Initial revision

FossilOrigin-Name: 2bf55ca9aa942b581137b9f474da5ad9c1480de4

1 files changed, 540 insertions, 0 deletions

diff --git a/generic/tkVisual.c b/generic/tkVisual.c
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+/* 
+ * tkVisual.c --
+ *
+ *	This file contains library procedures for allocating and
+ *	freeing visuals and colormaps.  This code is based on a
+ *	prototype implementation by Paul Mackerras.
+ *
+ * Copyright (c) 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: @(#) tkVisual.c 1.19 97/04/25 16:52:17
+ */
+
+#include "tkInt.h"
+#include "tkPort.h"
+
+/*
+ * The table below maps from symbolic names for visual classes
+ * to the associated X class symbols.
+ */
+
+typedef struct VisualDictionary {
+    char *name;			/* Textual name of class. */
+    int minLength;		/* Minimum # characters that must be
+				 * specified for an unambiguous match. */
+    int class;			/* X symbol for class. */
+} VisualDictionary;
+static VisualDictionary visualNames[] = {
+    {"best",		1,	0},
+    {"directcolor",	2,	DirectColor},
+    {"grayscale",	1,	GrayScale},
+    {"greyscale",	1,	GrayScale},
+    {"pseudocolor",	1,	PseudoColor},
+    {"staticcolor",	7,	StaticColor},
+    {"staticgray",	7,	StaticGray},
+    {"staticgrey",	7,	StaticGray},
+    {"truecolor",	1,	TrueColor},
+    {NULL,		0,	0},
+};
+
+/*
+ * One of the following structures exists for each distinct non-default
+ * colormap allocated for a display by Tk_GetColormap.
+ */
+
+struct TkColormap {
+    Colormap colormap;		/* X's identifier for the colormap. */
+    Visual *visual;		/* Visual for which colormap was
+				 * allocated. */
+    int refCount;		/* How many uses of the colormap are still
+				 * outstanding (calls to Tk_GetColormap
+				 * minus calls to Tk_FreeColormap). */
+    int shareable;		/* 0 means this colormap was allocated by
+				 * a call to Tk_GetColormap with "new",
+				 * implying that the window wants it all
+				 * for itself.  1 means that the colormap
+				 * was allocated as a default for a particular
+				 * visual, so it can be shared. */
+    struct TkColormap *nextPtr;	/* Next in list of colormaps for this display,
+				 * or NULL for end of list. */
+};
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tk_GetVisual --
+ *
+ *	Given a string identifying a particular kind of visual, this
+ *	procedure returns a visual and depth that matches the specification.
+ *
+ * Results:
+ *	The return value is normally a pointer to a visual.  If an
+ *	error occurred in looking up the visual, NULL is returned and
+ *	an error message is left in interp->result.  The depth of the
+ *	visual is returned to *depthPtr under normal returns.  If
+ *	colormapPtr is non-NULL, then this procedure also finds a
+ *	suitable colormap for use with the visual in tkwin, and it
+ *	returns that colormap in *colormapPtr unless an error occurs.
+ *
+ * Side effects:
+ *	A new colormap may be allocated.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Visual *
+Tk_GetVisual(interp, tkwin, string, depthPtr, colormapPtr)
+    Tcl_Interp *interp;			/* Interpreter to use for error
+					 * reporting. */
+    Tk_Window tkwin;			/* Window in which visual will be
+					 * used. */
+    char *string;			/* String describing visual.  See
+					 * manual entry for details. */
+    int *depthPtr;			/* The depth of the returned visual
+					 * is stored here. */
+    Colormap *colormapPtr;		/* If non-NULL, then a suitable
+					 * colormap for visual is placed here.
+					 * This colormap must eventually be
+					 * freed by calling Tk_FreeColormap. */
+{
+    Tk_Window tkwin2;
+    XVisualInfo template, *visInfoList, *bestPtr;
+    long mask;
+    Visual *visual;
+    int length, c, numVisuals, prio, bestPrio, i;
+    char *p;
+    VisualDictionary *dictPtr;
+    TkColormap *cmapPtr;
+    TkDisplay *dispPtr = ((TkWindow *) tkwin)->dispPtr;
+
+    /*
+     * Parse string and set up a template for use in searching for
+     * an appropriate visual.
+     */
+
+    c = string[0];
+    if (c == '.') {
+	/*
+	 * The string must be a window name.  If the window is on the
+	 * same screen as tkwin, then just use its visual.  Otherwise
+	 * use the information about the visual as a template for the
+	 * search.
