {
XFreeGC(DisplayOfScreen(screen), tkColPtr->gc);
tkColPtr->gc = None;
}
TkpFreeColor(tkColPtr);
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));
}