[Snippets/statShape] Handle empty shapes

Snippets/statShape.py

@@ -57,30 +57,31 @@ with cairo.SVGSurface("example.svg", hhea.advanceWidthMax, hhea.ascent-hhea.desc
 
     ellipse_area = math.sqrt(lambda1) * math.sqrt(lambda2) * math.pi/4 * mult * mult
 
-    context.save()
-    context.set_line_cap(cairo.LINE_CAP_ROUND)
-    context.transform(transform)
-    context.move_to(0, 0)
-    context.line_to(0, 0)
-    context.set_line_width(1)
-    context.set_source_rgba(1, 0, 0, abs(stats.area / ellipse_area))
-    context.stroke()
-    context.restore()
+    if stats.area:
+        context.save()
+        context.set_line_cap(cairo.LINE_CAP_ROUND)
+        context.transform(transform)
+        context.move_to(0, 0)
+        context.line_to(0, 0)
+        context.set_line_width(1)
+        context.set_source_rgba(1, 0, 0, abs(stats.area / ellipse_area))
+        context.stroke()
+        context.restore()
 
-    context.save()
-    context.set_line_cap(cairo.LINE_CAP_ROUND)
-    context.set_source_rgb(.8, 0, 0)
-    context.translate(stats.meanX, stats.meanY)
+        context.save()
+        context.set_line_cap(cairo.LINE_CAP_ROUND)
+        context.set_source_rgb(.8, 0, 0)
+        context.translate(stats.meanX, stats.meanY)
 
-    context.move_to(0, 0)
-    context.line_to(0, 0)
-    context.set_line_width(15)
-    context.stroke()
+        context.move_to(0, 0)
+        context.line_to(0, 0)
+        context.set_line_width(15)
+        context.stroke()
 
-    context.transform(cairo.Matrix(1, 0, stats.slant, 1, 0, 0))
-    context.move_to(0, -stats.meanY + font['hhea'].ascent)
-    context.line_to(0, -stats.meanY + font['hhea'].descent)
-    context.set_line_width(5)
-    context.stroke()
+        context.transform(cairo.Matrix(1, 0, stats.slant, 1, 0, 0))
+        context.move_to(0, -stats.meanY + font['hhea'].ascent)
+        context.line_to(0, -stats.meanY + font['hhea'].descent)
+        context.set_line_width(5)
+        context.stroke()
 
-    context.restore()
+        context.restore()