Javascript
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339行
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10.62 KB
(function() {
var waveMaxRadius = 150;
//
// INK EQUATIONS
//
function waveRadiusFn(touchDownMs, touchUpMs, anim) {
// Convert from ms to s.
var touchDown = touchDownMs / 1000;
var touchUp = touchUpMs / 1000;
var totalElapsed = touchDown + touchUp;
var ww = anim.width, hh = anim.height;
// use diagonal size of container to avoid floating point math sadness
var waveRadius = Math.min(Math.sqrt(ww * ww + hh * hh), waveMaxRadius) * 1.1 + 5;
var duration = 1.1 - .2 * (waveRadius / waveMaxRadius);
var tt = (totalElapsed / duration);
var size = waveRadius * (1 - Math.pow(80, -tt));
return Math.abs(size);
}
function waveOpacityFn(td, tu, anim) {
// Convert from ms to s.
var touchDown = td / 1000;
var touchUp = tu / 1000;
var totalElapsed = touchDown + touchUp;
if (tu <= 0) { // before touch up
return anim.initialOpacity;
}
return Math.max(0, anim.initialOpacity - touchUp * anim.opacityDecayVelocity);
}
function waveOuterOpacityFn(td, tu, anim) {
// Convert from ms to s.
var touchDown = td / 1000;
var touchUp = tu / 1000;
// Linear increase in background opacity, capped at the opacity
// of the wavefront (waveOpacity).
var outerOpacity = touchDown * 0.3;
var waveOpacity = waveOpacityFn(td, tu, anim);
return Math.max(0, Math.min(outerOpacity, waveOpacity));
}
// Determines whether the wave should be completely removed.
function waveDidFinish(wave, radius, anim) {
var waveOpacity = waveOpacityFn(wave.tDown, wave.tUp, anim);
// If the wave opacity is 0 and the radius exceeds the bounds
// of the element, then this is finished.
if (waveOpacity < 0.01 && radius >= Math.min(wave.maxRadius, waveMaxRadius)) {
return true;
}
return false;
};
function waveAtMaximum(wave, radius, anim) {
var waveOpacity = waveOpacityFn(wave.tDown, wave.tUp, anim);
if (waveOpacity >= anim.initialOpacity && radius >= Math.min(wave.maxRadius, waveMaxRadius)) {
return true;
}
return false;
}
//
// DRAWING
//
function drawRipple(ctx, x, y, radius, innerColor, outerColor) {
if (outerColor) {
ctx.fillStyle = outerColor;
ctx.fillRect(0,0,ctx.canvas.width, ctx.canvas.height);
}
ctx.beginPath();
ctx.arc(x, y, radius, 0, 2 * Math.PI, false);
ctx.fillStyle = innerColor;
ctx.fill();
}
//
// SETUP
//
function createWave(elem) {
var elementStyle = window.getComputedStyle(elem);
var fgColor = elementStyle.color;
var wave = {
waveColor: fgColor,
maxRadius: 0,
isMouseDown: false,
mouseDownStart: 0.0,
mouseUpStart: 0.0,
tDown: 0,
tUp: 0
};
return wave;
}
function removeWaveFromScope(scope, wave) {
if (scope.waves) {
var pos = scope.waves.indexOf(wave);
scope.waves.splice(pos, 1);
}
};
// Shortcuts.
var pow = Math.pow;
var now = Date.now;
if (window.performance && performance.now) {
now = performance.now.bind(performance);
}
function cssColorWithAlpha(cssColor, alpha) {
var parts = cssColor.match(/^rgb\((\d+),\s*(\d+),\s*(\d+)\)$/);
if (typeof alpha == 'undefined') {
alpha = 1;
}
if (!parts) {
return 'rgba(255, 255, 255, ' + alpha + ')';
}
return 'rgba(' + parts[1] + ', ' + parts[2] + ', ' + parts[3] + ', ' + alpha + ')';
}
function dist(p1, p2) {
return Math.sqrt(pow(p1.x - p2.x, 2) + pow(p1.y - p2.y, 2));
}
function distanceFromPointToFurthestCorner(point, size) {
var tl_d = dist(point, {x: 0, y: 0});
var tr_d = dist(point, {x: size.w, y: 0});
var bl_d = dist(point, {x: 0, y: size.h});
var br_d = dist(point, {x: size.w, y: size.h});
return Math.max(tl_d, tr_d, bl_d, br_d);
}
Polymer('paper-ripple', {
/**
* The initial opacity set on the wave.
*
* @attribute initialOpacity
* @type number
* @default 0.25
*/
initialOpacity: 0.25,
/**
* How fast (opacity per second) the wave fades out.
