How to find the height of a text in HTML canvas using JavaScript ?
In this article, we will find the height of the text canvas using JavaScript.
Approach: In the following example, the height attribute of the HTML canvas is used. First set the font in pt to set the height.
context.font = '26pt Calibri';
Then the current text is aligned in the center by using values ‘middle’ and color ‘yellow’.
context.textAlign = 'middle'; context.fillStyle = 'yellow';
Then, check the width of the text using the measureText() method before writing to the canvas. Finally, the text is written on the canvas using the fillText() method.
Example 1:
HTML
<!DOCTYPE HTML><html> <head> <style> body { margin: 0px; padding: 0px; } </style></head> <body> <canvas id="myCanvas" width="550" height="200"> </canvas> <script> var canvas = document.getElementById('myCanvas'); var context = canvas.getContext('2d'); var x = canvas.width / 3; var y = canvas.height / 2 - 15; var text = 'HI '; // Set the font to set the height context.font = '26pt Calibri'; context.textAlign = 'middle'; context.fillStyle = 'yellow'; context.fillText(text, x, y); context.font = '20pt Calibri'; // Check the width of the text var metrics = context.measureText(text); var width = metrics.width; // Text is aligned in the left context.textAlign = 'left'; context.fillStyle = '#010'; context.fillText('(' + width + 'px wide)', x, y + 40); </script></body> </html> |
Output:
Approach: First get the 2d drawing context of the canvas by using getContext() method. Set the font and the text string. Then write the text with x and y co-ordinates using fillText() method as given below.
Example 2:
HTML
<!DOCTYPE html><html> <body> <canvas id="Canvas" width="300" height="150" style="border:1px solid #010;"> Your browser isn't supporting HTML5 canvas tag. </canvas> <script> var c = document.getElementById("Canvas"); var x = c.getContext("2d"); x.font = "30px Arial"; var txt = "Computer Science" x.fillText("width:" + x.measureText(txt).width, 10, 50); x.fillText(txt, 10, 100); </script></body> </html> |
Output:
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