+	 */
+
+	tkwin2 = Tk_NameToWindow(interp, string, tkwin);
+	if (tkwin2 == NULL) {
+	    return NULL;
+	}
+	visual = Tk_Visual(tkwin2);
+	if (Tk_Screen(tkwin) == Tk_Screen(tkwin2)) {
+	    *depthPtr = Tk_Depth(tkwin2);
+	    if (colormapPtr != NULL) {
+		/*
+		 * Use the colormap from the other window too (but be sure
+		 * to increment its reference count if it's one of the ones
+		 * allocated here).
+		 */
+
+		*colormapPtr = Tk_Colormap(tkwin2);
+		for (cmapPtr = dispPtr->cmapPtr; cmapPtr != NULL;
+			cmapPtr = cmapPtr->nextPtr) {
+		    if (cmapPtr->colormap == *colormapPtr) {
+			cmapPtr->refCount += 1;
+			break;
+		    }
+		}
+	    }
+	    return visual;
+	}
+	template.depth = Tk_Depth(tkwin2);
+	template.class = visual->class;
+	template.red_mask = visual->red_mask;
+	template.green_mask = visual->green_mask;
+	template.blue_mask = visual->blue_mask;
+	template.colormap_size = visual->map_entries;
+	template.bits_per_rgb = visual->bits_per_rgb;
+	mask = VisualDepthMask|VisualClassMask|VisualRedMaskMask
+		|VisualGreenMaskMask|VisualBlueMaskMask|VisualColormapSizeMask
+		|VisualBitsPerRGBMask;
+    } else if ((c == 0) || ((c == 'd') && (string[1] != 0)
+	    && (strncmp(string, "default", strlen(string)) == 0))) {
+	/*
+	 * Use the default visual for the window's screen.
+	 */
+
+	if (colormapPtr != NULL) {
+	    *colormapPtr = DefaultColormapOfScreen(Tk_Screen(tkwin));
+	}
+	*depthPtr = DefaultDepthOfScreen(Tk_Screen(tkwin));
+	return DefaultVisualOfScreen(Tk_Screen(tkwin));
+    } else if (isdigit(UCHAR(c))) {
+	int visualId;
+
+	/*
+	* This is a visual ID.
+	*/
+
+	if (Tcl_GetInt(interp, string, &visualId) == TCL_ERROR) {
+	    Tcl_ResetResult(interp);
+	    Tcl_AppendResult(interp, "bad X identifier for visual: ",
+		    string, "\"", (char *) NULL);
+	    return NULL;
+	}
+	template.visualid = visualId;
+	mask = VisualIDMask;
+    } else {
+	/*
+	 * Parse the string into a class name (or "best") optionally
+	 * followed by whitespace and a depth.
+	 */
+
+	for (p = string; *p != 0; p++) {
+	    if (isspace(UCHAR(*p)) || isdigit(UCHAR(*p))) {
+		break;
+	    }
+	}
+	length = p - string;
+	template.class = -1;
+	for (dictPtr = visualNames; dictPtr->name != NULL; dictPtr++) {
+	    if ((dictPtr->name[0] == c) && (length >= dictPtr->minLength)
+		    && (strncmp(string, dictPtr->name,
+		    (size_t) length) == 0)) {
+		template.class = dictPtr->class;
+		break;
+	    }
+	}
+	if (template.class == -1) {
+	    Tcl_AppendResult(interp, "unknown or ambiguous visual name \"",
+		    string, "\": class must be ", (char *) NULL);
+	    for (dictPtr = visualNames; dictPtr->name != NULL; dictPtr++) {
+		Tcl_AppendResult(interp, dictPtr->name, ", ", (char *) NULL);
+	    }
+	    Tcl_AppendResult(interp, "or default", (char *) NULL);
+	    return NULL;
+	}
+	while (isspace(UCHAR(*p))) {
+	    p++;
+	}
+	if (*p == 0) {
+	    template.depth = 10000;
+	} else {
+	    if (Tcl_GetInt(interp, p, &template.depth) != TCL_OK) {
+		return NULL;
+	    }
+	}
+	if (c == 'b') {
+	    mask = 0;
+	} else {
+	    mask = VisualClassMask;
+	}
+    }
+
+    /*
+     * Find all visuals that match the template we've just created,
+     * and return an error if there are none that match.
+     */
+
+    template.screen = Tk_ScreenNumber(tkwin);
+    mask |= VisualScreenMask;
+    visInfoList = XGetVisualInfo(Tk_Display(tkwin), mask, &template,
+	    &numVisuals);
+    if (visInfoList == NULL) {
+	interp->result = "couldn't find an appropriate visual";
+	return NULL;
+    }
+
+    /*
+     * Search through the visuals that were returned to find the best
+     * one.  The choice is based on the following criteria, in decreasing
+     * order of importance:
+     *
+     * 1. Depth: choose a visual with exactly the desired depth,
+     *	  else one with more bits than requested but as few bits
+     *	  as possible, else one with fewer bits but as many as
+     *    possible.
