cs50/helpers.c

#include <math.h>
#include "helpers.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) / 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++)
        {
            float sumRed = 0, sumGreen = 0, sumBlue = 0;
            int count = 0;

            for (int k = -1; k < 2; k++)
            {
                for (int l = -1; l < 2; l++)
                {
                    if (i + k <= 0 || i + k >= height)
                    {
                        continue;
                    }
                    if (j + l <= 0 || j + l >= width)
                    {
                        continue;
                    }
                    sumRed += copy[i + k][j + l].rgbtRed;
                    sumGreen += copy[i + k][j + l].rgbtGreen;
                    sumBlue += copy[i + k][j + l].rgbtBlue;
                    count++;
                }
            }
            image[i][j].rgbtRed = round(sumRed / count);
            image[i][j].rgbtGreen = round(sumGreen / count);
            image[i][j].rgbtBlue = round(sumBlue / count);
        }
    }
    return;
}