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// animate
( function( window, factory ) {
// universal module definition
/* jshint strict: false */
if ( typeof define == 'function' && define.amd ) {
// AMD
define( [
'fizzy-ui-utils/utils'
], function( utils ) {
return factory( window, utils );
});
} else if ( typeof module == 'object' && module.exports ) {
// CommonJS
module.exports = factory(
window,
require('fizzy-ui-utils')
);
} else {
// browser global
window.Flickity = window.Flickity || {};
window.Flickity.animatePrototype = factory(
window,
window.fizzyUIUtils
);
}
}( window, function factory( window, utils ) {
'use strict';
// -------------------------- requestAnimationFrame -------------------------- //
// get rAF, prefixed, if present
var requestAnimationFrame = window.requestAnimationFrame ||
window.webkitRequestAnimationFrame;
// fallback to setTimeout
var lastTime = 0;
if ( !requestAnimationFrame ) {
requestAnimationFrame = function( callback ) {
var currTime = new Date().getTime();
var timeToCall = Math.max( 0, 16 - ( currTime - lastTime ) );
var id = setTimeout( callback, timeToCall );
lastTime = currTime + timeToCall;
return id;
};
}
// -------------------------- animate -------------------------- //
var proto = {};
proto.startAnimation = function() {
if ( this.isAnimating ) {
return;
}
this.isAnimating = true;
this.restingFrames = 0;
this.animate();
};
proto.animate = function() {
this.applyDragForce();
this.applySelectedAttraction();
var previousX = this.x;
this.integratePhysics();
this.positionSlider();
this.settle( previousX );
// animate next frame
if ( this.isAnimating ) {
var _this = this;
requestAnimationFrame( function animateFrame() {
_this.animate();
});
}
};
var transformProperty = ( function () {
var style = document.documentElement.style;
if ( typeof style.transform == 'string' ) {
return 'transform';
}
return 'WebkitTransform';
})();
proto.positionSlider = function() {
var x = this.x;
// wrap position around
if ( this.options.wrapAround && this.cells.length > 1 ) {
x = utils.modulo( x, this.slideableWidth );
x = x - this.slideableWidth;
this.shiftWrapCells( x );
}
x = x + this.cursorPosition;
// reverse if right-to-left and using transform
x = this.options.rightToLeft && transformProperty ? -x : x;
var value = this.getPositionValue( x );
// use 3D tranforms for hardware acceleration on iOS
// but use 2D when settled, for better font-rendering
this.slider.style[ transformProperty ] = this.isAnimating ?
'translate3d(' + value + ',0,0)' : 'translateX(' + value + ')';
// scroll event
var firstSlide = this.slides[0];
if ( firstSlide ) {
var positionX = -this.x - firstSlide.target;
var progress = positionX / this.slidesWidth;
this.dispatchEvent( 'scroll', null, [ progress, positionX ] );
}
};
proto.positionSliderAtSelected = function() {
if ( !this.cells.length ) {
return;
}
this.x = -this.selectedSlide.target;
this.positionSlider();
};
proto.getPositionValue = function( position ) {
if ( this.options.percentPosition ) {
// percent position, round to 2 digits, like 12.34%
return ( Math.round( ( position / this.size.innerWidth ) * 10000 ) * 0.01 )+ '%';
} else {
// pixel positioning
return Math.round( position ) + 'px';
}
};
proto.settle = function( previousX ) {
// keep track of frames where x hasn't moved
if ( !this.isPointerDown && Math.round( this.x * 100 ) == Math.round( previousX * 100 ) ) {
this.restingFrames++;
}
// stop animating if resting for 3 or more frames
if ( this.restingFrames > 2 ) {
this.isAnimating = false;
delete this.isFreeScrolling;
// render position with translateX when settled
this.positionSlider();
this.dispatchEvent('settle');
}
};
proto.shiftWrapCells = function( x ) {
// shift before cells
var beforeGap = this.cursorPosition + x;
this._shiftCells( this.beforeShiftCells, beforeGap, -1 );
// shift after cells
var afterGap = this.size.innerWidth - ( x + this.slideableWidth + this.cursorPosition );
this._shiftCells( this.afterShiftCells, afterGap, 1 );
};
proto._shiftCells = function( cells, gap, shift ) {
for ( var i=0; i < cells.length; i++ ) {
var cell = cells[i];
var cellShift = gap > 0 ? shift : 0;
cell.wrapShift( cellShift );
gap -= cell.size.outerWidth;
}
};
proto._unshiftCells = function( cells ) {
if ( !cells || !cells.length ) {
return;
}
for ( var i=0; i < cells.length; i++ ) {
cells[i].wrapShift( 0 );
}
};
// -------------------------- physics -------------------------- //
proto.integratePhysics = function() {
this.x += this.velocity;
this.velocity *= this.getFrictionFactor();
};
proto.applyForce = function( force ) {
this.velocity += force;
};
proto.getFrictionFactor = function() {
return 1 - this.options[ this.isFreeScrolling ? 'freeScrollFriction' : 'friction' ];
};
proto.getRestingPosition = function() {
// my thanks to Steven Wittens, who simplified this math greatly
return this.x + this.velocity / ( 1 - this.getFrictionFactor() );
};
proto.applyDragForce = function() {
if ( !this.isPointerDown ) {
return;
}
// change the position to drag position by applying force
var dragVelocity = this.dragX - this.x;
var dragForce = dragVelocity - this.velocity;
this.applyForce( dragForce );
};
proto.applySelectedAttraction = function() {
// do not attract if pointer down or no cells
if ( this.isPointerDown || this.isFreeScrolling || !this.cells.length ) {
return;
}
var distance = this.selectedSlide.target * -1 - this.x;
var force = distance * this.options.selectedAttraction;
this.applyForce( force );
};
return proto;
}));
|
