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

   1 /* GTK - The GIMP Toolkit
   2  * Copyright (C) 2010 Carlos Garnacho <carlosg@gnome.org>
   3  * Copyright (C) 2011 Red Hat, Inc.
   4  *
   5  * Authors: Carlos Garnacho <carlosg@gnome.org>
   6  *          Cosimo Cecchi <cosimoc@gnome.org>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2 of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library. If not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22 #include "config.h"
  23
  24 #include "gtkthemingbackgroundprivate.h"
  25
  26 #include "gtkcssarrayvalueprivate.h"
  27 #include "gtkcssbgsizevalueprivate.h"
  28 #include "gtkcssenumvalueprivate.h"
  29 #include "gtkcssimagevalueprivate.h"
  30 #include "gtkcssshadowsvalueprivate.h"
  31 #include "gtkcsspositionvalueprivate.h"
  32 #include "gtkcssrepeatvalueprivate.h"
  33 #include "gtkcsstypesprivate.h"
  34 #include "gtkthemingengineprivate.h"
  35
  36 #include <math.h>
  37
  38 #include <gdk/gdk.h>
  39
  40 /* this is in case round() is not provided by the compiler,
  41  * such as in the case of C89 compilers, like MSVC
  42  */
  43 #include "fallback-c89.c"
  44
  45 typedef struct {
  46   cairo_rectangle_t image_rect;
  47   GtkCssImage *image;
  48   GtkRoundedBox clip_box;
  49
  50   gint idx;
  51 } GtkThemingBackgroundLayer;
  52
  53 static void
  54 _gtk_theming_background_layer_apply_origin (GtkThemingBackground *bg,
  55                                             GtkThemingBackgroundLayer *layer)
  56 {
  57   cairo_rectangle_t image_rect;
  58   GtkCssValue *value = _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_ORIGIN);
  59   GtkCssArea origin = _gtk_css_area_value_get (_gtk_css_array_value_get_nth (value, layer->idx));
  60
  61   /* The default size of the background image depends on the
  62      background-origin value as this affects the top left
  63      and the bottom right corners. */
  64   switch (origin) {
  65   case GTK_CSS_AREA_BORDER_BOX:
  66     image_rect.x = 0;
  67     image_rect.y = 0;
  68     image_rect.width = bg->paint_area.width;
  69     image_rect.height = bg->paint_area.height;
  70     break;
  71   case GTK_CSS_AREA_CONTENT_BOX:
  72     image_rect.x = bg->border.left + bg->padding.left;
  73     image_rect.y = bg->border.top + bg->padding.top;
  74     image_rect.width = bg->paint_area.width - bg->border.left - bg->border.right - bg->padding.left - bg->padding.right;
  75     image_rect.height = bg->paint_area.height - bg->border.top - bg->border.bottom - bg->padding.top - bg->padding.bottom;
  76     break;
  77   case GTK_CSS_AREA_PADDING_BOX:
  78   default:
  79     image_rect.x = bg->border.left;
  80     image_rect.y = bg->border.top;
  81     image_rect.width = bg->paint_area.width - bg->border.left - bg->border.right;
  82     image_rect.height = bg->paint_area.height - bg->border.top - bg->border.bottom;
  83     break;
  84   }
  85
  86   /* XXX: image_rect might have negative width/height here.
