MediaWiki:Gadget-snowstorm.js

/** @license * DHTML Snowstorm! JavaScript-based snow for web pages * Making it snow on the internets since 2003. You're welcome. * --- * Version 1.44.20131215 (Previous rev: 1.44.20131208) * Copyright (c) 2007, Scott Schiller. All rights reserved. * Code provided under the BSD License * http://schillmania.com/projects/snowstorm/license.txt */

/*jslint nomen: true, plusplus: true, sloppy: true, vars: true, white: true */ /*global window, document, navigator, clearInterval, setInterval */ var snowStorm = (new function(window, document) {

// --- common properties --- this.autoStart = (typeof autoStart === 'boolean') ? autoStart : true; // Whether the snow should start automatically or not. this.onlyOasis = (typeof snowCfg_onlyOasis === 'boolean') ? snowCfg_onlyOasis : true; // Whether should be run only in Oasis or not. this.excludeMobile = (typeof excludeMobile === 'boolean') ? excludeMobile : true; // Snow is likely to be bad news for mobile phones' CPUs (and batteries.) Enable at your own risk. this.flakesMax = (typeof flakesMax === 'number') ? flakesMax : 128; // Limit total amount of snow made (falling + sticking) this.flakesMaxActive = (typeof flakesMaxActive === 'number') ? flakesMaxActive : 64; // Limit amount of snow falling at once (less = lower CPU use) this.animationInterval = (typeof animationInterval === 'number') ? animationInterval : 35; // Theoretical "milliseconds per frame" measurement. 20 = fast + smooth, but high // CPU use. 50 = more conservative, but slower this.useGPU = (typeof useGPU === 'boolean') ? useGPU : true; // Enable transform-based hardware acceleration, reduce CPU load. this.className = (typeof className === 'string') ? className : null; // CSS class name for further customization on snow elements this.flakeBottom = (typeof flakeBottom === 'number') ? flakeBottom : null; // Integer for Y axis snow limit, 0 or null for "full-screen" snow effect this.followMouse = (typeof followMouse === 'boolean') ? followMouse : true; // Snow movement can respond to the user's mouse this.snowColor = (typeof snowColor === 'string') ? snowColor : '#fff'; // Don't eat (or use?) yellow snow. this.snowCharacter = (typeof snowCharacter === 'string') ? snowCharacter : '&bull;'; // &bull; = bullet, &middot; is square on some systems etc.	this.snowStick = (typeof snowStick === 'boolean') ? snowStick : true; // Whether or not snow should "stick" at the bottom. When off, will never collect. this.targetElement = (typeof targetElement !== 'undefined') ? targetElement : null; // element which snow will be appended to (null = document.body) - can be an element // ID eg. 'myDiv', or a DOM node reference this.useMeltEffect = (typeof useMeltEffect === 'boolean') ? useMeltEffect : true; // When recycling fallen snow (or rarely, when falling), have it "melt" and fade out // if browser supports it	this.useTwinkleEffect = (typeof useTwinkleEffect === 'boolean') ? useTwinkleEffect : false; // Allow snow to randomly "flicker" in and out of view while falling this.usePositionFixed = (typeof usePositionFixed === 'boolean') ? usePositionFixed : false; // true = snow does not shift vertically when scrolling. May increase CPU load, // disabled by default - if enabled, used only where supported this.usePixelPosition = (typeof usePixelPosition === 'boolean') ? usePixelPosition : false; // Whether to use pixel values for snow top/left vs. percentages. Auto-enabled if // body is position:relative or targetElement is specified.

// --- less-used bits ---

this.freezeOnBlur = (typeof freezeOnBlur === 'boolean') ? freezeOnBlur : true; // Only snow when the window is in focus (foreground.) Saves CPU. this.flakeLeftOffset = (typeof flakeLeftOffset === 'number') ? flakeLeftOffset : 0; // Left margin/gutter space on edge of container (eg. browser window.) Bump up these values if seeing horizontal scrollbars. this.flakeRightOffset = (typeof flakeRightOffset === 'number') ? flakeRightOffset : 0; // Right margin/gutter space on edge of container this.flakeWidth = (typeof flakeWidth === 'number') ? flakeWidth : 8; // Max pixel width reserved for snow element this.flakeHeight = (typeof flakeHeight === 'number') ? flakeHeight : 8; // Max pixel height reserved for snow element this.vMaxX = (typeof vMaxX === 'number') ? vMaxX : 5; // Maximum X velocity range for snow this.vMaxY = (typeof vMaxY === 'number') ? vMaxY : 4; // Maximum Y velocity range for snow this.zIndex = (typeof zIndex === 'number') ? zIndex : 1; // CSS stacking order applied to each snowflake this.windOffset = (typeof windOffset === 'number') ? windOffset : 1; this.windMultiplier = (typeof windMultiplier === 'number') ? windMultiplier : 2; this.flakeTypes = (typeof flakeTypes === 'number') ? flakeTypes : 6;

