Fix tests: always fetch up-to-date pixel values, prevent adding loaded tile to the 'bestTiles' array. Enforce _needsDraw check to be based on lastDrawn - we are async now.

src/tiledimage.js

@@ -352,7 +352,8 @@ $.extend($.TiledImage.prototype, $.EventSource.prototype, /** @lends OpenSeadrag
      * @returns {Boolean} whether the item still needs to be drawn due to blending
      */
     setDrawn: function(){
-        this._needsDraw = this._isBlending || this._wasBlending;
+        this._needsDraw = this._isBlending || this._wasBlending ||
+            (this.opacity > 0 && this._lastDrawn.length < 1);
         return this._needsDraw;
     },
 
@@ -1825,7 +1826,8 @@ $.extend($.TiledImage.prototype, $.EventSource.prototype, /** @lends OpenSeadrag
         if ( tile.loading ) {
             // the tile is already in the download queue
             this._tilesLoading++;
-        } else if (!loadingCoverage) {
+        } else if (!tile.loaded && !loadingCoverage) {
+            // add tile to best tiles to load only when not loaded already
             best = this._compareTiles( best, tile, this.maxTilesPerFrame );
         }
 

src/webgldrawer.js

@@ -87,10 +87,6 @@
             this._clippingContext = null;
             this._renderingCanvas = null;
 
-            // Unique type per drawer: uploads texture to unique webgl context.
-            this._dataType = `${Date.now()}_TEX_2D`;
-            this._setupTextureHandlers(this._dataType);
-
             // Reject listening for the tile-drawing and tile-drawn events, which this drawer does not fire
             this.viewer.rejectEventHandler("tile-drawn", "The WebGLDrawer does not raise the tile-drawn event");
             this.viewer.rejectEventHandler("tile-drawing", "The WebGLDrawer does not raise the tile-drawing event");
@@ -101,6 +97,10 @@
             this._setupCanvases();
             this._setupRenderer();
 
+            // Unique type per drawer: uploads texture to unique webgl context.
+            this._dataType = `${Date.now()}_TEX_2D`;
+            this._setupTextureHandlers(this._dataType);
+
             this.context = this._outputContext; // API required by tests
 
        }
@@ -757,7 +757,6 @@
             this._renderingCanvas.height = this._clippingCanvas.height = this._outputCanvas.height;
 
             this._gl = this._renderingCanvas.getContext('webgl');
-
             //make the additional canvas elements mirror size changes to the output canvas
             this.viewer.addHandler("resize", function(){
 
@@ -784,12 +783,14 @@
         }
 
         _setupTextureHandlers(thisType) {
+            const _this = this;
             const tex2DCompatibleLoader = (tile, data) => {
                 let tiledImage = tile.tiledImage;
                 //todo verify we are calling conversion just right amount of time!
                 // e.g. no upload of cpu-existing texture
+                // also check textures are really getting destroyed (it is tested, but also do this with demos)
 
-                let gl = this._gl;
+                let gl = _this._gl;
 
                 // create a gl Texture for this tile and bind the canvas with the image data
                 let texture = gl.createTexture();
@@ -798,16 +799,16 @@
                 if( overlap > 0){
                     // calculate the normalized position of the rect to actually draw
                     // discarding overlap.
-                    let overlapFraction = this._calculateOverlapFraction(tile, tiledImage);
+                    let overlapFraction = _this._calculateOverlapFraction(tile, tiledImage);
 
                     let left = tile.x === 0 ? 0 : overlapFraction.x;
                     let top = tile.y === 0 ? 0 : overlapFraction.y;
                     let right = tile.isRightMost ? 1 : 1 - overlapFraction.x;
                     let bottom = tile.isBottomMost ? 1 : 1 - overlapFraction.y;
-                    position = this._makeQuadVertexBuffer(left, right, top, bottom);
+                    position = _this._makeQuadVertexBuffer(left, right, top, bottom);
                 } else {
                     // no overlap: this texture can use the unit quad as its position data
-                    position = this._unitQuad;
+                    position = _this._unitQuad;
                 }
 
                 gl.activeTexture(gl.TEXTURE0);
@@ -848,11 +849,12 @@
 
             this.declareSupportedDataFormats(imageTexType, c2dTexType);
 
-            // We should be OK uploading any of these types.
+            // We should be OK uploading any of these types. The complexity is selected to be O(3n), should be
-            $.convertor.learn("context2d", c2dTexType, tex2DCompatibleLoader, 1, 2);
+            // more than linear pass over pixels
-            $.convertor.learn("image", imageTexType, tex2DCompatibleLoader, 1, 2);
+            $.convertor.learn("context2d", c2dTexType, tex2DCompatibleLoader, 1, 3);
-            $.convertor.learn(c2dTexType, "context2d", dataRetrieval, 1, 2);
+            $.convertor.learn("image", imageTexType, tex2DCompatibleLoader, 1, 3);
-            $.convertor.learn(imageTexType, "image", dataRetrieval, 1, 2);
+            $.convertor.learn(c2dTexType, "context2d", dataRetrieval, 1, 3);
+            $.convertor.learn(imageTexType, "image", dataRetrieval, 1, 3);
 
             $.convertor.learnDestroy(c2dTexType, tex2DCompatibleDestructor);
             $.convertor.learnDestroy(imageTexType, tex2DCompatibleDestructor);

src/world.js

@@ -284,9 +284,9 @@ $.extend( $.World.prototype, $.EventSource.prototype, /** @lends OpenSeadragon.W
     draw: function() {
         this.viewer.drawer.draw(this._items);
         this._needsDraw = false;
-        this._items.forEach(function(item){
+        for (let item of this._items) {
             this._needsDraw = item.setDrawn() || this._needsDraw;
-        });
+        }
     },
 
