diff --git a/changelog.txt b/changelog.txt
index 83bf2f07..f253c23f 100644
--- a/changelog.txt
+++ b/changelog.txt
@@ -3,6 +3,8 @@ OPENSEADRAGON CHANGELOG
2.1.1: (in progress)
+* Tile edge smoothing at high zoom (#764)
+
2.1.0:
* BREAKING CHANGE: the tile does not hold a reference to its image anymore. Only the tile cache keep a reference to images.
diff --git a/src/drawer.js b/src/drawer.js
index 9b74b981..9e928bb6 100644
--- a/src/drawer.js
+++ b/src/drawer.js
@@ -290,21 +290,24 @@ $.Drawer.prototype = /** @lends OpenSeadragon.Drawer.prototype */{
* drawingHandler({context, tile, rendered})
* @param {Boolean} useSketch - Whether to use the sketch canvas or not.
* where rendered is the context with the pre-drawn image.
+ * @param {Float} [scale=1] - Apply a scale to tile position and size. Defaults to 1.
+ * @param {OpenSeadragon.Point} [translate] A translation vector to offset tile position
*/
- drawTile: function( tile, drawingHandler, useSketch ) {
+ drawTile: function( tile, drawingHandler, useSketch, scale, translate ) {
$.console.assert(tile, '[Drawer.drawTile] tile is required');
$.console.assert(drawingHandler, '[Drawer.drawTile] drawingHandler is required');
if ( this.useCanvas ) {
var context = this._getContext( useSketch );
+ scale = scale || 1;
// TODO do this in a more performant way
// specifically, don't save,rotate,restore every time we draw a tile
if( this.viewport.degrees !== 0 ) {
this._offsetForRotation( tile, this.viewport.degrees, useSketch );
- tile.drawCanvas( context, drawingHandler );
+ tile.drawCanvas( context, drawingHandler, scale, translate );
this._restoreRotationChanges( tile, useSketch );
} else {
- tile.drawCanvas( context, drawingHandler );
+ tile.drawCanvas( context, drawingHandler, scale, translate );
}
} else {
tile.drawHTML( this.canvas );
@@ -371,16 +374,33 @@ $.Drawer.prototype = /** @lends OpenSeadragon.Drawer.prototype */{
/**
* Blends the sketch canvas in the main canvas.
* @param {Float} opacity The opacity of the blending.
+ * @param {Float} [scale=1] The scale at which tiles were drawn on the sketch. Default is 1.
+ * Use scale to draw at a lower scale and then enlarge onto the main canvas.
+ * @param OpenSeadragon.Point} [translate] A translation vector that was used to draw the tiles
* @returns {undefined}
*/
- blendSketch: function(opacity) {
+ blendSketch: function(opacity, scale, translate) {
if (!this.useCanvas || !this.sketchCanvas) {
return;
}
+ scale = scale || 1;
+ var position = translate instanceof $.Point ?
+ translate :
+ new $.Point(0, 0);
this.context.save();
this.context.globalAlpha = opacity;
- this.context.drawImage(this.sketchCanvas, 0, 0);
+ this.context.drawImage(
+ this.sketchCanvas,
+ position.x,
+ position.y,
+ this.sketchCanvas.width * scale,
+ this.sketchCanvas.height * scale,
+ 0,
+ 0,
+ this.canvas.width,
+ this.canvas.height
+ );
this.context.restore();
},
diff --git a/src/openseadragon.js b/src/openseadragon.js
index c9504183..8613d2a8 100644
--- a/src/openseadragon.js
+++ b/src/openseadragon.js
@@ -249,6 +249,11 @@
* image though it is less effective visually if the HTML5 Canvas is not
* availble on the viewing device.
*
+ * @property {Number} [smoothTileEdgesMinZoom=1.1]
+ * A zoom percentage ( where 1 is 100% ) of the highest resolution level.
+ * When zoomed in beyond this value alternative compositing will be used to
+ * smooth out the edges between tiles. This will have a performance impact.
+ *
* @property {Boolean} [autoResize=true]
* Set to false to prevent polling for viewer size changes. Useful for providing custom resize behavior.
