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(function(win) {
// Constants
var PRECISION = 1e2; // 2 decimals
var VENDOR_PREFIXES = ['webkit','moz', ''];
var SVG_NAMESPACE = 'http://www.w3.org/2000/svg';
var CSS_PREFIX = 'peel-';
var clipProperty, transformProperty, boxShadowProperty, filterProperty;
var backgroundGradientSupport;
var docEl = document.documentElement;
var style = docEl.style;
// Support
function getCssProperty(name) {
var prefix, str;
for (var i = 0; i < VENDOR_PREFIXES.length; i++) {
prefix = VENDOR_PREFIXES[i];
str = prefix ? prefix + capitalize(name) : name;
if (str in style) {
return str;
}
}
}
function setCssProperties() {
clipProperty = getCssProperty('clipPath');
transformProperty = getCssProperty('transform');
boxShadowProperty = getCssProperty('boxShadow');
filterProperty = getCssProperty('filter');
setBackgroundGradientSupport();
Peel.supported = !!(clipProperty && transformProperty);
Peel.effectsSupported = backgroundGradientSupport;
}
function setBackgroundGradientSupport() {
var el = document.createElement('div');
var style = el.style;
style.cssText = 'background:linear-gradient(45deg,#9f9,white);';
backgroundGradientSupport = (style.backgroundImage || '').indexOf('gradient') > -1;
}
// General helpers
function round(n) {
return Math.round(n * PRECISION) / PRECISION;
}
// Clamps the number to be between 0 and 1.
function clamp(n) {
return Math.max(0, Math.min(1, n));
}
function normalize(n, min, max) {
return (n - min) / (max - min);
}
// Distributes a number between 0 and 1 along a bell curve.
function distribute(t, mult) {
return (mult || 1) * 2 * (.5 - Math.abs(t - .5));
}
function capitalize(str) {
return str.slice(0,1).toUpperCase() + str.slice(1);
}
function camelize(str) {
return str.replace(/-(\w)/g, function(a, b) {
return b.toUpperCase();
});
}
function prefix(str) {
return CSS_PREFIX + str;
}
// CSS Helpers
function setCSSClip(el, clip) {
el.style[clipProperty] = clip;
}
function setTransform(el, t) {
el.style[transformProperty] = t;
}
function setBoxShadow(el, x, y, blur, spread, intensity) {
el.style[boxShadowProperty] = getShadowCss(x, y, blur, spread, intensity);
}
function setDropShadow(el, x, y, blur, intensity) {
el.style[filterProperty] = 'drop-shadow(' + getShadowCss(x, y, blur, null, intensity) + ')';
}
function getShadowCss(x, y, blur, spread, intensity) {
return round(x) + 'px ' +
round(y) + 'px ' +
round(blur) + 'px ' +
(spread ? round(spread) + 'px ' : '') +
'rgba(0,0,0,' + round(intensity) + ')';
}
function setOpacity(el, t) {
el.style.opacity = t;
}
function setBackgroundGradient(el, rotation, stops) {
if (!backgroundGradientSupport) return;
var css;
if (stops.length === 0) {
css = 'none';
} else {
css = 'linear-gradient(' + round(rotation) + 'deg,' + stops.join(',') + ')';
}
el.style.backgroundImage = css;
}
// Event Helpers
function addEvent(el, type, fn) {
el.addEventListener(type, fn)
}
function removeEvent(el, type, fn) {
el.removeEventListener(type, fn);
}
function getEventCoordinates(evt, el) {
var pos = evt.changedTouches ? evt.changedTouches[0] : evt;
return {
'x': pos.clientX - el.offsetLeft + window.scrollX,
'y': pos.clientY - el.offsetTop + window.scrollY
}
}
function bindWithEvent(fn, scope, arg1, arg2) {
return function(evt) {
fn.call(scope, evt, arg1, arg2);
}
}
// Color Helpers
function getBlackStop(a, pos) {
return getColorStop(0, 0, 0, a, pos);
}
function getWhiteStop(a, pos) {
return getColorStop(255, 255, 255, a, pos);
}
function getColorStop(r, g, b, a, pos) {
a = round(clamp(a));
return 'rgba('+ r +','+ g +','+ b +','+ a +') ' + round(pos * 100) + '%';
}
// DOM Element Helpers
function getElement(obj, node) {
if (typeof obj === 'string') {
obj = (node || document).querySelector(obj);
}
return obj;
}
function createElement(parent, className) {
var el = document.createElement('div');
addClass(el, className);
parent.appendChild(el);
return el;
}
function removeClass(el, str) {
el.classList.remove(str);
}
function addClass(el, str) {
el.classList.add(str);
}
function getZIndex(el) {
return el.style.zIndex;
}
function setZIndex(el, index) {
el.style.zIndex = index;
}
// SVG Helpers
function createSVGElement(tag, parent, attributes) {
parent = parent || docEl;
var el = document.createElementNS(SVG_NAMESPACE, tag);
parent.appendChild(el);
for (var key in attributes) {
if (!attributes.hasOwnProperty(key)) continue;
setSVGAttribute(el, key, attributes[key]);
}
return el;
}
function setSVGAttribute(el, key, value) {
el.setAttributeNS(null, key, value);
}
/**
* Main class that controls the peeling effect.
* @param {HTMLElement|string} el The main container element (can be query).
* @param {object} options Options for the effect.
* @constructor
* @public
*/
function Peel (el, opt) {
this.setOptions(opt);
this.el = getElement(el, docEl);
this.constraints = [];
this.events = [];
this.setupLayers();
this.setupDimensions();
this.setCorner(this.getOption('corner'));
this.setMode(this.getOption('mode'));
this.init();
}
/**
* Four constants representing the corners of the element from which peeling can occur.
