CanvasRenderingContext2D.direction

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.direction 是Canvas 2D API 用来在绘制文本时,描述当前文本方向的属性。

语法

ctx.direction = "ltr" || "rtl" || "inherit";

选项

有效值:

ltr
文本方向从左向右。
rtl
文本方向从右向左。
inherit
根据情况继承 <canvas> 元素或者 Document

默认值是inherit。

示例

使用direction 属性

这是一段简单的代码片段,对文本设置不同的direction数值。

HTML

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

JavaScript

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

ctx.font = '48px serif';
ctx.fillText('Hi!', 150, 50);
ctx.direction = 'rtl';
ctx.fillText('Hi!', 150, 130);

结果

规范描述

Specification Status Comment
HTML Living Standard
CanvasRenderingContext2D.direction
Living Standard

浏览器兼容性

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
direction
Experimental
Chrome Full support Yes
Disabled
Full support Yes
Disabled
Disabled This feature is behind the Experimental Web Platform Features preference. To change preferences in Chrome, visit chrome://flags.
Edge Full support ≤79
Disabled
Full support ≤79
Disabled
Disabled From version ≤79: this feature is behind the Experimental Web Platform Features preference.
Firefox No support NoIE No support NoOpera No support NoSafari Full support YesWebView Android Full support YesChrome Android Full support YesFirefox Android No support NoOpera Android No support NoSafari iOS Full support YesSamsung Internet Android Full support Yes

Legend

Full support  
Full support
No support  
No support
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
User must explicitly enable this feature.
User must explicitly enable this feature.

参见