CODEWITHSUNDEEP
javascriptjqueryhtmlcanvas
Nicholas Murray
Nicholas Murray

Reputation: 13533

Download a Html5 canvas element as an image with the file extension with Javascript

I would like to be able to download a Html5 canvas element as an image with the file extension with Javascript.

The CanvasToImage library does not seem to be able to achieve this.

Here is my code so far which you can see at this JsFiddle.

<div id="canvas_container">
</div>
<p>
<a href='#' id="create_image">create</a> 
<a href="#" id="download_image">download</a>
</p>




$("#create_image").click(function() {
var cnvs = createSmileyOnCanvas();
$('#canvas_container').append(cnvs);
});


$("#download_image").click(function() {    
var img = $('#smiley_canvas').toDataURL("image/png");
var uriContent = "data:application/octet-stream," + encodeURIComponent(img);
window.open(uriContent, 'download smiley image');
});



function createSmileyOnCanvas() {
var canvas = document.createElement('canvas');      
canvas.id = 'smiley_canvas';    
var ctx = canvas.getContext('2d');        

// Draw shapes
ctx.beginPath();
ctx.arc(75,75,50,0,Math.PI*2,true); // Outer circle
ctx.moveTo(110,75);
ctx.arc(75,75,35,0,Math.PI,false);   // Mouth
ctx.moveTo(65,65);
ctx.arc(60,65,5,0,Math.PI*2,true);  // Left eye
ctx.moveTo(95,65);
ctx.arc(90,65,5,0,Math.PI*2,true);  // Right eye
ctx.stroke();

return canvas;
}

Upvotes: 5

Views: 14093

Answers (3)

Meir
Meir

Reputation: 171

This seems to work for me:

<a id="downloadImgLink" onclick="$('#downloadImgLink').attr('href', canvas.toDataURL());" download="MyImage.png" href="#" target="_blank">Download Drawing</a>

Upvotes: 10

Aman Virk
Aman Virk

Reputation: 3977

Hi i have created a jquery plugin which will let you do the same task with ease but it also make use of php to download the image. let me explain how it works

Plugin has 2 sub function that you can call independently to add image to the canvas and the other one is to download the current image lying on the canvas.

Add image to the canvas

For this you need to pass the id of the canvas element and the path of the image you want to add

download image from the canvas

For this you need to pass the id of the canvas element

 $('body').CanvasToPhp.upload({
    canvasId: "canvas",   // passing the canvasId
    image: "455.jpg"      // passing the image path
});

// downloading file
$('#download').click(function(){
    $('body').CanvasToPhp.download({
        canvasId: "canvas"   // passing the canvas id
    });  // 
});

First you need to download the plugin file which you can find here http://www.thetutlage.com/post=TUT213

I have also created a little demo http://thetutlage.com/demo/canvasImageDownload

Upvotes: 2

Jani Hartikainen
Jani Hartikainen

Reputation: 43243

In order to force/suggest a file name in the browser's download dialog, you would need to send the Content-Disposition: attachment; filename=foobar.png header.

This is not possible to do via window.open, so you're out of luck unless there are some browser-specific hacks for this.

If you really need the filename, you could try using the new download attribute in a, <a href="put stuff here" download="filename here">. It isn't very widely supported yet though.

Another alternative would be to first submit the data to the server using ajax, then redirect the browser to some server-side script which would then serve the data with the correct header.

Upvotes: 2

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