tkcolor.c

MPICH是MPI的重要研究,提供了一系列的接口函数,为并行计算的实现提供了编程环境.

/* 
 * 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) 1990-1993 The Regents of the University of California.
 * All rights reserved.
 *
 * Permission is hereby granted, without written agreement and without
 * license or royalty fees, to use, copy, modify, and distribute this
 * software and its documentation for any purpose, provided that the
 * above copyright notice and the following two paragraphs appear in
 * all copies of this software.
 * 
 * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
 * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF
 * CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 */


#include "tkConfig.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) 0xc6140277)

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. */
    Screen *screen;		/* Screen where this color is valid.  Used
				 * to delete it. */
    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. */

/*
 * 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 in window "tkwin".  If an error occurs,
 *	then 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, colormap, 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. */
    Colormap colormap;		/* Map from which to allocate color.  None
				 * means use current colormap for tkwin. */
    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;

    if (!initialized) {
	ColorInit();
    }

    /*
     * First, check to see if there's already a mapping for this color
     * name.
     */

    nameKey.name = name;
    if (colormap == None) {
	colormap = Tk_Colormap(tkwin);
    }
    nameKey.colormap = colormap;
    nameKey.display = Tk_Display(tkwin);
    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.  There are several tricks here:
     *
     * 1. Call XAllocNamedColor rather than XParseColor for non-# names:
     *    this saves a server round-trip for those names.
     * 2. If the display is supposed to be treated as mono, then look
     *    up the color value and translate to mono.
     * 3. If a color allocation fails, then reset the display's color model
     *    to mono, generate an error message, and retry with the mono
     *    approach.
     */

    if (*name != '#') {
	XColor screen;

	if (Tk_GetColorModel(tkwin) != TK_COLOR) {
	    if (XLookupColor(Tk_Display(tkwin), colormap, name, &color,
		    &screen) == 0) {
		badColorName:
		Tcl_AppendResult(interp, "unknown color name \"",
			name, "\"", (char *) NULL);
		Tcl_DeleteHashEntry(nameHashPtr);
		return (XColor *) NULL;
	    }
	    goto useMonoApproximation;
	}

	if (XAllocNamedColor(Tk_Display(tkwin), colormap, name,
		&screen, &color) == 0) {
	    char message[120];

	    /*
	     * 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
	     * put the display into mono mode and
	     */

	    if (XLookupColor(Tk_Display(tkwin), colormap, name, &color,
		    &screen) == 0) {
		goto badColorName;
	    }
	    outOfColors:
	    Tk_SetColorModel(tkwin, TK_MONO);
	    Tcl_AppendResult(interp, "no more colors left in colormap; ",
		    "changing screen's color model to monochrome",
		    (char *) NULL);
	    sprintf(message, "\n    (while allocating color \"%.50s\")", name);
	    Tcl_AddErrorInfo(interp, message);
	    Tk_BackgroundError(interp);
	    goto useMonoApproximation;
	}
    } else {
	if (XParseColor(Tk_Display(tkwin), colormap, name, &color) == 0) {
	    Tcl_AppendResult(interp, "invalid color name \"", name,
		    "\"", (char *) NULL);
	    Tcl_DeleteHashEntry(nameHashPtr);
	    return (XColor *) NULL;
	}
	if (Tk_GetColorModel(tkwin) != TK_COLOR) {
	    useMonoApproximation:
	    if ((((int) color.red) + ((int) color.green) + ((int) color.blue))
		    > (3*65535)/2) {
		color.pixel = WhitePixelOfScreen(Tk_Screen(tkwin));
	    } else {
		color.pixel = BlackPixelOfScreen(Tk_Screen(tkwin));
	    }
	} else if (XAllocColor(Tk_Display(tkwin), colormap, &color) == 0) {
	    goto outOfColors;
	}
    }

    /*
     * Now create a new TkColor structure and add it to nameTable.
     */

    tkColPtr = (TkColor *) ckalloc(sizeof(TkColor));
    tkColPtr->color = color;
    tkColPtr->magic = COLOR_MAGIC;
    tkColPtr->screen = Tk_Screen(tkwin);
    tkColPtr->colormap = 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 in window "tkwin".  If an
 *	error occurs, then 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_GetColorByValue(interp, tkwin, colormap, colorPtr)
    Tcl_Interp *interp;		/* Place to leave error message if
				 * color can't be found. */
    Tk_Window tkwin;		/* Window in which color will be used. */
    Colormap colormap;		/* Map from which to allocate color.  None
				 * means use current colormap for tkwin. */
    XColor *colorPtr;		/* Red, green, and blue fields indicate
				 * desired color. */
{
    ValueKey valueKey;
    Tcl_HashEntry *valueHashPtr;
    int new;
    TkColor *tkColPtr;

    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;
    if (colormap == None) {
	colormap = Tk_Colormap(tkwin);
    }
    valueKey.colormap = colormap;
    valueKey.display = Tk_Display(tkwin);
    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.
     */