drawImage and resize to Canvas

Question

I have an image which is 1836 x 3264 I want to drawImage() to canvas and resize to 739 x 1162.

After reading the documentation I thought this could be accomplished with the following:

ctx.drawImage(image, 0, 0, 739, 1162);

I have also tried:

ctx.drawImage(image, 0, 0, 1836, 3264, 0, 0, 739, 1162);

Both show only a small part of the full image instead of shrinking it down.

How do I pass through the values to resize from 1836 x 3264 -> 739 x 1162 ?

This should help: http://stackoverflow.com/questions/2303690/resizing-an-image-in-an-html5-canvas — bfavaretto, Mar 03 '13 at 23:52

score 40 · Accepted Answer · edited Feb 03 '19 at 01:27

40

What you have looks correct, so you might double-check for a typo somewhere.

[additional thought: Is your image really 1836x3264 and not 3264x1836.]

Here is working code and a Fiddle: http://jsfiddle.net/m1erickson/MLGr4/

<!doctype html>
<html>
<head>
<link rel="stylesheet" type="text/css" media="all" href="css/reset.css" /> <!-- reset css -->
<script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>

<style>
    body{ background-color: ivory; }
    canvas{border:1px solid red;}
</style>

<script>
$(function(){

    var canvas=document.getElementById("canvas");
    var ctx=canvas.getContext("2d");

    img=new Image();
    img.onload=function(){
        canvas.width=400;
        canvas.height=300;
        ctx.drawImage(img,0,0,img.width,img.height,0,0,400,300);
    }
    img.src="http://www.onestopwebmasters.com/wp-content/uploads/2011/06/eitai-bridge.jpg";

}); // end $(function(){});
</script>

</head>

<body>
    <canvas id="canvas" width=100 height=100></canvas>
</body>
</html>

edited Feb 03 '19 at 01:27

Neuron

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answered Mar 04 '13 at 02:30

markE

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1

Thanks code was right. It was just a glitch in how the mobile phone system was handling canvas. – Philip Kirkbride Mar 24 '13 at 00:50
1

@PhilipKirkbride Can you tell us what this mobile phone glitch was and how you fixed it, please? – palsch Aug 24 '16 at 15:13
4

This answer helped me realize I was setting `canvas.style.width` and `height` rather than `canvas.width`. Changing that helped the `ctx.drawImage` scaling render as expected, rather than the stretching it was doing before the canvas itself had dimension attributes. – crowjonah Nov 10 '17 at 21:21
2

@crowjonah, Your comment saved a lot of time for me today!. Many thanks. – Nitesh Saxena Aug 20 '18 at 06:03

drawImage and resize to Canvas

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