  87    * Do we need to do something about it? */
  88   layer->image_rect = image_rect;
  89 }
  90
  91 static void
  92 _gtk_theming_background_apply_clip (GtkThemingBackground *bg,
  93                                     GtkRoundedBox *box,
  94                                     GtkCssArea clip)
  95 {
  96   if (clip == GTK_CSS_AREA_PADDING_BOX)
  97     {
  98       _gtk_rounded_box_shrink (box,
  99                                bg->border.top, bg->border.right,
 100                                bg->border.bottom, bg->border.left);
 101     }
 102   else if (clip == GTK_CSS_AREA_CONTENT_BOX)
 103     {
 104       _gtk_rounded_box_shrink (box,
 105                                bg->border.top + bg->padding.top,
 106                                bg->border.right + bg->padding.right,
 107                                bg->border.bottom + bg->padding.bottom,
 108                                bg->border.left + bg->padding.left);
 109     }
 110 }
 111
 112 static void
 113 _gtk_theming_background_layer_apply_clip (GtkThemingBackground *bg,
 114                                           GtkThemingBackgroundLayer *layer)
 115 {
 116   GtkCssValue *value = _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_CLIP);
 117   GtkCssArea clip = _gtk_css_area_value_get (_gtk_css_array_value_get_nth (value, layer->idx));
 118
 119   _gtk_theming_background_apply_clip (bg, &layer->clip_box, clip);
 120 }
 121
 122 static void
 123 _gtk_theming_background_paint_color (GtkThemingBackground *bg,
 124                                      cairo_t              *cr,
 125                                      GtkCssValue          *background_image)
 126 {
 127   GtkRoundedBox clip_box;
 128   gint n_values = _gtk_css_array_value_get_n_values (background_image);
 129   GtkCssArea clip = _gtk_css_area_value_get
 130     (_gtk_css_array_value_get_nth
 131      (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_CLIP),
 132       n_values - 1));
 133
 134   clip_box = bg->border_box;
 135   _gtk_theming_background_apply_clip (bg, &clip_box, clip);
 136
 137   cairo_save (cr);
 138   _gtk_rounded_box_path (&clip_box, cr);
 139   cairo_clip (cr);
 140
 141   gdk_cairo_set_source_rgba (cr, &bg->bg_color);
 142   cairo_paint (cr);
 143
 144   cairo_restore (cr);
 145 }
 146
 147 static void
 148 _gtk_theming_background_paint_layer (GtkThemingBackground *bg,
 149                                      GtkThemingBackgroundLayer *layer,
 150                                      cairo_t              *cr)
 151 {
 152   cairo_save (cr);
 153
 154   _gtk_rounded_box_path (&layer->clip_box, cr);
 155   cairo_clip (cr);
 156
 157   if (layer->image
 158       && layer->image_rect.width > 0
 159       && layer->image_rect.height > 0)
 160     {
 161       const GtkCssValue *pos, *repeat;
 162       double image_width, image_height;
 163       double width, height;
 164       GtkCssRepeatStyle hrepeat, vrepeat;
 165
 166       pos = _gtk_css_array_value_get_nth (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_POSITION), layer->idx);
 167       repeat = _gtk_css_array_value_get_nth (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_REPEAT), layer->idx);
 168       hrepeat = _gtk_css_background_repeat_value_get_x (repeat);
 169       vrepeat = _gtk_css_background_repeat_value_get_y (repeat);
 170       width = layer->image_rect.width;
 171       height = layer->image_rect.height;
 172
 173       _gtk_css_bg_size_value_compute_size (_gtk_css_array_value_get_nth (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_SIZE), layer->idx),
 174                                            layer->image,
 175                                            width,
 176                                            height,
 177                                            &image_width,
 178                                            &image_height);
 179
 180       /* optimization */
 181       if (image_width == width)
 182         hrepeat = GTK_CSS_REPEAT_STYLE_NO_REPEAT;
 183       if (image_height == height)
 184         vrepeat = GTK_CSS_REPEAT_STYLE_NO_REPEAT;
 185
 186       cairo_translate (cr, layer->image_rect.x, layer->image_rect.y);
 187
 188       if (hrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT && vrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT)
 189         {
 190           cairo_translate (cr,
 191                            _gtk_css_position_value_get_x (pos, width - image_width),
 192                            _gtk_css_position_value_get_y (pos, height - image_height));
 193           /* shortcut for normal case */
 194           _gtk_css_image_draw (layer->image, cr, image_width, image_height);
 195         }
 196       else
 197         {
 198           int surface_width, surface_height;
 199           cairo_surface_t *surface;
 200           cairo_t *cr2;
 201
 202           /* If ‘background-repeat’ is ‘round’ for one (or both) dimensions,
 203            * there is a second step. The UA must scale the image in that
 204            * dimension (or both dimensions) so that it fits a whole number of
 205            * times in the background positioning area. In the case of the width
 206            * (height is analogous):
 207            *
 208            * If X ≠ 0 is the width of the image after step one and W is the width
 209            * of the background positioning area, then the rounded width
 210            * X' = W / round(W / X) where round() is a function that returns the
 211            * nearest natural number (integer greater than zero).
