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 static void
  46 _gtk_theming_background_apply_window_background (GtkThemingBackground *bg,
  47                                                  cairo_t              *cr)
  48 {
  49   if (gtk_style_context_has_class (bg->context, "background"))
  50     {
  51       cairo_set_source_rgba (cr, 1.0, 1.0, 1.0, 0.0); /* transparent */
  52       cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
  53       cairo_paint (cr);
  54     }
  55 }
  56
  57 static void
  58 _gtk_theming_background_apply_origin (GtkThemingBackground *bg)
  59 {
  60   cairo_rectangle_t image_rect;
  61   GtkCssValue *value = _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_ORIGIN);
  62   GtkCssArea origin = _gtk_css_area_value_get (_gtk_css_array_value_get_nth (value, 0));
  63
  64   /* The default size of the background image depends on the
  65      background-origin value as this affects the top left
  66      and the bottom right corners. */
  67   switch (origin) {
  68   case GTK_CSS_AREA_BORDER_BOX:
  69     image_rect.x = 0;
  70     image_rect.y = 0;
  71     image_rect.width = bg->paint_area.width;
  72     image_rect.height = bg->paint_area.height;
  73     break;
  74   case GTK_CSS_AREA_CONTENT_BOX:
  75     image_rect.x = bg->border.left + bg->padding.left;
  76     image_rect.y = bg->border.top + bg->padding.top;
  77     image_rect.width = bg->paint_area.width - bg->border.left - bg->border.right - bg->padding.left - bg->padding.right;
  78     image_rect.height = bg->paint_area.height - bg->border.top - bg->border.bottom - bg->padding.top - bg->padding.bottom;
  79     break;
  80   case GTK_CSS_AREA_PADDING_BOX:
  81   default:
  82     image_rect.x = bg->border.left;
  83     image_rect.y = bg->border.top;
  84     image_rect.width = bg->paint_area.width - bg->border.left - bg->border.right;
  85     image_rect.height = bg->paint_area.height - bg->border.top - bg->border.bottom;
  86     break;
  87   }
  88
  89   /* XXX: image_rect might have negative width/height here.
  90    * Do we need to do something about it? */
  91   bg->image_rect = image_rect;
  92 }
  93
  94 static void
  95 _gtk_theming_background_apply_clip (GtkThemingBackground *bg)
  96 {
  97   GtkCssValue *value = _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_CLIP);
  98   GtkCssArea clip = _gtk_css_area_value_get (_gtk_css_array_value_get_nth (value, 0));
  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_paint (GtkThemingBackground *bg,
 118                                cairo_t              *cr)
 119 {
 120   cairo_save (cr);
 121
 122   _gtk_rounded_box_path (&bg->clip_box, cr);
 123   cairo_clip (cr);
 124
 125   gdk_cairo_set_source_rgba (cr, &bg->bg_color);
 126   cairo_paint (cr);
 127
 128   if (bg->image
 129       && bg->image_rect.width > 0
 130       && bg->image_rect.height > 0)
 131     {
 132       const GtkCssValue *pos, *repeat;
 133       double image_width, image_height;
 134       double width, height;
 135       GtkCssRepeatStyle hrepeat, vrepeat;
 136
 137       pos = _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_POSITION);
 138       repeat = _gtk_css_array_value_get_nth (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_REPEAT), 0);
 139       hrepeat = _gtk_css_background_repeat_value_get_x (repeat);
 140       vrepeat = _gtk_css_background_repeat_value_get_y (repeat);
 141       width = bg->image_rect.width;
 142       height = bg->image_rect.height;
 143
 144       _gtk_css_bg_size_value_compute_size (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_SIZE),
 145                                            bg->image,
 146                                            width,
 147                                            height,
 148                                            &image_width,
 149                                            &image_height);
 150
 151       /* optimization */
 152       if (image_width == width)
 153         hrepeat = GTK_CSS_REPEAT_STYLE_NO_REPEAT;
 154       if (image_height == height)
 155         vrepeat = GTK_CSS_REPEAT_STYLE_NO_REPEAT;
 156
 157       cairo_translate (cr, bg->image_rect.x, bg->image_rect.y);
 158
 159       if (hrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT && vrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT)
 160         {
 161           cairo_translate (cr,
 162                            _gtk_css_position_value_get_x (pos, width - image_width),
 163                            _gtk_css_position_value_get_y (pos, height - image_height));
 164           /* shortcut for normal case */
 165           _gtk_css_image_draw (bg->image, cr, image_width, image_height);
 166         }
 167       else
 168         {
 169           int surface_width, surface_height;
 170           cairo_surface_t *surface;
 171           cairo_t *cr2;
 172
 173           /* If ‘background-repeat’ is ‘round’ for one (or both) dimensions,
 174            * there is a second step. The UA must scale the image in that
 175            * dimension (or both dimensions) so that it fits a whole number of
 176            * times in the background positioning area. In the case of the width
 177            * (height is analogous):
 178            *
 179            * If X ≠ 0 is the width of the image after step one and W is the width
 180            * of the background positioning area, then the rounded width
 181            * X' = W / round(W / X) where round() is a function that returns the
 182            * nearest natural number (integer greater than zero).
