Fix #242, onion skin rendered not cleared if 0 frames

test/js/rendering/OnionSkinRendererTest.js

@@ -0,0 +1,120 @@
+describe("Onion Skin Renderer test", function() {
+  var BLACK = '#000000';
+  var WHITE = '#ffffff';
+  var TRANS = Constants.TRANSPARENT_COLOR;
+
+  beforeEach(function() {});
+  afterEach(function() {});
+
+  it("renders correctly :)", function() {
+    var fakeRenderer = createMockRenderer();
+    var layer = createMockLayer();
+    var piskelController = createMockPiskelController();
+    piskelController.currentLayer_ = layer;
+
+    var onionSkinRenderer = new pskl.rendering.OnionSkinRenderer(fakeRenderer, piskelController);
+    // create frame
+    var previousFrame = pskl.model.Frame.fromPixelGrid(test.testutils.toFrameGrid([
+      [BLACK, TRANS],
+      [TRANS, TRANS]
+    ]));
+
+    var nextFrame = pskl.model.Frame.fromPixelGrid(test.testutils.toFrameGrid([
+      [TRANS, TRANS],
+      [TRANS, BLACK]
+    ]));
+
+    piskelController.currentFrameIndex_ = 1;
+    layer.frames = [previousFrame, {}, nextFrame];
+
+    // initial state, all counters at 0
+    expect(fakeRenderer.clearCounter_).toBe(0);
+    expect(fakeRenderer.renderCounter_).toBe(0);
+
+    // First rendering, should call clear + render
+    onionSkinRenderer.render();
+    expect(fakeRenderer.clearCounter_).toBe(1);
+    expect(fakeRenderer.renderCounter_).toBe(1);
+    test.testutils.frameEqualsGrid(fakeRenderer.renderedFrame_, [
+      [BLACK, TRANS],
+      [TRANS, BLACK]
+    ]);
+
+    // Second rendering, nothing changed, should not clear or render
+    onionSkinRenderer.render();
+    expect(fakeRenderer.clearCounter_).toBe(1);
+    expect(fakeRenderer.renderCounter_).toBe(1);
+
+    // remove one frame
+    layer.frames = [previousFrame, {}];
+    onionSkinRenderer.render();
+    expect(fakeRenderer.clearCounter_).toBe(2);
+    expect(fakeRenderer.renderCounter_).toBe(2);
+    test.testutils.frameEqualsGrid(fakeRenderer.renderedFrame_, [
+      [BLACK, TRANS],
+      [TRANS, TRANS]
+    ]);
+
+    // remove the other frame
+    layer.frames = [{}];
+    piskelController.currentFrameIndex_ = 0;
+    onionSkinRenderer.render();
+    // nothing to render, but the underlying renderer should still be cleared
+    expect(fakeRenderer.clearCounter_).toBe(3);
+    expect(fakeRenderer.renderCounter_).toBe(2);
+  });
+
+  var createMockLayer = function () {
+    return {
+      frames : [],
+      getFrameAt : function (index) {
+        return this.frames[index];
+      }
+    };
+  };
+
+  var createMockPiskelController = function () {
+    return {
+      currentFrameIndex_ : 1,
+      currentLayer_ : null,
+      getLayers : function () {
+        return [this.currentLayer_];
+      },
+
+      getCurrentFrameIndex : function () {
+        return this.currentFrameIndex_;
+      },
+
+      getCurrentLayer : function () {
+        return this.currentLayer_;
+      }
+    };
+  };
+
+  var createMockRenderer = function () {
+    return {
+      clearCounter_ : 0,
+      clear : function () {
+        this.clearCounter_++;
+      },
+      renderedFrame_ : null,
+      renderCounter_ : 0,
+      render : function (frame) {
+        this.renderCounter_++;
+        this.renderedFrame_ = frame;
+      },
+      getZoom : function () {
+        return 1;
+      },
+      getGridWidth : function () {
+        return 0;
+      },
+      getOffset : function () {
+        return {x:0,y:0};
+      },
+      getDisplaySize : function () {
+        return {width:10,height:10};
+      }
+    };
+  };
+});