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 "gtkcssenumvalueprivate.h"
  28 #include "gtkcssimagevalueprivate.h"
  29 #include "gtkcssshadowsvalueprivate.h"
  30 #include "gtkcsspositionvalueprivate.h"
  31 #include "gtkcssrepeatvalueprivate.h"
  32 #include "gtkcsstypesprivate.h"
  33 #include "gtkthemingengineprivate.h"
  34
  35 #include <math.h>
  36
  37 #include <gdk/gdk.h>
  38
  39 /* this is in case round() is not provided by the compiler,
  40  * such as in the case of C89 compilers, like MSVC
  41  */
  42 #include "fallback-c89.c"
  43
  44 static void
  45 _gtk_theming_background_apply_window_background (GtkThemingBackground *bg,
  46                                                  cairo_t              *cr)
  47 {
  48   if (gtk_style_context_has_class (bg->context, "background"))
  49     {
  50       cairo_set_source_rgba (cr, 1.0, 1.0, 1.0, 0.0); /* transparent */
  51       cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
  52       cairo_paint (cr);
  53     }
  54 }
  55
  56 static void
  57 _gtk_theming_background_apply_origin (GtkThemingBackground *bg)
  58 {
  59   GtkCssArea origin;
  60   cairo_rectangle_t image_rect;
  61
  62   origin = _gtk_css_area_value_get (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_CLIP));
  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   GtkCssArea clip = _gtk_css_area_value_get (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_CLIP));
  98
  99   if (clip == GTK_CSS_AREA_PADDING_BOX)
 100     {
 101       _gtk_rounded_box_shrink (&bg->clip_box,
 102                                bg->border.top, bg->border.right,
 103                                bg->border.bottom, bg->border.left);
 104     }
 105   else if (clip == GTK_CSS_AREA_CONTENT_BOX)
 106     {
 107       _gtk_rounded_box_shrink (&bg->clip_box,
 108                                bg->border.top + bg->padding.top,
 109                                bg->border.right + bg->padding.right,
 110                                bg->border.bottom + bg->padding.bottom,
 111                                bg->border.left + bg->padding.left);
 112     }
 113 }
 114
 115 static void
 116 _gtk_theming_background_get_cover_contain (GtkCssImage *image,
 117                                            gboolean     cover,
 118                                            double       width,
 119                                            double       height,
 120                                            double      *concrete_width,
 121                                            double      *concrete_height)
 122 {
 123   double aspect, image_aspect;
 124
 125   image_aspect = _gtk_css_image_get_aspect_ratio (image);
 126   if (image_aspect == 0.0)
 127     {
 128       *concrete_width = width;
 129       *concrete_height = height;
 130       return;
 131     }
 132
 133   aspect = width / height;
 134
 135   if ((aspect >= image_aspect && cover) ||
 136       (aspect < image_aspect && !cover))
 137     {
 138       *concrete_width = width;
 139       *concrete_height = width / image_aspect;
 140     }
 141   else
 142     {
 143       *concrete_height = height;
 144       *concrete_width = height * image_aspect;
 145     }
 146 }
 147
 148 static void
 149 _gtk_theming_background_paint (GtkThemingBackground *bg,
 150                                cairo_t              *cr)
 151 {
 152   cairo_save (cr);
 153
 154   _gtk_rounded_box_path (&bg->clip_box, cr);
 155   cairo_clip (cr);
 156
 157   gdk_cairo_set_source_rgba (cr, &bg->bg_color);
 158   cairo_paint (cr);
 159
 160   if (bg->image
 161       && bg->image_rect.width > 0
 162       && bg->image_rect.height > 0)
 163     {
 164       const GtkCssBackgroundSize *size;
 165       const GtkCssValue *pos, *repeat;
 166       double image_width, image_height;
 167       double width, height;
 168       GtkCssRepeatStyle hrepeat, vrepeat;
 169
 170       size = _gtk_css_value_get_background_size (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_SIZE));
 171       pos = _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_POSITION);
 172       repeat = _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_REPEAT);
 173       hrepeat = _gtk_css_background_repeat_value_get_x (repeat);
 174       vrepeat = _gtk_css_background_repeat_value_get_y (repeat);
 175       width = bg->image_rect.width;
 176       height = bg->image_rect.height;
 177
 178       if (size->contain || size->cover)
 179         _gtk_theming_background_get_cover_contain (bg->image,
 180                                                    size->cover,
 181                                                    width,
 182                                                    height,
 183                                                    &image_width,
 184                                                    &image_height);
