Make zDirection configurable on tile source

src/ol/renderer/canvas/TileLayer.js

@@ -63,12 +63,6 @@ class CanvasTileLayerRenderer extends CanvasLayerRenderer {
      * @type {import("../../TileRange.js").default}
      */
     this.tmpTileRange_ = new TileRange(0, 0, 0, 0);
-
-    /**
-     * @protected
-     * @type {number}
-     */
-    this.zDirection = 0;
   }
 
   /**
@@ -151,8 +145,7 @@ class CanvasTileLayerRenderer extends CanvasLayerRenderer {
     const tileSource = tileLayer.getSource();
     const sourceRevision = tileSource.getRevision();
     const tileGrid = tileSource.getTileGridForProjection(projection);
-    const zDirection = tileSource.zDirection === undefined ? this.zDirection : tileSource.zDirection;
-    const z = tileGrid.getZForResolution(viewResolution, zDirection);
+    const z = tileGrid.getZForResolution(viewResolution, tileSource.zDirection);
     const tileResolution = tileGrid.getResolution(z);
     let extent = frameState.extent;
 

src/ol/renderer/canvas/VectorTileLayer.js

@@ -113,8 +113,6 @@ class CanvasVectorTileLayerRenderer extends CanvasTileLayerRenderer {
      */
     this.tmpTransform_ = createTransform();
 
-    // Use nearest lower resolution.
-    this.zDirection = 1;
   }
 
   /**

src/ol/source/BingMaps.js

@@ -269,7 +269,8 @@ class BingMaps extends TileImage {
         const attributions = [];
         const viewState = frameState.viewState;
         const tileGrid = this.getTileGrid();
-        const tileCoord = tileGrid.getTileCoordForCoordAndResolution(viewState.center, viewState.resolution);
+        const z = tileGrid.getZForResolution(viewState.resolution, this.zDirection);
+        const tileCoord = tileGrid.getTileCoordForCoordAndZ(viewState.center, z);
         const zoom = tileCoord[0];
         resource.imageryProviders.map(function(imageryProvider) {
           let intersecting = false;

src/ol/source/IIIF.js

@@ -40,8 +40,8 @@ import TileImage from './TileImage.js';
  * @property {string} [url] Base URL of the IIIF Image service.
  * This should be the same as the IIIF Image ID.
  * @property {Versions} [version=Versions.VERSION2] Service's IIIF Image API version.
- * @property {number} [zDirection] Indicate which resolution should be used
- * by a renderer if the views resolution does not match any resolution of the tile source.
+ * @property {number} [zDirection=0] Indicate which resolution should be used
+ * by a renderer if the view resolution does not match any resolution of the tile source.
  * If 0, the nearest resolution will be used. If 1, the nearest lower resolution
  * will be used. If -1, the nearest higher resolution will be used.
  */

src/ol/source/Tile.js

@@ -24,6 +24,7 @@ import {wrapX, getForProjection as getTileGridForProjection} from '../tilegrid.j
  * @property {boolean} [wrapX=true]
  * @property {number} [transition]
  * @property {string} [key]
+ * @property {number} [zDirection=0]
  */
 
 
@@ -110,9 +111,9 @@ class TileSource extends Source {
      * by a renderer if the views resolution does not match any resolution of the tile source.
      * If 0, the nearest resolution will be used. If 1, the nearest lower resolution
      * will be used. If -1, the nearest higher resolution will be used.
-     * @type {number=}
+     * @type {number}
      */
-    this.zDirection;
+    this.zDirection = options.zDirection ? options.zDirection : 0;
   }
 
   /**

src/ol/source/TileDebug.js

@@ -80,6 +80,11 @@ class LabeledTile extends Tile {
  * @property {import("../proj.js").ProjectionLike} [projection='EPSG:3857'] Optional projection.
  * @property {import("../tilegrid/TileGrid.js").default} [tileGrid] Tile grid.
  * @property {boolean} [wrapX=true] Whether to wrap the world horizontally.
+ * @property {number} [zDirection=0] Set to `1` when debugging `VectorTile` sources with
+ * a default configuration. Indicates which resolution should be used by a renderer if
+ * the view resolution does not match any resolution of the tile source. If 0, the nearest
+ * resolution will be used. If 1, the nearest lower resolution will be used. If -1, the
+ * nearest higher resolution will be used.
  */
 
