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 "gtkcssenumvalueprivate.h"
  27 #include "gtkcssimagevalueprivate.h"
  28 #include "gtkcsstypesprivate.h"
  29 #include "gtkthemingengineprivate.h"
  30
  31 #include <math.h>
  32
  33 #include <gdk/gdk.h>
  34
  35 /* this is in case round() is not provided by the compiler,
  36  * such as in the case of C89 compilers, like MSVC
  37  */
  38 #include "fallback-c89.c"
  39
  40 static void
  41 _gtk_theming_background_apply_window_background (GtkThemingBackground *bg,
  42                                                  cairo_t              *cr)
  43 {
  44   if (gtk_style_context_has_class (bg->context, "background"))
  45     {
  46       cairo_set_source_rgba (cr, 1.0, 1.0, 1.0, 0.0); /* transparent */
  47       cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
  48       cairo_paint (cr);
  49     }
  50 }
  51
  52 static void
  53 _gtk_theming_background_apply_origin (GtkThemingBackground *bg)
  54 {
  55   GtkCssArea origin;
  56   cairo_rectangle_t image_rect;
  57
  58   origin = _gtk_css_area_value_get (_gtk_style_context_peek_property (bg->context, "background-clip"));
  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   bg->image_rect = image_rect;
  88 }
  89
  90 static void
  91 _gtk_theming_background_apply_clip (GtkThemingBackground *bg)
  92 {
  93   GtkCssArea clip = _gtk_css_area_value_get (_gtk_style_context_peek_property (bg->context, "background-clip"));
  94
  95   if (clip == GTK_CSS_AREA_PADDING_BOX)
  96     {
  97       _gtk_rounded_box_shrink (&bg->clip_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 (&bg->clip_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_get_cover_contain (GtkCssImage *image,
 113                                            gboolean     cover,
 114                                            double       width,
 115                                            double       height,
 116                                            double      *concrete_width,
 117                                            double      *concrete_height)
 118 {
 119   double aspect, image_aspect;
 120
 121   image_aspect = _gtk_css_image_get_aspect_ratio (image);
 122   if (image_aspect == 0.0)
 123     {
 124       *concrete_width = width;
 125       *concrete_height = height;
 126       return;
 127     }
 128
 129   aspect = width / height;
 130
 131   if ((aspect >= image_aspect && cover) ||
 132       (aspect < image_aspect && !cover))
 133     {
 134       *concrete_width = width;
 135       *concrete_height = width / image_aspect;
 136     }
 137   else
 138     {
 139       *concrete_height = height;
 140       *concrete_width = height * image_aspect;
 141     }
 142 }
 143
 144 static void
 145 _gtk_theming_background_paint (GtkThemingBackground *bg,
 146                                cairo_t              *cr)
 147 {
 148   cairo_save (cr);
 149
 150   _gtk_rounded_box_path (&bg->clip_box, cr);
 151   cairo_clip (cr);
 152
 153   gdk_cairo_set_source_rgba (cr, &bg->bg_color);
 154   cairo_paint (cr);
 155
 156   if (bg->image
 157       && bg->image_rect.width > 0
 158       && bg->image_rect.height > 0)
 159     {
 160       GtkCssBackgroundRepeat hrepeat, vrepeat;
 161       const GtkCssBackgroundSize *size;
 162       const GtkCssBackgroundPosition *pos;
 163       double image_width, image_height;
 164       double width, height;
 165
 166       size = _gtk_css_value_get_background_size (_gtk_style_context_peek_property (bg->context, "background-size"));
 167       pos = _gtk_css_value_get_background_position (_gtk_style_context_peek_property (bg->context, "background-position"));
 168       gtk_style_context_get (bg->context, bg->flags,
 169                              "background-repeat", &hrepeat,
 170                              NULL);
 171       vrepeat = GTK_CSS_BACKGROUND_VERTICAL (hrepeat);
 172       hrepeat = GTK_CSS_BACKGROUND_HORIZONTAL (hrepeat);
 173       width = bg->image_rect.width;
 174       height = bg->image_rect.height;
 175
 176       if (size->contain || size->cover)
 177         _gtk_theming_background_get_cover_contain (bg->image,
 178                                                    size->cover,
 179                                                    width,
 180                                                    height,
 181                                                    &image_width,
 182                                                    &image_height);
 183       else
 184         _gtk_css_image_get_concrete_size (bg->image,
 185                                           /* note: 0 does the right thing here for 'auto' */
 186                                           _gtk_css_number_get (&size->width, width),
 187                                           _gtk_css_number_get (&size->height, height),
 188                                           width, height,
 189                                           &image_width, &image_height);
 190
