Pileus Git - ~andy/gtk/blob - gtk/gtkcssimagecrossfade.c

   1 /*
   2  * Copyright © 2012 Red Hat Inc.
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * This library 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 GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library. If not, see <http://www.gnu.org/licenses/>.
  16  *
  17  * Authors: Benjamin Otte <otte@gnome.org>
  18  */
  19
  20 #include "config.h"
  21
  22 #include <math.h>
  23 #include <string.h>
  24
  25 #include "gtkcssimagecrossfadeprivate.h"
  26
  27 #include "gtkcssnumbervalueprivate.h"
  28
  29 G_DEFINE_TYPE (GtkCssImageCrossFade, _gtk_css_image_cross_fade, GTK_TYPE_CSS_IMAGE)
  30
  31 static int
  32 gtk_css_image_cross_fade_get_width (GtkCssImage *image)
  33 {
  34   GtkCssImageCrossFade *cross_fade = GTK_CSS_IMAGE_CROSS_FADE (image);
  35   int start_width, end_width;
  36
  37   if (cross_fade->start)
  38     {
  39       start_width = _gtk_css_image_get_width (cross_fade->start);
  40       /* no intrinsic width, what now? */
  41       if (start_width == 0)
  42         return 0;
  43     }
  44   else
  45     start_width = 0;
  46
  47   if (cross_fade->end)
  48     {
  49       end_width = _gtk_css_image_get_width (cross_fade->end);
  50       /* no intrinsic width, what now? */
  51       if (end_width == 0)
  52         return 0;
  53     }
  54   else
  55     end_width = 0;
  56
  57   return start_width + (end_width - start_width) * cross_fade->progress;
  58 }
  59
  60 static int
  61 gtk_css_image_cross_fade_get_height (GtkCssImage *image)
  62 {
  63   GtkCssImageCrossFade *cross_fade = GTK_CSS_IMAGE_CROSS_FADE (image);
  64   int start_height, end_height;
  65
  66   if (cross_fade->start)
  67     {
  68       start_height = _gtk_css_image_get_height (cross_fade->start);
  69       /* no intrinsic height, what now? */
  70       if (start_height == 0)
  71         return 0;
  72     }
  73   else
  74     start_height = 0;
  75
  76   if (cross_fade->end)
  77     {
  78       end_height = _gtk_css_image_get_height (cross_fade->end);
  79       /* no intrinsic height, what now? */
  80       if (end_height == 0)
  81         return 0;
  82     }
  83   else
  84     end_height = 0;
  85
  86   return start_height + (end_height - start_height) * cross_fade->progress;
  87 }
  88
  89 static gboolean
  90 gtk_css_image_cross_fade_equal (GtkCssImage *image1,
  91                                 GtkCssImage *image2)
  92 {
  93   GtkCssImageCrossFade *cross_fade1 = GTK_CSS_IMAGE_CROSS_FADE (image1);
  94   GtkCssImageCrossFade *cross_fade2 = GTK_CSS_IMAGE_CROSS_FADE (image2);
  95
  96   return cross_fade1->progress == cross_fade2->progress &&
  97          _gtk_css_image_equal (cross_fade1->start, cross_fade2->start) &&
  98          _gtk_css_image_equal (cross_fade1->end, cross_fade2->end);
  99 }
 100
 101 static void
 102 gtk_css_image_cross_fade_draw (GtkCssImage        *image,
 103                                cairo_t            *cr,
 104                                double              width,
 105                                double              height)
 106 {
 107   GtkCssImageCrossFade *cross_fade = GTK_CSS_IMAGE_CROSS_FADE (image);
 108
 109   if (cross_fade->progress <= 0.0)
 110     {
 111       if (cross_fade->start)
 112         _gtk_css_image_draw (cross_fade->start, cr, width, height);
 113     }
 114   else if (cross_fade->progress >= 1.0)
 115     {
 116       if (cross_fade->end)
 117         _gtk_css_image_draw (cross_fade->end, cr, width, height);
 118     }
 119   else
 120     {
 121       if (cross_fade->start && cross_fade->end)
 122         {
 123           /* to reduce the group size */
 124           cairo_rectangle (cr, 0, 0, ceil (width), ceil (height));
 125           cairo_clip (cr);
 126
 127           cairo_push_group (cr);
 128
 129           /* performance trick */
 130           cairo_reset_clip (cr);
 131
 132           _gtk_css_image_draw (cross_fade->start, cr, width, height);
 133
 134           cairo_push_group (cr);
 135           _gtk_css_image_draw (cross_fade->end, cr, width, height);
 136           cairo_pop_group_to_source (cr);
 137
 138           cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
 139           cairo_paint_with_alpha (cr, cross_fade->progress);
 140
 141           cairo_pop_group_to_source (cr);
 142           cairo_paint (cr);
 143         }
 144       else if (cross_fade->start || cross_fade->end)
 145         {
 146           cairo_push_group (cr);