 185       else
 186         _gtk_css_image_get_concrete_size (bg->image,
 187                                           /* note: 0 does the right thing here for 'auto' */
 188                                           _gtk_css_number_get (&size->width, width),
 189                                           _gtk_css_number_get (&size->height, height),
 190                                           width, height,
 191                                           &image_width, &image_height);
 192
 193       /* optimization */
 194       if (image_width == width)
 195         hrepeat = GTK_CSS_REPEAT_STYLE_NO_REPEAT;
 196       if (image_height == height)
 197         vrepeat = GTK_CSS_REPEAT_STYLE_NO_REPEAT;
 198
 199       cairo_translate (cr, bg->image_rect.x, bg->image_rect.y);
 200
 201       if (hrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT && vrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT)
 202         {
 203           cairo_translate (cr,
 204                            _gtk_css_position_value_get_x (pos, width - image_width),
 205                            _gtk_css_position_value_get_y (pos, height - image_height));
 206           /* shortcut for normal case */
 207           _gtk_css_image_draw (bg->image, cr, image_width, image_height);
 208         }
 209       else
 210         {
 211           int surface_width, surface_height;
 212           cairo_surface_t *surface;
 213           cairo_t *cr2;
 214
 215           /* If ‘background-repeat’ is ‘round’ for one (or both) dimensions,
 216            * there is a second step. The UA must scale the image in that
 217            * dimension (or both dimensions) so that it fits a whole number of
 218            * times in the background positioning area. In the case of the width
 219            * (height is analogous):
 220            *
 221            * If X ≠ 0 is the width of the image after step one and W is the width
 222            * of the background positioning area, then the rounded width
 223            * X' = W / round(W / X) where round() is a function that returns the
 224            * nearest natural number (integer greater than zero).
 225            *
 226            * If ‘background-repeat’ is ‘round’ for one dimension only and if
 227            * ‘background-size’ is ‘auto’ for the other dimension, then there is
 228            * a third step: that other dimension is scaled so that the original
 229            * aspect ratio is restored.
 230            */
 231           if (hrepeat == GTK_CSS_REPEAT_STYLE_ROUND)
 232             {
 233               double n = round (width / image_width);
 234
 235               n = MAX (1, n);
 236
 237               if (vrepeat != GTK_CSS_REPEAT_STYLE_ROUND
 238                   /* && vsize == auto (it is by default) */)
 239                 image_height *= width / (image_width * n);
 240               image_width = width / n;
 241             }
 242           if (vrepeat == GTK_CSS_REPEAT_STYLE_ROUND)
 243             {
 244               double n = round (height / image_height);
 245
 246               n = MAX (1, n);
 247
 248               if (hrepeat != GTK_CSS_REPEAT_STYLE_ROUND
 249                   /* && hsize == auto (it is by default) */)
 250                 image_width *= height / (image_height * n);
 251               image_height = height / n;
 252             }
 253
 254           /* if hrepeat or vrepeat is 'space', we create a somewhat larger surface
 255            * to store the extra space. */
 256           if (hrepeat == GTK_CSS_REPEAT_STYLE_SPACE)
 257             {
 258               double n = floor (width / image_width);
 259               surface_width = n ? round (width / n) : 0;
 260             }
 261           else
 262             surface_width = round (image_width);
 263
 264           if (vrepeat == GTK_CSS_REPEAT_STYLE_SPACE)
 265             {
 266               double n = floor (height / image_height);
 267               surface_height = n ? round (height / n) : 0;
 268             }
 269           else
 270             surface_height = round (image_height);
 271
 272           surface = cairo_surface_create_similar (cairo_get_target (cr),
 273                                                   CAIRO_CONTENT_COLOR_ALPHA,
 274                                                   surface_width, surface_height);
 275           cr2 = cairo_create (surface);
 276           cairo_translate (cr2,
 277                            0.5 * (surface_width - image_width),
 278                            0.5 * (surface_height - image_height));
 279           _gtk_css_image_draw (bg->image, cr2, image_width, image_height);
 280           cairo_destroy (cr2);
 281
 282           cairo_set_source_surface (cr, surface,
 283                                     _gtk_css_position_value_get_x (pos, width - image_width),
