我的缺点 - 比例确实适用于文本。我想出了一个解决方案:
context.font = "20px 'Segoe UI'";
var metrics = context.measureText("Testing!");
var textWidth = metrics.width;
var scalex = (canvas.width / textWidth);
var scaley = (canvas.height / 23);
var ypos = (canvas.height / (scaley * 1.25));
context.scale(scalex, scaley);
context.fillText("Testing!", 0, ypos);
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