 183            *
 184            * If ‘background-repeat’ is ‘round’ for one dimension only and if
 185            * ‘background-size’ is ‘auto’ for the other dimension, then there is
 186            * a third step: that other dimension is scaled so that the original
 187            * aspect ratio is restored.
 188            */
 189           if (hrepeat == GTK_CSS_REPEAT_STYLE_ROUND)
 190             {
 191               double n = round (width / image_width);
 192
 193               n = MAX (1, n);
 194
 195               if (vrepeat != GTK_CSS_REPEAT_STYLE_ROUND
 196                   /* && vsize == auto (it is by default) */)
 197                 image_height *= width / (image_width * n);
 198               image_width = width / n;
 199             }
 200           if (vrepeat == GTK_CSS_REPEAT_STYLE_ROUND)
 201             {
 202               double n = round (height / image_height);
 203
 204               n = MAX (1, n);
 205
 206               if (hrepeat != GTK_CSS_REPEAT_STYLE_ROUND
 207                   /* && hsize == auto (it is by default) */)
 208                 image_width *= height / (image_height * n);
 209               image_height = height / n;
 210             }
 211
 212           /* if hrepeat or vrepeat is 'space', we create a somewhat larger surface
 213            * to store the extra space. */
 214           if (hrepeat == GTK_CSS_REPEAT_STYLE_SPACE)
 215             {
 216               double n = floor (width / image_width);
 217               surface_width = n ? round (width / n) : 0;
 218             }
 219           else
 220             surface_width = round (image_width);
 221
 222           if (vrepeat == GTK_CSS_REPEAT_STYLE_SPACE)
 223             {
 224               double n = floor (height / image_height);
 225               surface_height = n ? round (height / n) : 0;
 226             }
 227           else
 228             surface_height = round (image_height);
 229
 230           surface = cairo_surface_create_similar (cairo_get_target (cr),
 231                                                   CAIRO_CONTENT_COLOR_ALPHA,
 232                                                   surface_width, surface_height);
 233           cr2 = cairo_create (surface);
 234           cairo_translate (cr2,
 235                            0.5 * (surface_width - image_width),
 236                            0.5 * (surface_height - image_height));
 237           _gtk_css_image_draw (bg->image, cr2, image_width, image_height);
 238           cairo_destroy (cr2);
 239
 240           cairo_set_source_surface (cr, surface,
 241                                     _gtk_css_position_value_get_x (pos, width - image_width),
 242                                     _gtk_css_position_value_get_y (pos, height - image_height));
 243           cairo_pattern_set_extend (cairo_get_source (cr), CAIRO_EXTEND_REPEAT);
 244           cairo_surface_destroy (surface);
 245
 246           cairo_rectangle (cr,
 247                            0, 0,
 248                            hrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT ? image_width : width,
 249                            vrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT ? image_height : height);
 250           cairo_fill (cr);
 251         }
 252     }
 253
 254   cairo_restore (cr);
 255 }
 256
 257 static void
 258 _gtk_theming_background_apply_shadow (GtkThemingBackground *bg,
 259                                       cairo_t              *cr)
 260 {
 261   _gtk_css_shadows_value_paint_box (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BOX_SHADOW),
 262                                     cr,
 263                                     &bg->padding_box);
 264 }
 265
 266 static void
