动态演示效果如图所示
代码
<script>
(function(name, factory) {
if (typeof window === "object") {
window[name] = factory()
}
})("Ribbons", function() {
var _w = window,
_b = document.body,
_d = document.documentElement;
var random = function() {
if (arguments.length === 1) {
if (Array.isArray(arguments[0])) {
var index = Math.round(random(0, arguments[0].length - 1));
return arguments[0][index]
}
return random(0, arguments[0])
} else if (arguments.length === 2) {
return Math.random() * (arguments[1] - arguments[0]) + arguments[0]
}
return 0
};
var screenInfo = function(e) {
var width = Math.max(0, _w.innerWidth || _d.clientWidth || _b.clientWidth || 0),
height = Math.max(0, _w.innerHeight || _d.clientHeight || _b.clientHeight || 0),
scrollx = Math.max(0, _w.pageXOffset || _d.scrollLeft || _b.scrollLeft || 0) - (_d.clientLeft || 0),
scrolly = Math.max(0, _w.pageYOffset || _d.scrollTop || _b.scrollTop || 0) - (_d.clientTop || 0);
return {
width: width,
height: height,
ratio: width / height,
centerx: width / 2,
centery: height / 2,
scrollx: scrollx,
scrolly: scrolly
}
};
var mouseInfo = function(e) {
var screen = screenInfo(e),
mousex = e ? Math.max(0, e.pageX || e.clientX || 0) : 0,
mousey = e ? Math.max(0, e.pageY || e.clientY || 0) : 0;
return {
mousex: mousex,
mousey: mousey,
centerx: mousex - screen.width / 2,
centery: mousey - screen.height / 2
}
};
var Point = function(x, y) {
this.x = 0;
this.y = 0;
this.set(x, y)
};
Point.prototype = {
constructor: Point,
set: function(x, y) {
this.x = x || 0;
this.y = y || 0
},
copy: function(point) {
this.x = point.x || 0;
this.y = point.y || 0;
return this
},
multiply: function(x, y) {
this.x *= x || 1;
this.y *= y || 1;
return this
},
divide: function(x, y) {
this.x /= x || 1;
this.y /= y || 1;
return this
},
add: function(x, y) {
this.x += x || 0;
this.y += y || 0;
return this
},
subtract: function(x, y) {
this.x -= x || 0;
this.y -= y || 0;
return this
},
clampX: function(min, max) {
this.x = Math.max(min, Math.min(this.x, max));
return this
},
clampY: function(min, max) {
this.y = Math.max(min, Math.min(this.y, max));
return this
},
flipX: function() {
this.x *= -1;
return this
},
flipY: function() {
this.y *= -1;
return this
}
};
var Factory = function(options) {
this._canvas = null;
this._context = null;
this._sto = null;
this._width = 0;
this._height = 0;
this._scroll = 0;
this._ribbons = [];
this._options = {
colorSaturation: "80%",
colorBrightness: "60%",
colorAlpha: 0.65,
colorCycleSpeed: 6,
verticalPosition: "center",
horizontalSpeed: 150,
ribbonCount: 5,
strokeSize: 5,
parallaxAmount: -0.5,
animateSections: true
};
this._onDraw = this._onDraw.bind(this);
this._onResize = this._onResize.bind(this);
this._onScroll = this._onScroll.bind(this);
this.setOptions(options);
this.init()
};
Factory.prototype = {
constructor: Factory,
setOptions: function(options) {
if (typeof options === "object") {
for (var key in options) {
if (options.hasOwnProperty(key)) {
this._options[key] = options[key]
}
}
}
},
init: function() {
try {
this._canvas = document.createElement("canvas");
this._canvas.style["display"] = "block";
this._canvas.style["position"] = "fixed";
this._canvas.style["margin"] = "0";
this._canvas.style["padding"] = "0";
this._canvas.style["border"] = "0";
this._canvas.style["outline"] = "0";
this._canvas.style["left"] = "0";
this._canvas.style["top"] = "0";
this._canvas.style["width"] = "100%";
this._canvas.style["height"] = "100%";
this._canvas.style["z-index"] = "-1";
this._onResize();
this._context = this._canvas.getContext("2d");
this._context.clearRect(0, 0, this._width, this._height);
this._context.globalAlpha = this._options.colorAlpha;
window.addEventListener("resize", this._onResize);
window.addEventListener("scroll", this._onScroll);
document.body.appendChild(this._canvas)
} catch (e) {
console.warn("Canvas Context Error: " + e.toString());
return
}
this._onDraw()
},
addRibbon: function() {
var dir = Math.round(random(1, 9)) > 5 ? "right" : "left",
stop = 1000,
hide = 200,
min = 0 - hide,
max = this._width + hide,