// --- "No user-serviceable parts inside" past this point, yadda yadda --- var storm = this, features, // UA sniffing and backCompat rendering mode checks for fixed position, etc.		isIE = navigator.userAgent.match(/msie/i), isIE6 = navigator.userAgent.match(/msie 6/i), isMobile = navigator.userAgent.match(/mobile|opera m(ob|in)/i), isBackCompatIE = (isIE && document.compatMode === 'BackCompat'), noFixed = (isBackCompatIE || isIE6), screenX = null, screenX2 = null, screenY = null, scrollY = null, docHeight = null, vRndX = null, vRndY = null, fixedForEverything = false, targetElementIsRelative = false, opacitySupported = (function {			try {				document.createElement('div').style.opacity = '0.5';			} catch(e) {				return false;			}			return true;		}), didInit = false, docFrag = document.createDocumentFragment;

features = (function {

var getAnimationFrame;

/**		 * hat tip: paul irish * http://paulirish.com/2011/requestanimationframe-for-smart-animating/ * https://gist.github.com/838785 */

function timeoutShim(callback) { window.setTimeout(callback, 1000 / (storm.animationInterval || 20)); }

var _animationFrame = (window.requestAnimationFrame ||			window.webkitRequestAnimationFrame ||			window.mozRequestAnimationFrame ||			window.oRequestAnimationFrame ||			window.msRequestAnimationFrame ||			timeoutShim);

// apply to window, avoid "illegal invocation" errors in Chrome getAnimationFrame = _animationFrame ? function { return _animationFrame.apply(window, arguments); } : null;

var testDiv;

testDiv = document.createElement('div');

function has(prop) {

// test for feature support var result = testDiv.style[prop]; return(result !== undefined ? prop : null);

}

// note local scope. var localFeatures = {

transform: { ie: has('-ms-transform'), moz: has('MozTransform'), opera: has('OTransform'), webkit: has('webkitTransform'), w3: has('transform'), prop: null // the normalized property value },

getAnimationFrame: getAnimationFrame

};

localFeatures.transform.prop = (			localFeatures.transform.w3 ||			localFeatures.transform.moz ||			localFeatures.transform.webkit ||			localFeatures.transform.ie ||			localFeatures.transform.opera		);

testDiv = null;

return localFeatures;

});

this.timer = null; this.flakes = []; this.disabled = false; this.active = false; this.meltFrameCount = 20; this.meltFrames = [];

this.setXY = function(o, x, y) {

if(!o) { return false; }

if(storm.usePixelPosition || targetElementIsRelative) {

o.style.left = (x - storm.flakeWidth) + 'px'; o.style.top = (y - storm.flakeHeight) + 'px';

} else if(noFixed) {

o.style.right = (100 - (x / screenX * 100)) + '%'; // avoid creating vertical scrollbars o.style.top = (Math.min(y, docHeight - storm.flakeHeight)) + 'px';

} else {

if(!storm.flakeBottom) {

// if not using a fixed bottom coordinate... o.style.right = (100 - (x / screenX * 100)) + '%'; o.style.bottom = (100 - (y / screenY * 100)) + '%';

} else {

// absolute top. o.style.right = (100 - (x / screenX * 100)) + '%'; o.style.top = (Math.min(y, docHeight - storm.flakeHeight)) + 'px';

}

}

};

this.events = (function {

var old = (!window.addEventListener && window.attachEvent), slice = Array.prototype.slice, evt = { add: (old ? 'attachEvent' : 'addEventListener'), remove: (old ? 'detachEvent' : 'removeEventListener') };

function getArgs(oArgs) { var args = slice.call(oArgs), len = args.length; if(old) { args[1] = 'on' + args[1]; // prefix if(len > 3) { args.pop; // no capture }			} else if(len === 3) { args.push(false); }			return args; }

function apply(args, sType) { var element = args.shift, method = [evt[sType]]; if(old) { element[method](args[0], args[1]); } else { element[method].apply(element, args); }		}

function addEvent { apply(getArgs(arguments), 'add'); }

function removeEvent { apply(getArgs(arguments), 'remove'); }

return { add: addEvent, remove: removeEvent };

