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 "gtkcsstypesprivate.h"
  25 #include "gtkthemingbackgroundprivate.h"
  26 #include "gtkthemingengineprivate.h"
  27
  28 #include <math.h>
  29
  30 #include <gdk/gdk.h>
  31
  32 /* this is in case round() is not provided by the compiler,
  33  * such as in the case of C89 compilers, like MSVC
  34  */
  35 #include "fallback-c89.c"
  36
  37 static void
  38 _gtk_theming_background_apply_window_background (GtkThemingBackground *bg,
  39                                                  cairo_t              *cr)
  40 {
  41   if (gtk_style_context_has_class (bg->context, "background"))
  42     {
  43       cairo_set_source_rgba (cr, 1.0, 1.0, 1.0, 0.0); /* transparent */
  44       cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
  45       cairo_paint (cr);
  46     }
  47 }
  48
  49 static void
  50 _gtk_theming_background_apply_origin (GtkThemingBackground *bg)
  51 {
  52   GtkCssArea origin;
  53   cairo_rectangle_t image_rect;
  54
  55   gtk_style_context_get (bg->context, bg->flags,
  56                          "background-origin", &origin,
  57                          NULL);
  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   bg->image_rect = image_rect;
  87 }
  88
  89 static void
  90 _gtk_theming_background_apply_clip (GtkThemingBackground *bg)
  91 {
  92   GtkCssArea clip;
  93
  94   gtk_style_context_get (bg->context, bg->flags,
  95                          "background-clip", &clip,
  96                          NULL);
  97
  98   if (clip == GTK_CSS_AREA_PADDING_BOX)
  99     {
 100       _gtk_rounded_box_shrink (&bg->clip_box,
 101                                bg->border.top, bg->border.right,
 102                                bg->border.bottom, bg->border.left);
 103     }
 104   else if (clip == GTK_CSS_AREA_CONTENT_BOX)
 105     {
 106       _gtk_rounded_box_shrink (&bg->clip_box,
 107                                bg->border.top + bg->padding.top,
 108                                bg->border.right + bg->padding.right,
 109                                bg->border.bottom + bg->padding.bottom,
 110                                bg->border.left + bg->padding.left);
 111     }
 112 }
 113
 114 static void
 115 _gtk_theming_background_get_cover_contain (GtkCssImage *image,
 116                                            gboolean     cover,
 117                                            double       width,
 118                                            double       height,
 119                                            double      *concrete_width,
 120                                            double      *concrete_height)
 121 {
 122   double aspect, image_aspect;
 123
 124   image_aspect = _gtk_css_image_get_aspect_ratio (image);
 125   if (image_aspect == 0.0)
 126     {
 127       *concrete_width = width;
 128       *concrete_height = height;
 129       return;
 130     }
 131
 132   aspect = width / height;
 133
 134   if ((aspect >= image_aspect && cover) ||
 135       (aspect < image_aspect && !cover))
 136     {
 137       *concrete_width = width;
 138       *concrete_height = width / image_aspect;
 139     }
 140   else
 141     {
 142       *concrete_height = height;
 143       *concrete_width = height * image_aspect;
 144     }
 145 }
 146
 147 static void
 148 _gtk_theming_background_paint (GtkThemingBackground *bg,
 149                                cairo_t              *cr)
 150 {
 151   cairo_save (cr);
 152
 153   _gtk_rounded_box_path (&bg->clip_box, cr);
 154   cairo_clip (cr);
 155
 156   gdk_cairo_set_source_rgba (cr, &bg->bg_color);
 157   cairo_paint (cr);
 158
 159   if (bg->image
 160       && bg->image_rect.width > 0
 161       && bg->image_rect.height > 0)
 162     {
 163       GtkCssBackgroundRepeat hrepeat, vrepeat;
 164       GtkCssBackgroundSize *size;
 165       double image_width, image_height;
 166       double width, height;
 167
 168       size = g_value_get_boxed (_gtk_style_context_peek_property (bg->context, "background-size"));
 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           /* shortcut for normal case */
 203           _gtk_css_image_draw (bg->image, cr, image_width, image_height);
 204         }
 205       else
 206         {
 207           int surface_width, surface_height;
 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_BACKGROUND_ROUND)
 228             {
 229               double n = round (width / image_width);
 230
 231               n = MAX (1, n);
 232
 233               if (vrepeat != GTK_CSS_BACKGROUND_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_BACKGROUND_ROUND)
 239             {
 240               double n = round (height / image_height);
 241
 242               n = MAX (1, n);
 243
 244               if (hrepeat != GTK_CSS_BACKGROUND_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_BACKGROUND_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_BACKGROUND_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 (bg->image, cr2, image_width, image_height);