+     * 2. Class: some visual classes are more desirable than others;
+     *    pick the visual with the most desirable class.
+     * 3. Default: the default visual for the screen gets preference
+     *    over other visuals, all else being equal.
+     */
+
+    bestPrio = 0;
+    bestPtr = NULL;
+    for (i = 0; i < numVisuals; i++) {
+	switch (visInfoList[i].class) {
+	    case DirectColor:	prio = 5; break;
+	    case GrayScale:	prio = 1; break;
+	    case PseudoColor:	prio = 7; break;
+	    case StaticColor:	prio = 3; break;
+	    case StaticGray:	prio = 1; break;
+	    case TrueColor:	prio = 5; break;
+	    default:		prio = 0; break;
+	}
+	if (visInfoList[i].visual
+		== DefaultVisualOfScreen(Tk_Screen(tkwin))) {
+	    prio++;
+	}
+	if (bestPtr == NULL) {
+	    goto newBest;
+	}
+	if (visInfoList[i].depth < bestPtr->depth) {
+	    if (visInfoList[i].depth >= template.depth) {
+		goto newBest;
+	    }
+	} else if (visInfoList[i].depth > bestPtr->depth) {
+	    if (bestPtr->depth < template.depth) {
+		goto newBest;
+	    }
+	} else {
+	    if (prio > bestPrio) {
+		goto newBest;
+	    }
+	}
+	continue;
+
+	newBest:
+	bestPtr = &visInfoList[i];
+	bestPrio = prio;
+    }
+    *depthPtr = bestPtr->depth;
+    visual = bestPtr->visual;
+    XFree((char *) visInfoList);
+
+    /*
+     * If we need to find a colormap for this visual, do it now.
+     * If the visual is the default visual for the screen, then
+     * use the default colormap.  Otherwise search for an existing
+     * colormap that's shareable.  If all else fails, create a new
+     * colormap.
+     */
+
+    if (colormapPtr != NULL) {
+	if (visual == DefaultVisualOfScreen(Tk_Screen(tkwin))) {
+	    *colormapPtr = DefaultColormapOfScreen(Tk_Screen(tkwin));
+	} else {
+	    for (cmapPtr = dispPtr->cmapPtr; cmapPtr != NULL;
+		    cmapPtr = cmapPtr->nextPtr) {
+		if (cmapPtr->shareable && (cmapPtr->visual == visual)) {
+		    *colormapPtr = cmapPtr->colormap;
+		    cmapPtr->refCount += 1;
+		    goto done;
+		}
+	    }
+	    cmapPtr = (TkColormap *) ckalloc(sizeof(TkColormap));
+	    cmapPtr->colormap = XCreateColormap(Tk_Display(tkwin),
+		    RootWindowOfScreen(Tk_Screen(tkwin)), visual,
+		    AllocNone);
+	    cmapPtr->visual = visual;
+	    cmapPtr->refCount = 1;
+	    cmapPtr->shareable = 1;
+	    cmapPtr->nextPtr = dispPtr->cmapPtr;
+	    dispPtr->cmapPtr = cmapPtr;
+	    *colormapPtr = cmapPtr->colormap;
+	}
+    }
+
+    done:
+    return visual;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tk_GetColormap --
+ *
+ *	Given a string identifying a colormap, this procedure finds
+ *	an appropriate colormap.
+ *
+ * Results:
+ *	The return value is normally the X resource identifier for the
+ *	colormap.  If an error occurs, None is returned and an error
+ *	message is placed in interp->result.
+ *
+ * Side effects:
+ *	A reference count is incremented for the colormap, so
+ *	Tk_FreeColormap must eventually be called exactly once for
+ *	each call to Tk_GetColormap.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Colormap
+Tk_GetColormap(interp, tkwin, string)
+    Tcl_Interp *interp;			/* Interpreter to use for error
+					 * reporting. */
+    Tk_Window tkwin;			/* Window where colormap will be
+					 * used. */
+    char *string;			/* String that identifies colormap:
+					 * either "new" or the name of
+					 * another window. */
+{
+    Colormap colormap;
+    TkColormap *cmapPtr;
+    TkDisplay *dispPtr = ((TkWindow *) tkwin)->dispPtr;
+    Tk_Window other;
+
+    /*
+     * Allocate a new colormap, if that's what is wanted.
