Initial revision

FossilOrigin-Name: 2bf55ca9aa942b581137b9f474da5ad9c1480de4

1 files changed, 424 insertions, 0 deletions

diff --git a/unix/tkUnixColor.c b/unix/tkUnixColor.c
new file mode 100644
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+/* 
+ * tkUnixColor.c --
+ *
+ *	This file contains the platform specific color routines
+ *	needed for X support.
+ *
+ * Copyright (c) 1996 by 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: @(#) tkUnixColor.c 1.1 96/10/22 16:52:31
+ */
+
+#include <tkColor.h>
+
+/*
+ * 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		DeleteStressedCmap _ANSI_ARGS_((Display *display,
+			    Colormap colormap));
+static void		FindClosestColor _ANSI_ARGS_((Tk_Window tkwin,
+			    XColor *desiredColorPtr, XColor *actualColorPtr));
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkpFreeColor --
+ *
+ *	Release the specified color back to the system.
+ *
+ * Results:
+ *	None
+ *
+ * Side effects:
+ *	Invalidates the colormap cache for the colormap associated with
+ *	the given color.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TkpFreeColor(tkColPtr)
+    TkColor *tkColPtr;		/* Color to be released.  Must have been
+				 * allocated by TkpGetColor or
+				 * TkpGetColorByValue. */
+{
+    Visual *visual;
+    Screen *screen = tkColPtr->screen;
+
+    /*
+     * 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);
+    }
+    DeleteStressedCmap(DisplayOfScreen(screen), tkColPtr->colormap);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkpGetColor --
+ *
+ *	Allocate a new TkColor for the color with the given name.
+ *
+ * Results:
+ *	Returns a newly allocated TkColor, or NULL on failure.
+ *
+ * Side effects:
+ *	May invalidate the colormap cache associated with tkwin upon
+ *	allocating a new colormap entry.  Allocates a new TkColor
+ *	structure.
+ *
+ *----------------------------------------------------------------------
+ */
+
+TkColor *
+TkpGetColor(tkwin, name)
+    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). */
+{
+    Display *display = Tk_Display(tkwin);
+    Colormap colormap = Tk_Colormap(tkwin);
+    XColor color;
+    TkColor *tkColPtr;
+
+    /*
+     * 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, colormap, name, &screen,
+		&color) != 0) {
+	    DeleteStressedCmap(display, 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, colormap, name, &color,
+		    &screen) == 0) {
+		return (TkColor *) NULL;
+	    }
+	    FindClosestColor(tkwin, &screen, &color);
+	}
+    } else {
+	if (XParseColor(display, colormap, name, &color) == 0) {
+	    return (TkColor *) NULL;
+	}
+	if (XAllocColor(display, colormap, &color) != 0) {
+	    DeleteStressedCmap(display, colormap);
+	} else {
+	    FindClosestColor(tkwin, &color, &color);
+	}
+    }
+
+    tkColPtr = (TkColor *) ckalloc(sizeof(TkColor));
+    tkColPtr->color = color;
+
+    return tkColPtr;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkpGetColorByValue --
+ *
+ *	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 TkColor 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:
+ *	May invalidate the colormap cache for the specified window.
+ *	Allocates a new TkColor structure.
+ *
+ *----------------------------------------------------------------------
+ */
+
+TkColor *
+TkpGetColorByValue(tkwin, colorPtr)
+    Tk_Window tkwin;		/* Window in which color will be used. */
+    XColor *colorPtr;		/* Red, green, and blue fields indicate
+				 * desired color. */
+{
+    Display *display = Tk_Display(tkwin);
+    Colormap colormap = Tk_Colormap(tkwin);
+    TkColor *tkColPtr = (TkColor *) ckalloc(sizeof(TkColor));
+
+    tkColPtr->color.red = colorPtr->red;
+    tkColPtr->color.green = colorPtr->green;
+    tkColPtr->color.blue = colorPtr->blue;
+    if (XAllocColor(display, colormap, &tkColPtr->color) != 0) {
+	DeleteStressedCmap(display, colormap);
+    } else {
+	FindClosestColor(tkwin, &tkColPtr->color, &tkColPtr->color);
+    }
+
+    return tkColPtr;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * 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;
+    double 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;
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * 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;
+	}
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkpCmapStressed --
+ *
+ *	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
+TkpCmapStressed(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;
+}