WhyCan Forum(哇酷开发者社区)

void sdl_display_flush(lv_disp_drv_t * disp_drv, const lv_area_t * area, lv_color_t * color_p)
{
    lv_coord_t hres = disp_drv->hor_res;
    lv_coord_t vres = disp_drv->ver_res;

//    printf("x1:%d,y1:%d,x2:%d,y2:%d\n", area->x1, area->y1, area->x2, area->y2);

    /*Return if the area is out the screen*/
    if(area->x2 < 0 || area->y2 < 0 || area->x1 > hres - 1 || area->y1 > vres - 1) {
        lv_disp_flush_ready(disp_drv);
        return;
    }

    /* TYPICALLY YOU DO NOT NEED THIS
     * If it was the last part to refresh update the texture of the window.*/
    if(lv_disp_flush_is_last(disp_drv)) {
        window_update(disp_drv, color_p);
    }

    /*IMPORTANT! It must be called to tell the system the flush is ready*/
    lv_disp_flush_ready(disp_drv);

}

static void window_update(lv_disp_drv_t *disp_drv, void * buf)
{
    SDL_Renderer *renderer = ((lv_draw_sdl_drv_param_t *) disp_drv->user_data)->renderer;
    SDL_Texture *texture = buf;
    SDL_SetRenderTarget(renderer, NULL);
    SDL_RenderClear(renderer);
#if LV_COLOR_SCREEN_TRANSP
    SDL_SetRenderDrawColor(renderer, 0xff, 0, 0, 0xff);
    SDL_Rect r;
    r.x = 0; r.y = 0; r.w = SDL_HOR_RES; r.h = SDL_VER_RES;
    SDL_RenderDrawRect(renderer, &r);
#endif

    /*Update the renderer with the texture containing the rendered image*/
    SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_BLEND);
    SDL_RenderSetClipRect(renderer, NULL);
    SDL_RenderCopy(renderer, texture, NULL, NULL);
    SDL_RenderPresent(renderer);
    SDL_SetRenderTarget(renderer, texture);
}