cssimage: Implement dynamic values

No image actually implements it yet, but this is the plumbing.

gtk/gtkcssimage.c

@@ -96,6 +96,19 @@ gtk_css_image_real_transition (GtkCssImage *start,
     return _gtk_css_image_cross_fade_new (start, end, progress);
 }
 
+static gboolean
+gtk_css_image_real_is_dynamic (GtkCssImage *image)
+{
+  return FALSE;
+}
+
+static GtkCssImage *
+gtk_css_image_real_get_dynamic_image (GtkCssImage *image,
+                                      gint64       monotonic_time)
+{
+  return g_object_ref (image);
+}
+
 static void
 _gtk_css_image_class_init (GtkCssImageClass *klass)
 {
@@ -105,6 +118,8 @@ _gtk_css_image_class_init (GtkCssImageClass *klass)
   klass->compute = gtk_css_image_real_compute;
   klass->equal = gtk_css_image_real_equal;
   klass->transition = gtk_css_image_real_transition;
+  klass->is_dynamic = gtk_css_image_real_is_dynamic;
+  klass->get_dynamic_image = gtk_css_image_real_get_dynamic_image;
 }
 
 static void
@@ -264,6 +279,31 @@ gtk_css_image_snapshot (GtkCssImage *image,
   klass->snapshot (image, snapshot, width, height);
 }
 
+gboolean
+gtk_css_image_is_dynamic (GtkCssImage *image)
+{
+  GtkCssImageClass *klass;
+
+  g_return_val_if_fail (GTK_IS_CSS_IMAGE (image), FALSE);
+
+  klass = GTK_CSS_IMAGE_GET_CLASS (image);
+
+  return klass->is_dynamic (image);
+}
+
+GtkCssImage *
+gtk_css_image_get_dynamic_image (GtkCssImage *image,
+                                 gint64       monotonic_time)
+{
+  GtkCssImageClass *klass;
+
+  g_return_val_if_fail (GTK_IS_CSS_IMAGE (image), NULL);
+
+  klass = GTK_CSS_IMAGE_GET_CLASS (image);
+
+  return klass->get_dynamic_image (image, monotonic_time);
+}
+
 void
 _gtk_css_image_print (GtkCssImage *image,
                       GString     *string)

gtk/gtkcssimageprivate.h

@@ -75,6 +75,11 @@ struct _GtkCssImageClass
                                                     GtkSnapshot                *snapshot,
                                                     double                      width,
                                                     double                      height);
+  /* does this image change based on timestamp? (optional) */
+  gboolean     (* is_dynamic)                      (GtkCssImage                *image);
+  /* get image for given timestamp or @image when not dynamic (optional) */
+  GtkCssImage *(* get_dynamic_image)               (GtkCssImage                *image,
+                                                    gint64                      monotonic_time);
   /* parse CSS, return TRUE on success */
   gboolean     (* parse)                           (GtkCssImage                *image,
                                                     GtkCssParser               *parser);
@@ -112,6 +117,9 @@ void           gtk_css_image_snapshot              (GtkCssImage                *
                                                     GtkSnapshot                *snapshot,
                                                     double                      width,
                                                     double                      height);
+gboolean       gtk_css_image_is_dynamic            (GtkCssImage                *image);
+GtkCssImage *  gtk_css_image_get_dynamic_image     (GtkCssImage                *image,
+                                                    gint64                      monotonic_time);
 void           _gtk_css_image_print                (GtkCssImage                *image,
                                                     GString                    *string);
 

gtk/gtkcssimagevalue.c

@@ -81,6 +81,37 @@ gtk_css_value_image_transition (GtkCssValue *start,
   return _gtk_css_image_value_new (transition);
 }
 
+static gboolean
+gtk_css_value_image_is_dynamic (GtkCssValue *value)
+{
+  GtkCssImage *image = _gtk_css_image_value_get_image (value);
+
+  if (image == NULL)
+    return FALSE;
+
+  return gtk_css_image_is_dynamic (image);
+}
+
+static GtkCssValue *
+gtk_css_value_image_get_dynamic_value (GtkCssValue *value,
+                                       gint64       monotonic_time)
+{
+  GtkCssImage *image, *dynamic;
+  
+  image = _gtk_css_image_value_get_image (value);
+  if (image == NULL)
+    return gtk_css_value_ref (value);
+
+  dynamic = gtk_css_image_get_dynamic_image (image, monotonic_time);
+  if (dynamic == image)
+    {
+      g_object_unref (dynamic);
+      return gtk_css_value_ref (value);
+    }
+
+  return _gtk_css_image_value_new (dynamic);
+}
+
 static void
 gtk_css_value_image_print (const GtkCssValue *value,
                            GString           *string)
@@ -96,8 +127,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_IMAGE = {
   gtk_css_value_image_compute,
   gtk_css_value_image_equal,
   gtk_css_value_image_transition,
-  NULL,
+  gtk_css_value_image_is_dynamic,
-  NULL,
+  gtk_css_value_image_get_dynamic_value,
   gtk_css_value_image_print
 };