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 void
  90 gtk_css_image_cross_fade_draw (GtkCssImage        *image,
  91                                cairo_t            *cr,
  92                                double              width,
  93                                double              height)
  94 {
  95   GtkCssImageCrossFade *cross_fade = GTK_CSS_IMAGE_CROSS_FADE (image);
  96
  97   if (cross_fade->progress <= 0.0)
  98     {
  99       if (cross_fade->start)
 100         _gtk_css_image_draw (cross_fade->start, cr, width, height);
 101     }
 102   else if (cross_fade->progress >= 1.0)
 103     {
 104       if (cross_fade->end)
 105         _gtk_css_image_draw (cross_fade->end, cr, width, height);
 106     }
 107   else
 108     {
 109       if (cross_fade->start && cross_fade->end)
 110         {
 111           /* to reduce the group size */
 112           cairo_rectangle (cr, 0, 0, ceil (width), ceil (height));
 113           cairo_clip (cr);
 114
 115           cairo_push_group (cr);
 116
 117           /* performance trick */
 118           cairo_reset_clip (cr);
 119
 120           _gtk_css_image_draw (cross_fade->start, cr, width, height);
 121
 122           cairo_push_group (cr);
 123           _gtk_css_image_draw (cross_fade->end, cr, width, height);
 124           cairo_pop_group_to_source (cr);
 125
 126           cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
 127           cairo_paint_with_alpha (cr, cross_fade->progress);
 128
 129           cairo_pop_group_to_source (cr);
 130           cairo_paint (cr);
 131         }
 132       else if (cross_fade->start || cross_fade->end)
 133         {
 134           cairo_push_group (cr);
 135           _gtk_css_image_draw (cross_fade->start ? cross_fade->start : cross_fade->end, cr, width, height);
 136           cairo_pop_group_to_source (cr);
 137
 138           cairo_paint_with_alpha (cr, cross_fade->start ? 1.0 - cross_fade->progress : cross_fade->progress);
 139         }
 140     }
 141 }
 142
 143 static gboolean
 144 gtk_css_image_cross_fade_parse (GtkCssImage  *image,
 145                                 GtkCssParser *parser)
 146 {
 147   GtkCssImageCrossFade *cross_fade = GTK_CSS_IMAGE_CROSS_FADE (image);
 148   if (!_gtk_css_parser_try (parser, "cross-fade(", TRUE))
 149     {
 150       _gtk_css_parser_error (parser, "Expected 'cross-fade('");
 151       return FALSE;
 152     }
 153
 154   if (_gtk_css_parser_has_number (parser))
 155     {
 156       GtkCssValue *number;
 157
 158       number = _gtk_css_number_value_parse (parser, GTK_CSS_PARSE_PERCENT | GTK_CSS_POSITIVE_ONLY);
 159       if (number == NULL)
 160         return FALSE;
 161       cross_fade->progress = _gtk_css_number_value_get (number, 1);
 162       _gtk_css_value_unref (number);
 163
 164       if (cross_fade->progress > 1.0)
 165         {
 166           _gtk_css_parser_error (parser, "Percentages over 100%% are not allowed");
 167           return FALSE;
 168         }
 169     }
 170   else
 171     cross_fade->progress = 0.5;
 172
 173   cross_fade->start = _gtk_css_image_new_parse (parser);
 174   if (cross_fade->start == NULL)
 175     return FALSE;
 176
 177   if (_gtk_css_parser_try (parser, ",", TRUE))
 178     {
 179       /* XXX: allow parsing colors here */
 180       cross_fade->end = _gtk_css_image_new_parse (parser);
 181       if (cross_fade->end == NULL)
 182         return FALSE;
 183     }
 184
 185   if (!_gtk_css_parser_try (parser, ")", TRUE))
 186     {
 187       _gtk_css_parser_error (parser, "Missing closing bracket");
 188       return FALSE;
 189     }
 190
 191   return TRUE;
 192 }
 193
 194 static void
 195 gtk_css_image_cross_fade_print (GtkCssImage *image,
 196                                 GString     *string)
 197 {
 198   GtkCssImageCrossFade *cross_fade = GTK_CSS_IMAGE_CROSS_FADE (image);
 199
 200   g_string_append (string, "cross-fade(");
 201   if (cross_fade->progress != 0.5)
 202     {
 203       g_string_append_printf (string, "%g%% ", cross_fade->progress * 100.0);
 204     }
 205
 206   if (cross_fade->start)
 207     _gtk_css_image_print (cross_fade->start, string);
 208   else
 209     g_string_append (string, "none");
 210   if (cross_fade->end)
 211     {
 212       g_string_append (string, ", ");
 213       _gtk_css_image_print (cross_fade->end, string);
 214     }
 215   g_string_append (string, ")");
 216 }
 217
 218 static void
 219 gtk_css_image_cross_fade_dispose (GObject *object)
 220 {
 221   GtkCssImageCrossFade *cross_fade = GTK_CSS_IMAGE_CROSS_FADE (object);
 222
 223   g_clear_object (&cross_fade->start);
 224   g_clear_object (&cross_fade->end);
 225
 226   G_OBJECT_CLASS (_gtk_css_image_cross_fade_parent_class)->dispose (object);
 227 }
 228
 229 static void
 230 _gtk_css_image_cross_fade_class_init (GtkCssImageCrossFadeClass *klass)
 231 {
 232   GtkCssImageClass *image_class = GTK_CSS_IMAGE_CLASS (klass);
 233   GObjectClass *object_class = G_OBJECT_CLASS (klass);
 234
 235   image_class->get_width = gtk_css_image_cross_fade_get_width;
 236   image_class->get_height = gtk_css_image_cross_fade_get_height;
 237   image_class->draw = gtk_css_image_cross_fade_draw;
 238   image_class->parse = gtk_css_image_cross_fade_parse;
 239   image_class->print = gtk_css_image_cross_fade_print;
 240
 241   object_class->dispose = gtk_css_image_cross_fade_dispose;
 242 }
 243
 244 static void
 245 _gtk_css_image_cross_fade_init (GtkCssImageCrossFade *image_cross_fade)
 246 {
 247 }
 248
 249 GtkCssImage *
 250 _gtk_css_image_cross_fade_new (GtkCssImage *start,
 251                                GtkCssImage *end,
 252                                double       progress)
 253 {
 254   GtkCssImageCrossFade *cross_fade;
 255
 256   g_return_val_if_fail (start == NULL || GTK_IS_CSS_IMAGE (start), NULL);
 257   g_return_val_if_fail (end == NULL || GTK_IS_CSS_IMAGE (end), NULL);
 258
 259   cross_fade = g_object_new (GTK_TYPE_CSS_IMAGE_CROSS_FADE, NULL);
 260   if (start)
 261     cross_fade->start = g_object_ref (start);
 262   if (end)
 263     cross_fade->end = g_object_ref (end);
 264   cross_fade->progress = progress;
 265
 266   return GTK_CSS_IMAGE (cross_fade);
 267 }
 268