Deprecate the imageSmoothing option for sources

src/ol/source/Stamen.js

@@ -87,7 +87,9 @@ const ProviderConfig = {
 /**
  * @typedef {Object} Options
  * @property {number} [cacheSize] Initial tile cache size. Will auto-grow to hold at least the number of tiles in the viewport.
- * @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 {string} layer Layer name.
  * @property {number} [minZoom] Minimum zoom.
  * @property {number} [maxZoom] Maximum zoom.
@@ -119,6 +121,12 @@ class Stamen extends XYZ {
    * @param {Options} options Stamen options.
    */
   constructor(options) {
+    let interpolate =
+      options.imageSmoothing !== undefined ? options.imageSmoothing : true;
+    if (options.interpolate !== undefined) {
+      interpolate = options.interpolate;
+    }
+
     const i = options.layer.indexOf('-');
     const provider = i == -1 ? options.layer : options.layer.slice(0, i);
     const providerConfig = ProviderConfig[provider];
@@ -137,7 +145,7 @@ class Stamen extends XYZ {
       attributions: ATTRIBUTIONS,
       cacheSize: options.cacheSize,
       crossOrigin: 'anonymous',
-      imageSmoothing: options.imageSmoothing,
+      interpolate: interpolate,
       maxZoom:
         options.maxZoom != undefined ? options.maxZoom : providerConfig.maxZoom,
       minZoom: