var result_arr = [];

let dom = document.getElementById(‘canvas‘),

ctx = dom.getContext(‘2d‘);

var img = new Image();

img.src = ‘../images/logo.png‘;

img.onload = function(){

ctx.drawImage(img,0,0,180,150);

var cw = canvas.width , ch = canvas.height;

let imgData = ctx.getImageData(0,0,cw,ch).data;

var i = 0 , len = imgData.length , j = 0;

var tmpx = 0;

for( ; i < len ; i++ ){

tmpx+=1;

if(i % 1200 == 0 && i!= 0){

j+=1;

tmpx = 0;

};

var rgbas = `rgba(${imgData[i]},${imgData[i+1]},${imgData[i+2]},${imgData[i+3]})`;

result_arr.push( { x : tmpx , y : j , rgbas : rgbas } );

i+=3;

};

ctx.clearRect(0,0,cw,ch);

result_arr = result_arr.filter(item=>{ return item.rgbas != ‘rgba(0,0,0,0)‘ });

var i = 0 ;

function draw(){

for( var i = 0 ;i < result_arr.length; i++ ){

ctx.fillStyle = result_arr[i].rgbas;

ctx.fillRect( result_arr[i].x , result_arr[i].y ,1,1);

};

}

draw();

};

原文：https://www.cnblogs.com/lkkk/p/12966936.html