});

function rnd(n, min) { if(isNaN(min)) { min = 0; }		return(Math.random * n) + min; }

function plusMinus(n) { return(parseInt(rnd(2), 10) === 1 ? n * -1 : n); }

this.randomizeWind = function { var i;		vRndX = plusMinus(rnd(storm.vMaxX, 0.2)); vRndY = rnd(storm.vMaxY, 0.2); if(this.flakes) { for(i = 0; i < this.flakes.length; i++) { if(this.flakes[i].active) { this.flakes[i].setVelocities; }			}		}	};

this.scrollHandler = function { var i;		// "attach" snowflakes to bottom of window if no absolute bottom value was given scrollY = (storm.flakeBottom ? 0 : parseInt(window.scrollY || document.documentElement.scrollTop || (noFixed ? document.body.scrollTop : 0), 10)); if(isNaN(scrollY)) { scrollY = 0; // Netscape 6 scroll fix }		if(!fixedForEverything && !storm.flakeBottom && storm.flakes) { for(i = 0; i < storm.flakes.length; i++) { if(storm.flakes[i].active === 0) { storm.flakes[i].stick; }			}		}	};

this.resizeHandler = function { if(window.innerWidth || window.innerHeight) { screenX = window.innerWidth - 16 - storm.flakeRightOffset; screenY = (storm.flakeBottom || window.innerHeight); } else { screenX = (document.documentElement.clientWidth || document.body.clientWidth || document.body.scrollWidth) - (!isIE ? 8 : 0) - storm.flakeRightOffset; screenY = storm.flakeBottom || document.documentElement.clientHeight || document.body.clientHeight || document.body.scrollHeight; }		docHeight = document.body.offsetHeight; screenX2 = parseInt(screenX / 2, 10); };

this.resizeHandlerAlt = function { screenX = storm.targetElement.offsetWidth - storm.flakeRightOffset; screenY = storm.flakeBottom || storm.targetElement.offsetHeight; screenX2 = parseInt(screenX / 2, 10); docHeight = document.body.offsetHeight; };

this.freeze = function { // pause animation if(!storm.disabled) { storm.disabled = 1; } else { return false; }		storm.timer = null; };

this.resume = function { if(storm.disabled) { storm.disabled = 0; } else { return false; }		storm.timerInit; };

this.toggleSnow = function { if(!storm.flakes.length) { // first run storm.start; } else { storm.active = !storm.active; if(storm.active) { storm.show; storm.resume; } else { storm.stop; storm.freeze; }		}	};

this.stop = function { var i;		this.freeze; for(i = 0; i < this.flakes.length; i++) { this.flakes[i].o.style.display = 'none'; }		storm.events.remove(window, 'scroll', storm.scrollHandler); storm.events.remove(window, 'resize', storm.resizeHandler); if(storm.freezeOnBlur) { if(isIE) { storm.events.remove(document, 'focusout', storm.freeze); storm.events.remove(document, 'focusin', storm.resume); } else { storm.events.remove(window, 'blur', storm.freeze); storm.events.remove(window, 'focus', storm.resume); }		}	};

this.show = function { var i;		for(i = 0; i < this.flakes.length; i++) { this.flakes[i].o.style.display = 'block'; }	};

this.SnowFlake = function(type, x, y) { var s = this; this.type = type; this.x = x || parseInt(rnd(screenX - 20), 10); this.y = (!isNaN(y) ? y : -rnd(screenY) - 12); this.vX = null; this.vY = null; this.vAmpTypes = [1, 1.2, 1.4, 1.6, 1.8]; // "amplification" for vX/vY (based on flake size/type) this.vAmp = this.vAmpTypes[this.type] || 1; this.melting = false; this.meltFrameCount = storm.meltFrameCount; this.meltFrames = storm.meltFrames; this.meltFrame = 0; this.twinkleFrame = 0; this.active = 1; this.fontSize = (10 + (this.type / 5) * 10); this.o = document.createElement('div'); this.o.innerHTML = storm.snowCharacter; if(storm.className) { this.o.setAttribute('class', storm.className); }		this.o.style.color = storm.snowColor; this.o.style.position = (fixedForEverything ? 'fixed' : 'absolute'); if(storm.useGPU && features.transform.prop) { // GPU-accelerated snow. this.o.style[features.transform.prop] = 'translate3d(0px, 0px, 0px)'; }		this.o.style.width = storm.flakeWidth + 'px'; this.o.style.height = storm.flakeHeight + 'px'; this.o.style.fontFamily = 'arial,verdana'; this.o.style.cursor = 'default'; this.o.style.overflow = 'hidden'; this.o.style.fontWeight = 'normal'; this.o.style.zIndex = storm.zIndex; docFrag.appendChild(this.o);

