css: Introduce the idea of dynamic values

Dynamic values are values that change their contents with the current
(monotonic) time.

This just introduces the GtkCssValue API for it.

gtk/gtkcssarrayvalue.c

@@ -323,6 +323,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_ARRAY = {
   gtk_css_value_array_compute,
   gtk_css_value_array_equal,
   gtk_css_value_array_transition,
+  NULL,
+  NULL,
   gtk_css_value_array_print
 };
 

gtk/gtkcssbgsizevalue.c

@@ -157,6 +157,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_BG_SIZE = {
   gtk_css_value_bg_size_compute,
   gtk_css_value_bg_size_equal,
   gtk_css_value_bg_size_transition,
+  NULL,
+  NULL,
   gtk_css_value_bg_size_print
 };
 

gtk/gtkcssbordervalue.c

@@ -144,6 +144,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_BORDER = {
   gtk_css_value_border_compute,
   gtk_css_value_border_equal,
   gtk_css_value_border_transition,
+  NULL,
+  NULL,
   gtk_css_value_border_print
 };
 

gtk/gtkcsscalcvalue.c

@@ -249,6 +249,8 @@ static const GtkCssNumberValueClass GTK_CSS_VALUE_CALC = {
     gtk_css_value_calc_compute,
     gtk_css_value_calc_equal,
     gtk_css_number_value_transition,
+    NULL,
+    NULL,
     gtk_css_value_calc_print
   },
   gtk_css_value_calc_get,

gtk/gtkcsscolorvalue.c

@@ -449,6 +449,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_COLOR = {
   gtk_css_value_color_compute,
   gtk_css_value_color_equal,
   gtk_css_value_color_transition,
+  NULL,
+  NULL,
   gtk_css_value_color_print
 };
 

gtk/gtkcsscornervalue.c

@@ -103,6 +103,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_CORNER = {
   gtk_css_value_corner_compute,
   gtk_css_value_corner_equal,
   gtk_css_value_corner_transition,
+  NULL,
+  NULL,
   gtk_css_value_corner_print
 };
 

gtk/gtkcssdimensionvalue.c

@@ -276,6 +276,8 @@ static const GtkCssNumberValueClass GTK_CSS_VALUE_DIMENSION = {
     gtk_css_value_dimension_compute,
     gtk_css_value_dimension_equal,
     gtk_css_number_value_transition,
+    NULL,
+    NULL,
     gtk_css_value_dimension_print
   },
   gtk_css_value_dimension_get,

gtk/gtkcsseasevalue.c

@@ -139,6 +139,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_EASE = {
   gtk_css_value_ease_compute,
   gtk_css_value_ease_equal,
   gtk_css_value_ease_transition,
+  NULL,
+  NULL,
   gtk_css_value_ease_print
 };
 

gtk/gtkcssenumvalue.c

@@ -82,6 +82,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_BORDER_STYLE = {
   gtk_css_value_enum_compute,
   gtk_css_value_enum_equal,
   gtk_css_value_enum_transition,
+  NULL,
+  NULL,
   gtk_css_value_enum_print
 };
 
@@ -137,6 +139,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_BLEND_MODE = {
   gtk_css_value_enum_compute,
   gtk_css_value_enum_equal,
   gtk_css_value_enum_transition,
+  NULL,
+  NULL,
   gtk_css_value_enum_print
 };
 
@@ -285,6 +289,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_FONT_SIZE = {
   gtk_css_value_font_size_compute,
   gtk_css_value_enum_equal,
   gtk_css_value_enum_transition,
+  NULL,
+  NULL,
   gtk_css_value_enum_print
 };
 
@@ -339,6 +345,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_FONT_STYLE = {
   gtk_css_value_enum_compute,
   gtk_css_value_enum_equal,
   gtk_css_value_enum_transition,
+  NULL,
+  NULL,
   gtk_css_value_enum_print
 };
 
@@ -451,6 +459,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_FONT_WEIGHT = {
   gtk_css_value_font_weight_compute,
   gtk_css_value_enum_equal,
   gtk_css_value_font_weight_transition,
+  NULL,
+  NULL,
   gtk_css_value_enum_print
 };
 
@@ -524,6 +534,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_FONT_STRETCH = {
   gtk_css_value_enum_compute,
   gtk_css_value_enum_equal,
   gtk_css_value_enum_transition,
+  NULL,
+  NULL,
   gtk_css_value_enum_print
 };
 
@@ -578,6 +590,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_TEXT_DECORATION_LINE = {
   gtk_css_value_enum_compute,
   gtk_css_value_enum_equal,
   gtk_css_value_enum_transition,
+  NULL,
+  NULL,
   gtk_css_value_enum_print
 };
 
