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 1.40 96/03/28 09:12:20
*/
#include "tkPort.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) 0x46140277)
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. */
GC gc; /* Simple gc with this color as foreground
* color and all other fields defaulted.
* May be None. */
Screen *screen; /* Screen where this color is valid. Used
* to delete it, and to find its display. */
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. */
/*
* If a colormap fills up, attempts to allocate new colors from that
* colormap will fail. When that happens, we'll just choose the
* closest color from those that are available in the colormap.
* One of the following structures will be created for each "stressed"
* colormap to keep track of the colors that are available in the
* colormap (otherwise we would have to re-query from the server on
* each allocation, which would be very slow). These entries are
* flushed after a few seconds, since other clients may release or
* reallocate colors over time.
*/
struct TkStressedCmap {
Colormap colormap; /* X's token for the colormap. */
int numColors; /* Number of entries currently active
* at *colorPtr. */
XColor *colorPtr; /* Pointer to malloc'ed array of all
* colors that seem to be available in
* the colormap. Some may not actually
* be available, e.g. because they are
* read-write for another client; when
* we find this out, we remove them
* from the array. */
struct TkStressedCmap *nextPtr; /* Next in list of all stressed
* colormaps for the display. */
};
/*
* Forward declarations for procedures defined in this file:
*/
static void ColorInit _ANSI_ARGS_((void));
static void DeleteStressedCmap _ANSI_ARGS_((Display *display,
Colormap colormap));
static void FindClosestColor _ANSI_ARGS_((Tk_Window tkwin,
XColor *desiredColorPtr, XColor *actualColorPtr));
/*
*----------------------------------------------------------------------
*
* 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;
XColor color;
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. Call XAllocNamedColor rather than XParseColor for non-# names:
* this saves a server round-trip for those names.
*/
if (*name != '#') {
XColor screen;
if (XAllocNamedColor(display, nameKey.colormap, name, &screen,
&color) != 0) {
DeleteStressedCmap(display, nameKey.colormap);
} else {
/*
* 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
* pick an approximation to the desired color.
*/
if (XLookupColor(display, nameKey.colormap, name, &color,
&screen) == 0) {
Tcl_AppendResult(interp, "unknown color name \"",
name, "\"", (char *) NULL);
Tcl_DeleteHashEntry(nameHashPtr);
return (XColor *) NULL;
}
FindClosestColor(tkwin, &screen, &color);
}
} else {
if (XParseColor(display, nameKey.colormap, name, &color) == 0) {
Tcl_AppendResult(interp, "invalid color name \"", name,
"\"", (char *) NULL);
Tcl_DeleteHashEntry(nameHashPtr);
return (XColor *) NULL;
}
if (XAllocColor(display, nameKey.colormap, &color) != 0) {
DeleteStressedCmap(display, nameKey.colormap);
} else {
FindClosestColor(tkwin, &color, &color);
}
}
/*
* Now create a new TkColor structure and add it to nameTable.
*/
tkColPtr = (TkColor *) ckalloc(sizeof(TkColor));
tkColPtr->color = color;
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 = (TkColor *) ckalloc(sizeof(TkColor));
tkColPtr->color.red = valueKey.red;
tkColPtr->color.green = valueKey.green;
tkColPtr->color.blue = valueKey.blue;
if (XAllocColor(display, valueKey.colormap, &tkColPtr->color) != 0) {
DeleteStressedCmap(display, valueKey.colormap);
} else {
FindClosestColor(tkwin, &tkColPtr->color, &tkColPtr->color);
}
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;
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);
}
if (tkColPtr->gc != None) {
XFreeGC(DisplayOfScreen(screen), tkColPtr->gc);
}
DeleteStressedCmap(DisplayOfScreen(screen), tkColPtr->colormap);
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));
}
/*
*----------------------------------------------------------------------
*
* FindClosestColor --
*
* When Tk can't allocate a color because a colormap has filled
* up, this procedure is called to find and allocate the closest
* available color in the colormap.
*
* Results:
* There is no return value, but *actualColorPtr is filled in
* with information about the closest available color in tkwin's
* colormap. This color has been allocated via X, so it must
* be released by the caller when the caller is done with it.
*
* Side effects:
* A color is allocated.
*
*----------------------------------------------------------------------
*/
static void
FindClosestColor(tkwin, desiredColorPtr, actualColorPtr)
Tk_Window tkwin; /* Window where color will be used. */
XColor *desiredColorPtr; /* RGB values of color that was
* wanted (but unavailable). */
XColor *actualColorPtr; /* Structure to fill in with RGB and
* pixel for closest available
* color. */
{
TkStressedCmap *stressPtr;
float tmp, distance, closestDistance;
int i, closest, numFound;
XColor *colorPtr;
TkDisplay *dispPtr = ((TkWindow *) tkwin)->dispPtr;
Colormap colormap = Tk_Colormap(tkwin);
XVisualInfo template, *visInfoPtr;
/*
* Find the TkStressedCmap structure for this colormap, or create
* a new one if needed.
