+/* Applies the algorithm outlined in
+ * http://dev.w3.org/csswg/css3-images/#default-sizing
+ */
+void
+_gtk_css_image_get_concrete_size (GtkCssImage *image,
+ double specified_width,
+ double specified_height,
+ double default_width,
+ double default_height,
+ double *concrete_width,
+ double *concrete_height)
+{
+ double image_width, image_height, image_aspect;
+
+ g_return_if_fail (GTK_IS_CSS_IMAGE (image));
+ g_return_if_fail (specified_width >= 0);
+ g_return_if_fail (specified_height >= 0);
+ g_return_if_fail (default_width > 0);
+ g_return_if_fail (default_height > 0);
+ g_return_if_fail (concrete_width != NULL);
+ g_return_if_fail (concrete_height != NULL);
+
+ /* If the specified size is a definite width and height,
+ * the concrete object size is given that width and height.
+ */
+ if (specified_width && specified_height)
+ {
+ *concrete_width = specified_width;
+ *concrete_height = specified_height;
+ return;
+ }
+
+ image_width = _gtk_css_image_get_width (image);
+ image_height = _gtk_css_image_get_height (image);
+ image_aspect = _gtk_css_image_get_aspect_ratio (image);
+
+ /* If the specified size has neither a definite width nor height,
+ * and has no additional contraints, the dimensions of the concrete
+ * object size are calculated as follows:
+ */
+ if (specified_width == 0.0 && specified_height == 0.0)
+ {
+ /* If the object has only an intrinsic aspect ratio,
+ * the concrete object size must have that aspect ratio,
+ * and additionally be as large as possible without either
+ * its height or width exceeding the height or width of the
+ * default object size.
+ */
+ if (image_aspect > 0 && image_width == 0 && image_height == 0)
+ {
+ if (image_aspect * default_height > default_width)
+ {
+ *concrete_width = default_height * image_aspect;
+ *concrete_height = default_height;
+ }
+ else
+ {
+ *concrete_width = default_width;
+ *concrete_height = default_width / image_aspect;
+ }
+ }
+
+ /* Otherwise, the width and height of the concrete object
+ * size is the same as the object's intrinsic width and
+ * intrinsic height, if they exist.
+ * If the concrete object size is still missing a width or
+ * height, and the object has an intrinsic aspect ratio,
+ * the missing dimension is calculated from the present
+ * dimension and the intrinsic aspect ratio.
+ * Otherwise, the missing dimension is taken from the default
+ * object size.
+ */
+ if (image_width)
+ *concrete_width = image_width;
+ else if (image_aspect)
+ *concrete_width = image_height * image_aspect;
+ else
+ *concrete_width = default_width;
+
+ if (image_height)
+ *concrete_height = image_height;
+ else if (image_aspect)
+ *concrete_height = image_width / image_aspect;
+ else
+ *concrete_height = default_height;
+
+ return;
+ }
+
+ /* If the specified size has only a width or height, but not both,
+ * then the concrete object size is given that specified width or height.
+ * The other dimension is calculated as follows:
+ * If the object has an intrinsic aspect ratio, the missing dimension of
+ * the concrete object size is calculated using the intrinsic aspect-ratio
+ * and the present dimension.
+ * Otherwise, if the missing dimension is present in the object's intrinsic
+ * dimensions, the missing dimension is taken from the object's intrinsic
+ * dimensions.
+ * Otherwise, the missing dimension of the concrete object size is taken
+ * from the default object size.
+ */
+ if (specified_width)
+ {
+ *concrete_width = specified_width;
+ if (image_aspect)
+ *concrete_height = specified_width / image_aspect;
+ else if (image_height)
+ *concrete_height = image_height;
+ else
+ *concrete_height = default_height;
+ }
+ else
+ {
+ *concrete_height = specified_height;
+ if (image_aspect)
+ *concrete_width = specified_height * image_aspect;
+ else if (image_width)
+ *concrete_width = image_width;
+ else
+ *concrete_width = default_width;
+ }
+}
+
+cairo_surface_t *
+_gtk_css_image_get_surface (GtkCssImage *image,
+ cairo_surface_t *target,
+ int surface_width,
+ int surface_height)
+{
+ cairo_surface_t *result;
+ cairo_t *cr;
+
+ g_return_val_if_fail (GTK_IS_CSS_IMAGE (image), NULL);
+ g_return_val_if_fail (surface_width > 0, NULL);
+ g_return_val_if_fail (surface_height > 0, NULL);
+
+ if (target)
+ result = cairo_surface_create_similar (target,
+ CAIRO_CONTENT_COLOR_ALPHA,
+ surface_width,
+ surface_height);
+ else
+ result = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
+ surface_width,
+ surface_height);
+
+ cr = cairo_create (result);
+ _gtk_css_image_draw (image, cr, surface_width, surface_height);
+ cairo_destroy (cr);
+
+ return result;
+}
+
+static GType
+gtk_css_image_get_parser_type (GtkCssParser *parser)
+{
+ static const struct {
+ const char *prefix;
+ GType (* type_func) (void);
+ } image_types[] = {
+ { "url", _gtk_css_image_url_get_type },
+ { "-gtk-gradient", _gtk_css_image_gradient_get_type },
+ { "-gtk-win32-theme-part", _gtk_css_image_win32_get_type },
+ { "linear-gradient", _gtk_css_image_linear_get_type },
+ { "repeating-linear-gradient", _gtk_css_image_linear_get_type },
+ { "cross-fade", _gtk_css_image_cross_fade_get_type }
+ };
+ guint i;
+
+ for (i = 0; i < G_N_ELEMENTS (image_types); i++)
+ {
+ if (_gtk_css_parser_has_prefix (parser, image_types[i].prefix))
+ return image_types[i].type_func ();
+ }
+
+ return G_TYPE_INVALID;
+}
+
+/**
+ * _gtk_css_image_can_parse:
+ * @parser: a css parser
+ *
+ * Checks if the parser can potentially parse the given stream as an
+ * image from looking at the first token of @parser. This is useful for
+ * implementing shorthand properties. A successful parse of an image
+ * can not be guaranteed.
+ *
+ * Returns: %TURE if it looks like an image.
+ **/
+gboolean
+_gtk_css_image_can_parse (GtkCssParser *parser)
+{
+ return gtk_css_image_get_parser_type (parser) != G_TYPE_INVALID;
+}
+