losing transparency when loading png file from jar into PImage

ottenm

I'm using the code below to successfully load and display jpg's, but when I try with a png file with a transparent background, I'm just getting a black box. I tried iterating through the pixels in img.pixels (with loadPixels() and updatePixels()) but everything's already set to -16777216....

Thanks for any suggestions.

InputStream istream = MyApp.class.getResourceAsStream("/res/images/xyz.png"); 
byte bytes[] = loadBytes(istream);
Image awtImage = new ImageIcon(bytes).getImage();
PImage img = new PImage(awtImage);

kfrajer

PImage img = new PImage(awtImage);

Problem here. If this is Processing (Java), the reference is clear by saying that you need to use loadImage() or createImage() and not to use new PImage(...).

Kf

koogs

i think that's ok, it's here in the source

https://github.com/processing/processing/blob/master/core/src/processing/core/PImage.java#L291

and those last 3 lines are pretty much taken from here:

https://github.com/processing/processing/blob/master/core/src/processing/core/PApplet.java#L5370

but it's missing the call to checkAlpha: https://github.com/processing/processing/blob/master/core/src/processing/core/PApplet.java#L5462

lol: https://github.com/processing/processing/blob/master/core/src/processing/core/PImage.java#L273

ottenm

Thanks a ton kfrajer! (and yes, definitely using Processing there with the PImage).

You reminded me I couldn't get loadImage() working from the jar/resource file, so I just re-surfed it and found this thread with the same problem with loadImage(). https://forum.processing.org/two/discussion/25493/eclipse-export-to-jar-images-don-t-load

The thread includes the working solution below! Super psyched and working like a charm! Thanks again!

BufferedImage bi = ImageIO.read(MyApp.class.getResourceAsStream("/res/images/xyz.png"));
PGraphics g = createGraphics(bi.getWidth(), bi.getHeight());
g.beginDraw();
Graphics2D g2d = (Graphics2D) g.getNative();
g2d.drawImage(bi, 0, 0, bi.getWidth(), bi.getHeight(), null);
g.endDraw();
PImage b = g.copy();

ottenm

Sorry I missed your post koogs! Another perfectly working solution below. I know the file has an alpha channel, so I just set it, which will bring me right back to this thread when it comes back to bite me! ;)

InputStream istream = MyApp.class.getResourceAsStream("/res/images/xyz.png"); 
byte bytes[] = loadBytes(istream);
Image awtImage = new ImageIcon(bytes).getImage();
b = new PImage(awtImage);
b.format = PCL.ARGB;

kfrajer

Thxs for sharing the solution @ottenm. It was simple. I checked the source code and the createImage() call a new PImage()and then it associates its parent field to the current PApplet. It seems this is important when saving an image.

@koogs Any ideas why the change of format by checkAlpha() drives to this result? I am just curious....

Kf

koogs

I'm guessing it's an efficiency thing. If there's no alpha then you don't need to worry about the current value of the screen pixel you're just about to overwrite, you can just copy the new value over it. If there is alpha involved then you have to blend the two.