openseadragon/src/tile.js
2014-11-05 13:48:27 -08:00

327 lines
10 KiB
JavaScript

/*
* OpenSeadragon - Tile
*
* Copyright (C) 2009 CodePlex Foundation
* Copyright (C) 2010-2013 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.Point} 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} url The URL of this tile's image.
*/
$.Tile = function(level, x, y, bounds, exists, url) {
/**
* 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.Point} bounds
* @memberof OpenSeadragon.Tile#
*/
this.bounds = bounds;
/**
* 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;
/**
* The URL of this tile's image.
* @member {String} url
* @memberof OpenSeadragon.Tile#
*/
this.url = url;
/**
* 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 Image object for this tile.
* @member {Object} image
* @memberof OpenSeadragon.Tile#
*/
this.image = 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;
/**
* 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 distance of this tile to the viewport center.
* @member {Number} distance
* @memberof OpenSeadragon.Tile#
*/
this.distance = null;
/**
* The visibility score of this tile.
* @member {Number} visibility
* @memberof OpenSeadragon.Tile#
*/
this.visibility = null;
/**
* 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;
};
$.Tile.prototype = /** @lends OpenSeadragon.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;
},
/**
* Renders the tile in an html container.
* @function
* @param {Element} container
*/
drawHTML: function( container ) {
if ( !this.loaded || !this.image ) {
$.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 ) {
this.element = $.makeNeutralElement( "div" );
this.imgElement = $.makeNeutralElement( "img" );
this.imgElement.src = this.url;
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";
$.setElementOpacity( this.element, this.opacity );
},
/**
* Renders the tile in a canvas-based context.
* @function
* @param {Canvas} context
* @param {Function} method for firing the drawing event. drawingHandler({context, tile, rendered})
* where <code>rendered</code> is the context with the pre-drawn image.
*/
drawCanvas: function( context, drawingHandler ) {
var position = this.position,
size = this.size,
rendered,
canvas;
if (!this.cacheImageRecord) {
$.console.warn('[Tile.drawCanvas] attempting to draw tile %s when it\'s not cached', this.toString());
return;
}
rendered = this.cacheImageRecord.getRenderedContext();
if ( !this.loaded || !( this.image || rendered) ){
$.console.warn(
"Attempting to draw tile %s when it's not yet loaded.",
this.toString()
);
return;
}
context.globalAlpha = this.opacity;
//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.url.match('.png') ){
//clearing only the inside of the rectangle occupied
//by the png prevents edge flikering
context.clearRect(
position.x+1,
position.y+1,
size.x-2,
size.y-2
);
}
if(!rendered){
canvas = document.createElement( 'canvas' );
canvas.width = this.image.width;
canvas.height = this.image.height;
rendered = canvas.getContext('2d');
rendered.drawImage( this.image, 0, 0 );
this.cacheImageRecord.setRenderedContext(rendered);
//since we are caching the prerendered image on a canvas
//allow the image to not be held in memory
this.image = null;
}
// This gives the application a chance to make image manipulation changes as we are rendering the image
drawingHandler({context: context, tile: this, rendered: rendered});
context.drawImage(
rendered.canvas,
0,
0,
rendered.canvas.width,
rendered.canvas.height,
position.x,
position.y,
size.x,
size.y
);
},
/**
* 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.image = null;
this.loaded = false;
this.loading = false;
}
};
}( OpenSeadragon ));