lca20-bt/plugin/zoom-js/zoom.js

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2012-10-09 13:22:16 +00:00
// Custom reveal.js integration
(function(){
document.querySelector( '.reveal' ).addEventListener( 'click', function( event ) {
if( event.altKey ) {
event.preventDefault();
zoom.to({ element: event.target, pan: false });
}
} );
})();
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/*!
* zoom.js 0.2 (modified version for use with reveal.js)
* http://lab.hakim.se/zoom-js
* MIT licensed
*
* Copyright (C) 2011-2012 Hakim El Hattab, http://hakim.se
*/
var zoom = (function(){
// The current zoom level (scale)
var level = 1;
// The current mouse position, used for panning
var mouseX = 0,
mouseY = 0;
// Timeout before pan is activated
var panEngageTimeout = -1,
panUpdateInterval = -1;
var currentOptions = null;
// Check for transform support so that we can fallback otherwise
var supportsTransforms = 'WebkitTransform' in document.body.style ||
'MozTransform' in document.body.style ||
'msTransform' in document.body.style ||
'OTransform' in document.body.style ||
'transform' in document.body.style;
if( supportsTransforms ) {
// The easing that will be applied when we zoom in/out
document.body.style.transition = 'transform 0.8s ease';
document.body.style.OTransition = '-o-transform 0.8s ease';
document.body.style.msTransition = '-ms-transform 0.8s ease';
document.body.style.MozTransition = '-moz-transform 0.8s ease';
document.body.style.WebkitTransition = '-webkit-transform 0.8s ease';
}
// Zoom out if the user hits escape
document.addEventListener( 'keyup', function( event ) {
if( level !== 1 && event.keyCode === 27 ) {
zoom.out();
}
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}, false );
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// Monitor mouse movement for panning
document.addEventListener( 'mousemove', function( event ) {
if( level !== 1 ) {
mouseX = event.clientX;
mouseY = event.clientY;
}
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}, false );
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/**
* Applies the CSS required to zoom in, prioritizes use of CSS3
* transforms but falls back on zoom for IE.
*
* @param {Number} pageOffsetX
* @param {Number} pageOffsetY
* @param {Number} elementOffsetX
* @param {Number} elementOffsetY
* @param {Number} scale
*/
function magnify( pageOffsetX, pageOffsetY, elementOffsetX, elementOffsetY, scale ) {
if( supportsTransforms ) {
var origin = pageOffsetX +'px '+ pageOffsetY +'px',
transform = 'translate('+ -elementOffsetX +'px,'+ -elementOffsetY +'px) scale('+ scale +')';
document.body.style.transformOrigin = origin;
document.body.style.OTransformOrigin = origin;
document.body.style.msTransformOrigin = origin;
document.body.style.MozTransformOrigin = origin;
document.body.style.WebkitTransformOrigin = origin;
document.body.style.transform = transform;
document.body.style.OTransform = transform;
document.body.style.msTransform = transform;
document.body.style.MozTransform = transform;
document.body.style.WebkitTransform = transform;
}
else {
// Reset all values
if( scale === 1 ) {
document.body.style.position = '';
document.body.style.left = '';
document.body.style.top = '';
document.body.style.width = '';
document.body.style.height = '';
document.body.style.zoom = '';
}
// Apply scale
else {
document.body.style.position = 'relative';
document.body.style.left = ( - ( pageOffsetX + elementOffsetX ) / scale ) + 'px';
document.body.style.top = ( - ( pageOffsetY + elementOffsetY ) / scale ) + 'px';
document.body.style.width = ( scale * 100 ) + '%';
document.body.style.height = ( scale * 100 ) + '%';
document.body.style.zoom = scale;
}
}
level = scale;
if( level !== 1 && document.documentElement.classList ) {
document.documentElement.classList.add( 'zoomed' );
}
else {
document.documentElement.classList.remove( 'zoomed' );
}
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}
/**
* Pan the document when the mosue cursor approaches the edges
* of the window.
*/
function pan() {
var range = 0.12,
rangeX = window.innerWidth * range,
rangeY = window.innerHeight * range,
scrollOffset = getScrollOffset();
// Up
if( mouseY < rangeY ) {
window.scroll( scrollOffset.x, scrollOffset.y - ( 1 - ( mouseY / rangeY ) ) * ( 14 / level ) );
}
// Down
else if( mouseY > window.innerHeight - rangeY ) {
window.scroll( scrollOffset.x, scrollOffset.y + ( 1 - ( window.innerHeight - mouseY ) / rangeY ) * ( 14 / level ) );
}
// Left
if( mouseX < rangeX ) {
window.scroll( scrollOffset.x - ( 1 - ( mouseX / rangeX ) ) * ( 14 / level ), scrollOffset.y );
}
// Right
else if( mouseX > window.innerWidth - rangeX ) {
window.scroll( scrollOffset.x + ( 1 - ( window.innerWidth - mouseX ) / rangeX ) * ( 14 / level ), scrollOffset.y );
}
}
function getScrollOffset() {
return {
x: window.scrollX !== undefined ? window.scrollX : window.pageXOffset,
y: window.scrollY !== undefined ? window.scrollY : window.pageXYffset
}
}
return {
/**
* Zooms in on either a rectangle or HTML element.
*
* @param {Object} options
* - element: HTML element to zoom in on
* OR
* - x/y: coordinates in non-transformed space to zoom in on
* - width/height: the portion of the screen to zoom in on
* - scale: can be used instead of width/height to explicitly set scale
*/
to: function( options ) {
// Due to an implementation limitation we can't zoom in
// to another element without zooming out first
if( level !== 1 ) {
zoom.out();
}
else {
options.x = options.x || 0;
options.y = options.y || 0;
// If an element is set, that takes precedence
if( !!options.element ) {
// Space around the zoomed in element to leave on screen
var padding = 20;
options.width = options.element.getBoundingClientRect().width + ( padding * 2 );
options.height = options.element.getBoundingClientRect().height + ( padding * 2 );
options.x = options.element.getBoundingClientRect().left - padding;
options.y = options.element.getBoundingClientRect().top - padding;
}
// If width/height values are set, calculate scale from those values
if( options.width !== undefined && options.height !== undefined ) {
options.scale = Math.max( Math.min( window.innerWidth / options.width, window.innerHeight / options.height ), 1 );
}
if( options.scale > 1 ) {
options.x *= options.scale;
options.y *= options.scale;
var scrollOffset = getScrollOffset();
if( options.element ) {
scrollOffset.x -= ( window.innerWidth - ( options.width * options.scale ) ) / 2;
}
magnify( scrollOffset.x, scrollOffset.y, options.x, options.y, options.scale );
if( options.pan !== false ) {
// Wait with engaging panning as it may conflict with the
// zoom transition
panEngageTimeout = setTimeout( function() {
panUpdateInterval = setInterval( pan, 1000 / 60 );
}, 800 );
}
}
currentOptions = options;
}
},
/**
* Resets the document zoom state to its default.
*/
out: function() {
clearTimeout( panEngageTimeout );
clearInterval( panUpdateInterval );
var scrollOffset = getScrollOffset();
if( currentOptions && currentOptions.element ) {
scrollOffset.x -= ( window.innerWidth - ( currentOptions.width * currentOptions.scale ) ) / 2;
}
magnify( scrollOffset.x, scrollOffset.y, 0, 0, 1 );
level = 1;
},
// Alias
magnify: function( options ) { this.to( options ) },
reset: function() { this.out() },
zoomLevel: function() {
return level;
}
}
})();