this.refresh = function { if(isNaN(s.x) || isNaN(s.y)) { // safety check return false; }			storm.setXY(s.o, s.x, s.y); };

this.stick = function { if(noFixed || (storm.targetElement !== document.documentElement && storm.targetElement !== document.body)) { s.o.style.top = (screenY + scrollY - storm.flakeHeight) + 'px'; } else if(storm.flakeBottom) { s.o.style.top = storm.flakeBottom + 'px'; } else { s.o.style.display = 'none'; s.o.style.top = 'auto'; s.o.style.bottom = '0%'; s.o.style.position = 'fixed'; s.o.style.display = 'block'; }		};

this.vCheck = function { if(s.vX >= 0 && s.vX < 0.2) { s.vX = 0.2; } else if(s.vX < 0 && s.vX > -0.2) { s.vX = -0.2; }			if(s.vY >= 0 && s.vY < 0.2) { s.vY = 0.2; }		};

this.move = function { var vX = s.vX * storm.windOffset, yDiff; s.x += vX; s.y += (s.vY * s.vAmp); if(s.x >= screenX || screenX - s.x < storm.flakeWidth) { // X-axis scroll check s.x = 0; } else if(vX < 0 && s.x - storm.flakeLeftOffset < -storm.flakeWidth) { s.x = screenX - storm.flakeWidth - 1; // flakeWidth; }			s.refresh; yDiff = screenY + scrollY - s.y + storm.flakeHeight; if(yDiff < storm.flakeHeight) { s.active = 0; if(storm.snowStick) { s.stick; } else { s.recycle; }			} else { if(storm.useMeltEffect && s.active && s.type < 3 && !s.melting && Math.random > 0.998) { // ~1/1000 chance of melting mid-air, with each frame s.melting = true; s.melt; // only incrementally melt one frame // s.melting = false; }				if(storm.useTwinkleEffect) { if(s.twinkleFrame < 0) { if(Math.random > 0.97) { s.twinkleFrame = parseInt(Math.random * 8, 10); }					} else { s.twinkleFrame--; if(!opacitySupported) { s.o.style.visibility = (s.twinkleFrame && s.twinkleFrame % 2 === 0 ? 'hidden' : 'visible'); } else { s.o.style.opacity = (s.twinkleFrame && s.twinkleFrame % 2 === 0 ? 0 : 1); }					}				}			}		};

this.animate = function { // main animation loop // move, check status, die etc.			s.move; };

this.setVelocities = function { s.vX = vRndX + rnd(storm.vMaxX * 0.12, 0.1); s.vY = vRndY + rnd(storm.vMaxY * 0.12, 0.1); };

this.setOpacity = function(o, opacity) { if(!opacitySupported) { return false; }			o.style.opacity = opacity; };

this.melt = function { if(!storm.useMeltEffect || !s.melting) { s.recycle; } else { if(s.meltFrame < s.meltFrameCount) { s.setOpacity(s.o, s.meltFrames[s.meltFrame]); s.o.style.fontSize = s.fontSize - (s.fontSize * (s.meltFrame / s.meltFrameCount)) + 'px'; s.o.style.lineHeight = storm.flakeHeight + 2 + (storm.flakeHeight * 0.75 * (s.meltFrame / s.meltFrameCount)) + 'px'; s.meltFrame++; } else { s.recycle; }			}		};

this.recycle = function { s.o.style.display = 'none'; s.o.style.position = (fixedForEverything ? 'fixed' : 'absolute'); s.o.style.bottom = 'auto'; s.setVelocities; s.vCheck; s.meltFrame = 0; s.melting = false; s.setOpacity(s.o, 1); s.o.style.padding = '0px'; s.o.style.margin = '0px'; s.o.style.fontSize = s.fontSize + 'px'; s.o.style.lineHeight = (storm.flakeHeight + 2) + 'px'; s.o.style.textAlign = 'center'; s.o.style.verticalAlign = 'baseline'; s.x = parseInt(rnd(screenX - storm.flakeWidth - 20), 10); s.y = parseInt(rnd(screenY) * -1, 10) - storm.flakeHeight; s.refresh; s.o.style.display = 'block'; s.active = 1; };

this.recycle; // set up x/y coords etc.		this.refresh;

