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   GtkRoundedBox clip_box;
  48
  49   gint idx;
  50 } GtkThemingBackgroundLayer;
  51
  52 static void
  53 _gtk_theming_background_layer_apply_origin (GtkThemingBackground *bg,
  54                                             GtkThemingBackgroundLayer *layer)
  55 {
  56   cairo_rectangle_t image_rect;
  57   GtkCssValue *value = _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_ORIGIN);
  58   GtkCssArea origin = _gtk_css_area_value_get (_gtk_css_array_value_get_nth (value, layer->idx));
  59
  60   /* The default size of the background image depends on the
  61      background-origin value as this affects the top left
  62      and the bottom right corners. */
  63   switch (origin) {
  64   case GTK_CSS_AREA_BORDER_BOX:
  65     image_rect.x = 0;
  66     image_rect.y = 0;
  67     image_rect.width = bg->paint_area.width;
  68     image_rect.height = bg->paint_area.height;
  69     break;
  70   case GTK_CSS_AREA_CONTENT_BOX:
  71     image_rect.x = bg->border.left + bg->padding.left;
  72     image_rect.y = bg->border.top + bg->padding.top;
  73     image_rect.width = bg->paint_area.width - bg->border.left - bg->border.right - bg->padding.left - bg->padding.right;
  74     image_rect.height = bg->paint_area.height - bg->border.top - bg->border.bottom - bg->padding.top - bg->padding.bottom;
  75     break;
  76   case GTK_CSS_AREA_PADDING_BOX:
  77   default:
  78     image_rect.x = bg->border.left;
  79     image_rect.y = bg->border.top;
  80     image_rect.width = bg->paint_area.width - bg->border.left - bg->border.right;
  81     image_rect.height = bg->paint_area.height - bg->border.top - bg->border.bottom;
  82     break;
  83   }
  84
  85   /* XXX: image_rect might have negative width/height here.
  86    * Do we need to do something about it? */
  87   layer->image_rect = image_rect;
  88 }
  89
  90 static void
  91 _gtk_theming_background_apply_clip (GtkThemingBackground *bg,
  92                                     GtkRoundedBox *box,
  93                                     GtkCssArea clip)
  94 {
  95   if (clip == GTK_CSS_AREA_PADDING_BOX)
  96     {
  97       _gtk_rounded_box_shrink (box,
  98                                bg->border.top, bg->border.right,
  99                                bg->border.bottom, bg->border.left);
 100     }
 101   else if (clip == GTK_CSS_AREA_CONTENT_BOX)
 102     {
 103       _gtk_rounded_box_shrink (box,
 104                                bg->border.top + bg->padding.top,
 105                                bg->border.right + bg->padding.right,
 106                                bg->border.bottom + bg->padding.bottom,
 107                                bg->border.left + bg->padding.left);
 108     }
 109 }
 110
 111 static void
 112 _gtk_theming_background_layer_apply_clip (GtkThemingBackground *bg,
 113                                           GtkThemingBackgroundLayer *layer)
 114 {
 115   GtkCssValue *value = _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_CLIP);
 116   GtkCssArea clip = _gtk_css_area_value_get (_gtk_css_array_value_get_nth (value, layer->idx));
 117
 118   _gtk_theming_background_apply_clip (bg, &layer->clip_box, clip);
 119 }
 120
 121 static void
 122 _gtk_theming_background_paint_color (GtkThemingBackground *bg,
 123                                      cairo_t              *cr,
 124                                      GtkCssValue          *background_image)
 125 {
 126   GtkRoundedBox clip_box;
 127   gint n_values = _gtk_css_array_value_get_n_values (background_image);
 128   GtkCssArea clip = _gtk_css_area_value_get
 129     (_gtk_css_array_value_get_nth
 130      (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_CLIP),
 131       n_values - 1));
 132
 133   clip_box = bg->border_box;
 134   _gtk_theming_background_apply_clip (bg, &clip_box, clip);
