split canvas from html rendering

Gruntfile.js

@@ -58,7 +58,8 @@ module.exports = function(grunt) {
             "src/tile.js",
             "src/overlay.js",
             "src/drawerbase.js",
-            "src/drawer.js",
+            "src/htmldrawer.js",
+            "src/canvasdrawer.js",
             "src/viewport.js",
             "src/tiledimage.js",
             "src/tilecache.js",

src/drawer.js

@@ -444,7 +444,7 @@ $.extend( $.Drawer.prototype, $.DrawerBase.prototype, /** @lends OpenSeadragon.D
                 fillStyle = tiledImage.placeholderFillStyle;
             }
 
-            this.drawRectangle(placeholderRect, fillStyle, useSketch);
+            this._drawRectangle(placeholderRect, fillStyle, useSketch);
         }
 
         var subPixelRoundingRule = determineSubPixelRoundingRule(tiledImage.subPixelRoundingForTransparency);
@@ -611,7 +611,7 @@ $.extend( $.Drawer.prototype, $.DrawerBase.prototype, /** @lends OpenSeadragon.D
             scale = scale || 1;
             this._drawTileToCanvas(tile, context, drawingHandler, scale, translate, shouldRoundPositionAndSize, source);
         } else {
-            tile._drawTileToHTML( tile, this.canvas );
+            this._drawTileToHTML( tile, this.canvas );
         }
     },
 
@@ -868,7 +868,7 @@ $.extend( $.Drawer.prototype, $.DrawerBase.prototype, /** @lends OpenSeadragon.D
     },
 
     // private
-    drawRectangle: function(rect, fillStyle, useSketch) {
+    _drawRectangle: function(rect, fillStyle, useSketch) {
         if (!this.useCanvas) {
             return;
         }

