Canvas Is Stretched When Using CSS But Normal With "Width"/"Height" Properties

Canvas is stretched when using CSS but normal with width / height properties

It seems that the width and height attributes determine the width or height of the canvas’s coordinate system, whereas the CSS properties just determine the size of the box in which it will be shown.

This is explained in the HTML specification:

The canvas element has two attributes to control the size of the element’s bitmap: width and height. These attributes, when specified, must have values that are valid non-negative integers. The rules for parsing non-negative integers must be used to obtain their numeric values. If an attribute is missing, or if parsing its value returns an error, then the default value must be used instead. The width attribute defaults to 300, and the height attribute defaults to 150.

Why do I need to have the width at 400px and height at 200px in a canvas element for this?

The style= defines the scaling - use width= and height= to set the size of the box.

Also explained here (MDN canvas element).

The displayed size of the canvas can be changed using CSS, but if you do this the image is scaled during rendering to fit the styled size, which can make the final graphics rendering end up being distorted.
It is better to specify your canvas dimensions by setting the width and height attributes directly on the elements, either directly in the HTML or by using JavaScript.

<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script>
$(document).ready(function(){
var a = document.getElementById("3d");
var b = a.getContext("2d");
b.beginPath();
b.moveTo(0,50);
b.lineTo(0,100);
b.lineTo(50,150);
b.lineTo(50,100);
b.lineTo(0,50);
b.lineTo(50,0);
b.lineTo(100,50);
b.lineTo(100,100);
b.lineTo(50,150);
b.lineTo(50,100);
b.lineTo(100,50);
b.stroke();
});
</script>
</head>
<body>
<canvas id="3d" width="200" height="200" style="border:1px solid black"></canvas>
</body>
</html>

Canvas Is Stretched When Using CSS But Normal With "Width"/"Height" Properties

Canvas is stretched when using CSS but normal with width / height properties

Why do I need to have the width at 400px and height at 200px in a canvas element for this?

Related Topics

Leave a reply