HTML5 canvas stroke() 粗而模糊 [英] HTML5 canvas stroke() thick and fuzzy

问题描述

我试图让用户在画布上绘制一个矩形(如选择框).我得到了一些荒谬的结果，但后来我注意到，即使只是尝试参考此处中的代码，我得到了巨大的模糊线条，不知道为什么.

I'm trying to allow the user to draw a rectangle on the canvas (like a selection box). I'm getting some ridiculous results, but then I noticed that even just trying the code from my reference here, I get huge fuzzy lines and don't know why.

它托管在 dylanstestserver.com/drawcss.javascript 是内联的，因此您可以查看它.我正在使用 jQuery 来简化获取鼠标坐标的过程.

it's hosted at dylanstestserver.com/drawcss. the javascript is inline so you can check it out. I am using jQuery to simplify getting the mouse coordinates.

推荐答案

由于某种原因，您的画布被拉伸了.因为您将其 css 属性 width 设置为 100%，所以它会从某种原生大小拉伸它.这是在 标签上使用 css width 属性和 width 属性之间的区别.您可能想尝试使用一些 javascript 来填充视口(参见 jQuery .width()):

For some reason, your canvas is stretched. Because you have its css property width set to 100%, it is stretching it from some sort of native size. It's the difference between using the css width property and the width attribute on the <canvas> tag. You might want to try using a bit of javascript to make it fill the viewport (see jQuery .width()):

jQuery(document).ready(function(){
    var canvas = document.getElementById('drawing');
    canvas.width(($(window).width()).height($(window).height());
    var context = canvas.getContext('2d');
    //...

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