src/htmldrawer.js

@@ -0,0 +1,347 @@
+/*
+ * OpenSeadragon - Drawer
+ *
+ * Copyright (C) 2009 CodePlex Foundation
+ * Copyright (C) 2010-2022 OpenSeadragon contributors
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * - Redistributions of source code must retain the above copyright notice,
+ *   this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * - Neither the name of CodePlex Foundation nor the names of its
+ *   contributors may be used to endorse or promote products derived from
+ *   this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+(function( $ ){
+
+/**
+ * @class HTMLDrawer
+ * @memberof OpenSeadragon
+ * @classdesc HTML-based implementation of DrawerBase for an {@link OpenSeadragon.Viewer}.
+ * @param {Object} options - Options for this Drawer.
+ * @param {OpenSeadragon.Viewer} options.viewer - The Viewer that owns this Drawer.
+ * @param {OpenSeadragon.Viewport} options.viewport - Reference to Viewer viewport.
+ * @param {Element} options.element - Parent element.
+ * @param {Number} [options.debugGridColor] - See debugGridColor in {@link OpenSeadragon.Options} for details.
+ */
+$.HTMLDrawer = function(options) {
+
+    $.DrawerBase.call(this, options);
+
+    /**
+     * 2d drawing context for {@link OpenSeadragon.Drawer#canvas} if it's a <canvas> element, otherwise null.
+     * @member {Object} context
+     * @memberof OpenSeadragon.Drawer#
+     */
+    this.context = null;
+
+
+    // We force our container to ltr because our drawing math doesn't work in rtl.
+    // This issue only affects our canvas renderer, but we do it always for consistency.
+    // Note that this means overlays you want to be rtl need to be explicitly set to rtl.
+    this.container.dir = 'ltr';
+
+};
+
+$.extend( $.HTMLDrawer.prototype, $.DrawerBase.prototype, /** @lends OpenSeadragon.Drawer.prototype */ {
+
+    /**
+     * Draws the TiledImages
+     */
+    draw: function(tiledImages) {
+        var _this = this;
+        this._prepareNewFrame(); // prepare to draw a new frame
+        tiledImages.forEach(function(tiledImage){
+            if (tiledImage.opacity !== 0 || tiledImage._preload) {
+                tiledImage._midDraw = true;
+                _this._updateViewportWithTiledImage(tiledImage);
+                tiledImage._midDraw = false;
+            }
+            else {
+                tiledImage._needsDraw = false;
+            }
+        });
+
+    },
+
+    /**
+     * @returns {Boolean} False - rotation is not supported.
+     */
+    canRotate: function() {
+        return false;
+    },
+
+    /**
+     * Destroy the drawer (unload current loaded tiles)
+     */
+    destroy: function() {
+        //force unloading of current canvas (1x1 will be gc later, trick not necessarily needed)
+        this.canvas.width  = 1;
+        this.canvas.height = 1;
+    },
+
+    /**
+     * Turns image smoothing on or off for this viewer. Note: Ignored by HTML Drawer
+     *
+     * @function
+     * @param {Boolean} [imageSmoothingEnabled] - Whether or not the image is
+     * drawn smoothly on the canvas; see imageSmoothingEnabled in
+     * {@link OpenSeadragon.Options} for more explanation.
+     */
+    setImageSmoothingEnabled: function(){
+        // noop - HTML Drawer does not deal with this property
+        $.console.warn('HTMLDrawer.setImageSmoothingEnabled does not have an effect.');
+    },
+
+    /**
+     * @private
+     * @inner
+     * Clears the Drawer so it's ready to draw another frame.
+     *
+     */
+    _prepareNewFrame: function() {
+        this.canvas.innerHTML = "";
+    },
+
+    /* Methods from TiledImage */
+
+    /**
+     * @private
+     * @inner
+     * Handles drawing a single TiledImage to the canvas
+     *
+     */
+    _updateViewportWithTiledImage: function(tiledImage) {
+        var _this = this;
+        tiledImage._needsDraw = false;
+        tiledImage._tilesLoading = 0;
+        tiledImage.loadingCoverage = {};
+
+        // Reset tile's internal drawn state
+        while (tiledImage.lastDrawn.length > 0) {
+            var tile = tiledImage.lastDrawn.pop();
+            tile.beingDrawn = false;
+        }
+
+
+        var drawArea = tiledImage.getDrawArea();
+        if(!drawArea){
+            return;
+        }
+
+        function updateTile(info){
+            var tile = info.tile;
+            if(tile && tile.loaded){
+                var needsDraw = _this._blendTile(
+                    tiledImage,
+                    tile,
+                    tile.x,
+                    tile.y,
+                    info.level,
+                    info.levelOpacity,
+                    info.currentTime
+                );
+                if(needsDraw){
+                    tiledImage._needsDraw = true;
+                }
+            }
+        }
+
+        var infoArray = tiledImage.getTileInfoForDrawing();
+        infoArray.forEach(updateTile);
+
+        this._drawTiles(tiledImage);
+
+    },
+
+
+
+    /**
+     * @private
+     * @inner
+     * Updates the opacity of a tile according to the time it has been on screen
+     * to perform a fade-in.
+     * Updates coverage once a tile is fully opaque.
+     * Returns whether the fade-in has completed.
+     *
+     * @param {OpenSeadragon.Tile} tile
+     * @param {Number} x
+     * @param {Number} y
+     * @param {Number} level
+     * @param {Number} levelOpacity
+     * @param {Number} currentTime
+     * @returns {Boolean}
+     */
+    _blendTile: function( tiledImage, tile, x, y, level, levelOpacity, currentTime ){
+        var blendTimeMillis = 1000 * tiledImage.blendTime,
+            deltaTime,
+            opacity;
+
+        if ( !tile.blendStart ) {
+            tile.blendStart = currentTime;
+        }
+
+        deltaTime   = currentTime - tile.blendStart;
+        opacity     = blendTimeMillis ? Math.min( 1, deltaTime / ( blendTimeMillis ) ) : 1;
+
+        if ( tiledImage.alwaysBlend ) {
+            opacity *= levelOpacity;
+        }
+
+        tile.opacity = opacity;
+
+        tiledImage.lastDrawn.push( tile );
+
+        if ( opacity === 1 ) {
+            tiledImage._setCoverage( tiledImage.coverage, level, x, y, true );
+            tiledImage._hasOpaqueTile = true;
+        } else if ( deltaTime < blendTimeMillis ) {
+            return true;
+        }
+
+        return false;
+    },
+
+    /**
+     * @private
+     * @inner
+     * Draws a TiledImage.
+     *
+     */
+    _drawTiles: function( tiledImage ) {
+        var lastDrawn = tiledImage.lastDrawn;
+        if (tiledImage.opacity === 0 || (lastDrawn.length === 0 && !tiledImage.placeholderFillStyle)) {
+            return;
+        }
+
+        // Iterate over the tiles to draw, and draw them
+        for (var i = lastDrawn.length - 1; i >= 0; i--) {
+            var tile = lastDrawn[ i ];
+            this._drawTile( tile );
+            tile.beingDrawn = true;
+
+            if( this.viewer ){
+                /**
+                 * Raised when a tile is drawn to the canvas
+                 *
+                 * @event tile-drawn
+                 * @memberof OpenSeadragon.Viewer
+                 * @type {object}
+                 * @property {OpenSeadragon.Viewer} eventSource - A reference to the Viewer which raised the event.
+                 * @property {OpenSeadragon.TiledImage} tiledImage - Which TiledImage is being drawn.
+                 * @property {OpenSeadragon.Tile} tile
+                 * @property {?Object} userData - Arbitrary subscriber-defined object.
+                 */
+                this.viewer.raiseEvent( 'tile-drawn', {
+                    tiledImage: tiledImage,
+                    tile: tile
+                });
+            }
+        }
+
+    },
+
+    /* Methods from Tile */
+
+    /**
+     * @private
+     * @inner
+     * Draws the given tile.
+     * @param {OpenSeadragon.Tile} tile - The tile to draw.
+     * @param {Function} drawingHandler - Method for firing the drawing event if using canvas.
+     * drawingHandler({context, tile, rendered})
+     */
+    _drawTile: function( tile ) {
+        $.console.assert(tile, '[Drawer._drawTile] tile is required');
+
+        this._drawTileToHTML( tile, this.canvas );
+    },
+
+
+    /**
+     * @private
+     * @inner
+     * Renders the tile in an html container.
+     * @function
+     * @param {OpenSeadragon.Tile} tile
+     * @param {Element} container
+     */
+    _drawTileToHTML: function( tile, container ) {
+        if (!tile.cacheImageRecord) {
+            $.console.warn(
+                '[Drawer._drawTileToHTML] attempting to draw tile %s when it\'s not cached',
+                tile.toString());
+            return;
+        }
+
+        if ( !tile.loaded ) {
+            $.console.warn(
+                "Attempting to draw tile %s when it's not yet loaded.",
+                tile.toString()
+            );
+            return;
+        }
+
+        //EXPERIMENTAL - trying to figure out how to scale the container
+        //               content during animation of the container size.
+
+        if ( !tile.element ) {
+            var image = tile.getImage();
+            if (!image) {
+                return;
+            }
+
+            tile.element                              = $.makeNeutralElement( "div" );
+            tile.imgElement                           = image.cloneNode();
+            tile.imgElement.style.msInterpolationMode = "nearest-neighbor";
+            tile.imgElement.style.width               = "100%";
+            tile.imgElement.style.height              = "100%";
+
+            tile.style                     = tile.element.style;
+            tile.style.position            = "absolute";
+        }
+        if ( tile.element.parentNode !== container ) {
+            container.appendChild( tile.element );
+        }
+        if ( tile.imgElement.parentNode !== tile.element ) {
+            tile.element.appendChild( tile.imgElement );
+        }
+
+        tile.style.top     = tile.position.y + "px";
+        tile.style.left    = tile.position.x + "px";
+        tile.style.height  = tile.size.y + "px";
+        tile.style.width   = tile.size.x + "px";
+
+        if (tile.flipped) {
+            tile.style.transform = "scaleX(-1)";
+        }
+
+        $.setElementOpacity( tile.element, tile.opacity );
+    },
+
+});
+
+
+
+
+}( OpenSeadragon ));

