Add a slider to change the triangle size

1 files changed, 41 insertions, 6 deletions

diff --git a/PascalTriangle.activity/pascaltriangle.py b/PascalTriangle.activity/pascaltriangle.py
index f087ec1..2463cf0 100755
--- a/PascalTriangle.activity/pascaltriangle.py
+++ b/PascalTriangle.activity/pascaltriangle.py
@@ -64,8 +64,30 @@ class PascalTriangleActivity(activity.Activity):
                              self._drawing_area_key_press_cb, None)
         drawing_area.connect('draw', self._drawing_area_draw_cb, None)
 
+        # Create an overlay and a slider to allow the triangle size to be
+        # adjusted. This is the number of cells on the triangle's base
+        # (equivalently, the number of rows in the triangle).
+        overlay = Gtk.Overlay()
+        overlay.connect('get-child-position', self._adjustment_get_position_cb,
+                        None)
+        overlay.show()
+        overlay.add(drawing_area)
+
+        slider = Gtk.VScale()
+        slider.props.digits = 0 # integers only
+        slider.props.draw_value = False
+        slider.props.has_origin = False
+        slider.set_range(2, 10)
+        slider.set_increments(1, 2)
+        slider.set_value(5) # initial triangle size
+        slider.show()
+        overlay.add_overlay(slider)
+
+        self._triangle_size = int(slider.get_value())
+        slider.connect('value-changed', self._slider_value_changed_cb, None)
+
         # Parent and show the drawing area.
-        self.set_canvas(drawing_area)
+        self.set_canvas(overlay)
         drawing_area.show()
         self._drawing_area = drawing_area
 
@@ -89,11 +111,6 @@ class PascalTriangleActivity(activity.Activity):
             self.remove_alert(self._alert)
             self._alert = None
 
-        # Set the initial size of the Pascal triangle to be drawn. This is
-        # the number of cells on its base (equivalently, the number of rows in
-        # the triangle).
-        self._triangle_size = 5
-
         # Padding around the edge of the drawing area.
         self._padding = 10.0 # Cairo units
 
@@ -385,6 +402,24 @@ class PascalTriangleActivity(activity.Activity):
     show_hints = property(get_show_hints, set_show_hints)
 
 
+    def _adjustment_get_position_cb(self, overlay, child, alloc, data = None):
+        # Hard-code the size and position of the triangle size slider.
+        alloc.x = 10
+        alloc.y = 10
+        alloc.width = 70
+        alloc.height = 150
+
+        return True
+
+    def _slider_value_changed_cb(self, widget, data = None):
+        new_triangle_size = int(widget.get_value())
+
+        if new_triangle_size != self._triangle_size:
+            # Start a new game with the new triangle size.
+            self._triangle_size = new_triangle_size
+            self._start_game()
+
+
 class NewGameButton(ToolButton):
     def __init__(self, activity, **kwargs):
         ToolButton.__init__(self, 'add', **kwargs)