* @constant
* @public
*/
Peel.Corners = {
TOP_LEFT: 0x0,
TOP_RIGHT: 0x1,
BOTTOM_LEFT: 0x2,
BOTTOM_RIGHT: 0x3
}
/**
* Defaults
* @constant
*/
Peel.Defaults = {
'topShadow': true,
'topShadowBlur': 5,
'topShadowAlpha': .5,
'topShadowOffsetX': 0,
'topShadowOffsetY': 1,
'topShadowCreatesShape': true,
'backReflection': false,
'backReflectionSize': .02,
'backReflectionOffset': 0,
'backReflectionAlpha': .15,
'backReflectionDistribute': true,
'backShadow': true,
'backShadowSize': .04,
'backShadowOffset': 0,
'backShadowAlpha': .1,
'backShadowDistribute': true,
'bottomShadow': true,
'bottomShadowSize': 1.5,
'bottomShadowOffset': 0,
'bottomShadowDarkAlpha': .7,
'bottomShadowLightAlpha': .1,
'bottomShadowDistribute': true,
'setPeelOnInit': true,
'clippingBoxScale': 4,
'flipConstraintOffset': 5,
'dragPreventsDefault': true
}
/**
* Sets the corner for the peel effect to happen from (default is bottom right).
* @param {Mixed} [...] Either x,y or a corner id.
* @public
*/
Peel.prototype.setCorner = function() {
var args = arguments;
if (args[0] === undefined) {
args = [Peel.Corners.BOTTOM_RIGHT];
} else if (args[0].length) {
args = args[0];
}
this.corner = this.getPointOrCorner(args);
}
/**
* Sets a pre-defined "mode".
* @param {string} mode The mode to set.
* @public
*/
Peel.prototype.setMode = function(mode) {
if (mode === 'book') {
// The order of constraints is important here so that the peel line
// approaches the horizontal smoothly without jumping.
this.addPeelConstraint(Peel.Corners.BOTTOM_LEFT);
this.addPeelConstraint(Peel.Corners.TOP_LEFT);
// Removing effect distribution will make the book still have some
// depth to the effect while fully open.
this.setOption('backReflection', false);
this.setOption('backShadowDistribute', false);
this.setOption('bottomShadowDistribute', false);
} else if (mode === 'calendar') {
this.addPeelConstraint(Peel.Corners.TOP_RIGHT);
this.addPeelConstraint(Peel.Corners.TOP_LEFT);
}
}
/**
* Sets a path along which the peel will follow.
* Can be a flat line segment or a bezier curve.
* @param {...number} x/y Points along the path. 4 arguments indicates a
* linear path along 2 points (p1 to p2), while 8 arguments indicates a
* bezier curve from p1 to p2 using control points c1 and c2. The first
* and last two arguments represent p1 and p2, respectively.
* @public
*/
Peel.prototype.setPeelPath = function(x1, y1) {
var args = arguments, p1, p2, c1, c2;
p1 = new Point(x1, y1);
if (args.length === 4) {
p2 = new Point(args[2], args[3]);
this.path = new LineSegment(p1, p2);
} else if (args.length === 8) {
c1 = new Point(args[2], args[3]);
c2 = new Point(args[4], args[5]);
p2 = new Point(args[6], args[7]);
this.path = new BezierCurve(p1, c1, c2, p2);
}
}
/**
* Sets a function to be called when the user drags, either with a mouse or
* with a finger (touch events).
* @param {Function} fn The function to be called on drag. This function will
* be called with the Peel instance as the "this" keyword, the original
* event as the first argument, and the x, y coordinates of the drag as
* the 2nd and 3rd arguments, respectively.
* @param {HTMLElement} el The element to initiate the drag on mouse/touch start.
* If not passed, this will be the element associated with the Peel
* instance. Allowing this to be passed lets another element serve as a
* "hit area" that can be larger than the element itself.
* @public
*/
Peel.prototype.handleDrag = function(fn, el) {
this.dragHandler = fn;
this.setupDragEvents(el);
}
/**
* Sets a function to be called when the user either clicks with a mouse or
* taps with a finger (touch events).
* @param {Function} fn The function to be called on press. This function will
* be called with the Peel instance as the "this" keyword, the original
* event as the first argument, and the x, y coordinates of the event as
* the 2nd and 3rd arguments, respectively.
* @param {HTMLElement} el The element to initiate the event.
* If not passed, this will be the element associated with the Peel
* instance. Allowing this to be passed lets another element serve as a
* "hit area" that can be larger than the element itself.
* @public
*/
Peel.prototype.handlePress = function(fn, el) {
this.pressHandler = fn;
this.setupDragEvents(el);
}
/**
* Sets up the drag events needed for both drag and press handlers.
* @param {HTMLElement} el The element to initiate the dragStart event on.
* @private
*/
Peel.prototype.setupDragEvents = function(el) {
var self = this, isDragging, moveName, endName;
if (this.dragEventsSetup) {
return;
}
el = el || this.el;
function dragStart (touch, evt) {
if (self.getOption('dragPreventsDefault')) {
evt.preventDefault();
}
moveName = touch ? 'touchmove' : 'mousemove';
endName = touch ? 'touchend' : 'mouseup';
addEvent(docEl, moveName, dragMove);
addEvent(docEl, endName, dragEnd);
isDragging = false;
}
function dragMove (evt) {
if (self.dragHandler) {
callHandler(self.dragHandler, evt);
}
isDragging = true;
}
function dragEnd(evt) {
if (!isDragging && self.pressHandler) {
callHandler(self.pressHandler, evt);
}
removeEvent(docEl, moveName, dragMove);
removeEvent(docEl, endName, dragEnd);
}
function callHandler(fn, evt) {
var coords = getEventCoordinates(evt, self.el);
fn.call(self, evt, coords.x, coords.y);
}
this.addEvent(el, 'mousedown', dragStart.bind(this, false));
this.addEvent(el, 'touchstart', dragStart.bind(this, true));
this.dragEventsSetup = true;
}
/**
* Remove all event handlers previously added to the instance.
