Does Processing transparency support removing backgrounds?

Question

I have an image with a green background.

I used this function to remove the background.

public void removeBackground(PImage img, color c, float thres) {
  colorMode(HSB);
  for(int i = 0; i < img.width; i++){
    for(int j = 0; j < img.height; j++){
      color cp = img.get(i, j);
      //threshold accounts for compression
      if(abs(hue(cp) - hue(c)) < thres){
        img.set(i, j, color(0,0,0,0));
      }
    }
  }
}

Using these parameters, I attempted to remove the background.

PImage FBSprite;
public void settings() {
  size(500, 500);
}

void setup(){
  FBSprite = loadImage("FlappyBirdSprite.jpg");
  FBSprite.resize(50, 0);
  removeBackground(FBSprite, FBSprite.get(0,0), 0.5);
  image(FBSprite, 0, 0);
}

void draw(){
  background(200);
  image(FBSprite, 0, 0);
}

The background turns to black instead of transparent.

ARGB result:

HSB result with 1 alpha:

Answer 1

You are going to love this: change this line

colorMode(HSB);

for this:

colorMode(ARGB);

And it should do the trick. What just happened? Unless you need to work in HSB at that very specific point, there's no point to it. ARGB is just like RGB but it has an ALPHA setting, or transparency if you prefer. Seems like you already were ready to work in ARGB since you set color(0,0,0,0) like this, so this may be a a copy and paste programming issue. Or maybe you just didn't notice. It happens to me all the time. If that's the first thing, though, try to keep a keen eye for this kind of problem in the future. Most people doesn't talk about other bad design patterns except for spaghetti code which everybody knows, but cut and paste programming is real and it hurts a lot, especially if you work with some in-house platform with inexistant documentation. Not that it happened to me.

Have fun!