[pyclutter] examples: Clutter.ScrollActor demo

[Emmanuele Bassi <ebassi src gnome org>]

commit a968ab9f4429d42ffeb25e71cbaa80df8ae88fe0
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Wed Apr 15 16:36:45 2015 +0100

    examples: Clutter.ScrollActor demo

 examples/Makefile.am     |    3 +-
 examples/scroll-actor.py |  123 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 125 insertions(+), 1 deletions(-)
---
diff --git a/examples/Makefile.am b/examples/Makefile.am
index eb0280d..0bffc87 100644
--- a/examples/Makefile.am
+++ b/examples/Makefile.am
@@ -3,4 +3,5 @@ EXTRA_DIST = \
        canvas.py \
        constraints.py \
        layout-manager.py \
-       rounded-rectangle.py
+       rounded-rectangle.py \
+       scroll-actor.py
diff --git a/examples/scroll-actor.py b/examples/scroll-actor.py
new file mode 100644
index 0000000..2ea799d
--- /dev/null
+++ b/examples/scroll-actor.py
@@ -0,0 +1,123 @@
+from gi.repository import Clutter
+
+class MenuItem(Clutter.Text):
+    def __init__(self, label=''):
+        Clutter.Text.__init__(self)
+        self.props.font_name = 'Sans Bold 24'
+        self.props.text = label
+        self.props.color = Clutter.Color.get_static(Clutter.StaticColor.WHITE)
+        self.props.margin_left = 12
+        self.props.margin_right = 12
+
+class Menu(Clutter.Actor):
+    def __init__(self):
+        Clutter.Actor.__init__(self)
+
+        layout = Clutter.BoxLayout(orientation=Clutter.Orientation.VERTICAL, spacing=12)
+        self.props.layout_manager = layout
+        self.props.background_color = Clutter.Color.get_static(Clutter.StaticColor.BLACK)
+
+        self._current_idx = 0
+
+    def select_next(self):
+        old_item = self.get_child_at_index(self._current_idx)
+        old_item.props.color = Clutter.Color.get_static(Clutter.StaticColor.WHITE)
+
+        self._current_idx += 1
+
+        if self._current_idx == self.get_n_children():
+            self._current_idx = 0
+
+        new_item = self.get_child_at_index(self._current_idx)
+        new_item.props.color = Clutter.Color.get_static(Clutter.StaticColor.SKY_BLUE_LIGHT)
+        return new_item
+
+    def select_prev(self):
+        old_item = self.get_child_at_index(self._current_idx)
+        old_item.props.color = Clutter.Color.get_static(Clutter.StaticColor.WHITE)
+
+        self._current_idx -= 1
+
+        if self._current_idx < 0:
+            self._current_idx = self.get_n_children() - 1;
+
+        new_item = self.get_child_at_index(self._current_idx)
+        new_item.props.color = Clutter.Color.get_static(Clutter.StaticColor.SKY_BLUE_LIGHT)
+        return new_item
+
+def create_menu_actor(scroll):
+    menu = Menu()
+    scroll.add_child(menu)
+
+    menu_items = [
+        'Option 1',
+        'Option 2',
+        'Option 3',
+        'Option 4',
+        'Option 5',
+        'Option 6',
+        'Option 7',
+        'Option 8',
+        'Option 9',
+        'Option 10',
+        'Option 11',
+        'Option 12'
+    ]
+
+    for label in menu_items:
+        menu.add_child(MenuItem(label))
+
+def create_scroll_actor(stage):
+    scroll = Clutter.ScrollActor(name='scroll')
+    scroll.set_position(0, 18)
+    scroll.add_constraint(Clutter.AlignConstraint(source=stage, align_axis=Clutter.AlignAxis.X_AXIS, 
factor=0.5))
+    scroll.add_constraint(Clutter.BindConstraint(source=stage, coordinate=Clutter.BindCoordinate.HEIGHT, 
offset=-36))
+    scroll.set_scroll_mode(Clutter.ScrollMode.VERTICALLY)
+    scroll.set_easing_duration(250)
+
+    create_menu_actor(scroll)
+
+    stage.add_child(scroll)
+
+def scroll_to_item(scroll, item):
+    pos = Clutter.Point()
+    pos.x, pos.y = item.get_position()
+    scroll.scroll_to_point(pos)
+
+def select_prev_item(scroll):
+    menu = scroll.get_first_child()
+    item = menu.select_prev()
+    scroll_to_item(scroll, item)
+
+def select_next_item(scroll):
+    menu = scroll.get_first_child()
+    item = menu.select_next()
+    scroll_to_item(scroll, item)
+
+def on_key_press(stage, event):
+    scroll = stage.get_first_child()
+    key = event.keyval
+
+    if key == Clutter.KEY_q:
+        Clutter.main_quit()
+        return True
+
+    if key == Clutter.KEY_Up:
+        select_prev_item(scroll)
+        return True
+
+    if key == Clutter.KEY_Down:
+        select_next_item(scroll)
+        return True
+
+    return False
+
+if __name__ == '__main__':
+    stage = Clutter.Stage(title='Scroll Actor', user_resizable=True)
+    stage.connect('destroy', Clutter.main_quit)
+    stage.connect('key-press-event', on_key_press)
+    stage.show()
+
+    create_scroll_actor(stage)
+
+    Clutter.main()