* @public
*/
Peel.prototype.removeEvents = function() {
this.events.forEach(function(e, i) {
removeEvent(e.el, e.type, e.handler);
});
this.events = [];
}
/**
* Sets the peel effect to a point in time along a previously
* specified path. Will throw an error if no path exists.
* @param {number} n The time value (between 0 and 1).
* @public
*/
Peel.prototype.setTimeAlongPath = function(t) {
t = clamp(t);
var point = this.path.getPointForTime(t);
this.timeAlongPath = t;
this.setPeelPosition(point.x, point.y);
}
/**
* Sets a threshold above which the top layer (including the backside) layer
* will begin to fade out. This is calculated based on the visible clipped
* area of the polygon. If a peel path is set, it will use the progress along
* the path instead.
* @param {number} n A point between 0 and 1.
* @public
*/
Peel.prototype.setFadeThreshold = function(n) {
this.fadeThreshold = n;
}
/**
* Sets the position of the peel effect. This point is the position
* of the corner that is being peeled back.
* @param {Mixed} [...] Either x,y or a corner id.
* @public
*/
Peel.prototype.setPeelPosition = function() {
var pos = this.getPointOrCorner(arguments);
pos = this.getConstrainedPeelPosition(pos);
if (!pos) {
return;
}
this.peelLineSegment = this.getPeelLineSegment(pos);
this.peelLineRotation = this.peelLineSegment.getAngle();
this.setClipping();
this.setBackTransform(pos);
this.setEffects();
}
/**
* Sets a constraint on the distance of the peel. This can be thought of as a
* point on the layers that are connected and cannot be torn apart. Typically
* this only makes sense as a point on the outer edge, such as the left edge
* of an open book, or the top edge of a calendar. In this case, simply using
* 2 constraint points (top-left/bottom-left for a book, etc) will create the
* desired effect. An arbitrary point can also be used with an effect like a
* thumbtack holding the pages together.
* @param {Mixed} [...] Either x,y or a corner id.
* @public
*/
/**
* Sets the corner for the peel effect to happen from.
* @public
*/
Peel.prototype.addPeelConstraint = function() {
var p = this.getPointOrCorner(arguments);
var radius = this.corner.subtract(p).getLength();
this.constraints.push(new Circle(p, radius));
this.calculateFlipConstraint();
}
/**
* Sets an option to use for the effect.
* @param {string} key The option to set.
* @param {Mixed} value The value for the option.
* @public
*/
Peel.prototype.setOption = function(key, value) {
this.options[key] = value;
}
/**
* Gets an option set by the user.
* @param {string} key The key of the option to get.
* @returns {Mixed}
* @public
*/
Peel.prototype.getOption = function(key) {
return this.options[camelize(key)];
}
/**
* Gets the ratio of the area of the clipped top layer to the total area.
* @returns {number} A value between 0 and 1.
* @public
*/
Peel.prototype.getAmountClipped = function() {
var topArea = this.getTopClipArea();
var totalArea = this.width * this.height;
return normalize(topArea, totalArea, 0);
}
/**
* Adds an event listener to the element and keeps track of it for later
* removal.
* @param {Element} el The element to add the handler to.
* @param {string} type The event type.
* @param {Function} fn The handler function.
* @private
*/
Peel.prototype.addEvent = function(el, type, fn) {
addEvent(el, type, fn);
this.events.push({
el: el,
type: type,
handler: fn
});
return fn;
}
/**
* Gets the area of the clipped top layer.
* @returns {number}
* @private
*/
Peel.prototype.getTopClipArea = function() {
var top = new Polygon();
this.elementBox.forEach(function(side) {
this.distributeLineByPeelLine(side, top);
}, this);
return Polygon.getArea(top.getPoints());
}
/**
* Determines which of the constraints should be used as the flip constraint
* by checking which has a y value closes to the corner (because the
* constraint operates relative to the vertical midline). Only one constraint
* should be required - changing the order of the constraints can help to
* achieve the proper effect and more than one will interfere with each other.
* @private
*/
Peel.prototype.calculateFlipConstraint = function() {
var corner = this.corner, arr = this.constraints.concat();
this.flipConstraint = arr.sort(function(a, b) {
var aY = corner.y - a.center.y;
var bY = corner.y - b.center.y;
return a - b;
})[0];
}
/**
* Called when the drag event starts.
* @param {Event} evt The original DOM event.
* @param {string} type The event type, "mouse" or "touch".
* @param {Function} fn The handler function to be called on drag.
* @private
*/
Peel.prototype.dragStart = function(evt, type, fn) {
}
/**
* Calls an event handler using the coordinates of the event.
* @param {Event} evt The original event.
* @param {Function} fn The handler to call.
* @private
*/
Peel.prototype.fireHandler = function(evt, fn) {
var coords = getEventCoordinates(evt, this.el);
fn.call(this, evt, coords.x, coords.y);
}
/**
* Sets the clipping points of the top and back layers based on a line
* segment that represents the peel line.
* @private
*/
Peel.prototype.setClipping = function() {
var top = new Polygon();
var back = new Polygon();
this.clippingBox.forEach(function(side) {
this.distributeLineByPeelLine(side, top, back);
}, this);
this.topClip.setPoints(top.getPoints());
this.backClip.setPoints(back.getPoints());
}
/**
* Distributes the first point in the given line segment and its intersect
* with the peel line, if there is one.
* @param {LineSegment} seg The line segment to check against.
* @param {Polygon} poly1 The first polygon.
* @param {Polygon} [poly2] The second polygon.
* @private
*/
Peel.prototype.distributeLineByPeelLine = function(seg, poly1, poly2) {
var intersect = this.peelLineSegment.getIntersectPoint(seg);
this.distributePointByPeelLine(seg.p1, poly1, poly2);
this.distributePointByPeelLine(intersect, poly1, poly2);
}
/**
* Distributes the given point to one of two polygons based on which side of
* the peel line it falls upon (if it falls directly on the line segment
* it is added to both).
* @param {Point} p The point to be distributed.
* @param {Polygon} poly1 The first polygon.