 212            *
 213            * If ‘background-repeat’ is ‘round’ for one dimension only and if
 214            * ‘background-size’ is ‘auto’ for the other dimension, then there is
 215            * a third step: that other dimension is scaled so that the original
 216            * aspect ratio is restored.
 217            */
 218           if (hrepeat == GTK_CSS_REPEAT_STYLE_ROUND)
 219             {
 220               double n = round (width / image_width);
 221
 222               n = MAX (1, n);
 223
 224               if (vrepeat != GTK_CSS_REPEAT_STYLE_ROUND
 225                   /* && vsize == auto (it is by default) */)
 226                 image_height *= width / (image_width * n);
 227               image_width = width / n;
 228             }
 229           if (vrepeat == GTK_CSS_REPEAT_STYLE_ROUND)
 230             {
 231               double n = round (height / image_height);
 232
 233               n = MAX (1, n);
 234
 235               if (hrepeat != GTK_CSS_REPEAT_STYLE_ROUND
 236                   /* && hsize == auto (it is by default) */)
 237                 image_width *= height / (image_height * n);
 238               image_height = height / n;
 239             }
 240
 241           /* if hrepeat or vrepeat is 'space', we create a somewhat larger surface
 242            * to store the extra space. */
 243           if (hrepeat == GTK_CSS_REPEAT_STYLE_SPACE)
 244             {
 245               double n = floor (width / image_width);
 246               surface_width = n ? round (width / n) : 0;
 247             }
 248           else
 249             surface_width = round (image_width);
 250
 251           if (vrepeat == GTK_CSS_REPEAT_STYLE_SPACE)
 252             {
 253               double n = floor (height / image_height);
 254               surface_height = n ? round (height / n) : 0;
 255             }
 256           else
 257             surface_height = round (image_height);
 258
 259           surface = cairo_surface_create_similar (cairo_get_target (cr),
 260                                                   CAIRO_CONTENT_COLOR_ALPHA,
 261                                                   surface_width, surface_height);
 262           cr2 = cairo_create (surface);
 263           cairo_translate (cr2,
 264                            0.5 * (surface_width - image_width),
 265                            0.5 * (surface_height - image_height));
 266           _gtk_css_image_draw (layer->image, cr2, image_width, image_height);
 267           cairo_destroy (cr2);
 268
 269           cairo_set_source_surface (cr, surface,
 270                                     _gtk_css_position_value_get_x (pos, width - image_width),
 271                                     _gtk_css_position_value_get_y (pos, height - image_height));
 272           cairo_pattern_set_extend (cairo_get_source (cr), CAIRO_EXTEND_REPEAT);
 273           cairo_surface_destroy (surface);
 274
 275           cairo_rectangle (cr,
 276                            0, 0,
 277                            hrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT ? image_width : width,
 278                            vrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT ? image_height : height);
 279           cairo_fill (cr);
 280         }
 281     }
 282
 283   cairo_restore (cr);
 284 }
 285
 286 static void
 287 _gtk_theming_background_apply_shadow (GtkThemingBackground *bg,
 288                                       cairo_t              *cr)
 289 {
 290   _gtk_css_shadows_value_paint_box (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BOX_SHADOW),
 291                                     cr,
 292                                     &bg->padding_box);
 293 }
 294
 295 static void
 296 _gtk_theming_background_init_layer (GtkThemingBackground *bg,
 297                                     GtkThemingBackgroundLayer *layer,
 298                                     GtkCssValue *background_image,
 299                                     gint idx)
 300 {
 301   layer->idx = idx;
 302   layer->clip_box = bg->border_box;
 303
 304   _gtk_theming_background_layer_apply_clip (bg, layer);
 305   _gtk_theming_background_layer_apply_origin (bg, layer);
 306
 307   layer->image = _gtk_css_image_value_get_image (_gtk_css_array_value_get_nth (background_image, layer->idx));
 308 }
 309
 310 static void
 311 _gtk_theming_background_init_context (GtkThemingBackground *bg)
 312 {
 313   bg->flags = gtk_style_context_get_state (bg->context);
 314
 315   gtk_style_context_get_border (bg->context, bg->flags, &bg->border);
 316   gtk_style_context_get_padding (bg->context, bg->flags, &bg->padding);
 317   gtk_style_context_get_background_color (bg->context, bg->flags, &bg->bg_color);
 318
 319   /* In the CSS box model, by default the background positioning area is
 320    * the padding-box, i.e. all the border-box minus the borders themselves,
 321    * which determines also its default size, see
 322    * http://dev.w3.org/csswg/css3-background/#background-origin
 323    *
 324    * In the future we might want to support different origins or clips, but
 325    * right now we just shrink to the default.
