TextMetrics.fontBoundingBoxAscent

The read-only fontBoundingBoxAscent property of the TextMetrics interface is a double giving the distance from the horizontal line indicated by the CanvasRenderingContext2D.textBaseline attribute to the top of the highest bounding rectangle of all the fonts used to render the text, in CSS pixels.

Examples

const canvas = document.createElement('canvas');
const ctx = canvas.getContext('2d');
const text = ctx.measureText('foo'); // returns TextMetrics object

text.fontBoundingBoxAscent; // 10;

Specifications

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
fontBoundingBoxAscent
87
Yes
79
74
No
73
11.1
87
87
Yes
No
No
11.3
14.0

See also

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https://developer.mozilla.org/en-US/docs/Web/API/TextMetrics/fontBoundingBoxAscent