From f6061f0589b8123105e4a88d7c478b5e0e2b5f84 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?St=C3=A9phane=20Brunner?= <stephane.brunner@camptocamp.com>
Date: Fri, 17 Jul 2020 11:22:26 +0200
Subject: [PATCH] Don't creates too many canvas

---
 src/ol/style/IconImage.js | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/src/ol/style/IconImage.js b/src/ol/style/IconImage.js
index 80c46684a3..a5f7793e0a 100644
--- a/src/ol/style/IconImage.js
+++ b/src/ol/style/IconImage.js
@@ -77,6 +77,11 @@ class IconImage extends EventTarget {
      * @private
      */
     this.tainted_;
+
+    /**
+     * @private
+     */
+    this.taintedTestContext_;
   }
 
   /**
@@ -85,12 +90,15 @@ class IconImage extends EventTarget {
    */
   isTainted_() {
     if (this.tainted_ === undefined && this.imageState_ === ImageState.LOADED) {
-      const context = createCanvasContext2D(1, 1);
-      context.drawImage(this.image_, 0, 0);
+      if (!this.taintedTestContext_) {
+        this.taintedTestContext_ = createCanvasContext2D(1, 1);
+      }
+      this.taintedTestContext_.drawImage(this.image_, 0, 0);
       try {
-        context.getImageData(0, 0, 1, 1);
+        this.taintedTestContext_.getImageData(0, 0, 1, 1);
         this.tainted_ = false;
       } catch (e) {
+        this.taintedTestContext_ = undefined;
         this.tainted_ = true;
       }
     }