From 6de566d95b316547942ee2bd97b7cb4177a5893a Mon Sep 17 00:00:00 2001
From: Frederic Junod <frederic.junod@camptocamp.com>
Date: Fri, 8 Mar 2019 13:19:17 +0100
Subject: [PATCH] Set the canvas size to 0 on dispose

---
 src/ol/render/canvas/ExecutorGroup.js     | 2 ++
 src/ol/renderer/canvas/Layer.js           | 8 ++++++++
 src/ol/renderer/canvas/VectorTileLayer.js | 1 +
 3 files changed, 11 insertions(+)

diff --git a/src/ol/render/canvas/ExecutorGroup.js b/src/ol/render/canvas/ExecutorGroup.js
index 60c03c08df..e14a9e9c14 100644
--- a/src/ol/render/canvas/ExecutorGroup.js
+++ b/src/ol/render/canvas/ExecutorGroup.js
@@ -143,6 +143,8 @@ class ExecutorGroup extends Disposable {
         executors[key].disposeInternal();
       }
     }
+    const canvas = this.hitDetectionContext_.canvas;
+    canvas.width = canvas.height = 0;
     super.disposeInternal();
   }
 
diff --git a/src/ol/renderer/canvas/Layer.js b/src/ol/renderer/canvas/Layer.js
index 6417f7807a..aa7531c0f0 100644
--- a/src/ol/renderer/canvas/Layer.js
+++ b/src/ol/renderer/canvas/Layer.js
@@ -63,6 +63,14 @@ class CanvasLayerRenderer extends LayerRenderer {
     canvas.className = this.getLayer().getClassName();
   }
 
+  /**
+   * @inheritDoc
+   */
+  disposeInternal() {
+    this.context.canvas.width = this.context.canvas.height = 0;
+    super.disposeInternal();
+  }
+
   /**
    * @param {CanvasRenderingContext2D} context Context.
    * @param {import("../../PluggableMap.js").FrameState} frameState Frame state.
diff --git a/src/ol/renderer/canvas/VectorTileLayer.js b/src/ol/renderer/canvas/VectorTileLayer.js
index 78e3bf2f6d..d10c9c5fdc 100644
--- a/src/ol/renderer/canvas/VectorTileLayer.js
+++ b/src/ol/renderer/canvas/VectorTileLayer.js
@@ -152,6 +152,7 @@ class CanvasVectorTileLayerRenderer extends CanvasTileLayerRenderer {
    */
   disposeInternal() {
     unlisten(labelCache, EventType.CLEAR, this.handleFontsChanged_, this);
+    this.overlayContext_.canvas.width = this.overlayContext_.canvas.height = 0;
     super.disposeInternal();
   }