From 3b2ca7d15ae4313102a70315e657f0e05db8b977 Mon Sep 17 00:00:00 2001
From: David Manthey <david.manthey@kitware.com>
Date: Tue, 21 Aug 2018 09:29:22 -0400
Subject: [PATCH] When tiles have overlap, rendering cropped tiles could throw
 an error.

This happened on IE11.  By ensuring we don't ask to crop to a size
larger than the image, it works properly.
---
 src/canvas/quadFeature.js | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/canvas/quadFeature.js b/src/canvas/quadFeature.js
index 37fd20e89e..fa8c07e522 100644
--- a/src/canvas/quadFeature.js
+++ b/src/canvas/quadFeature.js
@@ -174,8 +174,11 @@ var canvas_quadFeature = function (arg) {
         if (!quad.crop) {
           context2d.drawImage(src, 0, 0);
         } else {
-          context2d.drawImage(src, 0, 0, quad.crop.x, quad.crop.y, 0, 0,
-                              quad.crop.x, quad.crop.y);
+          var cropx = Math.min(src.w, quad.crop.x),
+              cropy = Math.min(src.h, quad.crop.y);
+          if (cropx > 0 && cropy > 0) {
+            context2d.drawImage(src, 0, 0, cropx, cropy, 0, 0, cropx, cropy);
+          }
         }
       });
     });