/*
    This file is placed into public domain. There is no warranty of any kind for any purpose.
    Read http://z0b.kapsi.fi/snippets.php before using this code. Thank you.
*/

/*
    Saves a 24/32-bit PNG image, returns false if fails. 'bpp' must be either
    3 (for RGB) or 4 (for RGBA) image.
*/
bool savePNG(const char *fileName, const uint32_t w, const uint32_t h, const uint8_t bpp, const uint8_t *data)
{
    // sanity checks
    if (!fileName || !data || w < 1 || h < 1 || (bpp != 3 && bpp != 4))
        return false;

    FILE *f = fopen(fileName, "wb");

    if (!f)
        return false;

    // initialize writing structures
    png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);

    if (!png_ptr) {
        fclose(f);
        return false;
    }

    png_infop info_ptr = png_create_info_struct(png_ptr);

    if (!info_ptr) {
        png_destroy_write_struct(&png_ptr, NULL);
        fclose(f);
        return false;
    }

    // setup error handling
    if (setjmp(png_jmpbuf(png_ptr))) {
        png_destroy_write_struct(&png_ptr, &info_ptr);
        fclose(f);
        return false;
    }

    // initialize output
    png_init_io(png_ptr, f);

    // this is optional, set the zlib compression level
    png_set_compression_level(png_ptr, Z_BEST_COMPRESSION);

    // set the image properties
    png_set_IHDR(png_ptr, info_ptr, w, h, 8,
                 (bpp == 3) ? PNG_COLOR_TYPE_RGB : PNG_COLOR_TYPE_RGBA,
                 PNG_INTERLACE_NONE,
                 PNG_COMPRESSION_TYPE_DEFAULT,
                 PNG_FILTER_TYPE_DEFAULT);

    png_write_info(png_ptr, info_ptr);

    // write the image data (one scanline at a time, it can be customized easily
    // and we don't have to mess with row pointers)
    const uint32_t stride = w * bpp;
    png_byte *row = (png_byte *)data;

    for (uint32_t y = 0; y < h; y++) {
        png_write_row(png_ptr, row);
        row += stride;
    }

    // done
    png_write_end(png_ptr, info_ptr);
    png_destroy_write_struct(&png_ptr, &info_ptr);

    fclose(f);
    return true;
}