*
* @attribute opacityDecayVelocity
* @type number
* @default 0.8
*/
opacityDecayVelocity: 0.8,
backgroundFill: true,
pixelDensity: 2,
eventDelegates: {
down: 'downAction',
up: 'upAction'
},
attached: function() {
// create the canvas element manually becase ios
// does not render the canvas element if it is not created in the
// main document (component templates are created in a
// different document). See:
// https://bugs.webkit.org/show_bug.cgi?id=109073.
if (!this.$.canvas) {
var canvas = document.createElement('canvas');
canvas.id = 'canvas';
this.shadowRoot.appendChild(canvas);
this.$.canvas = canvas;
}
},
ready: function() {
this.waves = [];
},
setupCanvas: function() {
this.$.canvas.setAttribute('width', this.$.canvas.clientWidth * this.pixelDensity + "px");
this.$.canvas.setAttribute('height', this.$.canvas.clientHeight * this.pixelDensity + "px");
var ctx = this.$.canvas.getContext('2d');
ctx.scale(this.pixelDensity, this.pixelDensity);
if (!this._loop) {
this._loop = this.animate.bind(this, ctx);
}
},
downAction: function(e) {
this.setupCanvas();
var wave = createWave(this.$.canvas);
this.cancelled = false;
wave.isMouseDown = true;
wave.tDown = 0.0;
wave.tUp = 0.0;
wave.mouseUpStart = 0.0;
wave.mouseDownStart = now();
var width = this.$.canvas.width / 2; // Retina canvas
var height = this.$.canvas.height / 2;
var rect = this.getBoundingClientRect();
var touchX = e.x - rect.left;
var touchY = e.y - rect.top;
wave.startPosition = {x:touchX, y:touchY};
if (this.classList.contains("recenteringTouch")) {
wave.endPosition = {x: width / 2, y: height / 2};
wave.slideDistance = dist(wave.startPosition, wave.endPosition);
}
wave.containerSize = Math.max(width, height);
wave.maxRadius = distanceFromPointToFurthestCorner(wave.startPosition, {w: width, h: height});
this.waves.push(wave);
requestAnimationFrame(this._loop);
},
upAction: function() {
for (var i = 0; i < this.waves.length; i++) {
// Declare the next wave that has mouse down to be mouse'ed up.
var wave = this.waves[i];
if (wave.isMouseDown) {
wave.isMouseDown = false
wave.mouseUpStart = now();
wave.mouseDownStart = 0;
wave.tUp = 0.0;
break;
}
}
this._loop && requestAnimationFrame(this._loop);
},
cancel: function() {
this.cancelled = true;
},
animate: function(ctx) {
var shouldRenderNextFrame = false;
// Clear the canvas
ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);
var deleteTheseWaves = [];
// The oldest wave's touch down duration
var longestTouchDownDuration = 0;
var longestTouchUpDuration = 0;
// Save the last known wave color
var lastWaveColor = null;
// wave animation values
var anim = {
initialOpacity: this.initialOpacity,
opacityDecayVelocity: this.opacityDecayVelocity,
height: ctx.canvas.height,
width: ctx.canvas.width
}
for (var i = 0; i < this.waves.length; i++) {
var wave = this.waves[i];
if (wave.mouseDownStart > 0) {
wave.tDown = now() - wave.mouseDownStart;
}
if (wave.mouseUpStart > 0) {
wave.tUp = now() - wave.mouseUpStart;
}
// Determine how long the touch has been up or down.
var tUp = wave.tUp;
var tDown = wave.tDown;
longestTouchDownDuration = Math.max(longestTouchDownDuration, tDown);
longestTouchUpDuration = Math.max(longestTouchUpDuration, tUp);
// Obtain the instantenous size and alpha of the ripple.
var radius = waveRadiusFn(tDown, tUp, anim);
var waveAlpha = waveOpacityFn(tDown, tUp, anim);
var waveColor = cssColorWithAlpha(wave.waveColor, waveAlpha);
lastWaveColor = wave.waveColor;
// Position of the ripple.
var x = wave.startPosition.x;
var y = wave.startPosition.y;
// Ripple gravitational pull to the center of the canvas.
if (wave.endPosition) {
// This translates from the origin to the center of the view based on the max dimension of
var translateFraction = Math.min(1, radius / wave.containerSize * 2 / Math.sqrt(2) );
x += translateFraction * (wave.endPosition.x - wave.startPosition.x);
y += translateFraction * (wave.endPosition.y - wave.startPosition.y);
}
// If we do a background fill fade too, work out the correct color.
var bgFillColor = null;
if (this.backgroundFill) {
var bgFillAlpha = waveOuterOpacityFn(tDown, tUp, anim);
bgFillColor = cssColorWithAlpha(wave.waveColor, bgFillAlpha);
}
// Draw the ripple.
drawRipple(ctx, x, y, radius, waveColor, bgFillColor);
// Determine whether there is any more rendering to be done.
var maximumWave = waveAtMaximum(wave, radius, anim);
var waveDissipated = waveDidFinish(wave, radius, anim);
var shouldKeepWave = !waveDissipated || maximumWave;
var shouldRenderWaveAgain = !waveDissipated && !maximumWave;
shouldRenderNextFrame = shouldRenderNextFrame || shouldRenderWaveAgain;
if (!shouldKeepWave || this.cancelled) {
deleteTheseWaves.push(wave);
}
}
if (shouldRenderNextFrame) {
requestAnimationFrame(this._loop);
}
for (var i = 0; i < deleteTheseWaves.length; ++i) {
var wave = deleteTheseWaves[i];
removeWaveFromScope(this, wave);
}
if (!this.waves.length) {
// If there is nothing to draw, clear any drawn waves now because
// we're not going to get another requestAnimationFrame any more.
ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);
this._loop = null;
}
}
});
})();