nodejs imagemagick converting svg to png adds a white background, how to keep it transparent?

Asked Oct 30 '15 at 12:21

Active Oct 30 '15 at 20:06

Viewed 1,527 times

I'm trying to use imagemagick to convert svgs to pngs, rescale them and put them in a response stream.

I'm using https://www.npmjs.com/package/imagemagick like this:

var imageUri = __dirname + '/images/' + project + '/' + image + '.svg';

console.log(imageUri);

var svg = fs.readFileSync(imageUri, 'utf8');
res.writeHead(200, {'Content-Type': 'image/png' });

var size = '' + (100 * scale);

var conv = im.convert(['svg:-', '-resize', size + 'x' + size, 'png:-']);
conv.on('data', function(data) {
    res.write(data, 'binary');
}); 
conv.on('end', function() {
    res.end();
});                                                                                
conv.stdin.write(svg);
conv.stdin.end();

Only problem is that it adds a background when I was hoping for something transparent. Any ideas of how I can fix this?

asked Oct 30 '15 at 12:21

just_user

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http://stackoverflow.com/questions/9853325/how-to-convert-a-svg-to-a-png-with-image-magick just exec this code : convert -density 1200 -resize 200x200 source.svg target.png – KoIIIeY Oct 30 '15 at 14:00
of course, after this send and unlink created file – KoIIIeY Oct 30 '15 at 14:00
and -background none, as sayed in link – KoIIIeY Oct 30 '15 at 14:01
That answer and question is a command line way of doing it. I'm doing it in a constantly running app. – just_user Oct 30 '15 at 14:34
yep, but image magick more powerfull in command line. So, your code do the same, just by library around real commands. – KoIIIeY Oct 30 '15 at 14:39
maybe it is, but I'm asking how to do this in node.js because I have to clue how to make console commands to serve get requests. – just_user Oct 30 '15 at 16:57
Try adding `-background none` – Mark Setchell Oct 30 '15 at 17:09
@MarkSetchell doesn't work :( – just_user Nov 02 '15 at 10:36

nodejs imagemagick converting svg to png adds a white background, how to keep it transparent?

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