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 "gtkcssenumvalueprivate.h"
  28 #include "gtkcssimagevalueprivate.h"
  29 #include "gtkcsstypesprivate.h"
  30 #include "gtkthemingengineprivate.h"
  31
  32 #include <math.h>
  33
  34 #include <gdk/gdk.h>
  35
  36 /* this is in case round() is not provided by the compiler,
  37  * such as in the case of C89 compilers, like MSVC
  38  */
  39 #include "fallback-c89.c"
  40
  41 static void
  42 _gtk_theming_background_apply_window_background (GtkThemingBackground *bg,
  43                                                  cairo_t              *cr)
  44 {
  45   if (gtk_style_context_has_class (bg->context, "background"))
  46     {
  47       cairo_set_source_rgba (cr, 1.0, 1.0, 1.0, 0.0); /* transparent */
  48       cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
  49       cairo_paint (cr);
  50     }
  51 }
  52
  53 static void
  54 _gtk_theming_background_apply_origin (GtkThemingBackground *bg)
  55 {
  56   GtkCssArea origin;
  57   cairo_rectangle_t image_rect;
  58
  59   origin = _gtk_css_area_value_get (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_CLIP));
  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   bg->image_rect = image_rect;
  89 }
  90
  91 static void
  92 _gtk_theming_background_apply_clip (GtkThemingBackground *bg)
  93 {
  94   GtkCssArea clip = _gtk_css_area_value_get (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_CLIP));
  95
  96   if (clip == GTK_CSS_AREA_PADDING_BOX)
  97     {
  98       _gtk_rounded_box_shrink (&bg->clip_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 (&bg->clip_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_get_cover_contain (GtkCssImage *image,
 114                                            gboolean     cover,
 115                                            double       width,
 116                                            double       height,
 117                                            double      *concrete_width,
 118                                            double      *concrete_height)
 119 {
 120   double aspect, image_aspect;
 121
 122   image_aspect = _gtk_css_image_get_aspect_ratio (image);
 123   if (image_aspect == 0.0)
 124     {
 125       *concrete_width = width;
 126       *concrete_height = height;
 127       return;
 128     }
 129
 130   aspect = width / height;
 131
 132   if ((aspect >= image_aspect && cover) ||
 133       (aspect < image_aspect && !cover))
 134     {
 135       *concrete_width = width;
 136       *concrete_height = width / image_aspect;
 137     }
 138   else
 139     {
 140       *concrete_height = height;
 141       *concrete_width = height * image_aspect;
 142     }
 143 }
 144
 145 static void
 146 _gtk_theming_background_paint (GtkThemingBackground *bg,
 147                                cairo_t              *cr)
 148 {
 149   cairo_save (cr);
 150
 151   _gtk_rounded_box_path (&bg->clip_box, cr);
 152   cairo_clip (cr);
 153
 154   gdk_cairo_set_source_rgba (cr, &bg->bg_color);
 155   cairo_paint (cr);
 156
 157   if (bg->image
 158       && bg->image_rect.width > 0
 159       && bg->image_rect.height > 0)
 160     {
 161       GtkCssBackgroundRepeat hrepeat, vrepeat;
 162       const GtkCssBackgroundSize *size;
 163       const GtkCssBackgroundPosition *pos;
 164       double image_width, image_height;
 165       double width, height;
 166
 167       size = _gtk_css_value_get_background_size (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_SIZE));
 168       pos = _gtk_css_value_get_background_position (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_POSITION));
 169       gtk_style_context_get (bg->context, bg->flags,
 170                              "background-repeat", &hrepeat,
 171                              NULL);
 172       vrepeat = GTK_CSS_BACKGROUND_VERTICAL (hrepeat);
 173       hrepeat = GTK_CSS_BACKGROUND_HORIZONTAL (hrepeat);
 174       width = bg->image_rect.width;
 175       height = bg->image_rect.height;
 176
 177       if (size->contain || size->cover)
 178         _gtk_theming_background_get_cover_contain (bg->image,
 179                                                    size->cover,
 180                                                    width,
 181                                                    height,
 182                                                    &image_width,
 183                                                    &image_height);
 184       else
 185         _gtk_css_image_get_concrete_size (bg->image,
 186                                           /* note: 0 does the right thing here for 'auto' */
 187                                           _gtk_css_number_get (&size->width, width),
