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