Deprecate the imageSmoothing option for sources

src/ol/source/ImageCanvas.js

@@ -36,7 +36,9 @@ import {
  * the value returned by the function is later changed then
  * `changed` should be called on the source for the source to
  * invalidate the current cached image. See: {@link module:ol/Observable~Observable#changed}
- * @property {boolean} [imageSmoothing=true] Enable image smoothing.
+ * @property {boolean} [imageSmoothing=true] Deprecated.  Use the `interpolate` option instead.
+ * @property {boolean} [interpolate=true] Use interpolated values when resampling.  By default,
+ * linear interpolation is used when resampling.  Set to false to use the nearest neighbor instead.
  * @property {import("../proj.js").ProjectionLike} [projection] Projection. Default is the view projection.
  * @property {number} [ratio=1.5] Ratio. 1 means canvases are the size of the map viewport, 2 means twice the
  * width and height of the map viewport, and so on. Must be `1` or higher.
@@ -57,9 +59,15 @@ class ImageCanvasSource extends ImageSource {
   constructor(opt_options) {
     const options = opt_options ? opt_options : {};
 
+    let interpolate =
+      options.imageSmoothing !== undefined ? options.imageSmoothing : true;
+    if (options.interpolate !== undefined) {
+      interpolate = options.interpolate;
+    }
+
     super({
       attributions: options.attributions,
-      imageSmoothing: options.imageSmoothing,
+      interpolate: interpolate,
       projection: options.projection,
       resolutions: options.resolutions,
       state: options.state,