lib/color.c

   1 /* Dia -- an diagram creation/manipulation program
   2  * Copyright (C) 1998 Alexander Larsson
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17  */
  18 #include <config.h>
  19
  20 #include <stdio.h>
  21 #include <gtk/gtk.h>
  22 #include <gdk/gdk.h>
  23
  24 #include "color.h"
  25
  26 static GdkColormap *colormap = NULL;
  27
  28 #ifndef G_OS_WIN32
  29 Color color_black = { 0.0f, 0.0f, 0.0f };
  30 Color color_white = { 1.0f, 1.0f, 1.0f };
  31 #endif
  32
  33 GdkColor color_gdk_black, color_gdk_white;
  34
  35 gboolean _color_initialized = FALSE;
  36
  37 /** Initialize color access (gdk) and set up default colors.
  38  */
  39 void
  40 color_init(void)
  41 {
  42   if (!_color_initialized) {
  43     GdkVisual *visual = gtk_widget_get_default_visual();
  44     colormap = gdk_colormap_new (visual, FALSE);
  45
  46     _color_initialized = TRUE;
  47
  48     color_convert(&color_black, &color_gdk_black);
  49     color_convert(&color_white, &color_gdk_white);
  50   }
  51 }
  52
  53 /** Allocate a new color object wtih the given values.
  54  * @param r Red component (0 <= r <= 1)
  55  * @param g Green component (0 <= g <= 1)
  56  * @param b Blue component (0 <= b <= 1)
  57  * @returns A newly allocated color object.  This should be freed after use.
  58  */
  59 Color *
  60 color_new_rgb(float r, float g, float b)
  61 {
  62   Color *col = g_new(Color, 1);
  63   col->red = r;
  64   col->green = g;
  65   col->blue = b;
  66   return col;
  67 }
  68
  69 /** Convert a Dia color object to GDK style, including handling allocation.
  70  * @param color A color object.  This will not be kept by this function.
  71  * @param gdkcolor Return value: GDK color object to fill in.
  72  */
  73 void
  74 color_convert(Color *color, GdkColor *gdkcolor)
  75 {
  76   gdkcolor->red = color->red*65535;
  77   gdkcolor->green = color->green*65535;
  78   gdkcolor->blue = color->blue*65535;
  79
  80   if (_color_initialized) {
  81     if (!gdk_colormap_alloc_color (colormap, gdkcolor, TRUE, TRUE))
  82       g_warning ("color_convert failed.");
  83   } else {
  84     g_warning("Can't color_convert in non-interactive app (w/o color_init())");
  85   }
  86 }
  87
  88 /** Compare two color objects.
  89  * @param color1 One color object
  90  * @param color2 Another color object.
  91  * @returns TRUE if the color objects are the same color.
  92  */
  93 gboolean
  94 color_equals(Color *color1, Color *color2)
  95 {
  96   return (color1->red == color2->red) &&
  97     (color1->green == color2->green) &&
  98     (color1->blue == color2->blue);
  99 }