PImage img, imgOriginal;//PImages
byte[][] imageArray;//byte array for image
byte[][] maskArray;//byte array for pixels that need to be removed
int currentImage = 0;//sets current image to inital image
String[] images = {"print1.png", "print1b.png", "print2.png", "print2b.png", "print3.png", "print3b.png"};//index to hold which image is being loaded

byte[][]thinnedArray;

void thinnedImage(byte[][]thinnedArray){
  for(int i = 1; i<img.width-1; i++){
    for (int j= 1; j<img.height-1;j++){
      if (brightness(img.get(i, j)) < 127){
        thinnedArray[i][j] = 1;//pixel is black
      }
      else
      {
        thinnedArray[i][j] = 0;//pixel is white
      }
    }
  }
}


void loadPixelArray(PImage anImage){//Loads pixels from its image into its pixel array
  anImage.loadPixels();
}

color getPixelColor(PImage anImage, int x, int y){//gets color of pixel from its pixel array at point x,y
  color pixelColor = anImage.get(x,y);
  return pixelColor;
}

void refreshImagePixels(PImage anImage){//refreshes pixels in pixel array, use to change pixels in image to what is in its array
  anImage.updatePixels();
}

void setPixelColor(PImage anImage, int x, int y, color aColor){//sets the color of a pixel in an images pixel array to  the color specified.
  anImage.set(x,y,aColor);
}

void initImage(String fileName){//Creates initial Image and acts like setup
  img = loadImage(fileName);//loads the image from the image array that will be thinned
  imgOriginal = loadImage(fileName);//this stores the image for side by side comparison
  size(img.width * 2, img.height);//screen size
  loadPixelArray(img);//loads the pixels into into img pixel array
  imageArray = new byte[img.width][img.height];//array to determine whether a pixel is black or white
  thinnedArray= new byte[img.width][img.height];
  maskArray = new byte[img.width][img.height];//array that stores pixels that need to be removed
  for (int col = 1; col < img.width - 1; col++){//filling the arrays with respective values
    for (int row=1; row<img.height-1; row++){
      maskArray[col][row] = 0;
      if (brightness(img.get(col, row)) < 127){
        imageArray[col][row] = 1;//pixel is black
      }
      else
      {
        imageArray[col][row] = 0;//pixel is white
      }
    }
  }
}

void setup(){
  initImage(images[0]);//call the procedure and puts the first image
}

void mousePressed(){//when mouse is pressed, the image is cycled to the next one in the array, then loops back when it reaches the end of the array
  currentImage = currentImage + 1;
  if (currentImage >= images.length){
    currentImage = 0;
  }
  initImage(images[currentImage]);
}

void thinning(PImage img, byte[][] imageArray, byte [][] maskArray){//thinning procedure
  for(int a = 0; a<2;a++){//hardcoded value for now
    for(int i = 1; i<img.width-1; i++){//goes through each row
      for (int j =1; j<img.height-1;j++){//goes through each column
        if (imageArray[i][j]==1){//checks if pixel is black
        //First Pass, Black below and White above
          if(imageArray[i][j-1]==0 && imageArray[i][j+1]==1){//checks if pixel above is white and pixel below is black
            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){//checks if any nearby pixels are black
              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){//Determine connectivity
                maskArray[i][j] = 1;//Says that this pixel will need to be removed
              }
            }
          }
        }
      }
    }
    processImagePixels();//procedure to refresh image and remove pixels from that pass
    for(int i = 0; i<img.width-1; i++){
      for (int j =0; j<img.height-1;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 = 1; i<img.width-1; i++){
      for (int j =1; j<img.height-1;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 = 1; i<img.width-1; i++){
      for (int j =1; j<img.height-1;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);
}