 
@@ -106,7 +111,8 @@ class TileDebug extends XYZ {
       opaque: false,
       projection: options.projection,
       tileGrid: options.tileGrid,
-      wrapX: options.wrapX !== undefined ? options.wrapX : true
+      wrapX: options.wrapX !== undefined ? options.wrapX : true,
+      zDirection: options.zDirection
     });
 
   }

src/ol/source/TileImage.js

@@ -52,6 +52,10 @@ import {getForProjection as getTileGridForProjection} from '../tilegrid.js';
  * @property {number} [transition] Duration of the opacity transition for rendering.
  * To disable the opacity transition, pass `transition: 0`.
  * @property {string} [key] Optional tile key for proper cache fetching
+ * @property {number} [zDirection=0] Indicate which resolution should be used
+ * by a renderer if the view resolution does not match any resolution of the tile source.
+ * If 0, the nearest resolution will be used. If 1, the nearest lower resolution
+ * will be used. If -1, the nearest higher resolution will be used.
  */
 
 
@@ -84,7 +88,8 @@ class TileImage extends UrlTile {
       wrapX: options.wrapX,
       transition: options.transition,
       key: options.key,
-      attributionsCollapsible: options.attributionsCollapsible
+      attributionsCollapsible: options.attributionsCollapsible,
+      zDirection: options.zDirection
     });
 
     /**

src/ol/source/TileWMS.js

@@ -168,7 +168,8 @@ class TileWMS extends TileImage {
       tileGrid = this.getTileGridForProjection(projectionObj);
     }
 
-    const tileCoord = tileGrid.getTileCoordForCoordAndResolution(coordinate, resolution);
+    const z = tileGrid.getZForResolution(resolution, this.zDirection);
+    const tileCoord = tileGrid.getTileCoordForCoordAndZ(coordinate, z);
 
     if (tileGrid.getResolutions().length <= tileCoord[0]) {
       return undefined;

src/ol/source/UTFGrid.js

@@ -385,8 +385,8 @@ class UTFGrid extends TileSource {
   forDataAtCoordinateAndResolution(
     coordinate, resolution, callback, opt_request) {
     if (this.tileGrid) {
-      const tileCoord = this.tileGrid.getTileCoordForCoordAndResolution(
-        coordinate, resolution);
+      const z = this.tileGrid.getZForResolution(resolution, this.zDirection);
+      const tileCoord = this.tileGrid.getTileCoordForCoordAndZ(coordinate, z);
       const tile = /** @type {!CustomTile} */(this.getTile(
         tileCoord[0], tileCoord[1], tileCoord[2], 1, this.getProjection()));
       tile.forDataAtCoordinate(coordinate, callback, opt_request);

src/ol/source/UrlTile.js

@@ -25,6 +25,7 @@ import {getKeyZXY} from '../tilecoord.js';
  * @property {boolean} [wrapX=true]
  * @property {number} [transition]
  * @property {string} [key]
+ * @property {number} [zDirection=0]
  */
 
 
@@ -51,7 +52,8 @@ class UrlTile extends TileSource {
       wrapX: options.wrapX,
       transition: options.transition,
       key: options.key,
-      attributionsCollapsible: options.attributionsCollapsible
+      attributionsCollapsible: options.attributionsCollapsible,
+      zDirection: options.zDirection
     });
 
     /**

src/ol/source/VectorTile.js

@@ -64,6 +64,10 @@ import {equals} from '../array.js';
  * When set to `false`, only one world
  * will be rendered. When set to `true`, tiles will be wrapped horizontally to
  * render multiple worlds.
+ * @property {number} [zDirection=1] Indicate which resolution should be used
+ * by a renderer if the view resolution does not match any resolution of the tile source.
+ * If 0, the nearest resolution will be used. If 1, the nearest lower resolution
+ * will be used. If -1, the nearest higher resolution will be used.
  */
 