@@ -626,6 +640,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_TEXT_DECORATION_STYLE = {
   gtk_css_value_enum_compute,
   gtk_css_value_enum_equal,
   gtk_css_value_enum_transition,
+  NULL,
+  NULL,
   gtk_css_value_enum_print
 };
 
@@ -674,6 +690,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_AREA = {
   gtk_css_value_enum_compute,
   gtk_css_value_enum_equal,
   gtk_css_value_enum_transition,
+  NULL,
+  NULL,
   gtk_css_value_enum_print
 };
 
@@ -728,6 +746,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_DIRECTION = {
   gtk_css_value_enum_compute,
   gtk_css_value_enum_equal,
   gtk_css_value_enum_transition,
+  NULL,
+  NULL,
   gtk_css_value_enum_print
 };
 
@@ -786,6 +806,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_PLAY_STATE = {
   gtk_css_value_enum_compute,
   gtk_css_value_enum_equal,
   gtk_css_value_enum_transition,
+  NULL,
+  NULL,
   gtk_css_value_enum_print
 };
 
@@ -839,6 +861,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_FILL_MODE = {
   gtk_css_value_enum_compute,
   gtk_css_value_enum_equal,
   gtk_css_value_enum_transition,
+  NULL,
+  NULL,
   gtk_css_value_enum_print
 };
 
@@ -894,6 +918,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_ICON_STYLE = {
   gtk_css_value_enum_compute,
   gtk_css_value_enum_equal,
   gtk_css_value_enum_transition,
+  NULL,
+  NULL,
   gtk_css_value_enum_print
 };
 
@@ -948,6 +974,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_FONT_KERNING = {
   gtk_css_value_enum_compute,
   gtk_css_value_enum_equal,
   gtk_css_value_enum_transition,
+  NULL,
+  NULL,
   gtk_css_value_enum_print
 };
 
@@ -1002,6 +1030,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_FONT_VARIANT_POSITION = {
   gtk_css_value_enum_compute,
   gtk_css_value_enum_equal,
   gtk_css_value_enum_transition,
+  NULL,
+  NULL,
   gtk_css_value_enum_print
 };
 
@@ -1056,6 +1086,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_FONT_VARIANT_CAPS = {
   gtk_css_value_enum_compute,
   gtk_css_value_enum_equal,
   gtk_css_value_enum_transition,
+  NULL,
+  NULL,
   gtk_css_value_enum_print
 };
 
@@ -1114,6 +1146,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_FONT_VARIANT_ALTERNATE = {
   gtk_css_value_enum_compute,
   gtk_css_value_enum_equal,
   gtk_css_value_enum_transition,
+  NULL,
+  NULL,
   gtk_css_value_enum_print
 };
 
@@ -1225,6 +1259,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_FONT_VARIANT_LIGATURE = {
   gtk_css_value_enum_compute,
   gtk_css_value_flags_equal,
   gtk_css_value_enum_transition,
+  NULL,
+  NULL,
   gtk_css_font_variant_ligature_value_print
 };
 
@@ -1329,6 +1365,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_FONT_VARIANT_NUMERIC = {
   gtk_css_value_enum_compute,
   gtk_css_value_flags_equal,
   gtk_css_value_enum_transition,
+  NULL,
+  NULL,
   gtk_css_font_variant_numeric_value_print
 };
 
@@ -1430,6 +1468,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_FONT_VARIANT_EAST_ASIAN = {
   gtk_css_value_enum_compute,
   gtk_css_value_flags_equal,
   gtk_css_value_enum_transition,
+  NULL,
+  NULL,
   gtk_css_font_variant_east_asian_value_print
 };
 

gtk/gtkcssfiltervalue.c

@@ -697,6 +697,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_FILTER = {
   gtk_css_value_filter_compute,
   gtk_css_value_filter_equal,
   gtk_css_value_filter_transition,
+  NULL,
+  NULL,
   gtk_css_value_filter_print
 };
 

gtk/gtkcssfontfeaturesvalue.c

@@ -181,6 +181,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_FONT_FEATURES = {
   gtk_css_value_font_features_compute,
   gtk_css_value_font_features_equal,
   gtk_css_value_font_features_transition,
+  NULL,
+  NULL,
   gtk_css_value_font_features_print
 };
 

gtk/gtkcssfontvariationsvalue.c

@@ -180,6 +180,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_FONT_VARIATIONS = {
   gtk_css_value_font_variations_compute,
   gtk_css_value_font_variations_equal,
   gtk_css_value_font_variations_transition,
+  NULL,
+  NULL,
   gtk_css_value_font_variations_print
 };
 

gtk/gtkcssiconthemevalue.c

@@ -115,6 +115,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_ICON_THEME = {
   gtk_css_value_icon_theme_compute,
   gtk_css_value_icon_theme_equal,
   gtk_css_value_icon_theme_transition,
+  NULL,
+  NULL,
   gtk_css_value_icon_theme_print
 };
 

gtk/gtkcssimagevalue.c

@@ -96,6 +96,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_IMAGE = {
   gtk_css_value_image_compute,
   gtk_css_value_image_equal,
   gtk_css_value_image_transition,
+  NULL,
+  NULL,
   gtk_css_value_image_print
 };
 

gtk/gtkcssinheritvalue.c

@@ -82,6 +82,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_INHERIT = {
   gtk_css_value_inherit_compute,
   gtk_css_value_inherit_equal,
   gtk_css_value_inherit_transition,
+  NULL,
+  NULL,
   gtk_css_value_inherit_print
 };
 

gtk/gtkcssinitialvalue.c

@@ -106,6 +106,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_INITIAL = {
   gtk_css_value_initial_compute,
   gtk_css_value_initial_equal,
   gtk_css_value_initial_transition,
+  NULL,
+  NULL,
   gtk_css_value_initial_print
 };
 

gtk/gtkcsspalettevalue.c

@@ -178,6 +178,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_PALETTE = {
   gtk_css_value_palette_compute,
   gtk_css_value_palette_equal,
   gtk_css_value_palette_transition,
+  NULL,
+  NULL,
   gtk_css_value_palette_print
 };
 

gtk/gtkcsspositionvalue.c

@@ -154,6 +154,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_POSITION = {
   gtk_css_value_position_compute,
   gtk_css_value_position_equal,
   gtk_css_value_position_transition,
+  NULL,
+  NULL,
   gtk_css_value_position_print
 };
 

gtk/gtkcssrepeatvalue.c

@@ -117,6 +117,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_BACKGROUND_REPEAT = {
   gtk_css_value_repeat_compute,
   gtk_css_value_repeat_equal,
   gtk_css_value_repeat_transition,
+  NULL,
+  NULL,
   gtk_css_value_background_repeat_print
 };
 
@@ -125,6 +127,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_BORDER_REPEAT = {
   gtk_css_value_repeat_compute,
   gtk_css_value_repeat_equal,
   gtk_css_value_repeat_transition,
+  NULL,
+  NULL,
   gtk_css_value_border_repeat_print
 };
 /* BACKGROUND REPEAT */

gtk/gtkcssrgbavalue.c

@@ -102,6 +102,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_RGBA = {
   gtk_css_value_rgba_compute,
   gtk_css_value_rgba_equal,
   gtk_css_value_rgba_transition,
+  NULL,
+  NULL,
   gtk_css_value_rgba_print
 };
 

gtk/gtkcssshadowsvalue.c

@@ -204,6 +204,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_SHADOWS = {
   gtk_css_value_shadows_compute,
   gtk_css_value_shadows_equal,
   gtk_css_value_shadows_transition,
+  NULL,
+  NULL,
   gtk_css_value_shadows_print
 };
 

gtk/gtkcssshadowvalue.c

@@ -159,6 +159,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_SHADOW = {
   gtk_css_value_shadow_compute,
   gtk_css_value_shadow_equal,
   gtk_css_value_shadow_transition,
+  NULL,
+  NULL,
   gtk_css_value_shadow_print
 };
 

gtk/gtkcssstringvalue.c

@@ -121,6 +121,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_STRING = {
   gtk_css_value_string_compute,
   gtk_css_value_string_equal,
   gtk_css_value_string_transition,
+  NULL,
+  NULL,
   gtk_css_value_string_print
 };
 
@@ -129,6 +131,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_IDENT = {
   gtk_css_value_string_compute,
   gtk_css_value_string_equal,
   gtk_css_value_string_transition,
+  NULL,
+  NULL,
   gtk_css_value_ident_print
 };
 

gtk/gtkcsstransformvalue.c

@@ -707,6 +707,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_TRANSFORM = {
   gtk_css_value_transform_compute,
   gtk_css_value_transform_equal,
   gtk_css_value_transform_transition,
+  NULL,
+  NULL,
   gtk_css_value_transform_print
 };
 

gtk/gtkcssunsetvalue.c

@@ -86,6 +86,8 @@ static const GtkCssValueClass GTK_CSS_VALUE_UNSET = {
   gtk_css_value_unset_compute,
   gtk_css_value_unset_equal,
   gtk_css_value_unset_transition,
+  NULL,
+  NULL,
   gtk_css_value_unset_print
 };
 

gtk/gtkcssvalue.c

@@ -44,7 +44,7 @@ _gtk_css_value_alloc (const GtkCssValueClass *klass,
 }
 
 GtkCssValue *
-_gtk_css_value_ref (GtkCssValue *value)
+gtk_css_value_ref (GtkCssValue *value)
 {
   gtk_internal_return_val_if_fail (value != NULL, NULL);
 
