HTML5 Canvas图像缩放问题 [英] HTML5 Canvas Image Scaling Issue

问题描述

我正在尝试在HTML5画布中制作像素艺术主题游戏，并且作为其中的一部分，我拍摄10x20左右大小的图像并使用以下代码将它们绘制到画布上：

I am trying to make a pixel art themed game in HTML5 canvas, and as part of that I take 10x20 or so sized images and draw them onto the canvas with the following code:

ctx.drawImage(image, 20, 20, 100, 200);

然而，画布使用双三次图像缩放，因此像素艺术图像在2x及以上时看起来很糟糕。有没有办法强制画布使用最近邻居缩放或可能使用自定义方法来缩放图像？如果不是这意味着图像必须事先在Paint.net中缩放？

However the canvas uses bicubic image scaling and hence the pixel art images look terrible at 2x and up. Is there a way to force canvas to use nearest neighbor scaling or possibly use a custom method to scale images? If not does that mean the images have to be scaled beforehand in something like Paint.net?

推荐答案

选择以下任何一种：

通过JavaScript：

ctx.imageSmoothingEnabled = false;

^{资料来源： http://www.whatwg.org/specs/web-apps/current-work/multipage /the-canvas-element.html#image-smoothing}

在Gecko上，你需要

On Gecko, you'll need

ctx.mozImageSmoothingEnabled = false;

^{来源： https://developer.mozilla.org/en/DOM/CanvasRenderingContext2D#Gecko-specific_attributes}

在Webkit上，你需要

On Webkit, you'll need

ctx.webkitImageSmoothingEnabled = false;

^{来源： https://bugs.webkit.org/show_bug.cgi?id=82804}

我无法在其他浏览器上找到有关此属性支持的信息，因此他们可能不支持。

I couldn't find information on support of this property on other browsers, so they probably don't support it.

通过CSS：

另一种选择是在画布上使用一组CSS规则。例如：

Another option is to use a set of CSS rules on the canvas. For example:

<canvas id="c" width="16" height="16"></canvas>
<script>
  var c = document.getElementById("c"),
      cx = c.getContext("2d"),
      im = new Image();
  im.src = "http://stackoverflow.com/favicon.ico"; // 16x16
  cx.drawImage(im, 0, 0);
</script>
<style>
  canvas {
    width: 32px;
    height: 32px;
    image-rendering: optimizeSpeed;
    image-rendering: crisp-edges;
    image-rendering: -moz-crisp-edges;
    image-rendering: -o-crisp-edges;
    image-rendering: -webkit-optimize-contrast;
    -ms-interpolation-mode: nearest-neighbor;
  }
</style>

<sup>来源： https://developer.mozilla.org/en/CSS/image-rendering

来源： https://bugs.webkit.org/show_bug.cgi?id=56627</sup>

通过像素例程：

另一种选择是使用画布像素操作例程自己完成： http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-element.html#pixel-manipulation 。不过，这还有很多工作要做。

Yet another option is to do it yourself using the canvas pixel manipulation routines: http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-element.html#pixel-manipulation. That's a lot more work, though.

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