 147           _gtk_css_image_draw (cross_fade->start ? cross_fade->start : cross_fade->end, cr, width, height);
 148           cairo_pop_group_to_source (cr);
 149
 150           cairo_paint_with_alpha (cr, cross_fade->start ? 1.0 - cross_fade->progress : cross_fade->progress);
 151         }
 152     }
 153 }
 154
 155 static gboolean
 156 gtk_css_image_cross_fade_parse (GtkCssImage  *image,
 157                                 GtkCssParser *parser)
 158 {
 159   GtkCssImageCrossFade *cross_fade = GTK_CSS_IMAGE_CROSS_FADE (image);
 160   if (!_gtk_css_parser_try (parser, "cross-fade(", TRUE))
 161     {
 162       _gtk_css_parser_error (parser, "Expected 'cross-fade('");
 163       return FALSE;
 164     }
 165
 166   if (_gtk_css_parser_has_number (parser))
 167     {
 168       GtkCssValue *number;
 169
 170       number = _gtk_css_number_value_parse (parser, GTK_CSS_PARSE_PERCENT | GTK_CSS_POSITIVE_ONLY);
 171       if (number == NULL)
 172         return FALSE;
 173       cross_fade->progress = _gtk_css_number_value_get (number, 1);
 174       _gtk_css_value_unref (number);
 175
 176       if (cross_fade->progress > 1.0)
 177         {
 178           _gtk_css_parser_error (parser, "Percentages over 100%% are not allowed");
 179           return FALSE;
 180         }
 181     }
 182   else
 183     cross_fade->progress = 0.5;
 184
 185   cross_fade->start = _gtk_css_image_new_parse (parser);
 186   if (cross_fade->start == NULL)
 187     return FALSE;
 188
 189   if (_gtk_css_parser_try (parser, ",", TRUE))
 190     {
 191       /* XXX: allow parsing colors here */
 192       cross_fade->end = _gtk_css_image_new_parse (parser);
 193       if (cross_fade->end == NULL)
 194         return FALSE;
 195     }
 196
 197   if (!_gtk_css_parser_try (parser, ")", TRUE))
 198     {
 199       _gtk_css_parser_error (parser, "Missing closing bracket");
 200       return FALSE;
 201     }
 202
 203   return TRUE;
 204 }
 205
 206 static void
 207 gtk_css_image_cross_fade_print (GtkCssImage *image,
 208                                 GString     *string)
 209 {
 210   GtkCssImageCrossFade *cross_fade = GTK_CSS_IMAGE_CROSS_FADE (image);
 211
 212   g_string_append (string, "cross-fade(");
 213   if (cross_fade->progress != 0.5)
 214     {
 215       g_string_append_printf (string, "%g%% ", cross_fade->progress * 100.0);
 216     }
 217
 218   if (cross_fade->start)
 219     _gtk_css_image_print (cross_fade->start, string);
 220   else
 221     g_string_append (string, "none");
 222   if (cross_fade->end)
 223     {
 224       g_string_append (string, ", ");
 225       _gtk_css_image_print (cross_fade->end, string);
 226     }
 227   g_string_append (string, ")");
 228 }
 229
 230 static void
 231 gtk_css_image_cross_fade_dispose (GObject *object)
 232 {
 233   GtkCssImageCrossFade *cross_fade = GTK_CSS_IMAGE_CROSS_FADE (object);
 234
 235   g_clear_object (&cross_fade->start);
 236   g_clear_object (&cross_fade->end);
 237
 238   G_OBJECT_CLASS (_gtk_css_image_cross_fade_parent_class)->dispose (object);
 239 }
 240
 241 static void
 242 _gtk_css_image_cross_fade_class_init (GtkCssImageCrossFadeClass *klass)
 243 {
 244   GtkCssImageClass *image_class = GTK_CSS_IMAGE_CLASS (klass);
 245   GObjectClass *object_class = G_OBJECT_CLASS (klass);
 246
 247   image_class->get_width = gtk_css_image_cross_fade_get_width;
 248   image_class->get_height = gtk_css_image_cross_fade_get_height;
 249   image_class->equal = gtk_css_image_cross_fade_equal;
 250   image_class->draw = gtk_css_image_cross_fade_draw;
 251   image_class->parse = gtk_css_image_cross_fade_parse;
 252   image_class->print = gtk_css_image_cross_fade_print;
 253
 254   object_class->dispose = gtk_css_image_cross_fade_dispose;
 255 }
 256
 257 static void
 258 _gtk_css_image_cross_fade_init (GtkCssImageCrossFade *image_cross_fade)
 259 {
 260 }
 261
 262 GtkCssImage *
 263 _gtk_css_image_cross_fade_new (GtkCssImage *start,
 264                                GtkCssImage *end,
 265                                double       progress)
 266 {
 267   GtkCssImageCrossFade *cross_fade;
 268
 269   g_return_val_if_fail (start == NULL || GTK_IS_CSS_IMAGE (start), NULL);
 270   g_return_val_if_fail (end == NULL || GTK_IS_CSS_IMAGE (end), NULL);
 271
 272   cross_fade = g_object_new (GTK_TYPE_CSS_IMAGE_CROSS_FADE, NULL);
 273   if (start)
 274     cross_fade->start = g_object_ref (start);
 275   if (end)
 276     cross_fade->end = g_object_ref (end);
 277   cross_fade->progress = progress;
 278
 279   return GTK_CSS_IMAGE (cross_fade);
 280 }
 281