canvas画数字

1HTML先写一个div给个ID名字

<canvas id="mycanvas"></canvas>

2js中获取元素

var myCanvas = document.getElementById('mycanvas');

3设置宽度和高度

myCanvas.width = document.documentElement.clientWidth;
myCanvas.height = document.documentElement.clientHeight;

4获取(2d对象绘画环境()

var cxt = myCanvas.getContext('2d');

5定义距离左侧的偏移

var l = 100;

6距离顶部的偏移

var t = 60;

7设计数字的存储描述5数字的组成

var dots = [
[1,1,1,1,1,1,1],
[1,1,0,0,0,0,0],
[1,1,0,0,0,0,0],
[1,1,1,1,1,1,0],
[0,0,0,0,0,1,1],
[0,0,0,0,0,1,1],
[0,0,0,0,0,1,1],
[0,0,0,0,0,1,1],
[1,1,0,0,0,1,1],
[0,1,1,1,1,1,0]
];

8圆的半径

var R = 10;

9遍历该数字下所有的圆

for(var i=0;i<dots.length;i++){
for(var j=0;j<dots[i].length;j++){
// 如果是1，化缘；否则跳过
if(dots[i][j]!=1){
continue;
}


// 当前的值
// dots[i][j]
// 此刻该位置的圆的圆心坐标 第(i,j)个圆
var centerX = l + j*2*(R+1) + R+1;
var centerY = t + i*2*(R+1) + R+1;


// 绘制
cxt.beginPath();


// 绘制圆
cxt.arc(centerX,centerY,R,0,2*Math.PI);


// 填充
cxt.fillStyle = 'blue';


// 填充
cxt.fill();


cxt.closePath();
}
}