* @param {Polygon} [poly2] The second polygon.
* @private
*/
Peel.prototype.distributePointByPeelLine = function(p, poly1, poly2) {
if (!p) return;
var d = this.peelLineSegment.getPointDeterminant(p);
if (d <= 0) {
poly1.addPoint(p);
}
if (d >= 0 && poly2) {
poly2.addPoint(this.flipPointHorizontally(p));
}
}
/**
* Sets the options for the effect, merging in defaults.
* @param {Object} opt User options.
* @private
*/
Peel.prototype.setOptions = function(opt) {
var options = opt || {}, defaults = Peel.Defaults;
for (var key in defaults) {
if (!defaults.hasOwnProperty(key) || key in options) {
continue;
}
options[key] = defaults[key];
}
this.options = options;
}
/**
* Finds or creates a layer in the dom.
* @param {string} id The internal id of the element to be found or created.
* @param {HTMLElement} parent The parent if the element needs to be created.
* @param {numer} zIndex The z index of the layer.
* @returns {HTMLElement}
* @private
*/
Peel.prototype.findOrCreateLayer = function(id, parent, zIndex) {
var optId = id + '-element';
var domId = prefix(id);
var el = getElement(this.getOption(optId) || '.' + domId, parent);
if (!el) {
el = createElement(parent, domId);
}
addClass(el, prefix('layer'));
setZIndex(el, zIndex);
return el;
}
/**
* Returns either a point created from 2 arguments (x/y) or a corner point
* created from the first argument as a corner id.
* @param {Arguments} args The arguments object from the original function.
* @returns {Point}
* @private
*/
Peel.prototype.getPointOrCorner = function(args) {
if (args.length === 2) {
return new Point(args[0], args[1]);
} else if(typeof args[0] === 'number') {
return this.getCornerPoint(args[0]);
}
return args[0];
}
/**
* Returns a corner point based on an id defined in Peel.Corners.
* @param {number} id The id of the corner.
* @private
*/
Peel.prototype.getCornerPoint = function(id) {
var x = +!!(id & 1) * this.width;
var y = +!!(id & 2) * this.height;
return new Point(x, y);
}
/**
* Gets an optional clipping shape that may be set by the user.
* @returns {Object}
* @private
*/
Peel.prototype.getOptionalShape = function() {
var shapes = ['rect', 'polygon', 'path', 'circle'], found;
shapes.some(function(type) {
var attr = this.getOption(type), obj;
if (attr) {
obj = {};
obj.attributes = attr;
obj.type = type;
found = obj;
}
return found;
}, this);
return found;
}
/**
* Sets up the main layers used for the effect that may include a possible
* subclip shape.
* @private
*/
Peel.prototype.setupLayers = function() {
var shape = this.getOptionalShape();
// The inner layers may be wrapped later, so keep a reference to them here.
var topInnerLayer = this.topLayer = this.findOrCreateLayer('top', this.el, 2);
var backInnerLayer = this.backLayer = this.findOrCreateLayer('back', this.el, 3);
this.bottomLayer = this.findOrCreateLayer('bottom', this.el, 1);
if (shape) {
// If there is an SVG shape specified in the options, then this needs to
// be a separate clipped element because Safari/Mobile Safari can't handle
// nested clip-paths. The current top/back element will become the shape
// clip, so wrap them with an "outer" clip element that will become the
// new layer for the peel effect. The bottom layer does not require this
// effect, so the shape clip can be set directly on it.
this.topLayer = this.wrapShapeLayer(this.topLayer, 'top-outer-clip');
this.backLayer = this.wrapShapeLayer(this.backLayer, 'back-outer-clip');
this.topShapeClip = new SVGClip(topInnerLayer, shape);
this.backShapeClip = new SVGClip(backInnerLayer, shape);
this.bottomShapeClip = new SVGClip(this.bottomLayer, shape);
if (this.getOption('topShadowCreatesShape')) {
this.topShadowElement = this.setupDropShadow(shape, topInnerLayer);
}
} else {
this.topShadowElement = this.findOrCreateLayer('top-shadow', topInnerLayer, 1);
}
this.topClip = new SVGClip(this.topLayer);
this.backClip = new SVGClip(this.backLayer);
this.backShadowElement = this.findOrCreateLayer('back-shadow', backInnerLayer, 1);
this.backReflectionElement = this.findOrCreateLayer('back-reflection', backInnerLayer, 2);
this.bottomShadowElement = this.findOrCreateLayer('bottom-shadow', this.bottomLayer, 1);
this.usesBoxShadow = !shape;
}
/**
* Creates an inline SVG element to be used as a layer for a drop shadow filter
* effect. Note that drop shadow filters currently have some odd quirks in
* Blink such as blur radius changing depending on rotation, etc.
* @param {Object} shape A shape describing the SVG element to be used.
* @param {HTMLElement} parent The parent element where the layer will be added.
* @returns {SVGElement}
* @private
*/
Peel.prototype.setupDropShadow = function(shape, parent) {
var svg = createSVGElement('svg', parent, {
'class': prefix('layer')
});
createSVGElement(shape.type, svg, shape.attributes);
return svg;
}
/**
* Wraps the passed element in another layer, preserving its z-index. Also
* add a "shape-layer" class to the layer which now becomes a shape clip.
* @param {HTMLElement} el The element to become the wrapped shape layer.
* @param {string} id The identifier for the new layer that will wrap the element.
* @returns {HTMLElement} The new element that wraps the shape layer.
* @private
*/
Peel.prototype.wrapShapeLayer = function(el, id) {
var zIndex = getZIndex(el);
addClass(el, prefix('shape-layer'));
var outerLayer = this.findOrCreateLayer(id, this.el, zIndex);
outerLayer.appendChild(el);
return outerLayer;
}
/**
* Sets up the dimensions of the element box and clipping box that area used
* in the effect.