 188                                           _gtk_css_number_get (&size->height, height),
 189                                           width, height,
 190                                           &image_width, &image_height);
 191
 192       /* optimization */
 193       if (image_width == width)
 194         hrepeat = GTK_CSS_BACKGROUND_NO_REPEAT;
 195       if (image_height == height)
 196         vrepeat = GTK_CSS_BACKGROUND_NO_REPEAT;
 197
 198       cairo_translate (cr, bg->image_rect.x, bg->image_rect.y);
 199
 200       if (hrepeat == GTK_CSS_BACKGROUND_NO_REPEAT && vrepeat == GTK_CSS_BACKGROUND_NO_REPEAT)
 201         {
 202           cairo_translate (cr,
 203                            _gtk_css_number_get (&pos->x, bg->image_rect.width - image_width),
 204                            _gtk_css_number_get (&pos->y, bg->image_rect.height - image_height));
 205           /* shortcut for normal case */
 206           _gtk_css_image_draw (bg->image, cr, image_width, image_height);
 207         }
 208       else
 209         {
 210           int surface_width, surface_height;
 211           cairo_surface_t *surface;
 212           cairo_t *cr2;
 213
 214           /* If ‘background-repeat’ is ‘round’ for one (or both) dimensions,
 215            * there is a second step. The UA must scale the image in that
 216            * dimension (or both dimensions) so that it fits a whole number of
 217            * times in the background positioning area. In the case of the width
 218            * (height is analogous):
 219            *
 220            * If X ≠ 0 is the width of the image after step one and W is the width
 221            * of the background positioning area, then the rounded width
 222            * X' = W / round(W / X) where round() is a function that returns the
 223            * nearest natural number (integer greater than zero).
 224            *
 225            * If ‘background-repeat’ is ‘round’ for one dimension only and if
 226            * ‘background-size’ is ‘auto’ for the other dimension, then there is
 227            * a third step: that other dimension is scaled so that the original
 228            * aspect ratio is restored.
 229            */
 230           if (hrepeat == GTK_CSS_BACKGROUND_ROUND)
 231             {
 232               double n = round (width / image_width);
 233
 234               n = MAX (1, n);
 235
 236               if (vrepeat != GTK_CSS_BACKGROUND_ROUND
 237                   /* && vsize == auto (it is by default) */)
 238                 image_height *= width / (image_width * n);
 239               image_width = width / n;
 240             }
 241           if (vrepeat == GTK_CSS_BACKGROUND_ROUND)
 242             {
 243               double n = round (height / image_height);
 244
 245               n = MAX (1, n);
 246
 247               if (hrepeat != GTK_CSS_BACKGROUND_ROUND
 248                   /* && hsize == auto (it is by default) */)
 249                 image_width *= height / (image_height * n);
 250               image_height = height / n;
 251             }
 252
 253           /* if hrepeat or vrepeat is 'space', we create a somewhat larger surface
 254            * to store the extra space. */
 255           if (hrepeat == GTK_CSS_BACKGROUND_SPACE)
 256             {
 257               double n = floor (width / image_width);
 258               surface_width = n ? round (width / n) : 0;
 259             }
 260           else
 261             surface_width = round (image_width);
 262
 263           if (vrepeat == GTK_CSS_BACKGROUND_SPACE)
 264             {
 265               double n = floor (height / image_height);
 266               surface_height = n ? round (height / n) : 0;
 267             }
 268           else
 269             surface_height = round (image_height);
 270
 271           surface = cairo_surface_create_similar (cairo_get_target (cr),
 272                                                   CAIRO_CONTENT_COLOR_ALPHA,
 273                                                   surface_width, surface_height);
 274           cr2 = cairo_create (surface);
 275           cairo_translate (cr2,
 276                            0.5 * (surface_width - image_width),
 277                            0.5 * (surface_height - image_height));
 278           _gtk_css_image_draw (bg->image, cr2, image_width, image_height);
 279           cairo_destroy (cr2);
 280
 281           cairo_set_source_surface (cr, surface,
 282                                     _gtk_css_number_get (&pos->x, bg->image_rect.width - image_width),
 283                                     _gtk_css_number_get (&pos->y, bg->image_rect.height - image_height));
 284           cairo_pattern_set_extend (cairo_get_source (cr), CAIRO_EXTEND_REPEAT);
