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CanvasRenderingContext2D.imageSmoothingQuality - Web API 接口参考编辑

这是一个实验中的功能
此功能某些浏览器尚在开发中，请参考浏览器兼容性表格以得到在不同浏览器中适合使用的前缀。由于该功能对应的标准文档可能被重新修订，所以在未来版本的浏览器中该功能的语法和行为可能随之改变。

CanvasRenderingContext2D.imageSmoothingQuality 是 Canvas 2D API，用于设置图像平滑度的属性。

示例

使用 imageSmoothingQuality 属性

这是一段简单的代码片段，对缩放的图片使用 imageSmoothingQuality 属性。

HTML

<canvas id="canvas"></canvas>

JavaScript

var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");

var img = new Image();
img.src = 'https://www.wenjiangs.com/wp-content/uploads/2020/mozilla/Canvas_createpattern.png';
img.onload = function() {
 ctx.mozImageSmoothingEnabled = false;
 ctx.imageSmoothingQuality = "Medium";
 ctx.webkitImageSmoothingEnabled = false;
 ctx.msImageSmoothingEnabled = false;
 ctx.imageSmoothingEnabled = false;
 ctx.drawImage(img, 0, 0, 400, 200);
};

编辑下面代码，在线查看 Canvas 的变化：

Playable code

<canvas id="canvas" width="400" height="200" class="playable-canvas"></canvas>
<div class="playable-buttons">
  <input id="edit" type="button" value="Edit" />
  <input id="reset" type="button" value="Reset" />
</div>
<textarea id="code" class="playable-code" style="height:140px;">
var img = new Image();
img.src = 'https://www.wenjiangs.com/wp-content/uploads/2020/mozilla/Canvas_createpattern.png';
img.onload = function() {
 ctx.mozImageSmoothingEnabled = false;
 ctx.webkitImageSmoothingEnabled = false;
 ctx.imageSmoothingQuality = "Medium";
 ctx.msImageSmoothingEnabled = false;
 ctx.imageSmoothingEnabled = false;
 ctx.drawImage(img, 0, 0, 400, 200);
};</textarea>

var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
var textarea = document.getElementById("code");
var reset = document.getElementById("reset");
var edit = document.getElementById("edit");
var code = textarea.value;

function drawCanvas() {
  ctx.clearRect(0, 0, canvas.width, canvas.height);
  eval(textarea.value);
}

reset.addEventListener("click", function() {
  textarea.value = code;
  drawCanvas();
});

edit.addEventListener("click", function() {
  textarea.focus();
})

textarea.addEventListener("input", drawCanvas);
window.addEventListener("load", drawCanvas);

规范

Specification	Status	Comment
HTML Living Standard imageSmoothingQuality	Living Standard	Initial definition.

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