From 39a4f42e3d673d9bcc4b322cf907d8672c8cb4f7 Mon Sep 17 00:00:00 2001
From: Tim Schaub <tim.schaub@gmail.com>
Date: Wed, 14 Nov 2018 15:47:26 +0100
Subject: [PATCH] Resize canvas to handle rotation

---
 src/ol/renderer/canvas/IntermediateCanvas.js | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/ol/renderer/canvas/IntermediateCanvas.js b/src/ol/renderer/canvas/IntermediateCanvas.js
index 27e325f132..fe4c4ddc98 100644
--- a/src/ol/renderer/canvas/IntermediateCanvas.js
+++ b/src/ol/renderer/canvas/IntermediateCanvas.js
@@ -127,8 +127,14 @@ class IntermediateCanvasRenderer extends CanvasLayerRenderer {
   clear(frameState) {
     const pixelRatio = frameState.pixelRatio;
     const canvas = this.layerContext.canvas;
-    const width = Math.round(frameState.size[0] * pixelRatio);
-    const height = Math.round(frameState.size[1] * pixelRatio);
+
+    let width = Math.round(frameState.size[0] * pixelRatio);
+    let height = Math.round(frameState.size[1] * pixelRatio);
+    const rotation = frameState.viewState.rotation;
+    if (rotation) {
+      const size = Math.round(Math.sqrt(width * width + height * height));
+      width = height = size;
+    }
 
     if (canvas.width != width || canvas.height != height) {
       canvas.width = width;