Add tests, remove unused code, encapsulate repeated code in functions

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

@@ -0,0 +1,68 @@
+goog.provide('ol.test.renderer.canvas.Layer');
+
+
+describe('ol.renderer.canvas.Layer', function() {
+
+  describe('#composeFrame()', function() {
+    it('clips to layer extent and draws image', function() {
+      var layer = new ol.layer.Image({
+        extent: [1, 2, 3, 4]
+      });
+      var renderer = new ol.renderer.canvas.Layer(layer);
+      var image = new Image();
+      image.width = 3;
+      image.height = 3;
+      renderer.getImage = function() {
+        return image;
+      };
+      var frameState = {
+        viewState: {
+          center: [2, 3],
+          resolution: 1,
+          rotation: 0
+        },
+        size: [10, 10],
+        pixelRatio: 1,
+        coordinateToPixelMatrix: goog.vec.Mat4.createNumber(),
+        pixelToCoordinateMatrix: goog.vec.Mat4.createNumber()
+      };
+      renderer.getImageTransform = function() {
+        return goog.vec.Mat4.createNumberIdentity();
+      }
+      ol.renderer.Map.prototype.calculateMatrices2D(frameState);
+      var layerState = layer.getLayerState();
+      var context = {
+        save: sinon.spy(),
+        restore: sinon.spy(),
+        translate: sinon.spy(),
+        rotate: sinon.spy(),
+        beginPath: sinon.spy(),
+        moveTo: sinon.spy(),
+        lineTo: sinon.spy(),
+        clip: sinon.spy(),
+        drawImage: sinon.spy()
+      }
+      renderer.composeFrame(frameState, layerState, context);
+      expect(context.save.callCount).to.be(1);
+      expect(context.translate.callCount).to.be(0);
+      expect(context.rotate.callCount).to.be(0);
+      expect(context.beginPath.callCount).to.be(1);
+      expect(context.moveTo.firstCall.args).to.eql([4, 4]);
+      expect(context.lineTo.firstCall.args).to.eql([6, 4]);
+      expect(context.lineTo.secondCall.args).to.eql([6, 6]);
+      expect(context.lineTo.thirdCall.args).to.eql([4, 6]);
+      expect(context.clip.callCount).to.be(1);
+      expect(context.drawImage.firstCall.args).to.eql(
+          [renderer.getImage(), 0, 0, 3, 3, 0, 0, 3, 3]);
+      expect(context.restore.callCount).to.be(1);
+    });
+  });
+
+});
+
+
+goog.require('ol.render.canvas');
+goog.require('goog.vec.Mat4');
+goog.require('ol.layer.Image');
+goog.require('ol.renderer.Map');
+goog.require('ol.renderer.canvas.Layer');