*/
for (stressPtr = dispPtr->stressPtr; ; stressPtr = stressPtr->nextPtr) {
if (stressPtr == NULL) {
stressPtr = (TkStressedCmap *) ckalloc(sizeof(TkStressedCmap));
stressPtr->colormap = colormap;
template.visualid = XVisualIDFromVisual(Tk_Visual(tkwin));
visInfoPtr = XGetVisualInfo(Tk_Display(tkwin),
VisualIDMask, &template, &numFound);
if (numFound < 1) {
panic("FindClosestColor couldn't lookup visual");
}
stressPtr->numColors = visInfoPtr->colormap_size;
XFree((char *) visInfoPtr);
stressPtr->colorPtr = (XColor *) ckalloc((unsigned)
(stressPtr->numColors * sizeof(XColor)));
for (i = 0; i < stressPtr->numColors; i++) {
stressPtr->colorPtr[i].pixel = (unsigned long) i;
}
XQueryColors(dispPtr->display, colormap, stressPtr->colorPtr,
stressPtr->numColors);
stressPtr->nextPtr = dispPtr->stressPtr;
dispPtr->stressPtr = stressPtr;
break;
}
if (stressPtr->colormap == colormap) {
break;
}
}
/*
* Find the color that best approximates the desired one, then
* try to allocate that color. If that fails, it must mean that
* the color was read-write (so we can't use it, since it's owner
* might change it) or else it was already freed. Try again,
* over and over again, until something succeeds.
*/
while (1) {
if (stressPtr->numColors == 0) {
panic("FindClosestColor ran out of colors");
}
closestDistance = 1e30;
closest = 0;
for (colorPtr = stressPtr->colorPtr, i = 0; i < stressPtr->numColors;
colorPtr++, i++) {
/*
* Use Euclidean distance in RGB space, weighted by Y (of YIQ)
* as the objective function; this accounts for differences
* in the color sensitivity of the eye.
*/
tmp = .30*(((int) desiredColorPtr->red) - (int) colorPtr->red);
distance = tmp*tmp;
tmp = .61*(((int) desiredColorPtr->green) - (int) colorPtr->green);
distance += tmp*tmp;
tmp = .11*(((int) desiredColorPtr->blue) - (int) colorPtr->blue);
distance += tmp*tmp;
if (distance < closestDistance) {
closest = i;
closestDistance = distance;
}
}
if (XAllocColor(dispPtr->display, colormap,
&stressPtr->colorPtr[closest]) != 0) {
*actualColorPtr = stressPtr->colorPtr[closest];
return;
}
/*
* Couldn't allocate the color. Remove it from the table and
* go back to look for the next best color.
*/
stressPtr->colorPtr[closest] =
stressPtr->colorPtr[stressPtr->numColors-1];
stressPtr->numColors -= 1;
}
}
/*
*----------------------------------------------------------------------
*
* TkCmapStressed --
*
* Check to see whether a given colormap is known to be out
* of entries.
*
* Results:
* 1 is returned if "colormap" is stressed (i.e. it has run out
* of entries recently), 0 otherwise.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
int
TkCmapStressed(tkwin, colormap)
Tk_Window tkwin; /* Window that identifies the display
* containing the colormap. */
Colormap colormap; /* Colormap to check for stress. */
{
TkStressedCmap *stressPtr;
for (stressPtr = ((TkWindow *) tkwin)->dispPtr->stressPtr;
stressPtr != NULL; stressPtr = stressPtr->nextPtr) {
if (stressPtr->colormap == colormap) {
return 1;
}
}
return 0;
}
/*
*----------------------------------------------------------------------
*
* DeleteStressedCmap --
*
* This procedure releases the information cached for "colormap"
* so that it will be refetched from the X server the next time
* it is needed.
*
* Results:
* None.
*
* Side effects:
* The TkStressedCmap structure for colormap is deleted; the
* colormap is no longer considered to be "stressed".
*
* Note:
* This procedure is invoked whenever a color in a colormap is
* freed, and whenever a color allocation in a colormap succeeds.
* This guarantees that TkStressedCmap structures are always
* deleted before the corresponding Colormap is freed.
*
*----------------------------------------------------------------------
*/
static void
DeleteStressedCmap(display, colormap)
Display *display; /* Xlib's handle for the display
* containing the colormap. */
Colormap colormap; /* Colormap to flush. */
{
TkStressedCmap *prevPtr, *stressPtr;
TkDisplay *dispPtr = TkGetDisplay(display);
for (prevPtr = NULL, stressPtr = dispPtr->stressPtr; stressPtr != NULL;
prevPtr = stressPtr, stressPtr = stressPtr->nextPtr) {
if (stressPtr->colormap == colormap) {
if (prevPtr == NULL) {
dispPtr->stressPtr = stressPtr->nextPtr;
} else {
prevPtr->nextPtr = stressPtr->nextPtr;
}
ckfree((char *) stressPtr->colorPtr);
ckfree((char *) stressPtr);
return;
}
}
}