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Diffstat (limited to 'generic/tkColor.c')
| -rw-r--r-- | generic/tkColor.c | 397 |
1 files changed, 397 insertions, 0 deletions
diff --git a/generic/tkColor.c b/generic/tkColor.c new file mode 100644 index 0000000..781971c --- /dev/null +++ b/generic/tkColor.c @@ -0,0 +1,397 @@ +/* + * 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)); +} |