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Commit b558f742 authored by Hakim El Hattab's avatar Hakim El Hattab
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zoom viewport is centered on target element #900

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plugin/zoom-js/zoom.js
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......@@ -16,11 +16,11 @@
})();
/*!
* zoom.js 0.2 (modified version for use with reveal.js)
* zoom.js 0.3 (modified for use with reveal.js)
* http://lab.hakim.se/zoom-js
* MIT licensed
*
* Copyright (C) 2011-2012 Hakim El Hattab, http://hakim.se
* Copyright (C) 2011-2014 Hakim El Hattab, http://hakim.se
*/
var zoom = (function(){
......@@ -35,8 +35,6 @@ var zoom = (function(){
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 ||
......@@ -58,7 +56,7 @@ var zoom = (function(){
if( level !== 1 && event.keyCode === 27 ) {
zoom.out();
}
}, false );
} );
// Monitor mouse movement for panning
document.addEventListener( 'mousemove', function( event ) {
......@@ -66,38 +64,56 @@ var zoom = (function(){
mouseX = event.clientX;
mouseY = event.clientY;
}
}, false );
} );
/**
* Applies the CSS required to zoom in, prioritizes use of CSS3
* Applies the CSS required to zoom in, prefers the use of CSS3
* transforms but falls back on zoom for IE.
*
* @param {Number} pageOffsetX
* @param {Number} pageOffsetY
* @param {Number} elementOffsetX
* @param {Number} elementOffsetY
* @param {Object} rect
* @param {Number} scale
*/
function magnify( pageOffsetX, pageOffsetY, elementOffsetX, elementOffsetY, scale ) {
function magnify( rect, scale ) {
var scrollOffset = getScrollOffset();
// Ensure a width/height is set
rect.width = rect.width || 1;
rect.height = rect.height || 1;
// Center the rect within the zoomed viewport
rect.x -= ( window.innerWidth - ( rect.width * scale ) ) / 2;
rect.y -= ( window.innerHeight - ( rect.height * scale ) ) / 2;
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;
// Reset
if( scale === 1 ) {
document.body.style.transform = '';
document.body.style.OTransform = '';
document.body.style.msTransform = '';
document.body.style.MozTransform = '';
document.body.style.WebkitTransform = '';
}
// Scale
else {
var origin = scrollOffset.x +'px '+ scrollOffset.y +'px',
transform = 'translate('+ -rect.x +'px,'+ -rect.y +'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
// Reset
if( scale === 1 ) {
document.body.style.position = '';
document.body.style.left = '';
......@@ -106,11 +122,11 @@ var zoom = (function(){
document.body.style.height = '';
document.body.style.zoom = '';
}
// Apply scale
// 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.left = ( - ( scrollOffset.x + rect.x ) / scale ) + 'px';
document.body.style.top = ( - ( scrollOffset.y + rect.y ) / scale ) + 'px';
document.body.style.width = ( scale * 100 ) + '%';
document.body.style.height = ( scale * 100 ) + '%';
document.body.style.zoom = scale;
......@@ -119,11 +135,13 @@ var zoom = (function(){
level = scale;
if( level !== 1 && document.documentElement.classList ) {
document.documentElement.classList.add( 'zoomed' );
}
else {
document.documentElement.classList.remove( 'zoomed' );
if( document.documentElement.classList ) {
if( level !== 1 ) {
document.documentElement.classList.add( 'zoomed' );
}
else {
document.documentElement.classList.remove( 'zoomed' );
}
}
}
......@@ -159,7 +177,7 @@ var zoom = (function(){
function getScrollOffset() {
return {
x: window.scrollX !== undefined ? window.scrollX : window.pageXOffset,
y: window.scrollY !== undefined ? window.scrollY : window.pageXYffset
y: window.scrollY !== undefined ? window.scrollY : window.pageYOffset
}
}
......@@ -175,6 +193,7 @@ var zoom = (function(){
* - 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 ) {
......@@ -188,11 +207,12 @@ var zoom = (function(){
if( !!options.element ) {
// Space around the zoomed in element to leave on screen
var padding = 20;
var bounds = options.element.getBoundingClientRect();
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;
options.x = bounds.left - padding;
options.y = bounds.top - padding;
options.width = bounds.width + ( padding * 2 );
options.height = bounds.height + ( padding * 2 );
}
// If width/height values are set, calculate scale from those values
......@@ -204,13 +224,7 @@ var zoom = (function(){
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 );
magnify( options, options.scale );
if( options.pan !== false ) {
......@@ -222,8 +236,6 @@ var zoom = (function(){
}
}
currentOptions = options;
}
},
......@@ -234,13 +246,7 @@ var zoom = (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 );
magnify( { x: 0, y: 0 }, 1 );
level = 1;
},
......@@ -256,3 +262,5 @@ var zoom = (function(){
})();
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