src/viewer.js

@@ -433,13 +433,20 @@ $.Viewer = function( options ) {
             throw('Viewer option customDrawer must derive from OpenSeadragon.DrawerBase');
         }
 
-    } else {
+    } else if(this.useCanvas && $.supportsCanvas) {
         this.drawer = new $.Drawer({
             viewer:             this,
             viewport:           this.viewport,
             element:            this.canvas,
             debugGridColor:     this.debugGridColor
         });
+    } else {
+        this.drawer = new $.HTMLDrawer({
+            viewer:             this,
+            viewport:           this.viewport,
+            element:            this.canvas,
+            debugGridColor:     this.debugGridColor
+        });
     }
 
 

test/demo/webgl.js

@@ -27,10 +27,11 @@ var viewer = window.viewer = OpenSeadragon({
     maxZoomPixelRatio:100,
     smoothTileEdgesMinZoom:1.1,
     crossOriginPolicy: 'Anonymous',
-    ajaxWithCredentials: false
+    ajaxWithCredentials: false,
+    useCanvas:false,
 });
 
-let threeRenderer = window.threeRenderer = new ThreeJSDrawer({viewer, viewport: viewer.viewport, element:viewer.element});
+// let threeRenderer = window.threeRenderer = new ThreeJSDrawer({viewer, viewport: viewer.viewport, element:viewer.element});
 
 var viewer2 = window.viewer2 = OpenSeadragon({
     id: "three-viewer",
@@ -45,15 +46,15 @@ var viewer2 = window.viewer2 = OpenSeadragon({
 });
 
 //make the test canvas mirror all changes to the viewer canvas
-let viewerCanvas = viewer.drawer.canvas;
-let canvas = threeRenderer.canvas;
-let canvasContainer = $('#three-canvas-container').append(canvas);
-viewer.addHandler("resize", function(){
-    canvasContainer[0].style.width = viewerCanvas.clientWidth+'px';
-    canvasContainer[0].style.height = viewerCanvas.clientHeight+'px';
-    // canvas.width = viewerCanvas.width;
-    // canvas.height = viewerCanvas.height;
-})
+// let viewerCanvas = viewer.drawer.canvas;
+// let canvas = threeRenderer.canvas;
+// let canvasContainer = $('#three-canvas-container').append(canvas);
+// viewer.addHandler("resize", function(){
+//     canvasContainer[0].style.width = viewerCanvas.clientWidth+'px';
+//     canvasContainer[0].style.height = viewerCanvas.clientHeight+'px';
+//     // canvas.width = viewerCanvas.width;
+//     // canvas.height = viewerCanvas.height;
+// })
 
 
 // viewer.addHandler("open", () => viewer.world.getItemAt(0).source.hasTransparency = function(){ return true; });