Make sure the margins are not smaller than the defaults
diff --git a/visualmetrics.py b/visualmetrics.py
index 12de902..03e7ecf 100755
--- a/visualmetrics.py
+++ b/visualmetrics.py
@@ -598,9 +598,9 @@
right_margin = 8
bottom_margin = 20
if height > 400 or width > 400:
- top = int(math.ceil(float(height) * 0.04))
- right_margin = int(math.ceil(float(width) * 0.04))
- bottom_margin = int(math.ceil(float(width) * 0.04))
+ top = max(top, int(math.ceil(float(height) * 0.04)))
+ right_margin = max( right_margin, int(math.ceil(float(width) * 0.04)))
+ bottom_margin = max(bottom_margin, int(math.ceil(float(width) * 0.04)))
height = max(height - top - bottom_margin, 1)
left = 0
width = max(width - right_margin, 1)
