Function stbi__png_test

lite/example/cpp_example/mge/cv/stb_image.h:5840–5845

}

static int stbi__png_test(stbi__context* s) {
    int r;
    r = stbi__check_png_header(s);
    stbi__rewind(s);
    return r;
}

static int stbi__png_info_raw(stbi__png* p, int* x, int* y, int* comp) {
    if (!stbi__parse_png_file(p, STBI__SCAN_header, 0)) {