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• 句法
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

CanvasRenderingContext2D .textAlign property of the Canvas 2D API specifies the current text alignment used when drawing text.

The alignment is relative to the x value of the fillText() method. For example, if textAlign is "center" , then the text's left edge will be at x - (textWidth / 2) .

句法

ctx.textAlign = "left" || "right" || "center" || "start" || "end";
					

选项

可能的值：

"left"

The text is left-aligned.

"right"

The text is right-aligned.

"center"

The text is centered.

"start"

The text is aligned at the normal start of the line (left-aligned for left-to-right locales, right-aligned for right-to-left locales).

"end"

The text is aligned at the normal end of the line (right-aligned for left-to-right locales, left-aligned for right-to-left locales).

默认值为 "start" .

范例

General text alignment

This example demonstrates the three "physical" values of the textAlign 特性： "left" , "center" ，和 "right" .

HTML

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

JavaScript

const canvas = document.getElementById('canvas');
canvas.width = 350;
const ctx = canvas.getContext('2d');
const x = canvas.width / 2;
ctx.beginPath();
ctx.moveTo(x, 0);
ctx.lineTo(x, canvas.height);
ctx.stroke();
ctx.font = '30px serif';
ctx.textAlign = 'left';
ctx.fillText('left-aligned', x, 40);
ctx.textAlign = 'center';
ctx.fillText('center-aligned', x, 85);
ctx.textAlign = 'right';
ctx.fillText('right-aligned', x, 130);
					

结果

Direction-dependent text alignment

This example demonstrates the two direction-dependent values of the textAlign 特性： "start" and "end" 。注意， direction property is manually specified as "ltr" , although this is also the default for English-language text.

HTML

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

JavaScript

const canvas = document.getElementById('canvas');
const ctx = canvas.getContext('2d');
ctx.font = '30px serif';
ctx.direction = 'ltr';
ctx.textAlign = 'start';
ctx.fillText('Start-aligned', 0, 50);
ctx.textAlign = 'end';
ctx.fillText('End-aligned', canvas.width, 120);
					

结果

规范

规范	状态	注释
HTML 实时标准 The definition of 'CanvasRenderingContext2D.textAlign' in that specification.	实时标准

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
textAlign	Chrome Yes	Edge 12	Firefox 3.5	IE Yes	Opera Yes	Safari Yes	WebView Android Yes	Chrome Android Yes	Firefox Android 4	Opera Android Yes	Safari iOS Yes	Samsung Internet Android Yes

图例

完整支持

完整支持

另请参阅

• The interface defining this property: CanvasRenderingContext2D

元数据

• 最后修改： Aug 19, 2019

相关话题

1. CanvasRenderingContext2D
2. 特性

   1. canvas
   2. currentTransform
   3. direction
   4. fillStyle
   5. filter
   6. font
   7. globalAlpha
   8. globalCompositeOperation
   9. imageSmoothingEnabled
   10. imageSmoothingQuality
   11. lineCap
   12. lineDashOffset
   13. lineJoin
   14. lineWidth
   15. miterLimit
   16. shadowBlur
   17. shadowColor
   18. shadowOffsetX
   19. shadowOffsetY
   20. strokeStyle
   21. textAlign
   22. textBaseline
3. 方法

   1. addHitRegion()
   2. arc()
   3. arcTo()
   4. beginPath()
   5. bezierCurveTo()
   6. clearHitRegions()
   7. clearRect()
   8. clip()
   9. closePath()
   10. createImageData()
   11. createLinearGradient()
   12. createPattern()
   13. createRadialGradient()
   14. drawFocusIfNeeded()
   15. drawImage()
   16. drawWidgetAsOnScreen()
   17. drawWindow()
   18. ellipse()
   19. fill()
   20. fillRect()
   21. fillText()
   22. getImageData()
   23. getLineDash()
   24. getTransform()
   25. isPointInPath()
   26. isPointInStroke()
   27. lineTo()
   28. measureText()
   29. moveTo()
   30. putImageData()
   31. quadraticCurveTo()
   32. rect()
   33. removeHitRegion()
   34. resetTransform()
   35. restore()
   36. rotate()
   37. save()
   38. scale()
   39. scrollPathIntoView()
   40. setLineDash()
   41. setTransform()
   42. stroke()
   43. strokeRect()
   44. strokeText()
   45. transform()
   46. translate()