fix #24 register_palette_entry: "hX" form with X>15

1 files changed, 14 insertions, 3 deletions

diff --git a/urwid/display_common.py b/urwid/display_common.py
index fc513f0..52b1704 100755
--- a/urwid/display_common.py
+++ b/urwid/display_common.py
@@ -816,18 +816,29 @@ class BaseScreen(object):
         if mono is None:
             mono = DEFAULT
         mono = AttrSpec(mono, DEFAULT, 1)
-        
+
         if foreground_high is None:
             foreground_high = foreground
         if background_high is None:
             background_high = background
-        high_88 = AttrSpec(foreground_high, background_high, 88)
         high_256 = AttrSpec(foreground_high, background_high, 256)
 
+        # 'hX' where X > 15 are different in 88/256 color, use
+        # basic colors for 88-color mode if high colors are specified
+        # in this way (also avoids crash when X > 87)
+        def large_h(desc):
+            if not desc.startswith('h'):
+                return False
+            num = int(desc[1:], 10)
+            return num > 15
+        if large_h(foreground_high) or large_h(background_high):
+            high_88 = basic
+        else:
+            high_88 = AttrSpec(foreground_high, background_high, 88)
+
         signals.emit_signal(self, UPDATE_PALETTE_ENTRY,
             name, basic, mono, high_88, high_256)
         self._palette[name] = (basic, mono, high_88, high_256)
-        
 
 
 def _test():