From 60a9abbf8f96a20b6ed8a21365fbefa4520bd4a9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89ric=20Lemoine?= <eric.lemoine@oslandia.com>
Date: Thu, 11 Apr 2019 10:36:15 +0200
Subject: [PATCH] Clear context when source revision changed

This is to avoid rendering artifacts when making a layer invisible,
changing its source's PARAMS, and making the layer visible again.
---
 src/ol/renderer/canvas/TileLayer.js | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/ol/renderer/canvas/TileLayer.js b/src/ol/renderer/canvas/TileLayer.js
index 4299e4d39f..680e5ba80b 100644
--- a/src/ol/renderer/canvas/TileLayer.js
+++ b/src/ol/renderer/canvas/TileLayer.js
@@ -234,7 +234,8 @@ class CanvasTileLayerRenderer extends IntermediateCanvasRenderer {
           canvas.width = width;
           canvas.height = height;
         } else {
-          if (this.renderedExtent_ && !equals(imageExtent, this.renderedExtent_)) {
+          if ((this.renderedExtent_ && !equals(imageExtent, this.renderedExtent_)) ||
+              this.renderedRevision != sourceRevision) {
             context.clearRect(0, 0, width, height);
           }
           oversampling = this.oversampling_;