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, write to the
  20  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  21  * Boston, MA 02111-1307, USA.
  22  */
  23
  24 #include "config.h"
  25
  26 #include "gtkcsstypesprivate.h"
  27 #include "gtkthemingbackgroundprivate.h"
  28 #include "gtkthemingengineprivate.h"
  29
  30 #include <math.h>
  31
  32 #include <gdk/gdk.h>
  33
  34 /* this is in case round() is not provided by the compiler,
  35  * such as in the case of C89 compilers, like MSVC
  36  */
  37 #include "fallback-c89.c"
  38
  39 static void
  40 _gtk_theming_background_apply_window_background (GtkThemingBackground *bg,
  41                                                  cairo_t              *cr)
  42 {
  43   if (gtk_style_context_has_class (bg->context, "background"))
  44     {
  45       cairo_set_source_rgba (cr, 1.0, 1.0, 1.0, 0.0); /* transparent */
  46       cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
  47       cairo_paint (cr);
  48     }
  49 }
  50
  51 static void
  52 _gtk_theming_background_apply_origin (GtkThemingBackground *bg)
  53 {
  54   GtkCssArea origin;
  55   cairo_rectangle_t image_rect;
  56
  57   gtk_style_context_get (bg->context, bg->flags,
  58                          "background-origin", &origin,
  59                          NULL);
  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;
  95
  96   gtk_style_context_get (bg->context, bg->flags,
  97                          "background-clip", &clip,
  98                          NULL);
  99
 100   if (clip == GTK_CSS_AREA_PADDING_BOX)
 101     {
 102       _gtk_rounded_box_shrink (&bg->clip_box,
 103                                bg->border.top, bg->border.right,
 104                                bg->border.bottom, bg->border.left);
 105     }
 106   else if (clip == GTK_CSS_AREA_CONTENT_BOX)
 107     {
 108       _gtk_rounded_box_shrink (&bg->clip_box,
 109                                bg->border.top + bg->padding.top,
 110                                bg->border.right + bg->padding.right,
 111                                bg->border.bottom + bg->padding.bottom,
 112                                bg->border.left + bg->padding.left);
 113     }
 114 }
 115
 116 static void
 117 _gtk_theming_background_get_cover_contain (GtkCssImage *image,
 118                                            gboolean     cover,
 119                                            double       width,
 120                                            double       height,
 121                                            double      *concrete_width,
 122                                            double      *concrete_height)
 123 {
 124   double aspect, image_aspect;
 125
 126   image_aspect = _gtk_css_image_get_aspect_ratio (image);
 127   if (image_aspect == 0.0)
 128     {
 129       *concrete_width = width;
 130       *concrete_height = height;
 131       return;
 132     }
 133
 134   aspect = width / height;
 135
 136   if ((aspect >= image_aspect && cover) ||
 137       (aspect < image_aspect && !cover))
 138     {
 139       *concrete_width = width;
 140       *concrete_height = width / image_aspect;
 141     }
 142   else
 143     {
 144       *concrete_height = height;
 145       *concrete_width = height * image_aspect;
 146     }
 147 }
 148
 149 static void
 150 _gtk_theming_background_paint (GtkThemingBackground *bg,
 151                                cairo_t              *cr)
 152 {
 153   cairo_save (cr);
 154
 155   _gtk_rounded_box_path (&bg->clip_box, cr);
 156   cairo_clip (cr);
 157
 158   gdk_cairo_set_source_rgba (cr, &bg->bg_color);
 159   cairo_paint (cr);
 160
 161   if (bg->image
 162       && bg->image_rect.width > 0
 163       && bg->image_rect.height > 0)
 164     {
 165       GtkCssBackgroundRepeat hrepeat, vrepeat;
 166       GtkCssBackgroundSize *size;
 167       double image_width, image_height;
 168       double width, height;
 169
 170       size = g_value_get_boxed (_gtk_style_context_peek_property (bg->context, "background-size"));
 171       gtk_style_context_get (bg->context, bg->flags,
 172                              "background-repeat", &hrepeat,
 173                              NULL);
 174       vrepeat = GTK_CSS_BACKGROUND_VERTICAL (hrepeat);
 175       hrepeat = GTK_CSS_BACKGROUND_HORIZONTAL (hrepeat);
 176       width = bg->image_rect.width;
 177       height = bg->image_rect.height;
 178
 179       if (size->contain || size->cover)
 180         _gtk_theming_background_get_cover_contain (bg->image,
 181                                                    size->cover,
 182                                                    width,
 183                                                    height,
 184                                                    &image_width,
