cs50/helpers.c

#include "helpers.h"
#include <math.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;
}

// Convert image to sepia
void sepia(int height, int width, RGBTRIPLE image[height][width])
{
    for (int i = 0; i < height; i++)
    {
        for (int j = 0; j < width; j++)
        {
            int sepiaRed = round(.393 * image[i][j].rgbtRed + .769 * image[i][j].rgbtGreen +
                                 .189 * image[i][j].rgbtBlue);
            int sepiaGreen = round(.349 * image[i][j].rgbtRed + .686 * image[i][j].rgbtGreen +
                                   .168 * image[i][j].rgbtBlue);
            int sepiaBlue = round(.272 * image[i][j].rgbtRed + .534 * image[i][j].rgbtGreen +
                                  .131 * image[i][j].rgbtBlue);

            if (sepiaRed > 255)
            {
                sepiaRed = 255;
            }
            if (sepiaGreen > 255)
            {
                sepiaGreen = 255;
            }
            if (sepiaBlue > 255)
            {
                sepiaBlue = 255;
            }

            image[i][j].rgbtBlue = sepiaBlue;
            image[i][j].rgbtGreen = sepiaGreen;
            image[i][j].rgbtRed = sepiaRed;
        }
    }

    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;
}