diff --git a/js/reveal.js b/js/reveal.js index e1d80b93..74545350 100644 --- a/js/reveal.js +++ b/js/reveal.js @@ -298,30 +298,36 @@ */ function checkCapabilities() { - features.transforms3d = 'WebkitPerspective' in document.body.style || - 'MozPerspective' in document.body.style || - 'msPerspective' in document.body.style || - 'OPerspective' in document.body.style || - 'perspective' in document.body.style; + isMobileDevice = /(iphone|ipod|ipad|android)/gi.test( navigator.userAgent ); - features.transforms2d = '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; + var testElement = document.createElement( 'div' ); + + features.transforms3d = 'WebkitPerspective' in testElement.style || + 'MozPerspective' in testElement.style || + 'msPerspective' in testElement.style || + 'OPerspective' in testElement.style || + 'perspective' in testElement.style; + + features.transforms2d = 'WebkitTransform' in testElement.style || + 'MozTransform' in testElement.style || + 'msTransform' in testElement.style || + 'OTransform' in testElement.style || + 'transform' in testElement.style; features.requestAnimationFrameMethod = window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame; features.requestAnimationFrame = typeof features.requestAnimationFrameMethod === 'function'; features.canvas = !!document.createElement( 'canvas' ).getContext; - features.touch = !!( 'ontouchstart' in window ); - // Transitions in the overview are disabled in desktop and - // mobile Safari due to lag + // Safari due to lag features.overviewTransitions = !/Version\/[\d\.]+.*Safari/.test( navigator.userAgent ); - isMobileDevice = /(iphone|ipod|ipad|android)/gi.test( navigator.userAgent ); + // Flags if we should use zoom instead of transform to scale + // up slides. Zoom produces crisper results but has a lot of + // xbrowser quirks so we only use it in whitelsited browsers. + features.zoom = 'zoom' in testElement.style && !isMobileDevice && + ( /chrome/i.test( navigator.userAgent ) || /Version\/[\d\.]+.*Safari/.test( navigator.userAgent ) ); } @@ -1592,10 +1598,10 @@ transformSlides( { layout: '' } ); } else { - // Use zoom to scale up in desktop Chrome so that content - // remains crisp. We don't use zoom to scale down since that - // can lead to shifts in text layout/line breaks. - if( scale > 1 && !isMobileDevice && /chrome/i.test( navigator.userAgent ) && typeof dom.slides.style.zoom !== 'undefined' ) { + // Prefer zoom for scaling up so that content remains crisp. + // Don't use zoom to scale down since that can lead to shifts + // in text layout/line breaks. + if( scale > 1 && features.zoom ) { dom.slides.style.zoom = scale; dom.slides.style.left = ''; dom.slides.style.top = '';