 326    */
 327   _gtk_rounded_box_init_rect (&bg->border_box, 0, 0, bg->paint_area.width, bg->paint_area.height);
 328   _gtk_rounded_box_apply_border_radius_for_context (&bg->border_box, bg->context, bg->junction);
 329
 330   bg->padding_box = bg->border_box;
 331   _gtk_rounded_box_shrink (&bg->padding_box,
 332                            bg->border.top, bg->border.right,
 333                            bg->border.bottom, bg->border.left);
 334 }
 335
 336 void
 337 _gtk_theming_background_init (GtkThemingBackground *bg,
 338                               GtkThemingEngine     *engine,
 339                               gdouble               x,
 340                               gdouble               y,
 341                               gdouble               width,
 342                               gdouble               height,
 343                               GtkJunctionSides      junction)
 344 {
 345   GtkStyleContext *context;
 346
 347   g_assert (bg != NULL);
 348
 349   context = _gtk_theming_engine_get_context (engine);
 350   _gtk_theming_background_init_from_context (bg, context,
 351                                              x, y, width, height,
 352                                              junction);
 353 }
 354
 355 void
 356 _gtk_theming_background_init_from_context (GtkThemingBackground *bg,
 357                                            GtkStyleContext      *context,
 358                                            gdouble               x,
 359                                            gdouble               y,
 360                                            gdouble               width,
 361                                            gdouble               height,
 362                                            GtkJunctionSides      junction)
 363 {
 364   g_assert (bg != NULL);
 365
 366   bg->context = context;
 367
 368   bg->paint_area.x = x;
 369   bg->paint_area.y = y;
 370   bg->paint_area.width = width;
 371   bg->paint_area.height = height;
 372
 373   bg->junction = junction;
 374
 375   _gtk_theming_background_init_context (bg);
 376 }
 377
 378 void
 379 _gtk_theming_background_render (GtkThemingBackground *bg,
 380                                 cairo_t              *cr)
 381 {
 382   gint idx;
 383   GtkThemingBackgroundLayer layer;
 384   GtkCssValue *background_image;
 385
 386   background_image = _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_IMAGE);
 387
 388   cairo_save (cr);
 389   cairo_translate (cr, bg->paint_area.x, bg->paint_area.y);
 390
 391   _gtk_theming_background_paint_color (bg, cr, background_image);
 392
 393   for (idx = _gtk_css_array_value_get_n_values (background_image) - 1; idx >= 0; idx--)
 394     {
 395       _gtk_theming_background_init_layer (bg, &layer, background_image, idx);
 396       _gtk_theming_background_paint_layer (bg, &layer, cr);
 397     }
 398
 399   _gtk_theming_background_apply_shadow (bg, cr);
 400
 401   cairo_restore (cr);
 402 }
 403
 404 gboolean
 405 _gtk_theming_background_has_background_image (GtkThemingBackground *bg)
 406 {
 407   GtkCssImage *image;
 408   GtkCssValue *value = _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_IMAGE);
 409
 410   if (_gtk_css_array_value_get_n_values (value) == 0)
 411     return FALSE;
 412
 413   image = _gtk_css_image_value_get_image (_gtk_css_array_value_get_nth (value, 0));
 414   return (image != NULL);
 415 }