 
@@ -109,7 +113,8 @@ class VectorTile extends UrlTile {
       url: options.url,
       urls: options.urls,
       wrapX: options.wrapX === undefined ? true : options.wrapX,
-      transition: options.transition
+      transition: options.transition,
+      zDirection: options.zDirection === undefined ? 1 : options.zDirection
     });
 
     /**

src/ol/source/XYZ.js

@@ -41,6 +41,10 @@ import {createXYZ, extentFromProjection} from '../tilegrid.js';
  * @property {boolean} [wrapX=true] Whether to wrap the world horizontally.
  * @property {number} [transition] Duration of the opacity transition for rendering.
  * To disable the opacity transition, pass `transition: 0`.
+ * @property {number} [zDirection=0] Indicate which resolution should be used
+ * by a renderer if the view resolution does not match any resolution of the tile source.
+ * If 0, the nearest resolution will be used. If 1, the nearest lower resolution
+ * will be used. If -1, the nearest higher resolution will be used.
  */
 
 
@@ -94,7 +98,8 @@ class XYZ extends TileImage {
       urls: options.urls,
       wrapX: options.wrapX !== undefined ? options.wrapX : true,
       transition: options.transition,
-      attributionsCollapsible: options.attributionsCollapsible
+      attributionsCollapsible: options.attributionsCollapsible,
+      zDirection: options.zDirection
     });
 
   }

src/ol/source/Zoomify.js

@@ -114,8 +114,8 @@ export class CustomTile extends ImageTile {
  * @property {number} [transition] Duration of the opacity transition for rendering.
  * To disable the opacity transition, pass `transition: 0`.
  * @property {number} [tileSize=256] Tile size. Same tile size is used for all zoom levels.
- * @property {number} [zDirection] Indicate which resolution should be used
- * by a renderer if the views resolution does not match any resolution of the tile source.
+ * @property {number} [zDirection=0] Indicate which resolution should be used
+ * by a renderer if the view resolution does not match any resolution of the tile source.
  * If 0, the nearest resolution will be used. If 1, the nearest lower resolution
  * will be used. If -1, the nearest higher resolution will be used.
  */

test/spec/ol/renderer/canvas/tilelayer.test.js

@@ -86,6 +86,17 @@ describe('ol.renderer.canvas.TileLayer', function() {
         done();
       });
     });
+
+    it('respects the source\'s zDirection setting', function(done) {
+      layer.getSource().zDirection = 1;
+      map.getView().setZoom(5.8); // would lead to z6 tile request with the default zDirection
+      map.once('rendercomplete', function() {
+        const tileCache = layer.getSource().tileCache;
+        const keys = tileCache.getKeys();
+        expect(keys.some(key => key.startsWith('6/'))).to.be(false);
+        done();
+      });
+    });
   });
 
 });

test/spec/ol/renderer/canvas/vectortilelayer.test.js

@@ -101,7 +101,7 @@ describe('ol.renderer.canvas.VectorTileLayer', function() {
     it('creates a new instance', function() {
       const renderer = new CanvasVectorTileLayerRenderer(layer);
       expect(renderer).to.be.a(CanvasVectorTileLayerRenderer);
-      expect(renderer.zDirection).to.be(1);
+      expect(renderer.getLayer()).to.equal(layer);
     });
 
     it('does not render replays for pure image rendering', function() {

test/spec/ol/source/vectortile.test.js

@@ -26,6 +26,10 @@ describe('ol.source.VectorTile', function() {
       expect(source.format_).to.equal(format);
     });
 
+    it('sets the default zDirection on the instance', function() {
+      expect(source.zDirection).to.be(1);
+    });
+
     it('uses ol.VectorTile as default tileClass', function() {
       expect(source.tileClass).to.equal(VectorTile);
     });

test/spec/ol/source/xyz.test.js

@@ -20,6 +20,13 @@ describe('ol.source.XYZ', function() {
       expect(source).to.be.an(TileSource);
     });
 
+    it('can be constructed with a custom zDirection', function() {
+      const source = new XYZ({
+        zDirection: -1
+      });
+      expect(source.zDirection).to.be(-1);
+    });
+
     it('can be constructed with a custom tile grid', function() {
       const tileGrid = createXYZ();
       const tileSource = new XYZ({