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
  19 /** \file color.c Diagram and object tinting */
  20
  21 #include <config.h>
  22
  23 #include <stdio.h>
  24 #include <gtk/gtk.h>
  25 #include <gdk/gdk.h>
  26
  27 #include "color.h"
  28
  29 static GdkColormap *colormap = NULL;
  30
  31 #ifndef G_OS_WIN32
  32 Color color_black = { 0.0f, 0.0f, 0.0f };
  33 Color color_white = { 1.0f, 1.0f, 1.0f };
  34 #endif
  35
  36 GdkColor color_gdk_black, color_gdk_white;
  37
  38 gboolean _color_initialized = FALSE;
  39
  40 /** Initialize color access (gdk) and set up default colors.
  41  */
  42 void
  43 color_init(void)
  44 {
  45   if (!_color_initialized) {
  46     GdkVisual *visual = gtk_widget_get_default_visual();
  47     colormap = gdk_colormap_new (visual, FALSE);
  48
  49     _color_initialized = TRUE;
  50
  51     color_convert(&color_black, &color_gdk_black);
  52     color_convert(&color_white, &color_gdk_white);
  53   }
  54 }
  55
  56 /** Allocate a new color object wtih the given values.
  57  * @param r Red component (0 <= r <= 1)
  58  * @param g Green component (0 <= g <= 1)
  59  * @param b Blue component (0 <= b <= 1)
  60  * @returns A newly allocated color object.  This should be freed after use.
  61  */
  62 Color *
  63 color_new_rgb(float r, float g, float b)
  64 {
  65   Color *col = g_new(Color, 1);
  66   col->red = r;
  67   col->green = g;
  68   col->blue = b;
  69   return col;
  70 }
  71
  72 /** Convert a Dia color object to GDK style, including handling allocation.
  73  * @param color A color object.  This will not be kept by this function.
  74  * @param gdkcolor Return value: GDK color object to fill in.
  75  */
  76 void
  77 color_convert(Color *color, GdkColor *gdkcolor)
  78 {
  79   gdkcolor->red = (guint16)(color->red*65535);
  80   gdkcolor->green = (guint16)(color->green*65535);
  81   gdkcolor->blue = (guint16)(color->blue*65535);
  82
  83   if (_color_initialized) {
  84     if (!gdk_colormap_alloc_color (colormap, gdkcolor, TRUE, TRUE))
  85       g_warning ("color_convert failed.");
  86   } else {
  87     g_warning("Can't color_convert in non-interactive app (w/o color_init())");
  88   }
  89 }
  90
  91 /** Compare two color objects.
  92  * @param color1 One color object
  93  * @param color2 Another color object.
  94  * @returns TRUE if the color objects are the same color.
  95  */
  96 gboolean
  97 color_equals(Color *color1, Color *color2)
  98 {
  99   return (color1->red == color2->red) &&
 100     (color1->green == color2->green) &&
 101     (color1->blue == color2->blue);
 102 }