[meld] gutterrendererchunk: Improve escape checks for chunk drawing

[Kai Willadsen <kaiw src gnome org>]

commit d7aca32d40352e029cd6ee9af2acd3e2397a818f
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Sun Sep 25 11:11:24 2016 +1000

    gutterrendererchunk: Improve escape checks for chunk drawing

 meld/gutterrendererchunk.py |   60 +++++++++++++++++++++++--------------------
 1 files changed, 32 insertions(+), 28 deletions(-)
---
diff --git a/meld/gutterrendererchunk.py b/meld/gutterrendererchunk.py
index 4ba672b..11c2ecb 100644
--- a/meld/gutterrendererchunk.py
+++ b/meld/gutterrendererchunk.py
@@ -48,37 +48,41 @@ class MeldGutterRenderer(object):
         line = start.get_line()
         chunk_index = self.linediffer.locate_chunk(self.from_pane, line)[0]
 
+        if chunk_index is None:
+            return
+
+        chunk = self.linediffer.get_chunk(
+            chunk_index, self.from_pane, self.to_pane)
+        if not chunk:
+            return
+
+        x = background_area.x - 1
+        y = background_area.y
+        width = background_area.width + 2
+        height = 1 if chunk[1] == chunk[2] else background_area.height
+
         context.save()
         context.set_line_width(1.0)
 
-        if chunk_index is not None:
-            chunk = self.linediffer.get_chunk(
-                chunk_index, self.from_pane, self.to_pane)
+        context.rectangle(x, y, width, height)
+        context.set_source_rgba(*self.fill_colors[chunk[0]])
+
+        if self.props.view.current_chunk_check(chunk):
+            context.fill_preserve()
+            highlight = self.fill_colors['current-chunk-highlight']
+            context.set_source_rgba(*highlight)
+        context.fill()
+
+        if line == chunk[1] or line == chunk[2] - 1:
+            context.set_source_rgba(*self.line_colors[chunk[0]])
+            if line == chunk[1]:
+                context.move_to(x, y + 0.5)
+                context.rel_line_to(width, 0)
+            if line == chunk[2] - 1:
+                context.move_to(x, y - 0.5 + height)
+                context.rel_line_to(width, 0)
+            context.stroke()
 
-            if chunk:
-                x = background_area.x - 1
-                width = background_area.width + 2
-
-                height = 1 if chunk[1] == chunk[2] else background_area.height
-                y = background_area.y
-                context.rectangle(x, y, width, height)
-                context.set_source_rgba(*self.fill_colors[chunk[0]])
-
-                if self.props.view.current_chunk_check(chunk):
-                    context.fill_preserve()
-                    highlight = self.fill_colors['current-chunk-highlight']
-                    context.set_source_rgba(*highlight)
-                context.fill()
-
-                if line == chunk[1] or line == chunk[2] - 1:
-                    context.set_source_rgba(*self.line_colors[chunk[0]])
-                    if line == chunk[1]:
-                        context.move_to(x, y + 0.5)
-                        context.rel_line_to(width, 0)
-                    if line == chunk[2] - 1:
-                        context.move_to(x, y - 0.5 + height)
-                        context.rel_line_to(width, 0)
-                    context.stroke()
         context.restore()