[英]HTML5 canvas text anti-aliases in chrome, not in firefox
我正在使用 JavaScript 在 HTML5 畫布上繪制自定義等寬位字體,並且在 Firefox 和 Chrome 之間得到不同的結果。 Firefox 以我喜歡的方式繪制它:
雖然 Chrome 使用抗鋸齒繪制它,但我不知道如何擺脫:
使用 CSS 和 JavaScript 重現該問題的 HTML 代碼如下。 (字體下載) 。
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<style>
@font-face {
font-family: tis-100-copy;
src: local("tis 100 copy"),
local("tis-100-copy"),
url(tis100copy.ttf);
font-weight: bold;
}
html {
position: relative;
background-color: #DDDDDD;
font-family: tis-100-copy;
}
canvas#game {
position: relative;
padding-left: 0;
padding-right: 0;
margin-left: auto;
margin-right: auto;
display: block;
}
</style>
</head>
<body>
<canvas id="game" width="1366" height="768"></canvas>
<script>
var canvas = document.getElementById("game");
var ctx = canvas.getContext("2d");
//ctx.translate(0.5, 0.5); // Just causes both browsers to anti-alias
ctx.mozImageSmoothingEnabled = false;
ctx.webkitImageSmoothingEnabled = false;
ctx.msImageSmoothingEnabled = false;
ctx.imageSmoothingEnabled = false;
ctx.font = "12pt tis-100-copy";
function gameLoop() {
ctx.beginPath();
ctx.fillStyle = "#000000";
ctx.fillRect(0, 0, canvas.width, canvas.height);
ctx.fillStyle = "#FFFFFF";
ctx.fillText("ThE qUiCk BrOwN fOx JuMpS oVeR tHe LaZy DoG.", 50, 50);
ctx.fillText("1234567890", 50, 62);
ctx.fillText("!#%()+,-./:<=>?[\\]_", 50, 74);
requestAnimationFrame(gameLoop);
}
requestAnimationFrame(gameLoop);
</script>
</body>
</html>
如何讓 Chrome 在沒有抗鋸齒的情況下干凈地繪制文本?
為了解決這個問題以實現跨瀏覽器兼容性,並考慮到它顯然是用於游戲的,我會建議一種不同的方法,將其轉換為位圖字體並將其用作位圖字體。
您可以將相關字體轉換為 sprite-sheet,然后構建一個簡單的自定義函數來呈現文本。
這個過程很簡單,如果沒有大量的文本需要渲染,性能就綽綽有余了。
這是一個例子:
// Note: font sprite-sheet premade using: // https://jsfiddle.net/epistemex/bdm3tbtu/ var ctx, cw = 8, ch = 19, img = new Image; img.onload = go; img.src = bmp; function go() { ctx = c.getContext("2d"); // Custom text drawing function demo: myFillText(ctx, "My custom text fill function", 12, 8); }; function myFillText(ctx, str, x, y) { x |= 0; y |= 0; // force x/y to integer positions for(var i = 0, ascii; i < str.length; i++) { // get ASCII code but offset -32 to match sprite-sheet ascii = str.charCodeAt(i) & 0xff - 32; // look-up bitmap font sprite-sheet and draw directly to canvas ctx.drawImage(img, ascii * cw, 0, cw, ch, x + i * cw, y, cw, ch); } }
<canvas id=c width=600></canvas> <script> var bmp = "data:image/png;base64,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"; </script>