*
@@ -1022,6 +1027,7 @@ if (typeof define === 'function' && define.amd) {
immediateRender: false,
minZoomImageRatio: 0.9, //-> closer to 0 allows zoom out to infinity
maxZoomPixelRatio: 1.1, //-> higher allows 'over zoom' into pixels
+ smoothTileEdgesMinZoom: 1.1, //-> higher than maxZoomPixelRatio disables it
pixelsPerWheelLine: 40,
autoResize: true,
preserveImageSizeOnResize: false, // requires autoResize=true
diff --git a/src/rectangle.js b/src/rectangle.js
index 5d3495af..abf1c947 100644
--- a/src/rectangle.js
+++ b/src/rectangle.js
@@ -201,6 +201,21 @@ $.Rect.prototype = /** @lends OpenSeadragon.Rect.prototype */{
);
},
+ /**
+ * Translate/move this Rect by a vector and return new Rect.
+ * @function
+ * @param {OpenSeadragon.Point} delta The translation vector.
+ * @returns {OpenSeadragon.Rect} A new rect with altered position
+ */
+ translate: function( delta ) {
+ return new OpenSeadragon.Rect(
+ this.x + delta.x,
+ this.y + delta.y,
+ this.width,
+ this.height
+ );
+ },
+
/**
* Returns the smallest rectangle that will contain this and the given rectangle.
* @param {OpenSeadragon.Rect} rect
diff --git a/src/tile.js b/src/tile.js
index 97d88e17..a07bec74 100644
--- a/src/tile.js
+++ b/src/tile.js
@@ -248,11 +248,13 @@ $.Tile.prototype = /** @lends OpenSeadragon.Tile.prototype */{
* @param {Function} drawingHandler - Method for firing the drawing event.
* drawingHandler({context, tile, rendered})
* where rendered is the context with the pre-drawn image.
+ * @param {Number} [scale=1] - Apply a scale to position and size
+ * @param {OpenSeadragon.Point} [translate] - A translation vector
*/
- drawCanvas: function( context, drawingHandler ) {
+ drawCanvas: function( context, drawingHandler, scale, translate ) {
- var position = this.position,
- size = this.size,
+ var position = this.position.times($.pixelDensityRatio),
+ size = this.size.times($.pixelDensityRatio),
rendered;
if (!this.context2D && !this.cacheImageRecord) {
@@ -286,10 +288,10 @@ $.Tile.prototype = /** @lends OpenSeadragon.Tile.prototype */{
//clearing only the inside of the rectangle occupied
//by the png prevents edge flikering
context.clearRect(
- (position.x * $.pixelDensityRatio)+1,
- (position.y * $.pixelDensityRatio)+1,
- (size.x * $.pixelDensityRatio)-2,
- (size.y * $.pixelDensityRatio)-2
+ position.x + 1,
+ position.y + 1,
+ size.x - 2,
+ size.y - 2
);
}
@@ -298,21 +300,70 @@ $.Tile.prototype = /** @lends OpenSeadragon.Tile.prototype */{
// changes as we are rendering the image
drawingHandler({context: context, tile: this, rendered: rendered});
+ if (typeof scale === 'number' && scale !== 1) {
+ // draw tile at a different scale
+ position = position.times(scale);
+ size = size.times(scale);
+ }
+
+ if (translate instanceof $.Point) {
+ // shift tile position slightly
+ position = position.plus(translate);
+ }
+
context.drawImage(
rendered.canvas,
0,
0,
rendered.canvas.width,
rendered.canvas.height,
- position.x * $.pixelDensityRatio,
- position.y * $.pixelDensityRatio,
- size.x * $.pixelDensityRatio,
- size.y * $.pixelDensityRatio
+ position.x,
+ position.y,
+ size.x,
+ size.y
);
context.restore();
},
+ /**
+ * Get the ratio between current and original size.
+ * @function
+ * @return {Float}
+ */
+ getScaleForEdgeSmoothing: function() {
+ if (!this.cacheImageRecord) {
+ $.console.warn(
+ '[Tile.drawCanvas] attempting to get tile scale %s when tile\'s not cached',
+ this.toString());
+ return 1;
+ }
+
+ var rendered = this.cacheImageRecord.getRenderedContext();
+ return rendered.canvas.width / this.size.times($.pixelDensityRatio).x;
+ },
+
+ /**
+ * Get a translation vector that when applied to the tile position produces integer coordinates.
