How to output a new image directly?

[hylin]

I want to use gm to create a captcha and directly output to browser , that means, do not use "write" to output to disk. I tryed this(used gm buffer plugin , express):

gm(opts.width || 70, opts.height || 30, '#000')
    .font("arial", 20)
    .stroke("#fff", 2)
    .fill("#888")
    .drawText(10, 22, text)
    .buffer(function(err,buf){
      res.send(buf);
    });

but buf.length is 0.
Any suggest?

[duyleekun]

If res is input stream, this may suite you better

gm(opts.width || 70, opts.height || 30, '#000')
    .font("arial", 20)
    .stroke("#fff", 2)
    .fill("#888")
    .drawText(10, 22, text)
    .stream(function(err,stdout){
      stdout.pipe(res)
    });

[hylin]

@duyleekun

This is ok：

gm('./public/static/img/image.png')
      .font("arial", 20)
      .stroke("#fff", 2)
      .fill("#888")
      .drawText(10, 22, 'test')
      .stream(function(err,stdout){
        stdout.pipe(res);
      });

But this does not work:

gm(opts.width || 70, opts.height || 30, '#000')
    .font("arial", 20)
    .stroke("#fff", 2)
    .fill("#888")
    .drawText(10, 22, text)
    .stream(function(err,stdout){
      stdout.pipe(res)
    });

I tried to use gm create a new image and use "write" to save image to disk and this is ok.
Is there a bug in "gm" create a new image and output by stream?

[jonathanong]

what happens when you do the second one?

[hylin]

@jonathanong nothing happened.no error occured and no image outputed.Like steam is empty.

[jonathanong]

does the response end or does it just hang?

[hylin]

@jonathanong response is end,and nothing output to browser.

[jonathanong]

no issues with gm. created a test for you: https://github.com/aheckmann/gm/blob/master/test/newImage.js. let us know if you can find a reproducible case.

no idea what could be going wrong with yoru code, maybe something like content type header.