discard tainted pixelContext

src/ol/renderer/canvas/Layer.js

@@ -120,6 +120,7 @@ class CanvasLayerRenderer extends LayerRenderer {
       pixelContext.drawImage(image, col, row, 1, 1, 0, 0, 1, 1);
       data = pixelContext.getImageData(0, 0, 1, 1).data;
     } catch (err) {
+      pixelContext = null;
       return null;
     }
     return data;

src/ol/webgl/TileTexture.js

@@ -412,6 +412,7 @@ class TileTexture extends EventTarget {
       );
       data = pixelContext.getImageData(0, 0, 1, 1).data;
     } catch (err) {
+      pixelContext = null;
       return null;
     }
     return data;