+ * Needed to avoid swimming and twitching.
+ * @function
+ * @param {Number} [scale=1] - Scale to be applied to position.
+ * @return {OpenSeadragon.Point}
+ */
+ getTranslationForEdgeSmoothing: function(scale) {
+ // The translation vector must have positive values, otherwise the image goes a bit off
+ // the sketch canvas to the top and left and we must use negative coordinates to repaint it
+ // to the main canvas. And FF does not like it. It crashes the viewer.
+ return new $.Point(1, 1).minus(
+ this.position
+ .times($.pixelDensityRatio)
+ .times(scale || 1)
+ .apply(function(x) {
+ return x % 1;
+ })
+ );
+ },
+
/**
* Removes tile from its container.
* @function
diff --git a/src/tiledimage.js b/src/tiledimage.js
index 76e113a9..b7b85995 100644
--- a/src/tiledimage.js
+++ b/src/tiledimage.js
@@ -64,6 +64,7 @@
* @param {Number} [options.blendTime] - See {@link OpenSeadragon.Options}.
* @param {Boolean} [options.alwaysBlend] - See {@link OpenSeadragon.Options}.
* @param {Number} [options.minPixelRatio] - See {@link OpenSeadragon.Options}.
+ * @param {Number} [options.smoothTileEdgesMinZoom] - See {@link OpenSeadragon.Options}.
* @param {Number} [options.opacity=1] - Opacity the tiled image should be drawn at.
* @param {Boolean} [options.debugMode] - See {@link OpenSeadragon.Options}.
* @param {String|CanvasGradient|CanvasPattern|Function} [options.placeholderFillStyle] - See {@link OpenSeadragon.Options}.
@@ -133,19 +134,20 @@ $.TiledImage = function( options ) {
_hasOpaqueTile: false, // Do we have even one fully opaque tile?
//configurable settings
- springStiffness: $.DEFAULT_SETTINGS.springStiffness,
- animationTime: $.DEFAULT_SETTINGS.animationTime,
- minZoomImageRatio: $.DEFAULT_SETTINGS.minZoomImageRatio,
- wrapHorizontal: $.DEFAULT_SETTINGS.wrapHorizontal,
- wrapVertical: $.DEFAULT_SETTINGS.wrapVertical,
- immediateRender: $.DEFAULT_SETTINGS.immediateRender,
- blendTime: $.DEFAULT_SETTINGS.blendTime,
- alwaysBlend: $.DEFAULT_SETTINGS.alwaysBlend,
- minPixelRatio: $.DEFAULT_SETTINGS.minPixelRatio,
- debugMode: $.DEFAULT_SETTINGS.debugMode,
- crossOriginPolicy: $.DEFAULT_SETTINGS.crossOriginPolicy,
- placeholderFillStyle: $.DEFAULT_SETTINGS.placeholderFillStyle,
- opacity: $.DEFAULT_SETTINGS.opacity
+ springStiffness: $.DEFAULT_SETTINGS.springStiffness,
+ animationTime: $.DEFAULT_SETTINGS.animationTime,
+ minZoomImageRatio: $.DEFAULT_SETTINGS.minZoomImageRatio,
+ wrapHorizontal: $.DEFAULT_SETTINGS.wrapHorizontal,
+ wrapVertical: $.DEFAULT_SETTINGS.wrapVertical,
+ immediateRender: $.DEFAULT_SETTINGS.immediateRender,
+ blendTime: $.DEFAULT_SETTINGS.blendTime,
+ alwaysBlend: $.DEFAULT_SETTINGS.alwaysBlend,
+ minPixelRatio: $.DEFAULT_SETTINGS.minPixelRatio,
+ smoothTileEdgesMinZoom: $.DEFAULT_SETTINGS.smoothTileEdgesMinZoom,
+ debugMode: $.DEFAULT_SETTINGS.debugMode,
+ crossOriginPolicy: $.DEFAULT_SETTINGS.crossOriginPolicy,
+ placeholderFillStyle: $.DEFAULT_SETTINGS.placeholderFillStyle,
+ opacity: $.DEFAULT_SETTINGS.opacity
}, options );
@@ -1305,13 +1307,26 @@ function compareTiles( previousBest, tile ) {
function drawTiles( tiledImage, lastDrawn ) {
var i,
- tile;
+ tile = lastDrawn[0];
if ( tiledImage.opacity <= 0 ) {
drawDebugInfo( tiledImage, lastDrawn );
return;
}
var useSketch = tiledImage.opacity < 1;
+ var sketchScale;
+ var sketchTranslate;
+
+ var zoom = tiledImage.viewport.getZoom(true);
+ var imageZoom = tiledImage.viewportToImageZoom(zoom);
+ if ( imageZoom > tiledImage.smoothTileEdgesMinZoom && tile) {
+ // When zoomed in a lot (>100%) the tile edges are visible.
