Error reading opacity levels from image?

[jmitch0901]

Hello, I am working on a small project for the Feed My Starving Children foundation. I really like the JIMP package, however I'm unsure if I'm either missing something, or the following is an error with JIMP.

Here is the following use case I'm trying to implement:

I read a SECRET-IMAGE.PNG stored on my server. I then read the RELEASABLE-IMAGE.PNG on my server. I have a mongo database which runs through 1,000,000 entries, to detect whether a pixel for that image has been bought or not. If it was bought, I reveal that pixel by writing the pixel color FROM the secret-image.png, TO the releasable-image.png.

Here is the issue:

For some reason my releasable-image.png becomes extremely blocky. I think it has something to do with not being able to read the alpha value correctly. I debugged this by logging the alpha value for each bought pixel, and every time it returned a alpha value of 255.

Here is the code:

function reloadImage(callbacks){

     return Jimp.read(imagePaths.secretPath)
    .then(function(secretPic){

        console.log("Reading secret image!");

        Jimp.read(imagePaths.mainPath)
        .then(function(releasedPic){

            console.log("Writing to Releasable image!");
            var count = 0;

            PixelSchema.find({})
              .lean()
              .stream()
              .on('data',function(pixelObj){


                var hex = pixelObj.isBought ? secretPic.getPixelColor(pixelObj.pixel.x,pixelObj.pixel.y)
                                            : 0xFFFFFFFF;

                if(pixelObj.isBought){
                  count++;
                }

                releasedPic.setPixelColor(hex,pixelObj.pixel.x,pixelObj.pixel.y);

              })
              .on('error',function(err){
                console.error("Error streaming the data!");
                console.error(err);
              })
              .on('close',function(){
                console.log('Done streaming the pixel data!');
                percentage = count / 1000000.0;
                pixelsBoughtCount = count;
                releasedPic.write(imagePaths.mainPath,function(){
                  console.log("done writing new image after bought pixels!");
                  if(callbacks){
                    return callbacks();
                  }
              });
            });
        });
    });
};`

Here is the result:

Am I missing something, or would this be an issue with JIMP? (Notice the child in the background)

SECRET-IMAGE.PNG

RELEASABLE-IMAGE.PNG

[oliver-moran]

Thanks. I've made a test case and can repeat the issue.

I've opened an issue at jpeg-js/jpeg-js#17.

[hipstersmoothie]

@jmitch0901 seems to be fixed in latest master. Open another issue if you see the behavior persisting