可以進行一些簡單的修改以允許顏色、漸變、圖案等。
// Note: font sprite-sheet premade using: // https://jsfiddle.net/epistemex/bdm3tbtu/ var cw = 8, ch = 19, c2, img = new Image; img.onload = go; img.src = bmp; var ctx = c.getContext("2d"), ctx2; function go() { // setup offscreen-canvas c2 = document.createElement("canvas"); c2.width = this.width; c2.height = this.height; ctx2 = c2.getContext("2d"); ctx2.drawImage(this, 0, 0); myFontColor("#c00"); myFillText(ctx, "My custom text fill function in red...", 12, 8); }; function myFontColor(style) { ctx2.globalCompositeOperation = "source-atop"; ctx2.fillStyle = style; ctx2.fillRect(0, 0, c2.width, c2.height); } function myFillText(ctx, str, x, y) { x |= 0; y |= 0; for(var i = 0, ascii; i < str.length; i++) { ascii = str.charCodeAt(i) & 0xff - 32; ctx.drawImage(c2, ascii * cw, 0, cw, ch, x + i * cw, y, cw, ch); } }
<canvas id=c width=600></canvas> <script> var bmp = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAvgAAAATBAMAAAAXEGS4AAAAG1BMVEUAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACUUeIgAAAACHRSTlMAljxY3CJ2uKuwIxoAAANySURBVFjD7VhNa9tAEH2SZUlH0ULPatJSH00/IEdBc8jREAg6OqSBHg29+LiR43R+djMfm9VXKKREDcRPrFc7mtGbeVptNsIBBxxwwP/GrMQBEyO53kNAt1BsdydoISrwPJgRbTA9Eq2nnpS7LiKWct/P5dte+6ujSsWu6q/t628vKzwH4htgUWJyfL7W3mE6xA0ioFcvAVnpkDtCfVwWYGRF8sku5pzg6RnGkBMBOfeOm/gT28hx77w9gDTOQe0f2FRZDIEsjpuMmZ/UmVx+b9eMuBkHfJ9bb4f52WG5CDimiCA4lpQm4Ue0QaTatgRkOwq95fcSgqz6deFVIkt4CEsCD3TI5ZetHfJA5gWA2ivURHf3Zj2srDASRw1QC8AyELyv9ebrKB8vHiSxzshnZbpq1T8JP1Kn4ifrrvgMfjoxLTkImFF5tgO8ksm7y4r7DvTmNhvIFPVnXfGZO9uL0YfKIC3jHTWhFD0gAhD6xXPTPGlQevAdKZ7V1FgTPwIKGAjT8GNm4ufLgfjiiuRGxVqcol6ZRjyOChsECI28a+jJHRYXckH8sNyYR87J5Oswj+DLBzceP1o8jRWPQfGSnnIpt9XzBrgKVUzDj2yt4qebjoZB/NnPDTumm5PlF4RkbX3XEQUlKecfczQivqwuZH8LqE9lwcAFfoAKEp+H4imMiVrFkwgonCIA1JfgY7rFW24S5+v392qDMA3/vIGKj8VqQev5iPhHDY/rMtkXPfFtYDAiYoJQFCdl9PZwtGcMZj4B57gD0WMzjzqvsl+P5Sy34pXtvheeQfFBeGnhCQRMxo9kqeLHFQpsb/tJuIvZx4YdT8pYL2pGI+IbF9NTeEi+tZM2RyNB517n8+axNVesw+L1l9AqPqfhmmv+ZhPROjkGTMbfX/MHM78+f19xwKKKaZN5hdu+zvdiHux2tO+Ir+beAyRt6XyXUUojuw2gX1DwCDLYmzT0JdcpXj00gaH4k/D/Xfw53YLVTOl3THuYvOPiOygxSQv7Ye7966bnECRNe59v4mPb0B0th/tsgAdWiDRyYa0N+2zAXnzlDdziZfHtfT4PBuJPwY+osq1m8aRvO0z5dKQjdDIJMvwLpLonQARRTMLf/idrcmRjKb7RyfgqMN+p+CcrvAxkFbDFK0GuH9ZezlyriV7RV+wIAX8AnAnL3b7xqFYAAAAASUVORK5CYII="; </script>
可以通過例如將常用詞預渲染到單獨的精靈表中來獲得一些優化,然后在自定義文本函數中檢測到這一點。
在這里查看答案,您可能會發現一些有用的東西。 不幸的是,我無法用你的字體嘗試它,所以我無法找到更多信息。
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