 191       /* optimization */
 192       if (image_width == width)
 193         hrepeat = GTK_CSS_BACKGROUND_NO_REPEAT;
 194       if (image_height == height)
 195         vrepeat = GTK_CSS_BACKGROUND_NO_REPEAT;
 196
 197       cairo_translate (cr, bg->image_rect.x, bg->image_rect.y);
 198
 199       if (hrepeat == GTK_CSS_BACKGROUND_NO_REPEAT && vrepeat == GTK_CSS_BACKGROUND_NO_REPEAT)
 200         {
 201           cairo_translate (cr,
 202                            _gtk_css_number_get (&pos->x, bg->image_rect.width - image_width),
 203                            _gtk_css_number_get (&pos->y, bg->image_rect.height - image_height));
 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                                     _gtk_css_number_get (&pos->x, bg->image_rect.width - image_width),
 282                                     _gtk_css_number_get (&pos->y, bg->image_rect.height - image_height));
 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   _gtk_css_shadow_value_paint_box (_gtk_style_context_peek_property (bg->context, "box-shadow"),
 302                                    cr,
 303                                    &bg->padding_box);
 304 }
 305
 306 static void
 307 _gtk_theming_background_init_context (GtkThemingBackground *bg)
 308 {
 309   bg->flags = gtk_style_context_get_state (bg->context);
 310
 311   gtk_style_context_get_border (bg->context, bg->flags, &bg->border);
 312   gtk_style_context_get_padding (bg->context, bg->flags, &bg->padding);
 313   gtk_style_context_get_background_color (bg->context, bg->flags, &bg->bg_color);
 314
 315   /* In the CSS box model, by default the background positioning area is
 316    * the padding-box, i.e. all the border-box minus the borders themselves,
 317    * which determines also its default size, see
 318    * http://dev.w3.org/csswg/css3-background/#background-origin
 319    *
 320    * In the future we might want to support different origins or clips, but
 321    * right now we just shrink to the default.
 322    */
 323   _gtk_rounded_box_init_rect (&bg->padding_box, 0, 0, bg->paint_area.width, bg->paint_area.height);
 324
 325   _gtk_rounded_box_apply_border_radius_for_context (&bg->padding_box, bg->context, bg->flags, bg->junction);
 326
 327   bg->clip_box = bg->padding_box;
 328   _gtk_rounded_box_shrink (&bg->padding_box,
 329                            bg->border.top, bg->border.right,
 330                            bg->border.bottom, bg->border.left);
 331
 332   _gtk_theming_background_apply_clip (bg);
 333   _gtk_theming_background_apply_origin (bg);
 334
 335   bg->image = _gtk_css_image_value_get_image (_gtk_style_context_peek_property (bg->context, "background-image"));
 336 }
 337
 338 void
 339 _gtk_theming_background_init (GtkThemingBackground *bg,
 340                               GtkThemingEngine     *engine,
 341                               gdouble               x,
 342                               gdouble               y,
 343                               gdouble               width,
 344                               gdouble               height,
 345                               GtkJunctionSides      junction)
 346 {
 347   GtkStyleContext *context;
 348
 349   g_assert (bg != NULL);
 350
 351   context = _gtk_theming_engine_get_context (engine);
 352   _gtk_theming_background_init_from_context (bg, context,
 353                                              x, y, width, height,
 354                                              junction);
 355 }
 356
 357 void
 358 _gtk_theming_background_init_from_context (GtkThemingBackground *bg,
 359                                            GtkStyleContext      *context,
 360                                            gdouble               x,
 361                                            gdouble               y,
 362                                            gdouble               width,
 363                                            gdouble               height,
 364                                            GtkJunctionSides      junction)
 365 {
 366   g_assert (bg != NULL);
 367
 368   bg->context = context;
 369
 370   bg->paint_area.x = x;
 371   bg->paint_area.y = y;
 372   bg->paint_area.width = width;
 373   bg->paint_area.height = height;
 374
 375   bg->image = NULL;
 376   bg->junction = junction;
 377
 378   _gtk_theming_background_init_context (bg);
 379 }
 380
 381 void
 382 _gtk_theming_background_render (GtkThemingBackground *bg,
 383                                 cairo_t              *cr)
 384 {
 385   cairo_save (cr);
 386   cairo_translate (cr, bg->paint_area.x, bg->paint_area.y);
 387
 388   _gtk_theming_background_apply_window_background (bg, cr);
 389   _gtk_theming_background_paint (bg, cr);
 390   _gtk_theming_background_apply_shadow (bg, cr);
 391
 392   cairo_restore (cr);
 393 }
 394
 395 gboolean
 396 _gtk_theming_background_has_background_image (GtkThemingBackground *bg)
 397 {
 398   return (bg->image != NULL) ? TRUE : FALSE;
 399 }