how to crop with node-imagemagick, with a buffer as input, and stdout as output?

Question

I'm using node-imagemagick for the first time. Disclaimer: I've never used imagemagick, and am not much of a javascript guy. Most experience is in C/C++, Objective-C.

I'm writing a snippet for a server side process that needs to take an input buffer, crop it to an arbitrary bounds, and then output that in stdout.

Currently, my code looks like this:

var im = require('imagemagick');
...
im.convert([
    binaryDataBlock,
    '-crop',
     cropStr], function(err, stdout, stderr) {....

I know my input is good... I've done this with imagemagick's "resize" routine. "cropStr" is a string, "100x100+10+10" -- any arbitrary values go here.

But I still get errors back in stderr:

  "result" : "convert: unable to open image `ï¿½ï¿½ï¿½ï¿½':  @ error/blob.c/OpenBlob/2587.\nconvert: no decode delegate for this
image format ï¿½ï¿½ï¿½ï¿½' @ error/constitute.c/ReadImage/532.\nconvert: option requires an argument-crop' @ error/convert.c/ConvertImageCommand/1081.\n"

I've tried putting in a "-format" argument, which I thought would set the output format. But then it complains about the argument.

I feel like I'm missing something obvious here. It shouldn't be so hard to just crop to an arbitrary rectangle in an image.

Any help would be tremendously appreciated.

how to crop with node-imagemagick, with a buffer as input, and stdout as output?

0 Answers0