69 lines
2.2 KiB
JavaScript
69 lines
2.2 KiB
JavaScript
/**
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* Support for swipe and tap on touch devices
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*
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* This plugin implements navigation for plugin devices, via swiping left/right,
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* or tapping on the left/right edges of the screen.
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*
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*
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*
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* Copyright 2015: Andrew Dunai (@and3rson)
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* Modified to a plugin, 2016: Henrik Ingo (@henrikingo)
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*
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* MIT License
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*/
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/* global document, window */
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( function( document, window ) {
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"use strict";
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// Touch handler to detect swiping left and right based on window size.
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// If the difference in X change is bigger than 1/20 of the screen width,
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// we simply call an appropriate API function to complete the transition.
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var startX = 0;
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var lastX = 0;
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var lastDX = 0;
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var threshold = window.innerWidth / 20;
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document.addEventListener( "touchstart", function( event ) {
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lastX = startX = event.touches[ 0 ].clientX;
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} );
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document.addEventListener( "touchmove", function( event ) {
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var x = event.touches[ 0 ].clientX;
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var diff = x - startX;
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// To be used in touchend
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lastDX = lastX - x;
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lastX = x;
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window.impress().swipe( diff / window.innerWidth );
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} );
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document.addEventListener( "touchend", function() {
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var totalDiff = lastX - startX;
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if ( Math.abs( totalDiff ) > window.innerWidth / 5 && ( totalDiff * lastDX ) <= 0 ) {
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if ( totalDiff > window.innerWidth / 5 && lastDX <= 0 ) {
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window.impress().prev();
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} else if ( totalDiff < -window.innerWidth / 5 && lastDX >= 0 ) {
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window.impress().next();
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}
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} else if ( Math.abs( lastDX ) > threshold ) {
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if ( lastDX < -threshold ) {
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window.impress().prev();
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} else if ( lastDX > threshold ) {
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window.impress().next();
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}
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} else {
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// No movement - move (back) to the current slide
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window.impress().goto( document.querySelector( "#impress .step.active" ) );
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}
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} );
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document.addEventListener( "touchcancel", function() {
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// Move (back) to the current slide
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window.impress().goto( document.querySelector( "#impress .step.active" ) );
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} );
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} )( document, window );
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