openseadragon/src/drawerbase.js
2023-12-14 19:14:05 -05:00

273 lines
10 KiB
JavaScript

/*
* OpenSeadragon - DrawerBase
*
* 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 DrawerBase
* @memberof OpenSeadragon
* @classdesc Base class for Drawers that handle rendering of tiles 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.
*/
$.DrawerBase = class DrawerBase{
constructor(options){
$.console.assert( options.viewer, "[Drawer] options.viewer is required" );
//backward compatibility for positional args while preferring more
//idiomatic javascript options object as the only argument
var args = arguments;
if( !$.isPlainObject( options ) ){
options = {
source: args[ 0 ], // Reference to Viewer tile source.
viewport: args[ 1 ], // Reference to Viewer viewport.
element: args[ 2 ] // Parent element.
};
}
$.console.assert( options.viewport, "[Drawer] options.viewport is required" );
$.console.assert( options.element, "[Drawer] options.element is required" );
if ( options.source ) {
$.console.error( "[Drawer] options.source is no longer accepted; use TiledImage instead" );
}
this.viewer = options.viewer;
this.viewport = options.viewport;
this.debugGridColor = typeof options.debugGridColor === 'string' ? [options.debugGridColor] : options.debugGridColor || $.DEFAULT_SETTINGS.debugGridColor;
this.options = options.options || {};
/**
* The parent element of this Drawer instance, passed in when the Drawer was created.
* The parent of {@link OpenSeadragon.DrawerBase#canvas}.
* @member {Element} container
* @memberof OpenSeadragon.DrawerBase#
*/
this.container = $.getElement( options.element );
this._renderingTarget = this._createDrawingElement();
this.canvas.style.width = "100%";
this.canvas.style.height = "100%";
this.canvas.style.position = "absolute";
this.canvas.style.left = "0";
$.setElementOpacity( this.canvas, this.viewer.opacity, true );
// Allow pointer events to pass through the canvas element so implicit
// pointer capture works on touch devices
$.setElementPointerEventsNone( this.canvas );
$.setElementTouchActionNone( this.canvas );
// explicit left-align
this.container.style.textAlign = "left";
this.container.appendChild( this.canvas );
this._checkForAPIOverrides();
}
// protect the canvas member with a getter
get canvas(){
return this._renderingTarget;
}
get element(){
$.console.error('Drawer.element is deprecated. Use Drawer.container instead.');
return this.container;
}
/**
* @returns {String|undefined} What type of drawer this is.
*/
getType(){
$.console.error('Drawer.getType must be implemented by child class');
return undefined;
}
/**
* @returns {Boolean} whether the drawer implementation is supported by the browser
*/
static isSupported() {
$.console.error('Drawer.isSupported must be implemented by child class');
}
/**
* create the HTML element (e.g. canvas, div) that the image will be drawn into
* @returns {Element} the element to draw into
*/
_createDrawingElement() {
$.console.error('Drawer._createDrawingElement must be implemented by child class');
return null;
}
/**
* @param {Array} tiledImages - An array of TiledImages that are ready to be drawn
*/
draw(tiledImages) {
$.console.error('Drawer.draw must be implemented by child class');
}
/**
* @returns {Boolean} True if rotation is supported.
*/
canRotate() {
$.console.error('Drawer.canRotate must be implemented by child class');
}
/**
* Destroy the drawer (unload current loaded tiles)
*/
destroy() {
$.console.error('Drawer.destroy must be implemented by child class');
}
/**
* @returns {Boolean} Whether this drawer requires enforcing minimum tile overlap to avoid showing seams.
*/
minimumOverlapRequired() {
return false;
}
/**
* Turns image smoothing on or off for this viewer. Note: Ignored in some (especially older) browsers that do not support this property.
*
* @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(imageSmoothingEnabled){
$.console.error('Drawer.setImageSmoothingEnabled must be implemented by child class');
}
/**
* Optional public API to draw a rectangle (e.g. for debugging purposes)
* Child classes can override this method if they wish to support this
* @param {OpenSeadragon.Rect} rect
*/
drawDebuggingRect(rect) {
$.console.warn('[drawer].drawDebuggingRect is not implemented by this drawer');
}
// Deprecated functions
clear(){
$.console.warn('[drawer].clear() is deprecated. The drawer is responsible for clearing itself as needed before drawing tiles.');
}
// Private functions
/**
* @private
* Ensures that child classes have provided implementations for public API methods
* draw, canRotate, destroy, and setImageSmoothinEnabled. Throws an exception if the original
* placeholder methods are still in place.
*/
_checkForAPIOverrides(){
if(this._createDrawingElement === $.DrawerBase.prototype._createDrawingElement){
throw(new Error("[drawer]._createDrawingElement must be implemented by child class"));
}
if(this.draw === $.DrawerBase.prototype.draw){
throw(new Error("[drawer].draw must be implemented by child class"));
}
if(this.canRotate === $.DrawerBase.prototype.canRotate){
throw(new Error("[drawer].canRotate must be implemented by child class"));
}
if(this.destroy === $.DrawerBase.prototype.destroy){
throw(new Error("[drawer].destroy must be implemented by child class"));
}
if(this.setImageSmoothingEnabled === $.DrawerBase.prototype.setImageSmoothingEnabled){
throw(new Error("[drawer].setImageSmoothingEnabled must be implemented by child class"));
}
}
// Utility functions
/**
* Scale from OpenSeadragon viewer rectangle to drawer rectangle
* (ignoring rotation)
* @param {OpenSeadragon.Rect} rectangle - The rectangle in viewport coordinate system.
* @returns {OpenSeadragon.Rect} Rectangle in drawer coordinate system.
*/
viewportToDrawerRectangle(rectangle) {
var topLeft = this.viewport.pixelFromPointNoRotate(rectangle.getTopLeft(), true);
var size = this.viewport.deltaPixelsFromPointsNoRotate(rectangle.getSize(), true);
return new $.Rect(
topLeft.x * $.pixelDensityRatio,
topLeft.y * $.pixelDensityRatio,
size.x * $.pixelDensityRatio,
size.y * $.pixelDensityRatio
);
}
/**
* This function converts the given point from to the drawer coordinate by
* multiplying it with the pixel density.
* This function does not take rotation into account, thus assuming provided
* point is at 0 degree.
* @param {OpenSeadragon.Point} point - the pixel point to convert
* @returns {OpenSeadragon.Point} Point in drawer coordinate system.
*/
viewportCoordToDrawerCoord(point) {
var vpPoint = this.viewport.pixelFromPointNoRotate(point, true);
return new $.Point(
vpPoint.x * $.pixelDensityRatio,
vpPoint.y * $.pixelDensityRatio
);
}
// Internal utility functions
/**
* @private
* Calculate width and height of the canvas based on viewport dimensions
* and pixelDensityRatio
* @returns {OpenSeadragon.Point} {x, y} size of the canvas
*/
_calculateCanvasSize() {
var pixelDensityRatio = $.pixelDensityRatio;
var viewportSize = this.viewport.getContainerSize();
return new OpenSeadragon.Point( Math.round(viewportSize.x * pixelDensityRatio), Math.round(viewportSize.y * pixelDensityRatio));
}
};
}( OpenSeadragon ));