+ // So we have to composite them at ~100% and scale them up together.
+ useSketch = true;
+ sketchScale = tile.getScaleForEdgeSmoothing();
+ sketchTranslate = tile.getTranslationForEdgeSmoothing(sketchScale);
+ }
+
if ( useSketch ) {
tiledImage._drawer._clear( true );
}
@@ -1322,6 +1337,12 @@ function drawTiles( tiledImage, lastDrawn ) {
var box = tiledImage.imageToViewportRectangle(tiledImage._clip, true);
var clipRect = tiledImage._drawer.viewportToDrawerRectangle(box);
+ if (sketchScale) {
+ clipRect = clipRect.times(sketchScale);
+ }
+ if (sketchTranslate) {
+ clipRect = clipRect.translate(sketchTranslate);
+ }
tiledImage._drawer.setClip(clipRect, useSketch);
usedClip = true;
@@ -1329,6 +1350,12 @@ function drawTiles( tiledImage, lastDrawn ) {
if ( tiledImage.placeholderFillStyle && tiledImage._hasOpaqueTile === false ) {
var placeholderRect = tiledImage._drawer.viewportToDrawerRectangle(tiledImage.getBounds(true));
+ if (sketchScale) {
+ placeholderRect = placeholderRect.times(sketchScale);
+ }
+ if (sketchTranslate) {
+ placeholderRect = placeholderRect.translate(sketchTranslate);
+ }
var fillStyle = null;
if ( typeof tiledImage.placeholderFillStyle === "function" ) {
@@ -1343,7 +1370,7 @@ function drawTiles( tiledImage, lastDrawn ) {
for ( i = lastDrawn.length - 1; i >= 0; i-- ) {
tile = lastDrawn[ i ];
- tiledImage._drawer.drawTile( tile, tiledImage._drawingHandler, useSketch );
+ tiledImage._drawer.drawTile( tile, tiledImage._drawingHandler, useSketch, sketchScale, sketchTranslate );
tile.beingDrawn = true;
if( tiledImage.viewer ){
@@ -1370,7 +1397,7 @@ function drawTiles( tiledImage, lastDrawn ) {
}
if ( useSketch ) {
- tiledImage._drawer.blendSketch( tiledImage.opacity );
+ tiledImage._drawer.blendSketch( tiledImage.opacity, sketchScale, sketchTranslate );
}
drawDebugInfo( tiledImage, lastDrawn );
}
diff --git a/src/viewer.js b/src/viewer.js
index b484364c..6dfa5c7c 100644
--- a/src/viewer.js
+++ b/src/viewer.js
@@ -1346,6 +1346,7 @@ $.extend( $.Viewer.prototype, $.EventSource.prototype, $.ControlDock.prototype,
blendTime: _this.blendTime,
alwaysBlend: _this.alwaysBlend,
minPixelRatio: _this.minPixelRatio,
+ smoothTileEdgesMinZoom: _this.smoothTileEdgesMinZoom,
crossOriginPolicy: _this.crossOriginPolicy,
debugMode: _this.debugMode
});
diff --git a/test/modules/basic.js b/test/modules/basic.js
index 8b7a513b..4ce56654 100644
--- a/test/modules/basic.js
+++ b/test/modules/basic.js
@@ -322,6 +322,7 @@
asyncTest( 'CrossOriginPolicyMissing', function () {
viewer.crossOriginPolicy = false;
+ viewer.smoothTileEdgesMinZoom = Infinity;
viewer.open( {
type: 'legacy-image-pyramid',
levels: [ {