javascript - 使用 canvas Javascript 绘制正方形

Question

为分配制作一个随机艺术生成器。我们应该让方 block 随机弹出，但我不知道要画一个方 block 。这是我目前所拥有的

function drawSquare(canvas, context, color){
    var x= Math.floor(Math.random()*canvas.width);
    var y= Math.floor(Math.random()*canvas.height);
    context.beginPath();
    context.fillStyle = color;
    context.fillRect (x,y, canvas.width, canvas.height)
 }

Answer 1

我不喜欢为别人做家庭作业，但再次克服技术问题并能够发挥创造力和艺术性是有趣的部分。所以，这里有一个随机方 block 生成器，您可以尝试并从中学习。有一些评论可以解释更多。

const canvas = document.getElementById("canv");
const ctx = canvas.getContext("2d");
const width = window.innerWidth;
const height = window.innerHeight;
const maxWH = Math.max(width, height);

//use resize event listener to change these on window resize...
canvas.width = width;
canvas.height = height;

//to generate random intergers from 0 to 255, for colour channels
function randomInteger(max = 256){
  return Math.floor(Math.random()*max);
}
//draw n squares at random places and sizes
function makeRandomSquares(n){
  for(let i = 0; i < n; i++){
    const size = Math.random()*(maxWH*0.15);
    //minus half the size from x,y
    //so they can overlap left and top of screen, not just bottom and right.
    const x = Math.random()*width-size/2;
    const y = Math.random()*height-size/2;
    //random rgba colour
    ctx.fillStyle = `rgba(${randomInteger()},${randomInteger()},${randomInteger()},${Math.random()*0.4})`;
    ctx.fillRect(x,y,size,size);
  }
}
//initialize with 2 squares
makeRandomSquares(2);
//make 2 more squares each click
document.addEventListener("click", function(){
  makeRandomSquares(2);
}, false);

html, body {
  margin: 0;
  padding: 0;
}
canvas {
  width: 100%;
  height: 100%;
}

<canvas id="canv"></canvas>