Make bulleted lists more robust0.2.1

Errors in pack methods could cause urwid to throw an exception
when rendering bullet lists which line-wrapped.

1 files changed, 14 insertions, 1 deletions

diff --git a/presentty/slide.py b/presentty/slide.py
index 4894f45..06860fc 100644
--- a/presentty/slide.py
+++ b/presentty/slide.py
@@ -20,6 +20,10 @@ class SlidePile(urwid.Pile):
         cols = 0
         rows = 0
         for x in self.contents:
+            # If we have no columns to use, we won't render, so don't
+            # erroneously accumulate rows.
+            if not size[0]:
+                continue
             c,r = x[0].pack((size[0],))
             if c>cols:
                 cols = c
@@ -35,16 +39,25 @@ class SlidePadding(urwid.Padding):
 
 class SlideColumns(urwid.Columns):
     def pack(self, size, focus=False):
+        # Unlike the normal Columns widget, find the mininum number of
+        # (character) columns necessary to render.  This probably only
+        # works for the limited 2-column case we have for bulleted
+        # lists.
+        # cols is the resulting number of columns needed
         cols = self.dividechars * (len(self.contents)-1)
         rows = 0
+        # Given our current width, col_budget is the number of columns
+        # remaining available.
+        col_budget = size[0]-cols
         for widget, packing in self.contents:
             if packing[0] == 'given':
                 allocated_cols = packing[1]
             else:
-                allocated_cols = size[0]
+                allocated_cols = col_budget
             c,r = widget.pack((allocated_cols,))
             if packing[0] == 'given':
                 c = allocated_cols
+            col_budget -= c
             if r>rows:
                 rows = r
             cols += c