openseadragon/src/tile.js
2024-04-01 09:44:52 -07:00

559 lines
19 KiB
JavaScript

/*
* OpenSeadragon - Tile
*
* Copyright (C) 2009 CodePlex Foundation
* Copyright (C) 2010-2024 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 Tile
* @memberof OpenSeadragon
* @param {Number} level The zoom level this tile belongs to.
* @param {Number} x The vector component 'x'.
* @param {Number} y The vector component 'y'.
* @param {OpenSeadragon.Rect} bounds Where this tile fits, in normalized
* coordinates.
* @param {Boolean} exists Is this tile a part of a sparse image? ( Also has
* this tile failed to load? )
* @param {String|Function} url The URL of this tile's image or a function that returns a url.
* @param {CanvasRenderingContext2D} context2D The context2D of this tile if it
* is provided directly by the tile source.
* @param {Boolean} loadWithAjax Whether this tile image should be loaded with an AJAX request .
* @param {Object} ajaxHeaders The headers to send with this tile's AJAX request (if applicable).
* @param {OpenSeadragon.Rect} sourceBounds The portion of the tile to use as the source of the
* drawing operation, in pixels. Note that this only works when drawing with canvas; when drawing
* with HTML the entire tile is always used.
* @param {String} postData HTTP POST data (usually but not necessarily in k=v&k2=v2... form,
* see TileSource::getPostData) or null
* @param {String} cacheKey key to act as a tile cache, must be unique for tiles with unique image data
*/
$.Tile = function(level, x, y, bounds, exists, url, context2D, loadWithAjax, ajaxHeaders, sourceBounds, postData, cacheKey) {
/**
* The zoom level this tile belongs to.
* @member {Number} level
* @memberof OpenSeadragon.Tile#
*/
this.level = level;
/**
* The vector component 'x'.
* @member {Number} x
* @memberof OpenSeadragon.Tile#
*/
this.x = x;
/**
* The vector component 'y'.
* @member {Number} y
* @memberof OpenSeadragon.Tile#
*/
this.y = y;
/**
* Where this tile fits, in normalized coordinates
* @member {OpenSeadragon.Rect} bounds
* @memberof OpenSeadragon.Tile#
*/
this.bounds = bounds;
/**
* The portion of the tile to use as the source of the drawing operation, in pixels. Note that
* this only works when drawing with canvas; when drawing with HTML the entire tile is always used.
* @member {OpenSeadragon.Rect} sourceBounds
* @memberof OpenSeadragon.Tile#
*/
this.sourceBounds = sourceBounds;
/**
* Is this tile a part of a sparse image? Also has this tile failed to load?
* @member {Boolean} exists
* @memberof OpenSeadragon.Tile#
*/
this.exists = exists;
/**
* Private property to hold string url or url retriever function.
* Consumers should access via Tile.getUrl()
* @private
* @member {String|Function} url
* @memberof OpenSeadragon.Tile#
*/
this._url = url;
/**
* Post parameters for this tile. For example, it can be an URL-encoded string
* in k1=v1&k2=v2... format, or a JSON, or a FormData instance... or null if no POST request used
* @member {String} postData HTTP POST data (usually but not necessarily in k=v&k2=v2... form,
* see TileSource::getPostData) or null
* @memberof OpenSeadragon.Tile#
*/
this.postData = postData;
/**
* The context2D of this tile if it is provided directly by the tile source.
* @member {CanvasRenderingContext2D} context2D
* @memberOf OpenSeadragon.Tile#
*/
this.context2D = context2D;
/**
* Whether to load this tile's image with an AJAX request.
* @member {Boolean} loadWithAjax
* @memberof OpenSeadragon.Tile#
*/
this.loadWithAjax = loadWithAjax;
/**
* The headers to be used in requesting this tile's image.
* Only used if loadWithAjax is set to true.
* @member {Object} ajaxHeaders
* @memberof OpenSeadragon.Tile#
*/
this.ajaxHeaders = ajaxHeaders;
if (cacheKey === undefined) {
$.console.warn("Tile constructor needs 'cacheKey' variable: creation tile cache" +
" in Tile class is deprecated. TileSource.prototype.getTileHashKey will be used.");
cacheKey = $.TileSource.prototype.getTileHashKey(level, x, y, url, ajaxHeaders, postData);
}
/**
* The unique cache key for this tile.
* @member {String} cacheKey
* @memberof OpenSeadragon.Tile#
*/
this.cacheKey = cacheKey;
/**
* Is this tile loaded?
* @member {Boolean} loaded
* @memberof OpenSeadragon.Tile#
*/
this.loaded = false;
/**
* Is this tile loading?
* @member {Boolean} loading
* @memberof OpenSeadragon.Tile#
*/
this.loading = false;
/**
* The HTML div element for this tile
* @member {Element} element
* @memberof OpenSeadragon.Tile#
*/
this.element = null;
/**
* The HTML img element for this tile.