};

this.snow = function { var active = 0, flake = null, i, j;		for(i = 0, j = storm.flakes.length; i < j; i++) { if(storm.flakes[i].active === 1) { storm.flakes[i].move; active++; }			if(storm.flakes[i].melting) { storm.flakes[i].melt; }		}		if(active < storm.flakesMaxActive) { flake = storm.flakes[parseInt(rnd(storm.flakes.length), 10)]; if(flake.active === 0) { flake.melting = true; }		}		if(storm.timer) { features.getAnimationFrame(storm.snow); }	};

this.mouseMove = function(e) { if(!storm.followMouse) { return true; }		var x = parseInt(e.clientX, 10); if(x < screenX2) { storm.windOffset = -storm.windMultiplier + (x / screenX2 * storm.windMultiplier); } else { x -= screenX2; storm.windOffset = (x / screenX2) * storm.windMultiplier; }	};

this.createSnow = function(limit, allowInactive) { var i;		for(i = 0; i < limit; i++) { storm.flakes[storm.flakes.length] = new storm.SnowFlake(parseInt(rnd(storm.flakeTypes), 10)); if(allowInactive || i > storm.flakesMaxActive) { storm.flakes[storm.flakes.length - 1].active = -1; }		}		storm.targetElement.appendChild(docFrag); };

this.timerInit = function { storm.timer = true; storm.snow; };

this.init = function { var i;		for(i = 0; i < storm.meltFrameCount; i++) { storm.meltFrames.push(1 - (i / storm.meltFrameCount)); }		storm.randomizeWind; storm.createSnow(storm.flakesMax); // create initial batch storm.events.add(window, 'resize', storm.resizeHandler); storm.events.add(window, 'scroll', storm.scrollHandler); if(storm.freezeOnBlur) { if(isIE) { storm.events.add(document, 'focusout', storm.freeze); storm.events.add(document, 'focusin', storm.resume); } else { storm.events.add(window, 'blur', storm.freeze); storm.events.add(window, 'focus', storm.resume); }		}		storm.resizeHandler; storm.scrollHandler; if(storm.followMouse) { storm.events.add(isIE ? document : window, 'mousemove', storm.mouseMove); }		storm.animationInterval = Math.max(20, storm.animationInterval); storm.timerInit; };

this.start = function(bFromOnLoad) { if(!didInit) { didInit = true; } else if(bFromOnLoad) { // already loaded and running return true; }		if(typeof storm.targetElement === 'string') { var targetID = storm.targetElement; storm.targetElement = document.getElementById(targetID); if(!storm.targetElement) { throw new Error('Snowstorm: Unable to get targetElement "' + targetID + '"'); }		}		if(!storm.targetElement) { storm.targetElement = (document.body || document.documentElement); }		if(storm.targetElement !== document.documentElement && storm.targetElement !== document.body) { // re-map handler to get element instead of screen dimensions storm.resizeHandler = storm.resizeHandlerAlt; //and force-enable pixel positioning storm.usePixelPosition = true; }		storm.resizeHandler; // get bounding box elements storm.usePositionFixed = (storm.usePositionFixed && !noFixed && !storm.flakeBottom); // whether or not position:fixed is to be used if(window.getComputedStyle) { // attempt to determine if body or user-specified snow parent element is relatlively-positioned. try { targetElementIsRelative = (window.getComputedStyle(storm.targetElement, null).getPropertyValue('position') === 'relative'); } catch(e) { // oh well targetElementIsRelative = false; }		}		fixedForEverything = storm.usePositionFixed; if(screenX && screenY && !storm.disabled) { storm.init; storm.active = true; }	};

function doDelayedStart { window.setTimeout(function {			storm.start(true);		}, 20); // event cleanup storm.events.remove(isIE ? document : window, 'mousemove', doDelayedStart); }

function doStart { if((!storm.excludeMobile || !isMobile) && (mw.config.get('skin') === 'oasis' || !storm.onlyOasis)) { doDelayedStart; }		// event cleanup storm.events.remove(window, 'load', doStart); }

// hooks for starting the snow if(storm.autoStart) { if(document.readyState === 'complete') { doStart; } else { storm.events.add(window, 'load', doStart, false); }	}

}(window, document));