 285           cairo_surface_destroy (surface);
 286
 287           cairo_rectangle (cr,
 288                            0, 0,
 289                            hrepeat == GTK_CSS_BACKGROUND_NO_REPEAT ? image_width : width,
 290                            vrepeat == GTK_CSS_BACKGROUND_NO_REPEAT ? image_height : height);
 291           cairo_fill (cr);
 292         }
 293     }
 294
 295   cairo_restore (cr);
 296 }
 297
 298 static void
 299 _gtk_theming_background_apply_shadow (GtkThemingBackground *bg,
 300                                       cairo_t              *cr)
 301 {
 302   GtkCssValue *shadows;
 303   guint i;
 304
 305   shadows = _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BOX_SHADOW);
 306
 307   for (i = 0; i < _gtk_css_array_value_get_n_values (shadows); i++)
 308     {
 309       _gtk_css_shadow_value_paint_box (_gtk_css_array_value_get_nth (shadows, i),
 310                                        cr,
 311                                        &bg->padding_box);
 312     }
 313 }
 314
 315 static void
 316 _gtk_theming_background_init_context (GtkThemingBackground *bg)
 317 {
 318   bg->flags = gtk_style_context_get_state (bg->context);
 319
 320   gtk_style_context_get_border (bg->context, bg->flags, &bg->border);
 321   gtk_style_context_get_padding (bg->context, bg->flags, &bg->padding);
 322   gtk_style_context_get_background_color (bg->context, bg->flags, &bg->bg_color);
 323
 324   /* In the CSS box model, by default the background positioning area is
 325    * the padding-box, i.e. all the border-box minus the borders themselves,
 326    * which determines also its default size, see
 327    * http://dev.w3.org/csswg/css3-background/#background-origin
 328    *
 329    * In the future we might want to support different origins or clips, but
 330    * right now we just shrink to the default.
 331    */
 332   _gtk_rounded_box_init_rect (&bg->padding_box, 0, 0, bg->paint_area.width, bg->paint_area.height);
 333
 334   _gtk_rounded_box_apply_border_radius_for_context (&bg->padding_box, bg->context, bg->flags, bg->junction);
 335
 336   bg->clip_box = bg->padding_box;
 337   _gtk_rounded_box_shrink (&bg->padding_box,
 338                            bg->border.top, bg->border.right,
 339                            bg->border.bottom, bg->border.left);
 340
 341   _gtk_theming_background_apply_clip (bg);
 342   _gtk_theming_background_apply_origin (bg);
 343
 344   bg->image = _gtk_css_image_value_get_image (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_IMAGE));
 345 }
 346
 347 void
 348 _gtk_theming_background_init (GtkThemingBackground *bg,
 349                               GtkThemingEngine     *engine,
 350                               gdouble               x,
 351                               gdouble               y,
 352                               gdouble               width,
 353                               gdouble               height,
 354                               GtkJunctionSides      junction)
 355 {
 356   GtkStyleContext *context;
 357
 358   g_assert (bg != NULL);
 359
 360   context = _gtk_theming_engine_get_context (engine);
 361   _gtk_theming_background_init_from_context (bg, context,
 362                                              x, y, width, height,
 363                                              junction);
 364 }
 365
 366 void
 367 _gtk_theming_background_init_from_context (GtkThemingBackground *bg,
 368                                            GtkStyleContext      *context,
 369                                            gdouble               x,
 370                                            gdouble               y,
 371                                            gdouble               width,
 372                                            gdouble               height,
 373                                            GtkJunctionSides      junction)
 374 {
 375   g_assert (bg != NULL);
 376
 377   bg->context = context;
 378
 379   bg->paint_area.x = x;
 380   bg->paint_area.y = y;
 381   bg->paint_area.width = width;
 382   bg->paint_area.height = height;
 383
 384   bg->image = NULL;
 385   bg->junction = junction;
 386
 387   _gtk_theming_background_init_context (bg);
 388 }
 389
 390 void
 391 _gtk_theming_background_render (GtkThemingBackground *bg,
 392                                 cairo_t              *cr)
 393 {
 394   cairo_save (cr);
 395   cairo_translate (cr, bg->paint_area.x, bg->paint_area.y);
 396
 397   _gtk_theming_background_apply_window_background (bg, cr);
 398   _gtk_theming_background_paint (bg, cr);
 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   return (bg->image != NULL) ? TRUE : FALSE;
 408 }