 185                                                    &image_height);
 186       else
 187         _gtk_css_image_get_concrete_size (bg->image,
 188                                           /* note: 0 does the right thing here for 'auto' */
 189                                           _gtk_css_number_get (&size->width, width),
 190                                           _gtk_css_number_get (&size->height, height),
 191                                           width, height,
 192                                           &image_width, &image_height);
 193
 194       /* optimization */
 195       if (image_width == width)
 196         hrepeat = GTK_CSS_BACKGROUND_NO_REPEAT;
 197       if (image_height == height)
 198         vrepeat = GTK_CSS_BACKGROUND_NO_REPEAT;
 199
 200       cairo_translate (cr, bg->image_rect.x, bg->image_rect.y);
 201
 202       if (hrepeat == GTK_CSS_BACKGROUND_NO_REPEAT && vrepeat == GTK_CSS_BACKGROUND_NO_REPEAT)
 203         {
 204           /* shortcut for normal case */
 205           _gtk_css_image_draw (bg->image, cr, image_width, image_height);
 206         }
 207       else
 208         {
 209           int surface_width, surface_height;
 210           cairo_surface_t *surface;
 211           cairo_t *cr2;
 212
 213           /* If ‘background-repeat’ is ‘round’ for one (or both) dimensions,
 214            * there is a second step. The UA must scale the image in that
 215            * dimension (or both dimensions) so that it fits a whole number of
 216            * times in the background positioning area. In the case of the width
 217            * (height is analogous):
 218            *
 219            * If X ≠ 0 is the width of the image after step one and W is the width
 220            * of the background positioning area, then the rounded width
 221            * X' = W / round(W / X) where round() is a function that returns the
 222            * nearest natural number (integer greater than zero).
 223            *
 224            * If ‘background-repeat’ is ‘round’ for one dimension only and if
 225            * ‘background-size’ is ‘auto’ for the other dimension, then there is
 226            * a third step: that other dimension is scaled so that the original
 227            * aspect ratio is restored.
 228            */
 229           if (hrepeat == GTK_CSS_BACKGROUND_ROUND)
 230             {
 231               double n = round (width / image_width);
 232
 233               n = MAX (1, n);
 234
 235               if (vrepeat != GTK_CSS_BACKGROUND_ROUND
 236                   /* && vsize == auto (it is by default) */)
 237                 image_height *= width / (image_width * n);
 238               image_width = width / n;
 239             }
 240           if (vrepeat == GTK_CSS_BACKGROUND_ROUND)
 241             {
 242               double n = round (height / image_height);
 243
 244               n = MAX (1, n);
 245
 246               if (hrepeat != GTK_CSS_BACKGROUND_ROUND
 247                   /* && hsize == auto (it is by default) */)
 248                 image_width *= height / (image_height * n);
 249               image_height = height / n;
 250             }
 251
 252           /* if hrepeat or vrepeat is 'space', we create a somewhat larger surface
 253            * to store the extra space. */
 254           if (hrepeat == GTK_CSS_BACKGROUND_SPACE)
 255             {
 256               double n = floor (width / image_width);
 257               surface_width = n ? round (width / n) : 0;
 258             }
 259           else
 260             surface_width = round (image_width);
 261
 262           if (vrepeat == GTK_CSS_BACKGROUND_SPACE)
 263             {
 264               double n = floor (height / image_height);
 265               surface_height = n ? round (height / n) : 0;
 266             }
 267           else
 268             surface_height = round (image_height);
 269
 270           surface = cairo_surface_create_similar (cairo_get_target (cr),
 271                                                   CAIRO_CONTENT_COLOR_ALPHA,
 272                                                   surface_width, surface_height);
 273           cr2 = cairo_create (surface);
 274           cairo_translate (cr2,
 275                            0.5 * (surface_width - image_width),
 276                            0.5 * (surface_height - image_height));
 277           _gtk_css_image_draw (bg->image, cr2, image_width, image_height);
 278           cairo_destroy (cr2);
 279
 280           cairo_set_source_surface (cr, surface,
 281                                     /* background-position goes here */
 282                                     0, 0);
 283           cairo_pattern_set_extend (cairo_get_source (cr), CAIRO_EXTEND_REPEAT);