 135
 136   cairo_save (cr);
 137   _gtk_rounded_box_path (&clip_box, cr);
 138   cairo_clip (cr);
 139
 140   gdk_cairo_set_source_rgba (cr, &bg->bg_color);
 141   cairo_paint (cr);
 142
 143   cairo_restore (cr);
 144 }
 145
 146 static void
 147 _gtk_theming_background_paint_layer (GtkThemingBackground *bg,
 148                                      GtkThemingBackgroundLayer *layer,
 149                                      cairo_t              *cr)
 150 {
 151   GtkCssRepeatStyle hrepeat, vrepeat;
 152   const GtkCssValue *pos, *repeat;
 153   GtkCssImage *image;
 154   double image_width, image_height;
 155   double width, height;
 156
 157   pos = _gtk_css_array_value_get_nth (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_POSITION), layer->idx);
 158   repeat = _gtk_css_array_value_get_nth (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_REPEAT), layer->idx);
 159   hrepeat = _gtk_css_background_repeat_value_get_x (repeat);
 160   vrepeat = _gtk_css_background_repeat_value_get_y (repeat);
 161   image = _gtk_css_image_value_get_image (
 162               _gtk_css_array_value_get_nth (
 163                   _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_IMAGE),
 164                   layer->idx));
 165   width = layer->image_rect.width;
 166   height = layer->image_rect.height;
 167
 168   if (image == NULL || width <= 0 || height <= 0)
 169     return;
 170
 171   _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),
 172                                        image,
 173                                        width,
 174                                        height,
 175                                        &image_width,
 176                                        &image_height);
 177
 178   if (image_width <= 0 || image_height <= 0)
 179     return;
 180
 181   /* optimization */
 182   if (image_width == width)
 183     hrepeat = GTK_CSS_REPEAT_STYLE_NO_REPEAT;
 184   if (image_height == height)
 185     vrepeat = GTK_CSS_REPEAT_STYLE_NO_REPEAT;
 186
 187
 188   cairo_save (cr);
 189
 190   _gtk_rounded_box_path (&layer->clip_box, cr);
 191   cairo_clip (cr);
 192
 193
 194   cairo_translate (cr, layer->image_rect.x, layer->image_rect.y);
 195
 196   if (hrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT && vrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT)
 197     {
 198       cairo_translate (cr,
 199                        _gtk_css_position_value_get_x (pos, width - image_width),
 200                        _gtk_css_position_value_get_y (pos, height - image_height));
 201       /* shortcut for normal case */
 202       _gtk_css_image_draw (image, cr, image_width, image_height);
 203     }
 204   else
 205     {
 206       int surface_width, surface_height;
 207       cairo_rectangle_t fill_rect;
 208       cairo_surface_t *surface;
 209       cairo_t *cr2;
 210
 211       /* If ‘background-repeat’ is ‘round’ for one (or both) dimensions,
 212        * there is a second step. The UA must scale the image in that
 213        * dimension (or both dimensions) so that it fits a whole number of
 214        * times in the background positioning area. In the case of the width
 215        * (height is analogous):
 216        *
 217        * If X ≠ 0 is the width of the image after step one and W is the width
 218        * of the background positioning area, then the rounded width
 219        * X' = W / round(W / X) where round() is a function that returns the
 220        * nearest natural number (integer greater than zero).
 221        *
 222        * If ‘background-repeat’ is ‘round’ for one dimension only and if
 223        * ‘background-size’ is ‘auto’ for the other dimension, then there is
 224        * a third step: that other dimension is scaled so that the original
 225        * aspect ratio is restored.
