Merge pull request #5482 from ischneider/layer-extent

Fix for regression in tile layer extent

examples/layer-extent.html

@@ -4,13 +4,12 @@ title: Limited Layer Extent
 shortdesc: Restricting layer rendering to a limited extent.
 docs: >
   This example uses the <code>layer.setExtent()</code> method to
-  modify the extent of the overlay layer.  Use the controls below
-  to limit rendering based on an extent.
+  modify the extent of the overlay layer.  Use the controls above
+  to limit rendering based on an extent (approximate country bounds).
 tags: "extent, tilejson"
 ---
 <div id="map" class="map"></div>
-<button type="button" class="btn btn-default" id="northwest">northwest</button>
-<button type="button" class="btn btn-default" id="northeast">northeast</button>
-<button type="button" class="btn btn-default" id="southeast">southeast</button>
-<button type="button" class="btn btn-default" id="southwest">southwest</button>
-<button type="button" class="btn btn-default" id="world">world</button>
+<button type="button" class="btn btn-default" id="India">India</button>
+<button type="button" class="btn btn-default" id="Argentina">Argentina</button>
+<button type="button" class="btn btn-default" id="Nigeria">Nigeria</button>
+<button type="button" class="btn btn-default" id="Sweden">Sweden</button>

examples/layer-extent.js

@@ -3,17 +3,17 @@ goog.require('ol.View');
 goog.require('ol.layer.Tile');
 goog.require('ol.proj');
 goog.require('ol.source.TileJSON');
+goog.require('ol.interaction.DragRotateAndZoom');
 
 function transform(extent) {
   return ol.proj.transformExtent(extent, 'EPSG:4326', 'EPSG:3857');
 }
 
 var extents = {
-  northwest: transform([-180, 0, 0, 85]),
-  northeast: transform([0, 0, 180, 85]),
-  southeast: transform([0, -85, 180, 0]),
-  southwest: transform([-180, -85, 0, 0]),
-  world: transform([-180, -85, 180, 85])
+  India: transform([68.17665, 7.96553, 97.40256, 35.49401]),
+  Argentina: transform([-73.41544, -55.25, -53.62835, -21.83231]),
+  Nigeria: transform([2.6917, 4.24059, 14.57718, 13.86592]),
+  Sweden: transform([11.02737, 55.36174, 23.90338, 69.10625])
 };
 
 var base = new ol.layer.Tile({
@@ -25,7 +25,7 @@ var base = new ol.layer.Tile({
 });
 
 var overlay = new ol.layer.Tile({
-  extent: extents.northwest,
+  extent: extents.India,
   source: new ol.source.TileJSON({
     url: 'http://api.tiles.mapbox.com/v3/' +
         'mapbox.world-glass.json',
@@ -43,6 +43,8 @@ var map = new ol.Map({
   })
 });
 
+map.addInteraction(new ol.interaction.DragRotateAndZoom());
+
 for (var key in extents) {
   document.getElementById(key).onclick = function(event) {
     overlay.setExtent(extents[event.target.id]);

