【发布时间】：2019-01-30 21:18:07
【问题描述】：
我是这个领域的新手，希望你能帮助我。 这个网站和他们拥有的粒子动画/功能让我非常受启发http://www.giantstepsmedias.com/
我发现这个和灵感很接近。但我不知道如何将其更改为图像而不是输入字段中的值。
var canvas = document.querySelector("#scene"),
ctx = canvas.getContext("2d"),
particles = [],
amount = 0,
mouse = {x:0,y:0},
radius = 1;
var colors = ["rgba(255,255,255,1)","rgba(255,255,255,.5)", "rgba(255,255,255,.25)","rgba(255,255,255,.1)"];
var copy = document.querySelector("#copy");
var ww = canvas.width = window.innerWidth;
var wh = canvas.height = window.innerHeight;
function Particle(x,y){
this.x = Math.random()*ww;
this.y = Math.random()*wh;
this.dest = {
x : x,
y: y
};
this.r = Math.random()*5 + 2;
this.vx = (Math.random()-0.5)*20;
this.vy = (Math.random()-0.5)*20;
this.accX = 0;
this.accY = 0;
this.friction = Math.random()*0.05 + 0.94;
this.color = colors[Math.floor(Math.random()*6)];
}
Particle.prototype.render = function() {
this.accX = (this.dest.x - this.x)/1000;
this.accY = (this.dest.y - this.y)/1000;
this.vx += this.accX;
this.vy += this.accY;
this.vx *= this.friction;
this.vy *= this.friction;
this.x += this.vx;
this.y += this.vy;
ctx.fillStyle = this.color;
ctx.beginPath();
ctx.arc(this.x, this.y, this.r, Math.PI * 2, false);
ctx.fill();
var a = this.x - mouse.x;
var b = this.y - mouse.y;
var distance = Math.sqrt( a*a + b*b );
if(distance<(radius*70)){
this.accX = (this.x - mouse.x)/100;
this.accY = (this.y - mouse.y)/100;
this.vx += this.accX;
this.vy += this.accY;
}
}
function onMouseMove(e){
mouse.x = e.clientX;
mouse.y = e.clientY;
}
function onTouchMove(e){
if(e.touches.length > 0 ){
mouse.x = e.touches[0].clientX;
mouse.y = e.touches[0].clientY;
}
}
function onTouchEnd(e){
mouse.x = -9999;
mouse.y = -9999;
}
function initScene(){
ww = canvas.width = window.innerWidth;
wh = canvas.height = window.innerHeight;
ctx.clearRect(0, 0, canvas.width, canvas.height);
ctx.font = "bold "+(ww/10)+"px sans-serif";
ctx.textAlign = "center";
ctx.fillText(copy.value, ww/2, wh/2);
var data = ctx.getImageData(0, 0, ww, wh).data;
ctx.clearRect(0, 0, canvas.width, canvas.height);
ctx.globalCompositeOperation = "screen";
particles = [];
for(var i=0;i<ww;i+=Math.round(ww/150)){
for(var j=0;j<wh;j+=Math.round(ww/150)){
if(data[ ((i + j*ww)*4) + 3] > 150){
particles.push(new Particle(i,j));
}
}
}
amount = particles.length;
}
function onMouseClick(){
radius++;
if(radius ===5){
radius = 0;
}
}
function render(a) {
requestAnimationFrame(render);
ctx.clearRect(0, 0, canvas.width, canvas.height);
for (var i = 0; i < amount; i++) {
particles[i].render();
}
};
copy.addEventListener("keyup", initScene);
window.addEventListener("resize", initScene);
window.addEventListener("mousemove", onMouseMove);
window.addEventListener("touchmove", onTouchMove);
window.addEventListener("click", onMouseClick);
window.addEventListener("touchend", onTouchEnd);
initScene();
requestAnimationFrame(render);canvas{
background: black;
width: 100vw;
height: 100vh;
} <canvas id="scene"></canvas>
<input id="copy" type="text" value="Hello Codepen ♥" />【问题讨论】：
-
将其从解释 ASCII 值转换为读取图像的二进制内容、解释该图像中显示的结构并相应地组织动画，这绝非易事。跨度>
-
相关的代码行是
ctx.fillText(copy.value, ww/2, wh/2);- 它渲染文本到ctx然后处理渲染，不是文本本身。因此，将简单的图像渲染到 ctx 而不是渲染文本似乎是微不足道的。该过程的其余部分处理呈现的数据。
标签： javascript jquery css canvas