 226        */
 227       if (hrepeat == GTK_CSS_REPEAT_STYLE_ROUND)
 228         {
 229           double n = round (width / image_width);
 230
 231           n = MAX (1, n);
 232
 233           if (vrepeat != GTK_CSS_REPEAT_STYLE_ROUND
 234               /* && vsize == auto (it is by default) */)
 235             image_height *= width / (image_width * n);
 236           image_width = width / n;
 237         }
 238       if (vrepeat == GTK_CSS_REPEAT_STYLE_ROUND)
 239         {
 240           double n = round (height / image_height);
 241
 242           n = MAX (1, n);
 243
 244           if (hrepeat != GTK_CSS_REPEAT_STYLE_ROUND
 245               /* && hsize == auto (it is by default) */)
 246             image_width *= height / (image_height * n);
 247           image_height = height / n;
 248         }
 249
 250       /* if hrepeat or vrepeat is 'space', we create a somewhat larger surface
 251        * to store the extra space. */
 252       if (hrepeat == GTK_CSS_REPEAT_STYLE_SPACE)
 253         {
 254           double n = floor (width / image_width);
 255           surface_width = n ? round (width / n) : 0;
 256         }
 257       else
 258         surface_width = round (image_width);
 259
 260       if (vrepeat == GTK_CSS_REPEAT_STYLE_SPACE)
 261         {
 262           double n = floor (height / image_height);
 263           surface_height = n ? round (height / n) : 0;
 264         }
 265       else
 266         surface_height = round (image_height);
 267
 268       surface = cairo_surface_create_similar (cairo_get_target (cr),
 269                                               CAIRO_CONTENT_COLOR_ALPHA,
 270                                               surface_width, surface_height);
 271       cr2 = cairo_create (surface);
 272       cairo_translate (cr2,
 273                        0.5 * (surface_width - image_width),
 274                        0.5 * (surface_height - image_height));
 275       _gtk_css_image_draw (image, cr2, image_width, image_height);
 276       cairo_destroy (cr2);
 277
 278       cairo_set_source_surface (cr, surface,
 279                                 _gtk_css_position_value_get_x (pos, width - image_width),
 280                                 _gtk_css_position_value_get_y (pos, height - image_height));
 281       cairo_pattern_set_extend (cairo_get_source (cr), CAIRO_EXTEND_REPEAT);
 282       cairo_surface_destroy (surface);
 283
 284       if (hrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT)
 285         {
 286           fill_rect.x = _gtk_css_position_value_get_x (pos, width - image_width);
 287           fill_rect.width = image_width;
 288         }
 289       else
 290         {
 291           fill_rect.x = 0;
 292           fill_rect.width = width;
 293         }
 294
 295       if (vrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT)
 296         {
 297           fill_rect.y = _gtk_css_position_value_get_y (pos, height - image_height);
 298           fill_rect.height = image_height;
 299         }
 300       else
 301         {
 302           fill_rect.y = 0;
 303           fill_rect.height = height;
 304         }
 305
 306       cairo_rectangle (cr, fill_rect.x, fill_rect.y,
 307                        fill_rect.width, fill_rect.height);
 308       cairo_fill (cr);
 309     }
 310
 311
 312   cairo_restore (cr);
 313 }
 314
 315 static void
 316 _gtk_theming_background_apply_shadow (GtkThemingBackground *bg,
 317                                       cairo_t              *cr)
 318 {
 319   _gtk_css_shadows_value_paint_box (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BOX_SHADOW),
 320                                     cr,
 321                                     &bg->padding_box);
 322 }
 323
 324 static void
 325 _gtk_theming_background_init_layer (GtkThemingBackground *bg,
 326                                     GtkThemingBackgroundLayer *layer,
 327                                     gint idx)
 328 {
 329   layer->idx = idx;
 330   layer->clip_box = bg->border_box;
 331
 332   _gtk_theming_background_layer_apply_clip (bg, layer);
 333   _gtk_theming_background_layer_apply_origin (bg, layer);
 334 }
 335
 336 static void
 337 _gtk_theming_background_init_context (GtkThemingBackground *bg)
 338 {
 339   GtkStateFlags flags = gtk_style_context_get_state (bg->context);
 340
 341   gtk_style_context_get_border (bg->context, flags, &bg->border);
 342   gtk_style_context_get_padding (bg->context, flags, &bg->padding);
 343   gtk_style_context_get_background_color (bg->context, flags, &bg->bg_color);
 344
 345   /* In the CSS box model, by default the background positioning area is
 346    * the padding-box, i.e. all the border-box minus the borders themselves,
 347    * which determines also its default size, see
 348    * http://dev.w3.org/csswg/css3-background/#background-origin
 349    *
 350    * In the future we might want to support different origins or clips, but
 351    * right now we just shrink to the default.
