debug

#include <cstdlib>
#include "png.h"
#include <iostream>
using namespace std;

//
// sets up the output image
PNG * setupOutput(int w, int h)
{
    PNG * image = new PNG(w, h);
    return image;
}


// Returns my favorite color
RGBAPixel * myFavoriteColor(int intensity)
{
    RGBAPixel * color = new RGBAPixel;
    color->red   = 0;
    color->green = intensity/2;
    color->blue  = intensity;
    return color;
}


void sketchify()
{
    // Load in.png
    PNG * original = new PNG;
    original->readFromFile("in.png");
    int width  = original->width();
    int height = original->height();
    // Create out.png
    PNG * output=new PNG;
    output=setupOutput(width, height);

    // Load our favorite color to color the outline
    RGBAPixel * myPixel = myFavoriteColor(192);

    // Go over the whole image, and if a pixel differs from that to its upper
    // left, color it my favorite color in the output

    for (int y = 1; y < height; y++)
    {
        for (int x = 1;  x < width; x++)
        {
            // Calculate the pixel difference
            RGBAPixel * prev = (*original)(x-1, y-1);
            RGBAPixel * curr = (*original)(x  , y  );
            int diff = abs(curr->red   - prev->red  ) +
                       abs(curr->green - prev->green) +
                       abs(curr->blue  - prev->blue );

            // If the pixel is an edge pixel,
            // color the output pixel with my favorite color
            RGBAPixel * currOutPixel = (*output)(x,y);


            if (diff > 100)
                * currOutPixel = * myPixel;

        }
    }

    // Save the output file
    output->writeToFile("out.png");


    // Clean up memory
    delete myPixel;
    delete output;
    delete original;
}