* @member {Element} imgElement
* @memberof OpenSeadragon.Tile#
*/
this.imgElement = null;
/**
* The alias of this.element.style.
* @member {String} style
* @memberof OpenSeadragon.Tile#
*/
this.style = null;
/**
* This tile's position on screen, in pixels.
* @member {OpenSeadragon.Point} position
* @memberof OpenSeadragon.Tile#
*/
this.position = null;
/**
* This tile's size on screen, in pixels.
* @member {OpenSeadragon.Point} size
* @memberof OpenSeadragon.Tile#
*/
this.size = null;
/**
* Whether to flip the tile when rendering.
* @member {Boolean} flipped
* @memberof OpenSeadragon.Tile#
*/
this.flipped = false;
/**
* The start time of this tile's blending.
* @member {Number} blendStart
* @memberof OpenSeadragon.Tile#
*/
this.blendStart = null;
/**
* The current opacity this tile should be.
* @member {Number} opacity
* @memberof OpenSeadragon.Tile#
*/
this.opacity = null;
/**
* The squared distance of this tile to the viewport center.
* Use for comparing tiles.
* @private
* @member {Number} squaredDistance
* @memberof OpenSeadragon.Tile#
*/
this.squaredDistance = null;
/**
* The visibility score of this tile.
* @member {Number} visibility
* @memberof OpenSeadragon.Tile#
*/
this.visibility = null;
/**
* The transparency indicator of this tile.
* @member {Boolean} hasTransparency true if tile contains transparency for correct rendering
* @memberof OpenSeadragon.Tile#
*/
this.hasTransparency = false;
/**
* Whether this tile is currently being drawn.
* @member {Boolean} beingDrawn
* @memberof OpenSeadragon.Tile#
*/
this.beingDrawn = false;
/**
* Timestamp the tile was last touched.
* @member {Number} lastTouchTime
* @memberof OpenSeadragon.Tile#
*/
this.lastTouchTime = 0;
/**
* Whether this tile is in the right-most column for its level.
* @member {Boolean} isRightMost
* @memberof OpenSeadragon.Tile#
*/
this.isRightMost = false;
/**
* Whether this tile is in the bottom-most row for its level.
* @member {Boolean} isBottomMost
* @memberof OpenSeadragon.Tile#
*/
this.isBottomMost = false;
};
/** @lends OpenSeadragon.Tile.prototype */
$.Tile.prototype = {
/**
* Provides a string representation of this tiles level and (x,y)
* components.
* @function
* @returns {String}
*/
toString: function() {
return this.level + "/" + this.x + "_" + this.y;
},
// private
_hasTransparencyChannel: function() {
console.warn("Tile.prototype._hasTransparencyChannel() has been " +
"deprecated and will be removed in the future. Use TileSource.prototype.hasTransparency() instead.");
return !!this.context2D || this.getUrl().match('.png');
},
/**
* Renders the tile in an html container.
* @function
* @param {Element} container
*/
drawHTML: function( container ) {
if (!this.cacheImageRecord) {
$.console.warn(
'[Tile.drawHTML] attempting to draw tile %s when it\'s not cached',
this.toString());
return;
}
if ( !this.loaded ) {
$.console.warn(
"Attempting to draw tile %s when it's not yet loaded.",
this.toString()
);
return;
}
//EXPERIMENTAL - trying to figure out how to scale the container
// content during animation of the container size.
if ( !this.element ) {
var image = this.getImage();
if (!image) {
return;
}
this.element = $.makeNeutralElement( "div" );
this.imgElement = image.cloneNode();
this.imgElement.style.msInterpolationMode = "nearest-neighbor";
this.imgElement.style.width = "100%";
this.imgElement.style.height = "100%";
this.style = this.element.style;
this.style.position = "absolute";
}
if ( this.element.parentNode !== container ) {
container.appendChild( this.element );
}
if ( this.imgElement.parentNode !== this.element ) {
this.element.appendChild( this.imgElement );
}
this.style.top = this.position.y + "px";
this.style.left = this.position.x + "px";
this.style.height = this.size.y + "px";
this.style.width = this.size.x + "px";
if (this.flipped) {
this.style.transform = "scaleX(-1)";
}
$.setElementOpacity( this.element, this.opacity );
},
/**
* The Image object for this tile.
* @member {Object} image
* @memberof OpenSeadragon.Tile#
* @deprecated
* @returns {Image}
*/
get image() {
$.console.error("[Tile.image] property has been deprecated. Use [Tile.prototype.getImage] instead.");
return this.getImage();
},
/**
* The URL of this tile's image.
* @member {String} url
* @memberof OpenSeadragon.Tile#
* @deprecated
* @returns {String}
*/
get url() {
$.console.error("[Tile.url] property has been deprecated. Use [Tile.prototype.getUrl] instead.");
return this.getUrl();
},
/**
* Get the Image object for this tile.
