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 const GtkRoundedBox *
  46 gtk_theming_background_get_box (GtkThemingBackground *bg,
  47                                 GtkCssArea            area)
  48 {
  49   switch (area)
  50     {
  51     case GTK_CSS_AREA_BORDER_BOX:
  52       return &bg->border_box;
  53     case GTK_CSS_AREA_PADDING_BOX:
  54       return &bg->padding_box;
  55     case GTK_CSS_AREA_CONTENT_BOX:
  56       return &bg->content_box;
  57     default:
  58       g_return_val_if_reached (&bg->border_box);
  59   }
  60 }
  61
  62 static void
  63 _gtk_theming_background_paint_color (GtkThemingBackground *bg,
  64                                      cairo_t              *cr,
  65                                      GtkCssValue          *background_image)
  66 {
  67   gint n_values = _gtk_css_array_value_get_n_values (background_image);
  68   GtkCssArea clip = _gtk_css_area_value_get
  69     (_gtk_css_array_value_get_nth
  70      (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_CLIP),
  71       n_values - 1));
  72
  73   cairo_save (cr);
  74   _gtk_rounded_box_path (gtk_theming_background_get_box (bg, clip), cr);
  75   cairo_clip (cr);
  76
  77   gdk_cairo_set_source_rgba (cr, &bg->bg_color);
  78   cairo_paint (cr);
  79
  80   cairo_restore (cr);
  81 }
  82
  83 static void
  84 _gtk_theming_background_paint_layer (GtkThemingBackground *bg,
  85                                      guint                 idx,
  86                                      cairo_t              *cr)
  87 {
  88   GtkCssRepeatStyle hrepeat, vrepeat;
  89   const GtkCssValue *pos, *repeat;
  90   GtkCssImage *image;
  91   const GtkRoundedBox *origin;
  92   double image_width, image_height;
  93   double width, height;
  94
  95   pos = _gtk_css_array_value_get_nth (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_POSITION), idx);
  96   repeat = _gtk_css_array_value_get_nth (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_REPEAT), idx);
  97   hrepeat = _gtk_css_background_repeat_value_get_x (repeat);
  98   vrepeat = _gtk_css_background_repeat_value_get_y (repeat);
  99   image = _gtk_css_image_value_get_image (
 100               _gtk_css_array_value_get_nth (
 101                   _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_IMAGE),
 102                   idx));
 103   origin = gtk_theming_background_get_box (
 104                bg,
 105                _gtk_css_area_value_get (
 106                    _gtk_css_array_value_get_nth (
 107                        _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_ORIGIN),
 108                        idx)));
 109   width = origin->box.width;
 110   height = origin->box.height;
 111
 112   if (image == NULL || width <= 0 || height <= 0)
 113     return;
 114
 115   _gtk_css_bg_size_value_compute_size (_gtk_css_array_value_get_nth (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_SIZE), idx),
 116                                        image,
 117                                        width,
 118                                        height,
 119                                        &image_width,
 120                                        &image_height);
 121
 122   if (image_width <= 0 || image_height <= 0)
 123     return;
 124
 125   /* optimization */
 126   if (image_width == width)
 127     hrepeat = GTK_CSS_REPEAT_STYLE_NO_REPEAT;
 128   if (image_height == height)
 129     vrepeat = GTK_CSS_REPEAT_STYLE_NO_REPEAT;
 130
 131
 132   cairo_save (cr);
 133
 134   _gtk_rounded_box_path (
 135       gtk_theming_background_get_box (
 136           bg,
 137           _gtk_css_area_value_get (
 138               _gtk_css_array_value_get_nth (
 139                   _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_CLIP),
 140                   idx))),
 141       cr);
 142   cairo_clip (cr);
 143
 144
 145   cairo_translate (cr, origin->box.x, origin->box.y);
 146
 147   if (hrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT && vrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT)
 148     {
 149       cairo_translate (cr,
 150                        _gtk_css_position_value_get_x (pos, width - image_width),
 151                        _gtk_css_position_value_get_y (pos, height - image_height));
 152       /* shortcut for normal case */
 153       _gtk_css_image_draw (image, cr, image_width, image_height);
 154     }
 155   else
 156     {
 157       int surface_width, surface_height;
 158       cairo_rectangle_t fill_rect;
 159       cairo_surface_t *surface;
 160       cairo_t *cr2;
 161
 162       /* If ‘background-repeat’ is ‘round’ for one (or both) dimensions,
 163        * there is a second step. The UA must scale the image in that
 164        * dimension (or both dimensions) so that it fits a whole number of
 165        * times in the background positioning area. In the case of the width
 166        * (height is analogous):
 167        *
 168        * If X ≠ 0 is the width of the image after step one and W is the width
 169        * of the background positioning area, then the rounded width
 170        * X' = W / round(W / X) where round() is a function that returns the
 171        * nearest natural number (integer greater than zero).