     /**

test/modules/multi-image.js

@@ -220,17 +220,23 @@
             var done = assert.async();
             viewer.open('/test/data/testpattern.dzi');
 
-            var density = OpenSeadragon.pixelDensityRatio;
+            function getPixelFromViewerScreenCoords(x, y) {
+                const density = OpenSeadragon.pixelDensityRatio;
+                const imageData = viewer.drawer.context.getImageData(x * density, y * density, 1, 1);
+                return {
+                    r: imageData.data[0],
+                    g: imageData.data[1],
+                    b: imageData.data[2],
+                    a: imageData.data[3]
+                };
+            }
 
             viewer.addHandler('open', function() {
                 var firstImage = viewer.world.getItemAt(0);
                 firstImage.addHandler('fully-loaded-change', function() {
                     viewer.addOnceHandler('update-viewport', function(){
-                        var imageData = viewer.drawer.context.getImageData(0, 0,
-                            500 * density, 500 * density);
-
                         // Pixel 250,250 will be in the hole of the A
-                        var expectedVal = getPixelValue(imageData, 250 * density, 250 * density);
+                        var expectedVal = getPixelFromViewerScreenCoords(250, 250);
 
                         assert.notEqual(expectedVal.r, 0, 'Red channel should not be 0');
                         assert.notEqual(expectedVal.g, 0, 'Green channel should not be 0');
@@ -243,8 +249,7 @@
                                 var secondImage = viewer.world.getItemAt(1);
                                 secondImage.addHandler('fully-loaded-change',  function() {
                                     viewer.addOnceHandler('update-viewport', function(){
-                                        var imageData = viewer.drawer.context.getImageData(0, 0, 500 * density, 500 * density);
+                                        var actualVal = getPixelFromViewerScreenCoords(250, 250);
-                                        var actualVal = getPixelValue(imageData, 250 * density, 250 * density);
 
                                         assert.equal(actualVal.r, expectedVal.r,
                                             'Red channel should not change in transparent part of the A');
@@ -255,10 +260,10 @@
                                         assert.equal(actualVal.a, expectedVal.a,
                                             'Alpha channel should not change in transparent part of the A');
 
-                                        var onAVal = getPixelValue(imageData, 333 * density, 250 * density);
+                                        var onAVal = getPixelFromViewerScreenCoords(333 , 250);
-                                        assert.equal(onAVal.r, 0, 'Red channel should be null on the A');
+                                        assert.equal(onAVal.r, 0, 'Red channel should be 0 on the A');
-                                        assert.equal(onAVal.g, 0, 'Green channel should be null on the A');
+                                        assert.equal(onAVal.g, 0, 'Green channel should be 0 on the A');
-                                        assert.equal(onAVal.b, 0, 'Blue channel should be null on the A');
+                                        assert.equal(onAVal.b, 0, 'Blue channel should be 0 on the A');
                                         assert.equal(onAVal.a, 255, 'Alpha channel should be 255 on the A');
 
                                         done();
@@ -271,17 +276,6 @@
                     });
                 });
             });
-
-            function getPixelValue(imageData, x, y) {
-                var offset = 4 * (y * imageData.width + x);
-                return {
-                    r: imageData.data[offset],
-                    g: imageData.data[offset + 1],
-                    b: imageData.data[offset + 2],
-                    a: imageData.data[offset + 3]
-                };
-            }
         });
     }
-
 })();

test/modules/tilecache.js

@@ -123,7 +123,13 @@
     QUnit.test('basics', function(assert) {
         const done = assert.async();
         const fakeViewer = {
-            raiseEvent: function() {}
+            raiseEvent: function() {},
+            drawer: {
+                // tile in safe mode inspects the supported formats upon cache set
+                getSupportedDataFormats() {
+                    return [T_A, T_B, T_C, T_D, T_E];
+                }
+            }
         };
         const fakeTiledImage0 = {
             viewer: fakeViewer,
@@ -170,7 +176,13 @@
     QUnit.test('maxImageCacheCount', function(assert) {
         const done = assert.async();
         const fakeViewer = {
-            raiseEvent: function() {}
+            raiseEvent: function() {},
+            drawer: {
+                // tile in safe mode inspects the supported formats upon cache set
+                getSupportedDataFormats() {
+                    return [T_A, T_B, T_C, T_D, T_E];
+                }
+            }
         };
         const fakeTiledImage0 = {
             viewer: fakeViewer,
@@ -218,7 +230,13 @@
     QUnit.test('Tile API: basic conversion', function(test) {
         const done = test.async();
         const fakeViewer = {
-            raiseEvent: function() {}
+            raiseEvent: function() {},
+            drawer: {
+                // tile in safe mode inspects the supported formats upon cache set
+                getSupportedDataFormats() {
+                    return [T_A, T_B, T_C, T_D, T_E];
+                }
+            }
         };
         const tileCache = new OpenSeadragon.TileCache();
         const fakeTiledImage0 = {
@@ -406,7 +424,13 @@
     QUnit.test('Tile API Cache Interaction', function(test) {
         const done = test.async();
         const fakeViewer = {
-            raiseEvent: function() {}
+            raiseEvent: function() {},
+            drawer: {
+                // tile in safe mode inspects the supported formats upon cache set
+                getSupportedDataFormats() {
+                    return [T_A, T_B, T_C, T_D, T_E];
+                }
+            }
         };
         const tileCache = new OpenSeadragon.TileCache();
         const fakeTiledImage0 = {