src/ol/renderer/canvas/canvastilelayerrenderer.js

@@ -276,6 +276,41 @@ ol.renderer.canvas.TileLayer.prototype.renderTileImages = function(context, fram
     tilesToDraw.reverse();
     pixelExtents = [];
   }
+
+  var extent = layerState.extent;
+  var clipped = extent !== undefined;
+  if (clipped) {
+    goog.asserts.assert(extent !== undefined,
+        'layerState extent is defined');
+    var topLeft = ol.extent.getTopLeft(extent);
+    var topRight = ol.extent.getTopRight(extent);
+    var bottomRight = ol.extent.getBottomRight(extent);
+    var bottomLeft = ol.extent.getBottomLeft(extent);
+
+    ol.vec.Mat4.multVec2(frameState.coordinateToPixelMatrix,
+        topLeft, topLeft);
+    ol.vec.Mat4.multVec2(frameState.coordinateToPixelMatrix,
+        topRight, topRight);
+    ol.vec.Mat4.multVec2(frameState.coordinateToPixelMatrix,
+        bottomRight, bottomRight);
+    ol.vec.Mat4.multVec2(frameState.coordinateToPixelMatrix,
+        bottomLeft, bottomLeft);
+
+    var ox = drawOffsetX || 0;
+    var oy = drawOffsetY || 0;
+    renderContext.save();
+    var cx = (renderContext.canvas.width * pixelRatio) / 2;
+    var cy = (renderContext.canvas.height * pixelRatio) / 2;
+    ol.render.canvas.rotateAtOffset(renderContext, -rotation, cx, cy);
+    renderContext.beginPath();
+    renderContext.moveTo(topLeft[0] * pixelRatio + ox, topLeft[1] * pixelRatio + oy);
+    renderContext.lineTo(topRight[0] * pixelRatio + ox, topRight[1] * pixelRatio + oy);
+    renderContext.lineTo(bottomRight[0] * pixelRatio + ox, bottomRight[1] * pixelRatio + oy);
+    renderContext.lineTo(bottomLeft[0] * pixelRatio + ox, bottomLeft[1] * pixelRatio + oy);
+    renderContext.clip();
+    ol.render.canvas.rotateAtOffset(renderContext, rotation, cx, cy);
+  }
+
   for (var i = 0, ii = tilesToDraw.length; i < ii; ++i) {
     var tile = tilesToDraw[i];
     var tileCoord = tile.getTileCoord();
@@ -324,6 +359,10 @@ ol.renderer.canvas.TileLayer.prototype.renderTileImages = function(context, fram
     }
   }
 
+  if (clipped) {
+    renderContext.restore();
+  }
+
   if (hasRenderListeners) {
     var dX = drawOffsetX - offsetX / drawScale + offsetX;
     var dY = drawOffsetY - offsetY / drawScale + offsetY;

test_rendering/spec/ol/layer/tile.test.js

@@ -29,7 +29,7 @@ describe('ol.rendering.layer.Tile', function() {
       }
     };
 
-    sources.forEach(function(source) {
+    sources.forEach(function(source, i) {
       source.on('tileloadstart', function(event) {
         tilesLoading++;
       });
@@ -44,7 +44,7 @@ describe('ol.rendering.layer.Tile', function() {
       var options = {
         source: source
       };
-      ol.object.assign(options, layerOptions);
+      ol.object.assign(options, layerOptions[i] || layerOptions);
       map.addLayer(new ol.layer.Tile(options));
     });
   }
@@ -112,6 +112,30 @@ describe('ol.rendering.layer.Tile', function() {
             IMAGE_TOLERANCE, done);
       });
     });
+
+    function centerExtent(map) {
+      var c = map.getView().calculateExtent(map.getSize());
+      var qw = ol.extent.getSize(c)[0] / 4;
+      var qh = ol.extent.getSize(c)[1] / 4;
+      return [c[0] + qw, c[1] + qh, c[2] - qw, c[3] - qh];
+    }
+
+    it('tests canvas layer extent clipping', function(done) {
+      map = createMap('canvas');
+      waitForTiles([source1, source2], [{}, {extent: centerExtent(map)}], function() {
+        expectResemble(map, 'spec/ol/layer/expected/2-layers-canvas-extent.png',
+            IMAGE_TOLERANCE, done);
+      });
+    });
+
+    it('tests canvas layer extent clipping with rotation', function(done) {
+      map = createMap('canvas');
+      map.getView().setRotation(Math.PI / 2);
+      waitForTiles([source1, source2], [{}, {extent: centerExtent(map)}], function() {
+        expectResemble(map, 'spec/ol/layer/expected/2-layers-canvas-extent-rotate.png',
+            IMAGE_TOLERANCE, done);
+      });
+    });
   });
 
   describe('tile layer with opacity', function() {