* @private
*/
Peel.prototype.setupDimensions = function() {
this.width = this.el.offsetWidth;
this.height = this.el.offsetHeight;
this.center = new Point(this.width / 2, this.height / 2);
this.elementBox = this.getScaledBox(1);
this.clippingBox = this.getScaledBox(this.getOption('clippingBoxScale'));
}
/**
* Gets a box defined by 4 line segments that is at a scale of the main
* element.
* @param {number} scale The scale for the box to be.
* @private
*/
Peel.prototype.getScaledBox = function(scale) {
// Box scale is equal to:
// 1 * the bottom/right scale
// 0 * the top/left scale.
var brScale = scale;
var tlScale = scale - 1;
var tl = new Point(-this.width * tlScale, -this.height * tlScale);
var tr = new Point( this.width * brScale, -this.height * tlScale);
var br = new Point( this.width * brScale, this.height * brScale);
var bl = new Point(-this.width * tlScale, this.height * brScale);
return [
new LineSegment(tl, tr),
new LineSegment(tr, br),
new LineSegment(br, bl),
new LineSegment(bl, tl)
];
}
/**
* Returns the peel position adjusted by constraints, if there are any.
* @param {Point} point The peel position to be constrained.
* @returns {Point}
* @private
*/
Peel.prototype.getConstrainedPeelPosition = function(pos) {
this.constraints.forEach(function(area) {
var offset = this.getFlipConstraintOffset(area, pos);
if (offset) {
area = new Circle(area.center, area.radius - offset);
}
pos = area.constrainPoint(pos);
}, this);
return pos;
}
/**
* Returns an offset to "pull" a corner in to prevent the peel effect from
* suddenly flipping around its axis. This offset is intended to be applied
* on the Y axis when dragging away from the center.
* @param {Circle} area The constraint to check against.
* @param {Point} point The peel position to be constrained.
* @returns {number|undefined}
* @private
*/
Peel.prototype.getFlipConstraintOffset = function(area, pos) {
var offset = this.getOption('flipConstraintOffset');
if (area === this.flipConstraint && offset) {
var cornerToCenter = this.corner.subtract(this.center);
var cornerToConstraint = this.corner.subtract(area.center);
var baseAngle = cornerToConstraint.getAngle();
// Normalized angles are rotated to be in the same space relative
// to the constraint.
var nCornerToConstraint = cornerToConstraint.rotate(-baseAngle);
var nPosToConstraint = pos.subtract(area.center).rotate(-baseAngle);
// Flip the vector vertically if the corner is in the bottom left or top
// right relative to the center, as the effect should always pull away
// from the vertical midline.
if (cornerToCenter.x * cornerToCenter.y < 0) {
nPosToConstraint.y *= -1;
}
if (nPosToConstraint.x > 0 && nPosToConstraint.y > 0) {
return normalize(nPosToConstraint.getAngle(), 45, 0) * offset;
}
}
}
/**
* Gets the line segment that represents the current peel line.
* @param {Point} point The position of the peel corner.
* @returns {LineSegment}
* @private
*/
Peel.prototype.getPeelLineSegment = function(point) {
// The point midway between the peel position and the corner.
var halfToCorner = this.corner.subtract(point).scale(.5);
var midpoint = point.add(halfToCorner);
if (halfToCorner.x === 0 && halfToCorner.y === 0) {
// If the corner is the same as the point, then set half to corner
// to be the center, and keep the midpoint where it is. This will
// ensure a non-zero peel line.
halfToCorner = point.subtract(this.center);
}
var l = halfToCorner.getLength()
var mult = (Math.max(this.width, this.height) / l) * 10;
var half = halfToCorner.rotate(-90).scale(mult);
var p1 = midpoint.add(half);
var p2 = midpoint.subtract(half);
return new LineSegment(p1, p2);
}
/**
* Sets the transform of the back layer.
* @param {Point} pos The position of the peeling corner.
* @private
*/
Peel.prototype.setBackTransform = function(pos) {
var mirroredCorner = this.flipPointHorizontally(this.corner);
var r = (this.peelLineRotation - 90) * 2;
var t = pos.subtract(mirroredCorner.rotate(r));
var css = 'translate('+ round(t.x) +'px, '+ round(t.y) +'px) rotate('+ round(r) +'deg)';
setTransform(this.backLayer, css);
// Set the top shadow element here as well, as the
// position and rotation matches that of the back layer.
setTransform(this.topShadowElement, css);
}
/**
* Gets the distance of the peel line along an imaginary line that runs
* between the corners that it "faces". For example, if the peel line
* is rotated 45 degrees, then it can be considered to be between the top left
* and bottom right corners. This function will return how far the peel line
* has advanced along that line.
* @returns {number} A position >= 0.
* @private
*/
Peel.prototype.getPeelLineDistance = function() {
var cornerId, opposingCornerId, corner, opposingCorner;
if (this.peelLineRotation < 90) {
cornerId = Peel.Corners.TOP_RIGHT;
opposingCornerId = Peel.Corners.BOTTOM_LEFT;
} else if (this.peelLineRotation < 180) {
cornerId = Peel.Corners.BOTTOM_RIGHT;
opposingCornerId = Peel.Corners.TOP_LEFT;
} else if (this.peelLineRotation < 270) {
cornerId = Peel.Corners.BOTTOM_LEFT;
opposingCornerId = Peel.Corners.TOP_RIGHT;
} else if (this.peelLineRotation < 360) {
cornerId = Peel.Corners.TOP_LEFT;
opposingCornerId = Peel.Corners.BOTTOM_RIGHT;
}
corner = this.getCornerPoint(cornerId);
opposingCorner = this.getCornerPoint(opposingCornerId);
// Scale the line segment past the original corners so that the effects
// can have a nice fadeout even past 1.
var cornerToCorner = new LineSegment(corner, opposingCorner).scale(2);
var intersect = this.peelLineSegment.getIntersectPoint(cornerToCorner);
if (!intersect) {
// If there is no intersect, then assume that it has run past the opposing
// corner and set the distance to well past the full distance.
return 2;
}
var distanceToPeelLine = corner.subtract(intersect).getLength();
var totalDistance = corner.subtract(opposingCorner).getLength();
return (distanceToPeelLine / totalDistance);
}
/**
* Sets shadows and fade effects.