 284           cairo_surface_destroy (surface);
 285
 286           cairo_rectangle (cr,
 287                            0, 0,
 288                            hrepeat == GTK_CSS_BACKGROUND_NO_REPEAT ? image_width : width,
 289                            vrepeat == GTK_CSS_BACKGROUND_NO_REPEAT ? image_height : height);
 290           cairo_fill (cr);
 291         }
 292     }
 293
 294   cairo_restore (cr);
 295 }
 296
 297 static void
 298 _gtk_theming_background_apply_shadow (GtkThemingBackground *bg,
 299                                       cairo_t              *cr)
 300 {
 301   GtkShadow *box_shadow;
 302
 303   gtk_style_context_get (bg->context, bg->flags,
 304                          "box-shadow", &box_shadow,
 305                          NULL);
 306
 307   if (box_shadow != NULL)
 308     {
 309       _gtk_box_shadow_render (box_shadow, cr, &bg->padding_box);
 310       _gtk_shadow_unref (box_shadow);
 311     }
 312 }
 313
 314 static void
 315 _gtk_theming_background_init_context (GtkThemingBackground *bg)
 316 {
 317   bg->flags = gtk_style_context_get_state (bg->context);
 318
 319   gtk_style_context_get_border (bg->context, bg->flags, &bg->border);
 320   gtk_style_context_get_padding (bg->context, bg->flags, &bg->padding);
 321   gtk_style_context_get_background_color (bg->context, bg->flags, &bg->bg_color);
 322
 323   /* In the CSS box model, by default the background positioning area is
 324    * the padding-box, i.e. all the border-box minus the borders themselves,
 325    * which determines also its default size, see
 326    * http://dev.w3.org/csswg/css3-background/#background-origin
 327    *
 328    * In the future we might want to support different origins or clips, but
 329    * right now we just shrink to the default.
 330    */
 331   _gtk_rounded_box_init_rect (&bg->padding_box, 0, 0, bg->paint_area.width, bg->paint_area.height);
 332
 333   _gtk_rounded_box_apply_border_radius_for_context (&bg->padding_box, bg->context, bg->flags, bg->junction);
 334
 335   bg->clip_box = bg->padding_box;
 336   _gtk_rounded_box_shrink (&bg->padding_box,
 337                            bg->border.top, bg->border.right,
 338                            bg->border.bottom, bg->border.left);
 339
 340   _gtk_theming_background_apply_clip (bg);
 341   _gtk_theming_background_apply_origin (bg);
 342
 343   bg->image = g_value_get_object (_gtk_style_context_peek_property (bg->context, "background-image"));
 344 }
 345
 346 void
 347 _gtk_theming_background_init (GtkThemingBackground *bg,
 348                               GtkThemingEngine     *engine,
 349                               gdouble               x,
 350                               gdouble               y,
 351                               gdouble               width,
 352                               gdouble               height,
 353                               GtkJunctionSides      junction)
 354 {
 355   GtkStyleContext *context;
 356
 357   g_assert (bg != NULL);
 358
 359   context = _gtk_theming_engine_get_context (engine);
 360   _gtk_theming_background_init_from_context (bg, context,
 361                                              x, y, width, height,
 362                                              junction);
 363 }
 364
 365 void
 366 _gtk_theming_background_init_from_context (GtkThemingBackground *bg,
 367                                            GtkStyleContext      *context,
 368                                            gdouble               x,
 369                                            gdouble               y,
 370                                            gdouble               width,
 371                                            gdouble               height,
 372                                            GtkJunctionSides      junction)
 373 {
 374   g_assert (bg != NULL);
 375
 376   bg->context = context;
 377
 378   bg->paint_area.x = x;
 379   bg->paint_area.y = y;
 380   bg->paint_area.width = width;
 381   bg->paint_area.height = height;
 382
 383   bg->image = NULL;
 384   bg->junction = junction;
 385
 386   _gtk_theming_background_init_context (bg);
 387 }
 388
 389 void
 390 _gtk_theming_background_render (GtkThemingBackground *bg,
 391                                 cairo_t              *cr)
 392 {
 393   cairo_save (cr);
 394   cairo_translate (cr, bg->paint_area.x, bg->paint_area.y);
 395
 396   _gtk_theming_background_apply_window_background (bg, cr);
 397   _gtk_theming_background_paint (bg, cr);
 398   _gtk_theming_background_apply_shadow (bg, cr);
 399
 400   cairo_restore (cr);
 401 }
 402
 403 gboolean
 404 _gtk_theming_background_has_background_image (GtkThemingBackground *bg)
 405 {
 406   return (bg->image != NULL) ? TRUE : FALSE;
 407 }