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有个 window 属性叫 devicePixelRatio
,能够算出过后设施的物理像素与 CSS 像素的比率。
语法:
value = window.devicePixelRatio;
用法:
<script>
/** @type {HTMLCanvasElement} */
let canvas = document.getElementById("canvas")
let ctx = canvas.getContext('2d')
let dpr = window.devicePixelRatio || window.webkitDevicePixelRatio || window.mozDevicePixelRatio || 1;
canvas.width = 600
canvas.height = 400
canvas.style.width = canvas.width + 'px'
canvas.style.height = canvas.height + 'px'
canvas.width = canvas.width * dpr
canvas.height = canvas.height * dpr
ctx.scale(dpr, dpr);
ctx.rect(20, 30, 400, 200)
ctx.fillStyle = "purple"
ctx.fillRect(20, 30, 400, 300)
ctx.font = '28px Arial'
ctx.fillStyle = '#fff'
ctx.fillText('ABCD', 100,150)
ctx.strokeStyle = '#fff'
ctx.strokeText('YES',100,180)
</script>
正文完
发表至: javascript
2021-03-09