scratch.txt

void box_blur(BMP_Image *image) {
    int width = image->bip_header->width;
    int height = image->bip_header->height;

    int row_jump = width; // * sizeof(Pixel); //PITFALL!!
    int col_jump = 1; //sizeof(Pixel);


    Pixel *new_pixels = malloc(sizeof(Pixel) * width * height);
    Pixel *new_cursor = new_pixels;

    Pixel *cursor = image->pixels;

    Pixel *neighbors[9];
    //  [0][1][2]
    //  [3][4][5]
    //  [6][7][8]


    for (int i = 0; i < height; i++) {
        for (int j = 0; j < width; j++) {
            if (i == 0) {
                neighbors[0] = NULL;
                neighbors[1] = NULL;
                neighbors[2] = NULL;
            } else {
                neighbors[0] = j == 0 ? NULL : cursor - row_jump - col_jump;
                neighbors[1] = cursor - row_jump;
                neighbors[2] = j == width - 1 ? NULL : cursor - row_jump + col_jump;
            }

            neighbors[3] = j == 0 ? NULL : cursor - col_jump;
            neighbors[4] = cursor;
            neighbors[5] = j == width - 1 ? NULL : cursor + col_jump;

            if (i == height - 1) {
                neighbors[6] = NULL;
                neighbors[7] = NULL;
                neighbors[8] = NULL;
            } else {
                neighbors[6] = j == 0 ? NULL : cursor + row_jump - col_jump;
                neighbors[7] = cursor + row_jump;
                neighbors[8] = j == width - 1 ? NULL : cursor + row_jump + col_jump;
            }

            blur(neighbors, new_cursor);

            cursor++;
            new_cursor++;
        }
    }

    free(image->pixels);
    image->pixels = new_pixels;
}