@@ -54,7 +54,7 @@ _gtk_css_value_ref (GtkCssValue *value)
 }
 
 void
-_gtk_css_value_unref (GtkCssValue *value)
+gtk_css_value_unref (GtkCssValue *value)
 {
   if (value == NULL)
     return;
@@ -175,3 +175,51 @@ _gtk_css_value_print (const GtkCssValue *value,
   value->class->print (value, string);
 }
 
+/**
+ * gtk_css_value_is_dynamic:
+ * @value: a #GtkCssValue
+ *
+ * A "dynamic" value has a different value at different times. This means that
+ * the value needs to be animated when time is progressing.
+ *
+ * Examples of dynamic values are animated images, such as videos or dynamic shaders.
+ *
+ * Use gtk_css_value_get_dynamic_value() to get the value for a given timestamp.
+ *
+ * Returns %TRUE if the value is dynamic
+ */
+gboolean
+gtk_css_value_is_dynamic (GtkCssValue *value)
+{
+  gtk_internal_return_val_if_fail (value != NULL, FALSE);
+
+  if (!value->class->is_dynamic)
+    return FALSE;
+
+  return value->class->is_dynamic (value);
+}
+
+/**
+ * gtk_css_value_get_dynamic_value:
+ * @value: a #GtkCssValue
+ * @monotonic_time: the timestamp for which to get the dynamic value
+ *
+ * Gets the dynamic value for a given timestamp. If @monotonic_time is 0,
+ * the default value is returned.
+ *
+ * See gtk_css_value_is_dynamic() for details about dynamic values.
+ *
+ * Returns: (transfer full): The dynamic value for @value at the given
+ *     timestamp
+ **/
+GtkCssValue *
+gtk_css_value_get_dynamic_value (GtkCssValue *value,
+                                 gint64       monotonic_time)
+{
+  gtk_internal_return_val_if_fail (value != NULL, NULL);
+
+  if (!value->class->get_dynamic_value)
+    return gtk_css_value_ref (value);
+
+  return value->class->get_dynamic_value (value, monotonic_time);
+}

gtk/gtkcssvalueprivate.h

@@ -51,6 +51,9 @@ struct _GtkCssValueClass {
                                                        GtkCssValue                *end,
                                                        guint                       property_id,
                                                        double                      progress);
+  gboolean      (* is_dynamic)                        (GtkCssValue                *value);
+  GtkCssValue * (* get_dynamic_value)                 (GtkCssValue                *value,
+                                                       gint64                      monotonic_time);
   void          (* print)                             (const GtkCssValue          *value,
                                                        GString                    *string);
 };
@@ -61,8 +64,10 @@ GtkCssValue *_gtk_css_value_alloc                     (const GtkCssValueClass
                                                        gsize                       size);
 #define _gtk_css_value_new(_name, _klass) ((_name *) _gtk_css_value_alloc ((_klass), sizeof (_name)))
 
-GtkCssValue *_gtk_css_value_ref                       (GtkCssValue                *value);
-void         _gtk_css_value_unref                     (GtkCssValue                *value);
+#define _gtk_css_value_ref gtk_css_value_ref
+GtkCssValue *   gtk_css_value_ref                     (GtkCssValue                *value);
+#define _gtk_css_value_unref gtk_css_value_unref
+void            gtk_css_value_unref                   (GtkCssValue                *value);
 
 GtkCssValue *_gtk_css_value_compute                   (GtkCssValue                *value,
                                                        guint                       property_id,
@@ -77,6 +82,9 @@ GtkCssValue *_gtk_css_value_transition                (GtkCssValue
                                                        GtkCssValue                *end,
                                                        guint                       property_id,
                                                        double                      progress);
+gboolean        gtk_css_value_is_dynamic              (GtkCssValue                *value);
+GtkCssValue *   gtk_css_value_get_dynamic_value       (GtkCssValue                *value,
+                                                       gint64                      monotonic_time);
 
 char *       _gtk_css_value_to_string                 (const GtkCssValue          *value);
 void         _gtk_css_value_print                     (const GtkCssValue          *value,

gtk/gtkcsswin32sizevalue.c

@@ -253,6 +253,8 @@ static const GtkCssNumberValueClass GTK_CSS_VALUE_WIN32_SIZE = {
     gtk_css_value_win32_size_compute,
     gtk_css_value_win32_size_equal,
     gtk_css_number_value_transition,
+    NULL,
+    NULL,
     gtk_css_value_win32_size_print
   },
   gtk_css_value_win32_size_get,