mirror of
https://github.com/Jermolene/TiddlyWiki5
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112 lines
3.2 KiB
JavaScript
112 lines
3.2 KiB
JavaScript
/*\
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title: $:/core/modules/utils/dom/scroller.js
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type: application/javascript
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module-type: utils
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Module that creates a $tw.utils.Scroller object prototype that manages scrolling in the browser
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\*/
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(function(){
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/*jslint node: true, browser: true */
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/*global $tw: false */
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"use strict";
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/*
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Event handler for when the `tm-scroll` event hits the document body
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*/
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var PageScroller = function() {
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this.idRequestFrame = null;
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this.requestAnimationFrame = window.requestAnimationFrame ||
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window.webkitRequestAnimationFrame ||
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window.mozRequestAnimationFrame ||
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function(callback) {
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return window.setTimeout(callback, 1000/60);
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};
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this.cancelAnimationFrame = window.cancelAnimationFrame ||
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window.webkitCancelAnimationFrame ||
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window.webkitCancelRequestAnimationFrame ||
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window.mozCancelAnimationFrame ||
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window.mozCancelRequestAnimationFrame ||
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function(id) {
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window.clearTimeout(id);
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};
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};
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PageScroller.prototype.cancelScroll = function() {
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if(this.idRequestFrame) {
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this.cancelAnimationFrame.call(window,this.idRequestFrame);
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this.idRequestFrame = null;
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}
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};
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/*
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Handle an event
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*/
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PageScroller.prototype.handleEvent = function(event) {
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if(event.type === "tm-scroll") {
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return this.scrollIntoView(event.target);
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}
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return true;
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};
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/*
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Handle a scroll event hitting the page document
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*/
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PageScroller.prototype.scrollIntoView = function(element) {
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var self = this,
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duration = $tw.utils.getAnimationDuration();
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// Now get ready to scroll the body
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this.cancelScroll();
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this.startTime = Date.now();
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// Get the client bounds of the element and adjust by the scroll position
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var getBounds = function() {
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var clientBounds = element.getBoundingClientRect(),
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scrollPosition = $tw.utils.getScrollPosition();
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return {
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left: clientBounds.left + scrollPosition.x,
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top: clientBounds.top + scrollPosition.y,
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width: clientBounds.width,
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height: clientBounds.height
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};
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},
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// We'll consider the horizontal and vertical scroll directions separately via this function
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// targetPos/targetSize - position and size of the target element
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// currentPos/currentSize - position and size of the current scroll viewport
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// returns: new position of the scroll viewport
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getEndPos = function(targetPos,targetSize,currentPos,currentSize) {
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var newPos = targetPos;
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// If we are scrolling within 50 pixels of the top/left then snap to zero
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if(newPos < 50) {
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newPos = 0;
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}
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return newPos;
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},
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drawFrame = function drawFrame() {
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var t;
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if(duration <= 0) {
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t = 1;
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} else {
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t = ((Date.now()) - self.startTime) / duration;
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}
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if(t >= 1) {
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self.cancelScroll();
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t = 1;
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}
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t = $tw.utils.slowInSlowOut(t);
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var scrollPosition = $tw.utils.getScrollPosition(),
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bounds = getBounds(),
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endX = getEndPos(bounds.left,bounds.width,scrollPosition.x,window.innerWidth),
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endY = getEndPos(bounds.top,bounds.height,scrollPosition.y,window.innerHeight);
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window.scrollTo(scrollPosition.x + (endX - scrollPosition.x) * t,scrollPosition.y + (endY - scrollPosition.y) * t);
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if(t < 1) {
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self.idRequestFrame = self.requestAnimationFrame.call(window,drawFrame);
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}
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};
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drawFrame();
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};
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exports.PageScroller = PageScroller;
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})();
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