* @returns {Image}
*/
getImage: function() {
return this.cacheImageRecord.getImage();
},
/**
* Get the url string for this tile.
* @returns {String}
*/
getUrl: function() {
if (typeof this._url === 'function') {
return this._url();
}
return this._url;
},
/**
* Get the CanvasRenderingContext2D instance for tile image data drawn
* onto Canvas if enabled and available
* @returns {CanvasRenderingContext2D}
*/
getCanvasContext: function() {
return this.context2D || this.cacheImageRecord.getRenderedContext();
},
/**
* Renders the tile in a canvas-based context.
* @function
* @param {Canvas} context
* @param {Function} drawingHandler - Method for firing the drawing event.
* drawingHandler({context, tile, rendered})
* where <code>rendered</code> is the context with the pre-drawn image.
* @param {Number} [scale=1] - Apply a scale to position and size
* @param {OpenSeadragon.Point} [translate] - A translation vector
* @param {Boolean} [shouldRoundPositionAndSize] - Tells whether to round
* position and size of tiles supporting alpha channel in non-transparency
* context.
* @param {OpenSeadragon.TileSource} source - The source specification of the tile.
*/
drawCanvas: function( context, drawingHandler, scale, translate, shouldRoundPositionAndSize, source) {
var position = this.position.times($.pixelDensityRatio),
size = this.size.times($.pixelDensityRatio),
rendered;
if (!this.context2D && !this.cacheImageRecord) {
$.console.warn(
'[Tile.drawCanvas] attempting to draw tile %s when it\'s not cached',
this.toString());
return;
}
rendered = this.getCanvasContext();
if ( !this.loaded || !rendered ){
$.console.warn(
"Attempting to draw tile %s when it's not yet loaded.",
this.toString()
);
return;
}
context.save();
context.globalAlpha = this.opacity;
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);
}
//if we are supposed to be rendering fully opaque rectangle,
//ie its done fading or fading is turned off, and if we are drawing
//an image with an alpha channel, then the only way
//to avoid seeing the tile underneath is to clear the rectangle
if (context.globalAlpha === 1 && this.hasTransparency) {
if (shouldRoundPositionAndSize) {
// Round to the nearest whole pixel so we don't get seams from overlap.
position.x = Math.round(position.x);
position.y = Math.round(position.y);
size.x = Math.round(size.x);
size.y = Math.round(size.y);
}
//clearing only the inside of the rectangle occupied
//by the png prevents edge flikering
context.clearRect(
position.x,
position.y,
size.x,
size.y
);
}
// This gives the application a chance to make image manipulation
// changes as we are rendering the image
drawingHandler({context: context, tile: this, rendered: rendered});
var sourceWidth, sourceHeight;
if (this.sourceBounds) {
sourceWidth = Math.min(this.sourceBounds.width, rendered.canvas.width);
sourceHeight = Math.min(this.sourceBounds.height, rendered.canvas.height);
} else {
sourceWidth = rendered.canvas.width;
sourceHeight = rendered.canvas.height;
}
context.translate(position.x + size.x / 2, 0);
if (this.flipped) {
context.scale(-1, 1);
}
context.drawImage(
rendered.canvas,
0,
0,
sourceWidth,
sourceHeight,
-size.x / 2,
position.y,
size.x,
size.y
);
context.restore();
},
/**
* Get the ratio between current and original size.
* @function
* @returns {Float}
*/
getScaleForEdgeSmoothing: function() {
var context;
if (this.cacheImageRecord) {
context = this.cacheImageRecord.getRenderedContext();
} else if (this.context2D) {
context = this.context2D;
} else {
$.console.warn(
'[Tile.drawCanvas] attempting to get tile scale %s when tile\'s not cached',
this.toString());
return 1;
}
return context.canvas.width / (this.size.x * $.pixelDensityRatio);
},
/**
* 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.
* @returns {OpenSeadragon.Point}
*/
getTranslationForEdgeSmoothing: function(scale, canvasSize, sketchCanvasSize) {
// 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. In that case, some browsers throw:
// INDEX_SIZE_ERR: DOM Exception 1: Index or size was negative, or greater than the allowed value.
var x = Math.max(1, Math.ceil((sketchCanvasSize.x - canvasSize.x) / 2));
var y = Math.max(1, Math.ceil((sketchCanvasSize.y - canvasSize.y) / 2));
return new $.Point(x, y).minus(
this.position
.times($.pixelDensityRatio)
.times(scale || 1)
.apply(function(x) {
return x % 1;
})
);
},
/**
* Removes tile from its container.
* @function
*/
unload: function() {
if ( this.imgElement && this.imgElement.parentNode ) {
this.imgElement.parentNode.removeChild( this.imgElement );
}
if ( this.element && this.element.parentNode ) {
this.element.parentNode.removeChild( this.element );
}
this.element = null;
this.imgElement = null;
this.loaded = false;
this.loading = false;
}
};
}( OpenSeadragon ));