The CanvasRenderingContext2D
.textBaseline
property of the Canvas 2D API specifies the current text baseline being used when drawing text.
Syntax
ctx.textBaseline = "top" || "hanging" || "middle" || "alphabetic" || "ideographic" || "bottom";
Options
Possible values:
- top
- The text baseline is the top of the em square.
- hanging
- The text baseline is the hanging baseline. (Used by Tibetan and other Indic scripts.)
- middle
- The text baseline is the middle of the em square.
- alphabetic (default value)
- The text baseline is the normal alphabetic baseline.
- ideographic
- The text baseline is the ideographic baseline; this is the bottom of the body of the characters, if the main body of characters protrudes beneath the alphabetic baseline. (Used by Chinese, Japanese and Korean scripts.)
- bottom
- The text baseline is the bottom of the bounding box. This differs from the ideographic baseline in that the ideographic baseline doesn't consider descenders.
The default value is alphabetic
.
Examples
Using the textBaseline
property
This demonstrates the different textBaseline
property values.
HTML
<canvas id="canvas" width="550" height="500"></canvas>
JavaScript
var canvas = document.getElementById('canvas'); var ctx = canvas.getContext('2d'); var baselines = ['top', 'hanging', 'middle', 'alphabetic', 'ideographic', 'bottom']; ctx.font = '36px serif'; ctx.strokeStyle = 'red'; baselines.forEach(function (baseline, index) { ctx.textBaseline = baseline; var y = 75 + index * 75; ctx.beginPath(); ctx.moveTo(0, y + 0.5); ctx.lineTo(550, y + 0.5); ctx.stroke(); ctx.fillText('Abcdefghijklmnop (' + baseline + ')', 0, y); });
Edit the code below and see your changes update live in the canvas:
Playable code
<canvas id="canvas" width="550" height="500" 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"> var baselines = ['top', 'hanging', 'middle', 'alphabetic', 'ideographic', 'bottom']; ctx.font = '36px serif'; ctx.strokeStyle = 'red'; baselines.forEach(function (baseline, index) { ctx.textBaseline = baseline; var y = 75 + index * 75; ctx.beginPath(); ctx.moveTo(0, y + 0.5); ctx.lineTo(550, y + 0.5); ctx.stroke(); ctx.fillText('Abcdefghijklmnop (' + baseline + ')', 0, y); }); </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.save(); ctx.clearRect(0, 0, canvas.width, canvas.height); eval(textarea.value); ctx.restore(); } reset.addEventListener('click', function() { textarea.value = code; drawCanvas(); }); edit.addEventListener('click', function() { textarea.focus(); }) textarea.addEventListener('input', drawCanvas); window.addEventListener('load', drawCanvas);
Specifications
Specification | Status | Comment |
---|---|---|
HTML Living Standard The definition of 'CanvasRenderingContext2D.textBaseline' in that specification. |
Living Standard |
Browser compatibility
Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | 3.5 (1.9.1) | 9 | (Yes) | (Yes) |
Feature | Android | Chrome for Android | Edge | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | (Yes) | 1.0 (1.9.1) | (Yes) | (Yes) | (Yes) |
See also
- The interface defining it,
CanvasRenderingContext2D
.