cs50/helpers.c

#include "helpers.h"
#include <math.h>
#include <stdio.h>

// Convert image to grayscale
void grayscale(int height, int width, RGBTRIPLE image[height][width])
{
    for (int i = 0; i < height; i++)
    {
        for (int j = 0; j < width; j++)
        {
            int avg = round((image[i][j].rgbtBlue + image[i][j].rgbtGreen + image[i][j].rgbtRed) /
                            (float) 3);
            image[i][j].rgbtBlue = image[i][j].rgbtGreen = image[i][j].rgbtRed = avg;
        }
    }
    return;
}

// Reflect image horizontally
void reflect(int height, int width, RGBTRIPLE image[height][width])
{
    RGBTRIPLE tmp[height][width];

    for (int i = 0; i < height; i++)
    {
        for (int j = 0; j < width; j++)
        {
            tmp[i][j] = image[i][width - j - 1];
        }
    }

    for (int i = 0; i < height; i++)
    {
        for (int j = 0; j < width; j++)
        {
            image[i][j] = tmp[i][j];
        }
    }
    return;
}

// Blur image
void blur(int height, int width, RGBTRIPLE image[height][width])
{
    RGBTRIPLE copy[height][width];

    for (int i = 0; i < height; i++)
    {
        for (int j = 0; j < width; j++)
        {
            copy[i][j] = image[i][j];
        }
    }

    for (int i = 0; i < height; i++)
    {
        for (int j = 0; j < width; j++)
        {
            int sumRed = 0, sumGreen = 0, sumBlue = 0, count = 0;

            for (int k = (i - 1); k <= (i + 1); k++)
            {
                for (int l = (j - 1); l <= (j + 1); l++)
                {
                    if ((k >= 0 && k <= (height - 1)) && (l >= 0 && l <= (width - 1)))
                    {
                        sumRed += copy[k][l].rgbtRed;
                        sumGreen += copy[k][l].rgbtGreen;
                        sumBlue += copy[k][l].rgbtBlue;
                        count++;
                    }
                }
            }
            image[i][j].rgbtRed = round(sumRed / (float) count);
            image[i][j].rgbtGreen = round(sumGreen / (float) count);
            image[i][j].rgbtBlue = round(sumBlue / (float) count);
        }
    }
    return;
}

// Detect edges
void edges(int height, int width, RGBTRIPLE image[height][width])
{
    int Gx[3][3] = {{-1, 0, 1}, {-2, 0, 2}, {-1, 0, 1}};
    int Gy[3][3] = {{-1, -2, -1}, {0, 0, 0}, {1, 2, 1}};

    RGBTRIPLE copy[height][width];

    for (int i = 0; i < height; i++)
    {
        for (int j = 0; j < width; j++)
        {
            copy[i][j] = image[i][j];
        }
    }

    for (int i = 0; i < height; i++)
    {
        for (int j = 0; j < width; j++)
        {
            int sumRedGx = 0, sumGreenGx = 0, sumBlueGx = 0, sumRedGy = 0, sumGreenGy = 0,
                sumBlueGy = 0;

            for (int k = (i - 1); k <= (i + 1); k++)
            {
                for (int l = (j - 1); l <= (j + 1); l++)
                {
                    if ((k >= 0 && k <= (height - 1)) && (l >= 0 && l <= (width - 1)))
                    {
                        sumRedGx += copy[k][l].rgbtRed * Gx[i - k + 1][j - l + 1];
                        sumGreenGx += copy[k][l].rgbtGreen * Gx[i - k + 1][j - l + 1];
                        sumBlueGx += copy[k][l].rgbtBlue * Gx[i - k + 1][j - l + 1];
                        sumRedGy += copy[k][l].rgbtRed * Gy[i - k + 1][j - l + 1];
                        sumGreenGy += copy[k][l].rgbtGreen * Gy[i - k + 1][j - l + 1];
                        sumBlueGy += copy[k][l].rgbtBlue * Gy[i - k + 1][j - l + 1];
                    }
                }
            }
            image[i][j].rgbtRed = fmin(round(sqrt(pow(sumRedGx, 2) + pow(sumRedGy, 2))), 255);
            image[i][j].rgbtGreen = fmin(round(sqrt(pow(sumGreenGx, 2) + pow(sumGreenGy, 2))), 255);
            image[i][j].rgbtBlue = fmin(round(sqrt(pow(sumBlueGx, 2) + pow(sumBlueGy, 2))), 255);
        }
    }
    return;
}