 267 _gtk_theming_background_init_context (GtkThemingBackground *bg)
 268 {
 269   bg->flags = gtk_style_context_get_state (bg->context);
 270
 271   gtk_style_context_get_border (bg->context, bg->flags, &bg->border);
 272   gtk_style_context_get_padding (bg->context, bg->flags, &bg->padding);
 273   gtk_style_context_get_background_color (bg->context, bg->flags, &bg->bg_color);
 274
 275   /* In the CSS box model, by default the background positioning area is
 276    * the padding-box, i.e. all the border-box minus the borders themselves,
 277    * which determines also its default size, see
 278    * http://dev.w3.org/csswg/css3-background/#background-origin
 279    *
 280    * In the future we might want to support different origins or clips, but
 281    * right now we just shrink to the default.
 282    */
 283   _gtk_rounded_box_init_rect (&bg->padding_box, 0, 0, bg->paint_area.width, bg->paint_area.height);
 284
 285   _gtk_rounded_box_apply_border_radius_for_context (&bg->padding_box, bg->context, bg->junction);
 286
 287   bg->clip_box = bg->padding_box;
 288   _gtk_rounded_box_shrink (&bg->padding_box,
 289                            bg->border.top, bg->border.right,
 290                            bg->border.bottom, bg->border.left);
 291
 292   _gtk_theming_background_apply_clip (bg);
 293   _gtk_theming_background_apply_origin (bg);
 294
 295   bg->image = _gtk_css_image_value_get_image (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_IMAGE));
 296 }
 297
 298 void
 299 _gtk_theming_background_init (GtkThemingBackground *bg,
 300                               GtkThemingEngine     *engine,
 301                               gdouble               x,
 302                               gdouble               y,
 303                               gdouble               width,
 304                               gdouble               height,
 305                               GtkJunctionSides      junction)
 306 {
 307   GtkStyleContext *context;
 308
 309   g_assert (bg != NULL);
 310
 311   context = _gtk_theming_engine_get_context (engine);
 312   _gtk_theming_background_init_from_context (bg, context,
 313                                              x, y, width, height,
 314                                              junction);
 315 }
 316
 317 void
 318 _gtk_theming_background_init_from_context (GtkThemingBackground *bg,
 319                                            GtkStyleContext      *context,
 320                                            gdouble               x,
 321                                            gdouble               y,
 322                                            gdouble               width,
 323                                            gdouble               height,
 324                                            GtkJunctionSides      junction)
 325 {
 326   g_assert (bg != NULL);
 327
 328   bg->context = context;
 329
 330   bg->paint_area.x = x;
 331   bg->paint_area.y = y;
 332   bg->paint_area.width = width;
 333   bg->paint_area.height = height;
 334
 335   bg->image = NULL;
 336   bg->junction = junction;
 337
 338   _gtk_theming_background_init_context (bg);
 339 }
 340
 341 void
 342 _gtk_theming_background_render (GtkThemingBackground *bg,
 343                                 cairo_t              *cr)
 344 {
 345   cairo_save (cr);
 346   cairo_translate (cr, bg->paint_area.x, bg->paint_area.y);
 347
 348   _gtk_theming_background_apply_window_background (bg, cr);
 349   _gtk_theming_background_paint (bg, cr);
 350   _gtk_theming_background_apply_shadow (bg, cr);
 351
 352   cairo_restore (cr);
 353 }
 354
 355 gboolean
 356 _gtk_theming_background_has_background_image (GtkThemingBackground *bg)
 357 {
 358   return (bg->image != NULL) ? TRUE : FALSE;
 359 }