 352    */
 353   _gtk_rounded_box_init_rect (&bg->border_box, 0, 0, bg->paint_area.width, bg->paint_area.height);
 354   _gtk_rounded_box_apply_border_radius_for_context (&bg->border_box, bg->context, bg->junction);
 355
 356   bg->padding_box = bg->border_box;
 357   _gtk_rounded_box_shrink (&bg->padding_box,
 358                            bg->border.top, bg->border.right,
 359                            bg->border.bottom, bg->border.left);
 360 }
 361
 362 void
 363 _gtk_theming_background_init (GtkThemingBackground *bg,
 364                               GtkThemingEngine     *engine,
 365                               gdouble               x,
 366                               gdouble               y,
 367                               gdouble               width,
 368                               gdouble               height,
 369                               GtkJunctionSides      junction)
 370 {
 371   GtkStyleContext *context;
 372
 373   g_assert (bg != NULL);
 374
 375   context = _gtk_theming_engine_get_context (engine);
 376   _gtk_theming_background_init_from_context (bg, context,
 377                                              x, y, width, height,
 378                                              junction);
 379 }
 380
 381 void
 382 _gtk_theming_background_init_from_context (GtkThemingBackground *bg,
 383                                            GtkStyleContext      *context,
 384                                            gdouble               x,
 385                                            gdouble               y,
 386                                            gdouble               width,
 387                                            gdouble               height,
 388                                            GtkJunctionSides      junction)
 389 {
 390   g_assert (bg != NULL);
 391
 392   bg->context = context;
 393
 394   bg->paint_area.x = x;
 395   bg->paint_area.y = y;
 396   bg->paint_area.width = width;
 397   bg->paint_area.height = height;
 398
 399   bg->junction = junction;
 400
 401   _gtk_theming_background_init_context (bg);
 402 }
 403
 404 void
 405 _gtk_theming_background_render (GtkThemingBackground *bg,
 406                                 cairo_t              *cr)
 407 {
 408   gint idx;
 409   GtkThemingBackgroundLayer layer;
 410   GtkCssValue *background_image;
 411
 412   background_image = _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_IMAGE);
 413
 414   cairo_save (cr);
 415   cairo_translate (cr, bg->paint_area.x, bg->paint_area.y);
 416
 417   _gtk_theming_background_paint_color (bg, cr, background_image);
 418
 419   for (idx = _gtk_css_array_value_get_n_values (background_image) - 1; idx >= 0; idx--)
 420     {
 421       _gtk_theming_background_init_layer (bg, &layer, idx);
 422       _gtk_theming_background_paint_layer (bg, &layer, cr);
 423     }
 424
 425   _gtk_theming_background_apply_shadow (bg, cr);
 426
 427   cairo_restore (cr);
 428 }
 429
 430 gboolean
 431 _gtk_theming_background_has_background_image (GtkThemingBackground *bg)
 432 {
 433   GtkCssImage *image;
 434   GtkCssValue *value = _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_IMAGE);
 435
 436   if (_gtk_css_array_value_get_n_values (value) == 0)
 437     return FALSE;
 438
 439   image = _gtk_css_image_value_get_image (_gtk_css_array_value_get_nth (value, 0));
 440   return (image != NULL);
 441 }