PImage img, imgOriginal;
byte[][] imageArray;
byte[][] maskArray;
int currentImage = 0;
String[] images = {"print1.png", "print1b.png", "print2.png", "print2b.png", "print3.png", "print3b.png"};

void loadPixelArray(PImage anImage){
  anImage.loadPixels();
}

color getPixelColor(PImage anImage, int x, int y){
  color pixelColor = anImage.get(x,y);
  return pixelColor;
}

void refreshImagePixels(PImage anImage){
  anImage.updatePixels();
}

void setPixelColor(PImage anImage, int x, int y, color aColor){
  anImage.set(x,y,aColor);
}

void initImage(String fileName){
  img = loadImage(fileName);
  imgOriginal = loadImage(fileName);
  size(img.width * 2, img.height);
  frame.setSize(img.width * 2, img.height);
  loadPixelArray(img);
  imageArray = new byte[img.width][img.height];
  maskArray = new byte[img.width][img.height];
  for (int col = 1; col < img.width - 1; col++){
    for (int row=1; row<img.height-1; row++){
      maskArray[col][row] = 0;
      if (brightness(img.get(col, row)) < 127){
        imageArray[col][row] = 1;
      }
      else
      {
        imageArray[col][row] = 0;
      }
    }
  }
}

void setup(){
  initImage(images[0]);
}

void mousePressed(){
  currentImage = currentImage + 1;
  if (currentImage >= images.length){
    currentImage = 0;
  }
  initImage(images[currentImage]);
}

void thinning(PImage img, byte[][] imageArray, byte [][] maskArray){
  for(int a = 0; a<5;a++){
    for(int i = 0; i<img.width; i++){
      for (int j =0; j<img.height;j++){
        if (imageArray[i][j]==1){
          if(imageArray[i][j-1]==0 && imageArray[i][j+1]==1){
            if(imageArray[i-1][j]== 1 || imageArray[i-1][j+1]==1 || imageArray[i-1][j-1]==1 || imageArray[i+1][j]==1 || imageArray[i+1][j-1]==1 || imageArray[i+1][j+1] == 1){
              if ((1-imageArray[i+1][j]) - ((1-imageArray[i+1][j])*(1-imageArray[i+1][j-1])*(1-imageArray[i][j-1])) + (1-imageArray[i][j-1]) - ((1-imageArray[i][j-1])*(1-imageArray[i-1][j-1])*(1-imageArray[i-1][j])) + (1-imageArray[i-1][j]) - ((1-imageArray[i-1][j])*(1-imageArray[i-1][j+1])*(1-imageArray[i][j+1])) + (1-imageArray[i][j+1]) - ((1-imageArray[i][j+1])*(1-imageArray[i+1][j+1])*(1-imageArray[i+1][j]))==1){
                maskArray[i][j] = 1;
              }
            }
          }
        }
      }
    }
    processImagePixels();
    for(int i = 0; i<img.width; i++){
      for (int j =0; j<img.height;j++){
        if (imageArray[i][j]==1){
          if(imageArray[i-1][j]==0 && imageArray[i+1][j]== 1){
            if(imageArray[i-1][j+1]== 1 || imageArray[i-1][j-1]==1 || imageArray[i][j-1]==1 || imageArray[i][j+1]==1 || imageArray[i+1][j-1]==1 || imageArray[i+1][j+1] == 1){
              if ((1-imageArray[i+1][j]) - ((1-imageArray[i+1][j])*(1-imageArray[i+1][j-1])*(1-imageArray[i][j-1])) + (1-imageArray[i][j-1]) - ((1-imageArray[i][j-1])*(1-imageArray[i-1][j-1])*(1-imageArray[i-1][j])) + (1-imageArray[i-1][j]) - ((1-imageArray[i-1][j])*(1-imageArray[i-1][j+1])*(1-imageArray[i][j+1])) + (1-imageArray[i][j+1]) - ((1-imageArray[i][j+1])*(1-imageArray[i+1][j+1])*(1-imageArray[i+1][j]))==1){
                maskArray[i][j] = 1;
              }
            }
          }
        }
      }
    }
    processImagePixels();
    for(int i = 0; i<img.width; i++){
      for (int j =0; j<img.height;j++){
        if (imageArray[i][j]==1){
          if(imageArray[i][j+1]==0 && imageArray[i][j-1]== 1){
            if(imageArray[i-1][j+1]== 1 || imageArray[i-1][j-1]==1 || imageArray[i-1][j]==1 || imageArray[i+1][j]==1 || imageArray[i+1][j-1]==1 || imageArray[i+1][j+1] == 1){
              if ((1-imageArray[i+1][j]) - ((1-imageArray[i+1][j])*(1-imageArray[i+1][j-1])*(1-imageArray[i][j-1])) + (1-imageArray[i][j-1]) - ((1-imageArray[i][j-1])*(1-imageArray[i-1][j-1])*(1-imageArray[i-1][j])) + (1-imageArray[i-1][j]) - ((1-imageArray[i-1][j])*(1-imageArray[i-1][j+1])*(1-imageArray[i][j+1])) + (1-imageArray[i][j+1]) - ((1-imageArray[i][j+1])*(1-imageArray[i+1][j+1])*(1-imageArray[i+1][j]))==1){
                maskArray[i][j] = 1;
              }
            }
          }
        }
      }
    }
    processImagePixels();
    for(int i = 0; i<img.width; i++){
      for (int j =0; j<img.height;j++){
        if (imageArray[i][j]==1){
          if(imageArray[i+1][j]==0 && imageArray[i-1][j]== 1){
            if(imageArray[i-1][j+1]== 1 || imageArray[i-1][j-1]==1 || imageArray[i][j-1]==1 || imageArray[i][j+1]==1 || imageArray[i+1][j-1]==1 || imageArray[i+1][j+1] == 1){
              if ((1-imageArray[i+1][j]) - ((1-imageArray[i+1][j])*(1-imageArray[i+1][j-1])*(1-imageArray[i][j-1])) + (1-imageArray[i][j-1]) - ((1-imageArray[i][j-1])*(1-imageArray[i-1][j-1])*(1-imageArray[i-1][j])) + (1-imageArray[i-1][j]) - ((1-imageArray[i-1][j])*(1-imageArray[i-1][j+1])*(1-imageArray[i][j+1])) + (1-imageArray[i][j+1]) - ((1-imageArray[i][j+1])*(1-imageArray[i+1][j+1])*(1-imageArray[i+1][j]))==1){
                maskArray[i][j] = 1;
              }
            }
          }
        }
      }
    }
    processImagePixels();
  }
}



void processImagePixels(){
  for(int i = 0; i<img.width; i++){
    for (int j =0 ; j<img.height;j++){
      if (maskArray[i][j] == 1){
        setPixelColor(img,i,j, color(255));
      }
      maskArray[i][j] = 0;
      if (brightness(img.get(i, j)) < 127){
        imageArray[i][j] = 1;
      }
      else
      {
        imageArray[i][j] = 0;
      }
    }
    refreshImagePixels(img);
  }
}


void draw(){
  image(imgOriginal,0,0);
  thinning(img, imageArray, maskArray);
  image(img,img.width,0);
}