[pitivi] effects: Allow custom property widgets when auto-generating UI of effects

[Alexandru Băluț <alexbalut src gnome org>]

commit 495359ba15749d781292e62deae91565c72f285f
Author: Suhas Nayak <suhas2go gmail com>
Date:   Thu Jul 6 03:21:22 2017 +0530

    effects: Allow custom property widgets when auto-generating UI of effects
    
    Differential Revision: https://phabricator.freedesktop.org/D1777

 pitivi/effects.py                     |   15 ++++++++++++++-
 pitivi/utils/custom_effect_widgets.py |   15 +++++++++++++++
 pitivi/utils/widgets.py               |    7 ++++---
 3 files changed, 33 insertions(+), 4 deletions(-)
---
diff --git a/pitivi/effects.py b/pitivi/effects.py
index 6897051..29d2f86 100644
--- a/pitivi/effects.py
+++ b/pitivi/effects.py
@@ -583,16 +583,24 @@ class EffectsPropertiesManager(GObject.Object, Loggable):
     __gsignals__ = {
         "create_widget": (GObject.SIGNAL_RUN_LAST, Gtk.Widget, (GstElementSettingsWidget, GES.Effect,),
                           create_widget_accumulator),
+        "create_property_widget": (
+            GObject.SIGNAL_RUN_LAST, object, (GstElementSettingsWidget, GES.Effect, object, object,),
+            create_widget_accumulator),
     }
 
     def do_create_widget(self, effect_widget, effect):
         """Creates a widget if the `create_widget` handlers did not."""
         effect_name = effect.get_property("bin-description")
         self.log('UI is being auto-generated for "%s"', effect_name)
-        effect_widget.add_widgets(with_reset_button=True)
+        effect_widget.add_widgets(create_property_widget=self.create_property_widget, with_reset_button=True)
         self._postConfiguration(effect, effect_widget)
         return None
 
+    def do_create_property_widget(self, effect_widget, effect, prop, prop_value):
+        """Creates a widget if the `create_property_widget` handlers did not."""
+        widget = effect_widget.make_property_widget(prop, prop_value)
+        return widget
+
     def __init__(self, app):
         GObject.Object.__init__(self)
         Loggable.__init__(self)
@@ -659,3 +667,8 @@ class EffectsPropertiesManager(GObject.Object, Loggable):
                                              toplevel=True):
                 effect.set_child_property(prop.name, value)
             self._current_element_values[prop.name] = value
+
+    def create_property_widget(self, element_settings_widget, prop, prop_value):
+        prop_widget = self.emit("create_property_widget", element_settings_widget, 
element_settings_widget.element,
+                                prop, prop_value)
+        return prop_widget
diff --git a/pitivi/utils/custom_effect_widgets.py b/pitivi/utils/custom_effect_widgets.py
index 3b34b5d..ebcdb14 100644
--- a/pitivi/utils/custom_effect_widgets.py
+++ b/pitivi/utils/custom_effect_widgets.py
@@ -30,6 +30,7 @@ CUSTOM_WIDGETS_DIR = os.path.join(configure.get_ui_dir(), "customwidgets")
 def setup_custom_effect_widgets(effect_prop_manager):
     """Sets up the specified effects manager to be able to create custom UI."""
     effect_prop_manager.connect("create_widget", create_custom_widget_cb)
+    effect_prop_manager.connect("create_property_widget", create_custom_prop_widget_cb)
 
 
 def setup_from_ui_file(element_setting_widget, path):
@@ -42,6 +43,13 @@ def setup_from_ui_file(element_setting_widget, path):
     return builder
 
 
+def create_custom_prop_widget_cb(unused_effect_prop_manager, effect_widget, effect, prop, prop_value):
+    """Creates custom effect property UI."""
+    effect_name = effect.get_property("bin-description")
+    if effect_name == "alpha":
+        return create_custom_alpha_prop_widget(effect_widget, effect, prop, prop_value)
+
+
 def create_custom_widget_cb(unused_effect_prop_manager, effect_widget, effect):
     """Creates custom effect UI."""
     effect_name = effect.get_property("bin-description")
@@ -58,4 +66,11 @@ def create_custom_widget_cb(unused_effect_prop_manager, effect_widget, effect):
 
 def create_alpha_widget(unused_element_setting_widget, unused_element):
     """Not implemented yet."""
+    # Main alpha widget would go here
+    return None
+
+
+def create_custom_alpha_prop_widget(unused_element_setting_widget, unused_element, unused_prop, 
unused_prop_value):
+    """Not implemented yet."""
+    # In the auto-generated UI, replace a property widget with a custom one
     return None
diff --git a/pitivi/utils/widgets.py b/pitivi/utils/widgets.py
index 09465e4..2d35724 100644
--- a/pitivi/utils/widgets.py
+++ b/pitivi/utils/widgets.py
@@ -813,7 +813,7 @@ class GstElementSettingsWidget(Gtk.Box, Loggable):
             props = GObject.list_properties(self.element)
         return [prop for prop in props if prop.name not in self.ignore]
 
-    def add_widgets(self, values={}, with_reset_button=False):
+    def add_widgets(self, create_property_widget, values={}, with_reset_button=False):
         """Prepares a Gtk.Grid containing the property widgets of an element.
 
         Each property is on a separate row.
@@ -822,6 +822,7 @@ class GstElementSettingsWidget(Gtk.Box, Loggable):
         If there are no properties, returns a "No properties" label.
 
         Args:
+            create_property_widget (function): The function that gets the widget for an effect property.
             values (dict): The current values of the element props, by name.
                 If empty, the default values will be used.
             with_reset_button (bool): Whether to show a reset button for each
@@ -869,7 +870,7 @@ class GstElementSettingsWidget(Gtk.Box, Loggable):
                 else:
                     prop_value = values[prop.name]
 
-            prop_widget = self._makePropertyWidget(prop, prop_value)
+            prop_widget = create_property_widget(self, prop, prop_value)
             element_name = None
             if isinstance(self.element, Gst.Element):
                 element_name = self.element.get_factory().get_name()
@@ -1038,7 +1039,7 @@ class GstElementSettingsWidget(Gtk.Box, Loggable):
                 values[prop.name] = value
         return values
 
-    def _makePropertyWidget(self, prop, value=None):
+    def make_property_widget(self, prop, value=None):
         """Creates a widget for the specified element property."""
         type_name = GObject.type_name(prop.value_type.fundamental)
         if type_name == "gchararray":