Loading a PNG drops the alpha channel

[Nateowami]

When I load a PNG image only 3 channels are loaded into the matrix:

cv.readImage('path/to/image.png', function(err, img){
  if(err) throw err;
  console.log(img.channels()); // Prints '3'
  img.save('out.png');
});

When the file is saved, it is saved without an alpha channel. Looking at the source code for OpenCV.cc I see the image is loaded with cv::imread(filename, CV_LOAD_IMAGE_UNCHANGED). I understood from other sources that CV_LOAD_IMAGE_UNCHANGED should preserve the alpha channel.

[danschultzer]

In package.json load from master:

"opencv": "peterbraden/node-opencv"

CV_LOAD_IMAGE_UNCHANGED fix was merged in back in May, but there's not been a new release yet.

[Nateowami]

@danschultzer Ah, I see. Thanks. Should have checked the git blame. Is the master branch pretty stable then, or is it better to select a specific commit?

[danschultzer]

Yeah, the master branch has been pretty stable for me.