 172        *
 173        * If ‘background-repeat’ is ‘round’ for one dimension only and if
 174        * ‘background-size’ is ‘auto’ for the other dimension, then there is
 175        * a third step: that other dimension is scaled so that the original
 176        * aspect ratio is restored.
 177        */
 178       if (hrepeat == GTK_CSS_REPEAT_STYLE_ROUND)
 179         {
 180           double n = round (width / image_width);
 181
 182           n = MAX (1, n);
 183
 184           if (vrepeat != GTK_CSS_REPEAT_STYLE_ROUND
 185               /* && vsize == auto (it is by default) */)
 186             image_height *= width / (image_width * n);
 187           image_width = width / n;
 188         }
 189       if (vrepeat == GTK_CSS_REPEAT_STYLE_ROUND)
 190         {
 191           double n = round (height / image_height);
 192
 193           n = MAX (1, n);
 194
 195           if (hrepeat != GTK_CSS_REPEAT_STYLE_ROUND
 196               /* && hsize == auto (it is by default) */)
 197             image_width *= height / (image_height * n);
 198           image_height = height / n;
 199         }
 200
 201       /* if hrepeat or vrepeat is 'space', we create a somewhat larger surface
 202        * to store the extra space. */
 203       if (hrepeat == GTK_CSS_REPEAT_STYLE_SPACE)
 204         {
 205           double n = floor (width / image_width);
 206           surface_width = n ? round (width / n) : 0;
 207         }
 208       else
 209         surface_width = round (image_width);
 210
 211       if (vrepeat == GTK_CSS_REPEAT_STYLE_SPACE)
 212         {
 213           double n = floor (height / image_height);
 214           surface_height = n ? round (height / n) : 0;
 215         }
 216       else
 217         surface_height = round (image_height);
 218
 219       surface = cairo_surface_create_similar (cairo_get_target (cr),
 220                                               CAIRO_CONTENT_COLOR_ALPHA,
 221                                               surface_width, surface_height);
 222       cr2 = cairo_create (surface);
 223       cairo_translate (cr2,
 224                        0.5 * (surface_width - image_width),
 225                        0.5 * (surface_height - image_height));
 226       _gtk_css_image_draw (image, cr2, image_width, image_height);
 227       cairo_destroy (cr2);
 228
 229       cairo_set_source_surface (cr, surface,
 230                                 _gtk_css_position_value_get_x (pos, width - image_width),
 231                                 _gtk_css_position_value_get_y (pos, height - image_height));
 232       cairo_pattern_set_extend (cairo_get_source (cr), CAIRO_EXTEND_REPEAT);
 233       cairo_surface_destroy (surface);
 234
 235       if (hrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT)
 236         {
 237           fill_rect.x = _gtk_css_position_value_get_x (pos, width - image_width);
 238           fill_rect.width = image_width;
 239         }
 240       else
 241         {
 242           fill_rect.x = 0;
 243           fill_rect.width = width;
 244         }
 245
 246       if (vrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT)
 247         {
 248           fill_rect.y = _gtk_css_position_value_get_y (pos, height - image_height);
 249           fill_rect.height = image_height;
 250         }
 251       else
 252         {
 253           fill_rect.y = 0;
 254           fill_rect.height = height;
 255         }
 256
 257       cairo_rectangle (cr, fill_rect.x, fill_rect.y,
 258                        fill_rect.width, fill_rect.height);
 259       cairo_fill (cr);
 260     }
 261
 262
 263   cairo_restore (cr);
 264 }
 265
 266 static void
 267 _gtk_theming_background_apply_shadow (GtkThemingBackground *bg,
 268                                       cairo_t              *cr)
 269 {
 270   _gtk_css_shadows_value_paint_box (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BOX_SHADOW),
 271                                     cr,
 272                                     &bg->padding_box);
 273 }
 274
 275 static void
 276 _gtk_theming_background_init_context (GtkThemingBackground *bg)
 277 {
 278   GtkStateFlags flags = gtk_style_context_get_state (bg->context);
 279   GtkBorder border, padding;
 280
 281   gtk_style_context_get_border (bg->context, flags, &border);
 282   gtk_style_context_get_padding (bg->context, flags, &padding);
 283   gtk_style_context_get_background_color (bg->context, flags, &bg->bg_color);
 284
 285   /* In the CSS box model, by default the background positioning area is
 286    * the padding-box, i.e. all the border-box minus the borders themselves,
 287    * which determines also its default size, see
 288    * http://dev.w3.org/csswg/css3-background/#background-origin
 289    *
 290    * In the future we might want to support different origins or clips, but
 291    * right now we just shrink to the default.