+     */
+
+    if (strcmp(string, "new") == 0) {
+	cmapPtr = (TkColormap *) ckalloc(sizeof(TkColormap));
+	cmapPtr->colormap = XCreateColormap(Tk_Display(tkwin),
+		RootWindowOfScreen(Tk_Screen(tkwin)), Tk_Visual(tkwin),
+		AllocNone);
+	cmapPtr->visual = Tk_Visual(tkwin);
+	cmapPtr->refCount = 1;
+	cmapPtr->shareable = 0;
+	cmapPtr->nextPtr = dispPtr->cmapPtr;
+	dispPtr->cmapPtr = cmapPtr;
+	return cmapPtr->colormap;
+    }
+
+    /*
+     * Use a colormap from an existing window.  It must have the same
+     * visual as tkwin (which means, among other things, that the
+     * other window must be on the same screen).
+     */
+
+    other = Tk_NameToWindow(interp, string, tkwin);
+    if (other == NULL) {
+	return None;
+    }
+    if (Tk_Screen(other) != Tk_Screen(tkwin)) {
+	Tcl_AppendResult(interp, "can't use colormap for ", string,
+		": not on same screen", (char *) NULL);
+	return None;
+    }
+    if (Tk_Visual(other) != Tk_Visual(tkwin)) {
+	Tcl_AppendResult(interp, "can't use colormap for ", string,
+		": incompatible visuals", (char *) NULL);
+	return None;
+    }
+    colormap = Tk_Colormap(other);
+
+    /*
+     * If the colormap was a special one allocated by code in this file,
+     * increment its reference count.
+     */
+
+    for (cmapPtr = dispPtr->cmapPtr; cmapPtr != NULL;
+	    cmapPtr = cmapPtr->nextPtr) {
+	if (cmapPtr->colormap == colormap) {
+	    cmapPtr->refCount += 1;
+	}
+    }
+    return colormap;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tk_FreeColormap --
+ *
+ *	This procedure is called to release a colormap that was
+ *	previously allocated by Tk_GetColormap.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The colormap's reference count is decremented.  If this was the
+ *	last reference to the colormap, then the colormap is freed.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tk_FreeColormap(display, colormap)
+    Display *display;			/* Display for which colormap was
+					 * allocated. */
+    Colormap colormap;			/* Colormap that is no longer needed.
+					 * Must have been returned by previous
+					 * call to Tk_GetColormap, or
+					 * preserved by a previous call to
+					 * Tk_PreserveColormap. */
+{
+    TkDisplay *dispPtr;
+    TkColormap *cmapPtr, *prevPtr;
+
+    /*
+     * Find Tk's information about the display, then see if this
+     * colormap is a non-default one (if it's a default one, there
+     * won't be an entry for it in the display's list).
+     */
+
+    dispPtr = TkGetDisplay(display);
+    if (dispPtr == NULL) {
+	panic("unknown display passed to Tk_FreeColormap");
+    }
+    for (prevPtr = NULL, cmapPtr = dispPtr->cmapPtr; cmapPtr != NULL;
+	    prevPtr = cmapPtr, cmapPtr = cmapPtr->nextPtr) {
+	if (cmapPtr->colormap == colormap) {
+	    cmapPtr->refCount -= 1;
+	    if (cmapPtr->refCount == 0) {
+		XFreeColormap(display, colormap);
+		if (prevPtr == NULL) {
+		    dispPtr->cmapPtr = cmapPtr->nextPtr;
+		} else {
+		    prevPtr->nextPtr = cmapPtr->nextPtr;
+		}
+		ckfree((char *) cmapPtr);
+	    }
+	    return;
+	}
+    } 
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tk_PreserveColormap --
+ *
+ *	This procedure is called to indicate to Tk that the specified
+ *	colormap is being referenced from another location and should
+ *	not be freed until all extra references are eliminated.  The
+ *	colormap must have been returned by Tk_GetColormap.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The colormap's reference count is incremented, so
+ *	Tk_FreeColormap must eventually be called exactly once for
+ *	each call to Tk_PreserveColormap.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tk_PreserveColormap(display, colormap)
+    Display *display;			/* Display for which colormap was
+					 * allocated. */
+    Colormap colormap;			/* Colormap that should be
+					 * preserved. */
+{
+    TkDisplay *dispPtr;
+    TkColormap *cmapPtr;
+
+    /*
+     * Find Tk's information about the display, then see if this
+     * colormap is a non-default one (if it's a default one, there
+     * won't be an entry for it in the display's list).
+     */
+
+    dispPtr = TkGetDisplay(display);
+    if (dispPtr == NULL) {
+	panic("unknown display passed to Tk_PreserveColormap");
+    }
+    for (cmapPtr = dispPtr->cmapPtr; cmapPtr != NULL;
+	    cmapPtr = cmapPtr->nextPtr) {
+	if (cmapPtr->colormap == colormap) {
+	    cmapPtr->refCount += 1;
+	    return;
+	}
+    } 
+}