movex = 0,
movey = 0,
startx = dir === "right" ? min : max,
starty = Math.round(random(0, this._height));
if (/^(top|min)$/i.test(this._options.verticalPosition)) {
starty = 0 + hide
} else if (/^(middle|center)$/i.test(this._options.verticalPosition)) {
starty = this._height / 2
} else if (/^(bottom|max)$/i.test(this._options.verticalPosition)) {
starty = this._height - hide
}
var ribbon = [],
point1 = new Point(startx, starty),
point2 = new Point(startx, starty),
point3 = null,
color = Math.round(random(0, 360)),
delay = 0;
while (true) {
if (stop <= 0) break;
stop--;
movex = Math.round((Math.random() * 1 - 0.2) * this._options.horizontalSpeed);
movey = Math.round((Math.random() * 1 - 0.5) * (this._height * 0.25));
point3 = new Point();
point3.copy(point2);
if (dir === "right") {
point3.add(movex, movey);
if (point2.x >= max) break
} else if (dir === "left") {
point3.subtract(movex, movey);
if (point2.x <= min) break
}
ribbon.push({
point1: new Point(point1.x, point1.y),
point2: new Point(point2.x, point2.y),
point3: point3,
color: color,
delay: delay,
dir: dir,
alpha: 0,
phase: 0
});
point1.copy(point2);
point2.copy(point3);
delay += 4;
color += this._options.colorCycleSpeed
}
this._ribbons.push(ribbon)
},
_drawRibbonSection: function(section) {
if (section) {
if (section.phase >= 1 && section.alpha <= 0) {
return true
}
if (section.delay <= 0) {
section.phase += 0.02;
section.alpha = Math.sin(section.phase) * 1;
section.alpha = section.alpha <= 0 ? 0 : section.alpha;
section.alpha = section.alpha >= 1 ? 1 : section.alpha;
if (this._options.animateSections) {
var mod = Math.sin(1 + section.phase * Math.PI / 2) * 0.1;
if (section.dir === "right") {
section.point1.add(mod, 0);
section.point2.add(mod, 0);
section.point3.add(mod, 0)
} else {
section.point1.subtract(mod, 0);
section.point2.subtract(mod, 0);
section.point3.subtract(mod, 0)
}
section.point1.add(0, mod);
section.point2.add(0, mod);
section.point3.add(0, mod)
}
} else {
section.delay -= 0.5
}
var s = this._options.colorSaturation,
l = this._options.colorBrightness,
c = "hsla(" + section.color + ", " + s + ", " + l + ", " + section.alpha + " )";
this._context.save();
if (this._options.parallaxAmount !== 0) {
this._context.translate(0, this._scroll * this._options.parallaxAmount)
}
this._context.beginPath();
this._context.moveTo(section.point1.x, section.point1.y);
this._context.lineTo(section.point2.x, section.point2.y);
this._context.lineTo(section.point3.x, section.point3.y);
this._context.fillStyle = c;
this._context.fill();
if (this._options.strokeSize > 0) {
this._context.lineWidth = this._options.strokeSize;
this._context.strokeStyle = c;
this._context.lineCap = "round";
this._context.stroke()
}
this._context.restore()
}
return false
},
_onDraw: function() {
for (var i = 0, t = this._ribbons.length; i < t; ++i) {
if (!this._ribbons[i]) {
this._ribbons.splice(i, 1)
}
}
this._context.clearRect(0, 0, this._width, this._height);
for (var a = 0; a < this._ribbons.length; ++a) {
var ribbon = this._ribbons[a],
numSections = ribbon.length,
numDone = 0;
for (var b = 0; b < numSections; ++b) {
if (this._drawRibbonSection(ribbon[b])) {
numDone++
}
}
if (numDone >= numSections) {
this._ribbons[a] = null
}
}
if (this._ribbons.length < this._options.ribbonCount) {
this.addRibbon()
}
requestAnimationFrame(this._onDraw)
},
_onResize: function(e) {
var screen = screenInfo(e);
this._width = screen.width;
this._height = screen.height;
if (this._canvas) {
this._canvas.width = this._width;
this._canvas.height = this._height;
if (this._context) {
this._context.globalAlpha = this._options.colorAlpha
}
}
},
_onScroll: function(e) {
var screen = screenInfo(e);
this._scroll = screen.scrolly
}
};
return Factory
});
new Ribbons({
colorSaturation: "60%",
colorBrightness: "50%",
colorAlpha: 0.5,
colorCycleSpeed: 5,
verticalPosition: "random",
horizontalSpeed: 200,
ribbonCount: 3,
strokeSize: 0,
parallaxAmount: -0.2,
animateSections: true
});
</script>© 版权声明
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