 284                                     _gtk_css_position_value_get_y (pos, height - image_height));
 285           cairo_pattern_set_extend (cairo_get_source (cr), CAIRO_EXTEND_REPEAT);
 286           cairo_surface_destroy (surface);
 287
 288           cairo_rectangle (cr,
 289                            0, 0,
 290                            hrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT ? image_width : width,
 291                            vrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT ? image_height : height);
 292           cairo_fill (cr);
 293         }
 294     }
 295
 296   cairo_restore (cr);
 297 }
 298
 299 static void
 300 _gtk_theming_background_apply_shadow (GtkThemingBackground *bg,
 301                                       cairo_t              *cr)
 302 {
 303   _gtk_css_shadows_value_paint_box (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BOX_SHADOW),
 304                                     cr,
 305                                     &bg->padding_box);
 306 }
 307
 308 static void
 309 _gtk_theming_background_init_context (GtkThemingBackground *bg)
 310 {
 311   bg->flags = gtk_style_context_get_state (bg->context);
 312
 313   gtk_style_context_get_border (bg->context, bg->flags, &bg->border);
 314   gtk_style_context_get_padding (bg->context, bg->flags, &bg->padding);
 315   gtk_style_context_get_background_color (bg->context, bg->flags, &bg->bg_color);
 316
 317   /* In the CSS box model, by default the background positioning area is
 318    * the padding-box, i.e. all the border-box minus the borders themselves,
 319    * which determines also its default size, see
 320    * http://dev.w3.org/csswg/css3-background/#background-origin
 321    *
 322    * In the future we might want to support different origins or clips, but
 323    * right now we just shrink to the default.
 324    */
 325   _gtk_rounded_box_init_rect (&bg->padding_box, 0, 0, bg->paint_area.width, bg->paint_area.height);
 326
 327   _gtk_rounded_box_apply_border_radius_for_context (&bg->padding_box, bg->context, bg->junction);
 328
 329   bg->clip_box = bg->padding_box;
 330   _gtk_rounded_box_shrink (&bg->padding_box,
 331                            bg->border.top, bg->border.right,
 332                            bg->border.bottom, bg->border.left);
 333
 334   _gtk_theming_background_apply_clip (bg);
 335   _gtk_theming_background_apply_origin (bg);
 336
 337   bg->image = _gtk_css_image_value_get_image (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_IMAGE));
 338 }
 339
 340 void
 341 _gtk_theming_background_init (GtkThemingBackground *bg,
 342                               GtkThemingEngine     *engine,
 343                               gdouble               x,
 344                               gdouble               y,
 345                               gdouble               width,
 346                               gdouble               height,
 347                               GtkJunctionSides      junction)
 348 {
 349   GtkStyleContext *context;
 350
 351   g_assert (bg != NULL);
 352
 353   context = _gtk_theming_engine_get_context (engine);
 354   _gtk_theming_background_init_from_context (bg, context,
 355                                              x, y, width, height,
 356                                              junction);
 357 }
 358
 359 void
 360 _gtk_theming_background_init_from_context (GtkThemingBackground *bg,
 361                                            GtkStyleContext      *context,
 362                                            gdouble               x,
 363                                            gdouble               y,
 364                                            gdouble               width,
 365                                            gdouble               height,
 366                                            GtkJunctionSides      junction)
 367 {
 368   g_assert (bg != NULL);
 369
 370   bg->context = context;
 371
 372   bg->paint_area.x = x;
 373   bg->paint_area.y = y;
 374   bg->paint_area.width = width;
 375   bg->paint_area.height = height;
 376
 377   bg->image = NULL;
 378   bg->junction = junction;
 379
 380   _gtk_theming_background_init_context (bg);
 381 }
 382
 383 void
 384 _gtk_theming_background_render (GtkThemingBackground *bg,
 385                                 cairo_t              *cr)
 386 {
 387   cairo_save (cr);
 388   cairo_translate (cr, bg->paint_area.x, bg->paint_area.y);
 389
 390   _gtk_theming_background_apply_window_background (bg, cr);
 391   _gtk_theming_background_paint (bg, cr);
 392   _gtk_theming_background_apply_shadow (bg, cr);
 393
 394   cairo_restore (cr);
 395 }
 396
 397 gboolean
 398 _gtk_theming_background_has_background_image (GtkThemingBackground *bg)
 399 {
 400   return (bg->image != NULL) ? TRUE : FALSE;
 401 }