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CanvasRenderingContext2D.strokeRect() 是 Canvas 2D API 在 canvas 中,使用当前的绘画样式,描绘一个起点在 (x, y) 、宽度为 w 、高度为 h 的矩形的方法。

语法

void ctx.strokeRect(x, y, width, height);

参数

x
矩形起点的 x 轴坐标。
y
矩形起点的 y 轴坐标。
width
矩形的宽度。
height
矩形的高度。

示例

使用 strokeRect 方法

这是一段使用 strokeRect 方法的简单的代码片段。

HTML

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

JavaScript

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

ctx.strokeStyle = "green";
ctx.strokeRect(10, 10, 100, 100);

修改下面的代码并在线查看 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">
ctx.strokeStyle = "green";
ctx.strokeRect(10, 10, 100, 100);</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);

规范描述

Specification Status Comment
HTML Living Standard
CanvasRenderingContext2D.strokeRect
Living Standard  

浏览器兼容性

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) (Yes) (Yes) (Yes) (Yes)
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)

参见

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