css: Add a GtkCssValue for GtkCssImageEffect

This will allow us to use the CSS machinery to apply a highlight or dim
effect when images are prelit or insensitive.

https://bugzilla.gnome.org/show_bug.cgi?id=705443

gtk/gtkcssenumvalue.c

@@ -653,3 +653,56 @@ _gtk_css_fill_mode_value_get (const GtkCssValue *value)
   return value->value;
 }
 
+/* GtkCssImageEffect */
+
+static const GtkCssValueClass GTK_CSS_VALUE_IMAGE_EFFECT = {
+  gtk_css_value_enum_free,
+  gtk_css_value_enum_compute,
+  gtk_css_value_enum_equal,
+  gtk_css_value_enum_transition,
+  gtk_css_value_enum_print
+};
+
+static GtkCssValue image_effect_values[] = {
+  { &GTK_CSS_VALUE_IMAGE_EFFECT, 1, GTK_CSS_IMAGE_EFFECT_NONE, "none" },
+  { &GTK_CSS_VALUE_IMAGE_EFFECT, 1, GTK_CSS_IMAGE_EFFECT_HIGHLIGHT, "highlight" },
+  { &GTK_CSS_VALUE_IMAGE_EFFECT, 1, GTK_CSS_IMAGE_EFFECT_DIM, "dim" }
+};
+
+GtkCssValue *
+_gtk_css_image_effect_value_new (GtkCssImageEffect image_effect)
+{
+  guint i;
+
+  for (i = 0; i < G_N_ELEMENTS (image_effect_values); i++)
+    {
+      if (image_effect_values[i].value == image_effect)
+        return _gtk_css_value_ref (&image_effect_values[i]);
+    }
+
+  g_return_val_if_reached (NULL);
+}
+
+GtkCssValue *
+_gtk_css_image_effect_value_try_parse (GtkCssParser *parser)
+{
+  guint i;
+
+  g_return_val_if_fail (parser != NULL, NULL);
+
+  for (i = 0; i < G_N_ELEMENTS (image_effect_values); i++)
+    {
+      if (_gtk_css_parser_try (parser, image_effect_values[i].name, TRUE))
+        return _gtk_css_value_ref (&image_effect_values[i]);
+    }
+
+  return NULL;
+}
+
+GtkCssImageEffect
+_gtk_css_image_effect_value_get (const GtkCssValue *value)
+{
+  g_return_val_if_fail (value->class == &GTK_CSS_VALUE_IMAGE_EFFECT, GTK_CSS_IMAGE_EFFECT_NONE);
+
+  return value->value;
+}

gtk/gtkcssenumvalueprivate.h

@@ -64,6 +64,10 @@ GtkCssValue *   _gtk_css_fill_mode_value_new          (GtkCssFillMode     fill_m
 GtkCssValue *   _gtk_css_fill_mode_value_try_parse    (GtkCssParser      *parser);
 GtkCssFillMode  _gtk_css_fill_mode_value_get          (const GtkCssValue *value);
 
+GtkCssValue *     _gtk_css_image_effect_value_new       (GtkCssImageEffect  image_effect);
+GtkCssValue *     _gtk_css_image_effect_value_try_parse (GtkCssParser      *parser);
+GtkCssImageEffect _gtk_css_image_effect_value_get       (const GtkCssValue *value);
+
 G_END_DECLS
 
 #endif /* __GTK_CSS_ENUM_VALUE_PRIVATE_H__ */

gtk/gtkcssstylepropertyimpl.c

@@ -464,6 +464,18 @@ parse_css_fill_mode (GtkCssStyleProperty *property,
   return _gtk_css_array_value_parse (parser, parse_one_css_fill_mode);
 }
 
+static GtkCssValue *
+image_effect_parse (GtkCssStyleProperty *property,
+		    GtkCssParser        *parser)
+{
+  GtkCssValue *value = _gtk_css_image_effect_value_try_parse (parser);
+
+  if (value == NULL)
+    _gtk_css_parser_error (parser, "unknown value for property");
+
+  return value;
+}
+
 static GtkCssValue *
 bindings_value_parse_one (GtkCssParser *parser)
 {
@@ -1398,6 +1410,14 @@ _gtk_css_style_property_init_properties (void)
                                           NULL,
                                           NULL,
                                           _gtk_css_number_value_new (1, GTK_CSS_NUMBER));
+  gtk_css_style_property_register        ("-gtk-image-effect",
+					  GTK_CSS_PROPERTY_GTK_IMAGE_EFFECT,
+					  G_TYPE_NONE,
+					  GTK_STYLE_PROPERTY_INHERIT | GTK_STYLE_PROPERTY_NO_RESIZE,
+					  image_effect_parse,
+					  NULL,
+					  NULL,
+					  _gtk_css_image_effect_value_new (GTK_CSS_IMAGE_EFFECT_NONE));
 
   gtk_css_style_property_register        ("engine",
                                           GTK_CSS_PROPERTY_ENGINE,

gtk/gtkcsstypesprivate.h

@@ -133,6 +133,7 @@ enum { /*< skip >*/
   GTK_CSS_PROPERTY_ANIMATION_DELAY,
   GTK_CSS_PROPERTY_ANIMATION_FILL_MODE,
   GTK_CSS_PROPERTY_OPACITY,
+  GTK_CSS_PROPERTY_GTK_IMAGE_EFFECT,
   GTK_CSS_PROPERTY_ENGINE,
   GTK_CSS_PROPERTY_GTK_KEY_BINDINGS,
   /* add more */
@@ -164,6 +165,12 @@ typedef enum /*< skip >*/ {
   GTK_CSS_FILL_BOTH
 } GtkCssFillMode;
 
+typedef enum /*< skip >*/ {
+  GTK_CSS_IMAGE_EFFECT_NONE,
+  GTK_CSS_IMAGE_EFFECT_HIGHLIGHT,
+  GTK_CSS_IMAGE_EFFECT_DIM
+} GtkCssImageEffect;
+
 typedef enum /*< skip >*/ {
   /* relative font sizes */
   GTK_CSS_FONT_SIZE_SMALLER,