* @private
*/
Peel.prototype.setEffects = function() {
var t = this.getPeelLineDistance();
this.setTopShadow(t);
this.setBackShadow(t);
this.setBackReflection(t);
this.setBottomShadow(t);
this.setFade();
}
/**
* Sets the top shadow as either a box-shadow or a drop-shadow filter.
* @param {number} t Position of the peel line from corner to corner.
* @private
*/
Peel.prototype.setTopShadow = function(t) {
if (!this.getOption('topShadow')) {
return;
}
var sBlur = this.getOption('topShadowBlur');
var sX = this.getOption('topShadowOffsetX');
var sY = this.getOption('topShadowOffsetY');
var alpha = this.getOption('topShadowAlpha');
var sAlpha = this.exponential(t, 5, alpha);
if (this.usesBoxShadow) {
setBoxShadow(this.topShadowElement, sX, sY, sBlur, 0, sAlpha);
} else {
setDropShadow(this.topShadowElement, sX, sY, sBlur, sAlpha);
}
}
/**
* Gets a number either distributed along a bell curve or increasing linearly.
* @param {number} n The number to transform.
* @param {boolean} dist Whether or not to use distribution.
* @param {number} mult A multiplier for the result.
* @returns {number}
* @private
*/
Peel.prototype.distributeOrLinear = function(n, dist, mult) {
if (dist) {
return distribute(n, mult);
} else {
return n * mult;
}
}
/**
* Gets a number either distributed exponentially, clamped to a range between
* 0 and 1, and multiplied by a multiplier.
* @param {number} n The number to transform.
* @param {number} exp The exponent to be used.
* @param {number} mult A multiplier for the result.
* @returns {number}
* @private
*/
Peel.prototype.exponential = function(n, exp, mult) {
return mult * clamp(Math.pow(1 + n, exp) - 1);
}
/**
* Sets reflection of the back face as a linear gradient.
* @param {number} t Position of the peel line from corner to corner.
* @private
*/
Peel.prototype.setBackReflection = function(t) {
var stops = [];
if (this.canSetLinearEffect('backReflection', t)) {
var rDistribute = this.getOption('backReflectionDistribute');
var rSize = this.getOption('backReflectionSize');
var rOffset = this.getOption('backReflectionOffset');
var rAlpha = this.getOption('backReflectionAlpha');
var reflectionSize = this.distributeOrLinear(t, rDistribute, rSize);
var rStop = t - rOffset;
var rMid = rStop - reflectionSize;
var rStart = rMid - reflectionSize;
stops.push(getWhiteStop(0, 0));
stops.push(getWhiteStop(0, rStart));
stops.push(getWhiteStop(rAlpha, rMid));
stops.push(getWhiteStop(0, rStop));
}
setBackgroundGradient(this.backReflectionElement, 180 - this.peelLineRotation, stops);
}
/**
* Sets shadow of the back face as a linear gradient.
* @param {number} t Position of the peel line from corner to corner.
* @private
*/
Peel.prototype.setBackShadow = function(t) {
var stops = [];
if (this.canSetLinearEffect('backShadow', t)) {
var sSize = this.getOption('backShadowSize');
var sOffset = this.getOption('backShadowOffset');
var sAlpha = this.getOption('backShadowAlpha');
var sDistribute = this.getOption('backShadowDistribute');
var shadowSize = this.distributeOrLinear(t, sDistribute, sSize);
var shadowStop = t - sOffset;
var shadowMid = shadowStop - shadowSize;
var shadowStart = shadowMid - shadowSize;
stops.push(getBlackStop(0, 0));
stops.push(getBlackStop(0, shadowStart));
stops.push(getBlackStop(sAlpha, shadowMid));
stops.push(getBlackStop(sAlpha, shadowStop));
}
setBackgroundGradient(this.backShadowElement, 180 - this.peelLineRotation, stops);
}
/**
* Sets the bottom shadow as a linear gradient.
* @param {number} t Position of the peel line from corner to corner.
* @private
*/
Peel.prototype.setBottomShadow = function(t) {
var stops = [];
if (this.canSetLinearEffect('bottomShadow', t)) {
// Options
var sSize = this.getOption('bottomShadowSize');
var offset = this.getOption('bottomShadowOffset');
var darkAlpha = this.getOption('bottomShadowDarkAlpha');
var lightAlpha = this.getOption('bottomShadowLightAlpha');
var sDistribute = this.getOption('bottomShadowDistribute');
var darkShadowStart = t - (.025 - offset);
var midShadowStart = darkShadowStart - (this.distributeOrLinear(t, sDistribute, .03) * sSize) - offset;
var lightShadowStart = midShadowStart - ((.02 * sSize) - offset);
stops = [
getBlackStop(0, 0),
getBlackStop(0, lightShadowStart),
getBlackStop(lightAlpha, midShadowStart),
getBlackStop(lightAlpha, darkShadowStart),
getBlackStop(darkAlpha, t)
];
}
setBackgroundGradient(this.bottomShadowElement, this.peelLineRotation + 180, stops);
}
/**
* Whether a linear effect can be set.
* @param {string} name Name of the effect
* @param {number} t Current position of the linear effect line.
* @returns {boolean}
* @private
*/
Peel.prototype.canSetLinearEffect = function(name, t) {
return this.getOption(name) && t > 0;
}
/**
* Sets the fading effect of the top layer, if a threshold is set.
* @private
*/
Peel.prototype.setFade = function() {
var threshold = this.fadeThreshold, opacity = 1, n;
if (threshold) {
if (this.timeAlongPath !== undefined) {
n = this.timeAlongPath;
} else {
n = this.getAmountClipped();
}
if (n > threshold) {
opacity = (1 - n) / (1 - threshold);
}
setOpacity(this.topLayer, opacity);
setOpacity(this.backLayer, opacity);
setOpacity(this.bottomShadowElement, opacity);
}
}
/**
* Flips a point along an imaginary vertical midpoint.
