Function Image_LoadBuffer

engine/gamesys/src/gamesys/scripts/script_image.cpp:249–331

load image from a string into a buffer object * Load image (PNG or JPEG) from a string buffer. * * @name image.load_buffer * @param buffer [type:string] image data buffer * @param [options] [type:table] An optional table containing parameters for loading the image. Supported entries: * * `premultiply_alpha` * : [type:boolean] True if alpha should be premultiplied in

    *
    */
    static int Image_LoadBuffer(lua_State* L)
    {
        int top = lua_gettop(L);
        luaL_checktype(L, 1, LUA_TSTRING);
        size_t buffer_len = 0;
        const char* buffer = lua_tolstring(L, 1, &buffer_len);

        bool premult = false;
        bool flip_vertically = false;

        if (top >= 2)
        {
            // Parse as options table
            if (lua_istable(L, 2))
            {
                lua_pushvalue(L, 2);

                lua_getfield(L, -1, "premultiply_alpha");
                if (!lua_isnil(L, -1))
                    premult = dmScript::CheckBoolean(L, -1);
                lua_pop(L, 1);

                lua_getfield(L, -1, "flip_vertically");
                if (!lua_isnil(L, -1))
                    flip_vertically = dmScript::CheckBoolean(L, -1);
                lua_pop(L, 1);

                lua_pop(L, 1);
            }
            // backwards compatability
            else
            {
                premult = dmScript::CheckBoolean(L, 2);
            }
        }

        dmImage::Image image;
        dmImage::Result r = dmImage::Load(buffer, buffer_len, premult, flip_vertically, &image);
        if (r == dmImage::RESULT_OK) {

            uint8_t bytes_per_pixel = dmImage::BytesPerPixel(image.m_Type);
            if (bytes_per_pixel == 0) {
                dmImage::Free(&image);
                luaL_error(L, "unknown image type %d", image.m_Type);
            }

            lua_newtable(L);

            PushImageParameters(L, image);

            uint32_t imagesize = image.m_Width * image.m_Height;
            uint32_t datasize = bytes_per_pixel * imagesize;

            lua_pushliteral(L, "buffer");

            dmBuffer::StreamDeclaration streams_decl[] = {
                { dmHashString64("data"), dmBuffer::VALUE_TYPE_UINT8, bytes_per_pixel }
            };