Add a tilt transition

The tilt transition is like pan, only vertical instead of
horizontal.

2 files changed, 11 insertions, 0 deletions

diff --git a/presentty/rst.py b/presentty/rst.py
index e96ff21..ab06f76 100644
--- a/presentty/rst.py
+++ b/presentty/rst.py
@@ -65,6 +65,7 @@ class UrwidTranslator(docutils.nodes.GenericNodeVisitor):
     transition_map = {'dissolve': transition_mod.DissolveTransition,
                       'cut': transition_mod.CutTransition,
                       'pan': transition_mod.PanTransition,
+                      'tilt': transition_mod.TiltTransition,
                       }
 
     def __init__(self, document, palette, hinter=None, basedir='.'):
diff --git a/presentty/transition.py b/presentty/transition.py
index c699ddb..5592cd9 100644
--- a/presentty/transition.py
+++ b/presentty/transition.py
@@ -46,6 +46,16 @@ class PanTransition(Transition):
         c.pad_trim_left_right(0-offset, 0-(size[0]-offset))
         return c
 
+class TiltTransition(Transition):
+    def render(self, size, focus=False):
+        old = self.old.render((size[0], size[1]))
+        new = self.new.render((size[0], size[1]))
+        c = urwid.CanvasCombine([(old, None, False),
+                              (new, None, False)])
+        offset = int(size[1] * self.progress)
+        c.pad_trim_top_bottom(0-offset, 0-(size[1]-offset))
+        return c
+
 class DissolveTransition(Transition):
     def __init__(self, *args, **kw):
         super(DissolveTransition, self).__init__(*args, **kw)