* @param {Array} points The points to be flipped.
* @returns {Array}
* @private
*/
Peel.prototype.flipPointHorizontally = function(p) {
return new Point(p.x - ((p.x - this.center.x) * 2), p.y);
}
/**
* Post setup initialization.
* @private
*/
Peel.prototype.init = function() {
if (this.getOption('setPeelOnInit')) {
this.setPeelPosition(this.corner);
}
addClass(this.el, prefix('ready'));
}
/**
* Class that clips an HTMLElement by an SVG path.
* @param {HTMLElement} el The element to be clipped.
* @param {Object} [shape] An object defining the SVG element to use in the new
* clip path. Defaults to a polygon.
* @constructor
*/
function SVGClip (el, shape) {
this.el = el;
this.shape = SVGClip.createClipPath(el, shape || {
'type': 'polygon'
});
// Chrome needs this for some reason for the clipping to work.
setTransform(this.el, 'translate(0px,0px)');
}
/**
* Sets up the global SVG element and its nested defs object to use for new
* clip paths.
* @returns {SVGElement}
* @public
*/
SVGClip.getDefs = function() {
if (!this.defs) {
this.svg = createSVGElement('svg', null, {
'class': prefix('svg-clip-element')
});
this.defs = createSVGElement('defs', this.svg);
}
return this.defs;
}
/**
* Creates a new <clipPath> SVG element and sets the passed html element to be
* clipped by it.
* @param {HTMLElement} el The html element to be clipped.
* @param {Object} obj An object defining the SVG element to be used in the
* clip path.
* @returns {SVGElement}
* @public
*/
SVGClip.createClipPath = function(el, obj) {
var id = SVGClip.getId();
var clipPath = createSVGElement('clipPath', this.getDefs());
var svgEl = createSVGElement(obj.type, clipPath, obj.attributes);
setSVGAttribute(clipPath, 'id', id);
setCSSClip(el, 'url(#' + id + ')');
return svgEl;
}
/**
* Gets the next svg clipping id.
* @public
*/
SVGClip.getId = function() {
if (!SVGClip.id) {
SVGClip.id = 1;
}
return 'svg-clip-' + SVGClip.id++;
}
/**
* Sets the "points" attribute of the clip path shape. This only makes sense
* for polygon shapes.
* @param {Array} points The points to be used.
* @public
*/
SVGClip.prototype.setPoints = function(points) {
var str = points.map(function(p) {
return round(p.x) + ',' + round(p.y);
}).join(' ');
setSVGAttribute(this.shape, 'points', str);
}
/**
* A class that represents a circle.
* @param {Point} center The center point.
* @param {Point} radius The radius.
* @constructor
*/
function Circle (center, radius) {
this.center = center;
this.radius = radius;
}
/**
* Determines whether a point is contained within the circle.
* @param {Point} p The point.
* @returns {boolean}
* @public
*/
Circle.prototype.containsPoint = function(p) {
if(this.boundingRectContainsPoint(p)) {
var dx = this.center.x - p.x;
var dy = this.center.y - p.y;
dx *= dx;
dy *= dy;
var distanceSquared = dx + dy;
var radiusSquared = this.radius * this.radius;
return distanceSquared <= radiusSquared;
}
return false;
}
/**
* Determines whether a point is contained within the bounding box of the circle.
* @param {Point} p The point.
* @returns {boolean}
* @private
*/
Circle.prototype.boundingRectContainsPoint = function(p) {
return p.x >= this.center.x - this.radius && p.x <= this.center.x + this.radius &&
p.y >= this.center.y - this.radius && p.y <= this.center.y + this.radius;
}
/**
* Moves a point outside the circle to the closest point on the circumference.
* Rotated angle from the center point should be the same.
* @param {Point} p The point.
* @returns {boolean}
* @public
*/
Circle.prototype.constrainPoint = function(p) {
if (!this.containsPoint(p)) {
var rotation = p.subtract(this.center).getAngle();
p = this.center.add(new Point(this.radius, 0).rotate(rotation));
}
return p;
}
/**
* A class that represents a polygon.
* @constructor
*/
function Polygon() {
this.points = [];
}
/**
* Gets the area of the polygon.
* @param {Array} points The points describing the polygon.
* @public
*/
Polygon.getArea = function(points) {
var sum1 = 0, sum2 = 0;
points.forEach(function(p, i, arr) {
var next = arr[(i + 1) % arr.length];
sum1 += (p.x * next.y);
sum2 += (p.y * next.x);
});
return (sum1 - sum2) / 2;
}
/**
* Adds a point to the polygon.
* @param {Point} point
* @public
*/
Polygon.prototype.addPoint = function(point) {
this.points.push(point);
}
/**
* Gets the points of the polygon as an array.
* @returns {Array}
* @public
*/
Polygon.prototype.getPoints = function() {
return this.points;
}
/**
* A class representing a bezier curve.
* @param {Point} p1 The starting point.
* @param {Point} c1 The control point of p1.
* @param {Point} c2 The control point of p2.
* @param {Point} p2 The ending point.
* @constructor
*/
function BezierCurve (p1, c1, c2, p2) {
this.p1 = p1;
this.c1 = c1;
this.p2 = p2;
this.c2 = c2;
}
/**
* Gets a point along the line segment for a given time.
* @param {number} t The time along the segment, between 0 and 1.
* @returns {Point}
*/
BezierCurve.prototype.getPointForTime = function(t) {
var b0 = Math.pow(1 - t, 3);
var b1 = 3 * t * Math.pow(1 - t, 2);
var b2 = 3 * Math.pow(t, 2) * (1 - t);
var b3 = Math.pow(t, 3);
var x = (b0 * this.p1.x) + (b1 * this.c1.x) + (b2 * this.c2.x) + (b3 * this.p2.x)
var y = (b0 * this.p1.y) + (b1 * this.c1.y) + (b2 * this.c2.y) + (b3 * this.p2.y)
return new Point(x, y);
}
/**
* A class that represents a line segment.
