include gutter in offsets

src/ol/renderer/canvas/TileLayer.js

@@ -208,7 +208,11 @@ class CanvasTileLayerRenderer extends CanvasLayerRenderer {
             tileCoord[2] * tileSize[1])
       );
 
-      return this.getImageData(tile.getImage(), col, row);
+      const gutter = Math.round(
+        tilePixelRatio * source.getGutterForProjection(viewState.projection)
+      );
+
+      return this.getImageData(tile.getImage(), col + gutter, row + gutter);
     }
 
     return null;

src/ol/webgl/TileTexture.js

@@ -397,8 +397,19 @@ class TileTexture extends EventTarget {
 
     let data;
     const image = this.tile.getImage();
+    const gutter = Math.round(this.tilePixelRatio_ * this.gutter_);
     try {
-      pixelContext.drawImage(image, col, row, 1, 1, 0, 0, 1, 1);
+      pixelContext.drawImage(
+        image,
+        col + gutter,
+        row + gutter,
+        1,
+        1,
+        0,
+        0,
+        1,
+        1
+      );
       data = pixelContext.getImageData(0, 0, 1, 1).data;
     } catch (err) {
       return null;