Dispaly problem in SDL simulator

Hello,when I set LV_COLOR_SCREEN_TRANSP to 1,There has a display problem in my simulator(like the pictur1).How do I solve this problem.The lvgl version is v8.3.0(Latest code).
There is no problem with v8.1.0.

@kisvegabor This might be a bug with the recent transformation update?

Yes, probably. I’ve pushed a fix to lv_drivers.

But there has the same problem in my Embedded device!

Do use SDL on the embedded device too? If so what kind of device is it?

If not what driver do you use?

This variable (driver->screen_transp) is set to 0 in v8.3.0 dev(lv_hal_disp.c).But it was set to LV_COLOR_SCREEN_TRANSP in v8.2.0.
When I set LV_COLOR_SCREEN_TRANSP to 1,this judgment is invalid:
if(d->driver->screen_transp) {
SDL_SetRenderDrawColor(m->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(m->renderer, &r);

And my Embedded device is linux fb;

Yes, I’ve changed it because some updates require LV_COLOR_SCREEN_TRANSP 1 although the screen doesn’t needs to be transparent. In v9 LV_COLOR_SCREEN_TRANSP should be renamed to something more generic.

Why is it invalid?

You can set LV_COLOR_SCREEN_TRANSP 1 and and also driver->screen_transp=1.