* @param {Point} p1 The start of the segment.
* @param {Point} p2 The end of the segment.
* @constructor
*/
function LineSegment (p1, p2) {
this.p1 = p1;
this.p2 = p2;
}
/**
* @constant
*/
LineSegment.EPSILON = 1e-6;
/**
* Gets a point along the line segment for a given time.
* @param {number} t The time along the segment, between 0 and 1.
* @returns {Point}
* @public
*/
LineSegment.prototype.getPointForTime = function(t) {
return this.p1.add(this.getVector().scale(t));
}
/**
* Takes a scalar and returns a new scaled line segment.
* @param {number} n The amount to scale the segment by.
* @returns {LineSegment}
* @public
*/
LineSegment.prototype.scale = function(n) {
var half = 1 + (n / 2);
var p1 = this.p1.add(this.p2.subtract(this.p1).scale(n));
var p2 = this.p2.add(this.p1.subtract(this.p2).scale(n));
return new LineSegment(p1, p2);
}
/**
* The determinant is a number that indicates which side of a line a point
* falls on. A positive number means that the point falls inside the area
* "clockwise" of the line, ie. the area that the line would sweep if it were
* rotated 180 degrees. A negative number would mean the point is in the area
* the line would sweep if it were rotated counter-clockwise, or -180 degrees.
* 0 indicates that the point falls exactly on the line.
* @param {Point} p The point to test against.
* @returns {number} A signed number.
* @public
*/
LineSegment.prototype.getPointDeterminant = function(p) {
var d = ((p.x - this.p1.x) * (this.p2.y - this.p1.y)) - ((p.y - this.p1.y) * (this.p2.x - this.p1.x));
// Tolerance for near-zero.
if (d > -LineSegment.EPSILON && d < LineSegment.EPSILON) {
d = 0;
}
return d;
}
/**
* Calculates the point at which another line segment intersects, if any.
* @param {LineSegment} seg The second line segment.
* @returns {Point|null}
* @public
*/
LineSegment.prototype.getIntersectPoint = function(seg2) {
var seg1 = this;
function crossProduct(p1, p2) {
return p1.x * p2.y - p1.y * p2.x;
}
var r = seg1.p2.subtract(seg1.p1);
var s = seg2.p2.subtract(seg2.p1);
var uNumerator = crossProduct(seg2.p1.subtract(seg1.p1), r);
var denominator = crossProduct(r, s);
if (denominator == 0) {
// ignoring colinear and parallel
return null;
}
var u = uNumerator / denominator;
var t = crossProduct(seg2.p1.subtract(seg1.p1), s) / denominator;
if ((t >= 0) && (t <= 1) && (u >= 0) && (u <= 1)) {
return seg1.p1.add(r.scale(t));
}
return null;
}
/**
* Returns the angle of the line segment in degrees.
* @returns {number}
* @public
*/
LineSegment.prototype.getAngle = function() {
return this.getVector().getAngle();
}
/**
* Gets the vector that represents the line segment.
* @returns {Point}
* @private
*/
LineSegment.prototype.getVector = function() {
if (!this.vector) {
this.vector = this.p2.subtract(this.p1);
}
return this.vector;
}
/**
* A class representing a point or 2D vector.
* @param {number} x The x coordinate.
* @param {number} y The y coordinate.
* @constructor
*/
function Point (x, y) {
this.x = x;
this.y = y;
}
/**
* @constant
*/
Point.DEGREES_IN_RADIANS = 180 / Math.PI;
/**
* Gets degrees in radians.
* @param {number} deg
* @returns {number}
*/
Point.degToRad = function(deg) {
return deg / Point.DEGREES_IN_RADIANS;
};
/**
* Gets radians in degrees.
* @param {number} rad
* @returns {number}
*/
Point.radToDeg = function(rad) {
var deg = rad * Point.DEGREES_IN_RADIANS;
while(deg < 0) deg += 360;
return deg;
};
/**
* Creates a new point given a rotation in degrees and a length.
* @param {number} deg The rotation of the vector.
* @param {number} len The length of the vector.
* @returns {Point}
*/
Point.vector = function(deg, len) {
var rad = Point.degToRad(deg);
return new Point(Math.cos(rad) * len, Math.sin(rad) * len);
};
/**
* Adds a point.
* @param {Point} p
* @returns {Point}
*/
Point.prototype.add = function(p) {
return new Point(this.x + p.x, this.y + p.y);
};
/**
* Subtracts a point.
* @param {Point} p
* @returns {Point}
*/
Point.prototype.subtract = function(p) {
return new Point(this.x - p.x, this.y - p.y);
};
/**
* Scales a point by a scalar.
* @param {number} n
* @returns {Point}
*/
Point.prototype.scale = function(n) {
return new Point(this.x * n, this.y * n);
};
/**
* Gets the length of the distance to the point.
* @returns {number}
*/
Point.prototype.getLength = function() {
return Math.sqrt(Math.pow(this.x, 2) + Math.pow(this.y, 2));
};
/**
* Gets the angle of the point in degrees.
* @returns {number}
*/
Point.prototype.getAngle = function() {
return Point.radToDeg(Math.atan2(this.y, this.x));
};
/**
* Returns a new point of the same length with a different angle.
* @param {number} deg The angle in degrees.
* @returns {Point}
*/
Point.prototype.setAngle = function(deg) {
return Point.vector(deg, this.getLength());
};
/**
* Rotates the point.
* @param {number} deg The amount to rotate by in degrees.
* @returns {Point}
*/
Point.prototype.rotate = function(deg) {
return this.setAngle(this.getAngle() + deg);
};
setCssProperties();
win.Peel = Peel;
})(window);