 276           cairo_destroy (cr2);
 277
 278           cairo_set_source_surface (cr, surface,
 279                                     /* background-position goes here */
 280                                     0, 0);
 281           cairo_pattern_set_extend (cairo_get_source (cr), CAIRO_EXTEND_REPEAT);
 282           cairo_surface_destroy (surface);
 283
 284           cairo_rectangle (cr,
 285                            0, 0,
 286                            hrepeat == GTK_CSS_BACKGROUND_NO_REPEAT ? image_width : width,
 287                            vrepeat == GTK_CSS_BACKGROUND_NO_REPEAT ? image_height : height);
 288           cairo_fill (cr);
 289         }
 290     }
 291
 292   cairo_restore (cr);
 293 }
 294
 295 static void
 296 _gtk_theming_background_apply_shadow (GtkThemingBackground *bg,
 297                                       cairo_t              *cr)
 298 {
 299   GtkShadow *box_shadow;
 300
 301   gtk_style_context_get (bg->context, bg->flags,
 302                          "box-shadow", &box_shadow,
 303                          NULL);
 304
 305   if (box_shadow != NULL)
 306     {
 307       _gtk_box_shadow_render (box_shadow, cr, &bg->padding_box);
 308       _gtk_shadow_unref (box_shadow);
 309     }
 310 }
 311
 312 static void
 313 _gtk_theming_background_init_context (GtkThemingBackground *bg)
 314 {
 315   bg->flags = gtk_style_context_get_state (bg->context);
 316
 317   gtk_style_context_get_border (bg->context, bg->flags, &bg->border);
 318   gtk_style_context_get_padding (bg->context, bg->flags, &bg->padding);
 319   gtk_style_context_get_background_color (bg->context, bg->flags, &bg->bg_color);
 320
 321   /* In the CSS box model, by default the background positioning area is
 322    * the padding-box, i.e. all the border-box minus the borders themselves,
 323    * which determines also its default size, see
 324    * http://dev.w3.org/csswg/css3-background/#background-origin
 325    *
 326    * In the future we might want to support different origins or clips, but
 327    * right now we just shrink to the default.
 328    */
 329   _gtk_rounded_box_init_rect (&bg->padding_box, 0, 0, bg->paint_area.width, bg->paint_area.height);
 330
 331   _gtk_rounded_box_apply_border_radius_for_context (&bg->padding_box, bg->context, bg->flags, bg->junction);
 332
 333   bg->clip_box = bg->padding_box;
 334   _gtk_rounded_box_shrink (&bg->padding_box,
 335                            bg->border.top, bg->border.right,
 336                            bg->border.bottom, bg->border.left);
 337
 338   _gtk_theming_background_apply_clip (bg);
 339   _gtk_theming_background_apply_origin (bg);
 340
 341   bg->image = g_value_get_object (_gtk_style_context_peek_property (bg->context, "background-image"));
 342 }
 343
 344 void
 345 _gtk_theming_background_init (GtkThemingBackground *bg,
 346                               GtkThemingEngine     *engine,
 347                               gdouble               x,
 348                               gdouble               y,
 349                               gdouble               width,
 350                               gdouble               height,
 351                               GtkJunctionSides      junction)
 352 {
 353   GtkStyleContext *context;
 354
 355   g_assert (bg != NULL);
 356
 357   context = _gtk_theming_engine_get_context (engine);
 358   _gtk_theming_background_init_from_context (bg, context,
 359                                              x, y, width, height,
 360                                              junction);
 361 }
 362
 363 void
 364 _gtk_theming_background_init_from_context (GtkThemingBackground *bg,
 365                                            GtkStyleContext      *context,
 366                                            gdouble               x,
 367                                            gdouble               y,
 368                                            gdouble               width,
 369                                            gdouble               height,
 370                                            GtkJunctionSides      junction)
 371 {
 372   g_assert (bg != NULL);
 373
 374   bg->context = context;
 375
 376   bg->paint_area.x = x;
 377   bg->paint_area.y = y;
 378   bg->paint_area.width = width;
 379   bg->paint_area.height = height;
 380
 381   bg->image = NULL;
 382   bg->junction = junction;
 383
 384   _gtk_theming_background_init_context (bg);
 385 }
 386
 387 void
 388 _gtk_theming_background_render (GtkThemingBackground *bg,
 389                                 cairo_t              *cr)
 390 {
 391   cairo_save (cr);
 392   cairo_translate (cr, bg->paint_area.x, bg->paint_area.y);
 393
 394   _gtk_theming_background_apply_window_background (bg, cr);
 395   _gtk_theming_background_paint (bg, cr);
 396   _gtk_theming_background_apply_shadow (bg, cr);
 397
 398   cairo_restore (cr);
 399 }
 400
 401 gboolean
 402 _gtk_theming_background_has_background_image (GtkThemingBackground *bg)
 403 {
 404   return (bg->image != NULL) ? TRUE : FALSE;
 405 }