 292    */
 293   _gtk_rounded_box_init_rect (&bg->border_box, 0, 0, bg->paint_area.width, bg->paint_area.height);
 294   _gtk_rounded_box_apply_border_radius_for_context (&bg->border_box, bg->context, bg->junction);
 295
 296   bg->padding_box = bg->border_box;
 297   _gtk_rounded_box_shrink (&bg->padding_box,
 298                            border.top, border.right,
 299                            border.bottom, border.left);
 300
 301   bg->content_box = bg->padding_box;
 302   _gtk_rounded_box_shrink (&bg->content_box,
 303                            padding.top, padding.right,
 304                            padding.bottom, padding.left);
 305 }
 306
 307 void
 308 _gtk_theming_background_init (GtkThemingBackground *bg,
 309                               GtkThemingEngine     *engine,
 310                               gdouble               x,
 311                               gdouble               y,
 312                               gdouble               width,
 313                               gdouble               height,
 314                               GtkJunctionSides      junction)
 315 {
 316   GtkStyleContext *context;
 317
 318   g_assert (bg != NULL);
 319
 320   context = _gtk_theming_engine_get_context (engine);
 321   _gtk_theming_background_init_from_context (bg, context,
 322                                              x, y, width, height,
 323                                              junction);
 324 }
 325
 326 void
 327 _gtk_theming_background_init_from_context (GtkThemingBackground *bg,
 328                                            GtkStyleContext      *context,
 329                                            gdouble               x,
 330                                            gdouble               y,
 331                                            gdouble               width,
 332                                            gdouble               height,
 333                                            GtkJunctionSides      junction)
 334 {
 335   g_assert (bg != NULL);
 336
 337   bg->context = context;
 338
 339   bg->paint_area.x = x;
 340   bg->paint_area.y = y;
 341   bg->paint_area.width = width;
 342   bg->paint_area.height = height;
 343
 344   bg->junction = junction;
 345
 346   _gtk_theming_background_init_context (bg);
 347 }
 348
 349 void
 350 _gtk_theming_background_render (GtkThemingBackground *bg,
 351                                 cairo_t              *cr)
 352 {
 353   gint idx;
 354   GtkCssValue *background_image;
 355
 356   background_image = _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_IMAGE);
 357
 358   cairo_save (cr);
 359   cairo_translate (cr, bg->paint_area.x, bg->paint_area.y);
 360
 361   _gtk_theming_background_paint_color (bg, cr, background_image);
 362
 363   for (idx = _gtk_css_array_value_get_n_values (background_image) - 1; idx >= 0; idx--)
 364     {
 365       _gtk_theming_background_paint_layer (bg, idx, cr);
 366     }
 367
 368   _gtk_theming_background_apply_shadow (bg, cr);
 369
 370   cairo_restore (cr);
 371 }
 372
 373 gboolean
 374 _gtk_theming_background_has_background_image (GtkThemingBackground *bg)
 375 {
 376   GtkCssImage *image;
 377   GtkCssValue *value = _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_IMAGE);
 378
 379   if (_gtk_css_array_value_get_n_values (value) == 0)
 380     return FALSE;
 381
 382   image = _gtk_css_image_value_get_image (_gtk_css_array_value_get_nth (value, 0));
 383   return (image != NULL);
 384 }