actualBoundingBoxAscent

Summary

The distance from the horizontal line indicated by the textBaseline attribute to the top of the bounding rectangle of the given text, in CSS pixels; positive numbers indicating a distance going up from the given baseline.

Property of apis/canvas/TextMetrics apis/canvas/TextMetrics

Syntax

Note: This property is read-only.

var result = TextMetrics.actualBoundingBoxAscent;

Return Value

Returns an object of type NumberNumber

Examples

<canvas id="myCanvas" width="300" height="150" style="border:1px solid blue;"></canvas>
<p>. . .</p>
<script>
var can = document.getElementById("myCanvas");
var ctxt = can.getContext("2d");
ctxt.font = "24px Arial";
var txt = "Hello world!"
ctxt.fillText(txt, 10, 75);
var mets = ctxt.measureText(txt);
alert("actualBoundingBoxAscent: " + mets.actualBoundingBoxAscent);
//Use with caution: may return "undefined" even in supported browsers
</script>

Related specifications

W3C HTML Canvas 2D Specification: W3C Candidate Recommendation

Attributions

Microsoft Developer Network: Windows Internet Explorer API reference Article