Screen transparent display

When I set LV_COLOR_SCREEN_TRANSP to 1,I create some widgets on screen,but the widget display exception.As shown in the figure,I need your help. Looking forward to your reply!

How do you mean it? What is the issue?

I opened this macro LV_COLOR_SCREEN_TRANSP .I want to set the screen background transparent; But after I open this macro, The widget drawn on the transparent background show jagged, not smooth, and the text also shows exceptions.
But drawn the background is opaque, it displays normally

I’ve pushed a fix to lvgl master. Is it better?

No change.

Can you reproduce it a simulator? If so you please attach your project and I’ll try it out.

It is normal in the simulator.Because there is a red background color on the simulator,just like the 1st picture.But it is abnormal on my embedded device,just like 2nd picture.


Sorry,I know why it show red background color on the simulator,because when the
macro LV_COLOR_SCREEN_TRANSP is opened,the red color will be drawn on the screen. When I comment out these codes(just like 1st pictrue,in the red box).it is also show normal on the simulator,but the background
color is black(just like 2nd picture).

It seems good to me in the simulator so it should be a hardware config issue. Please tell more about your hardware

  • MCU/MPU?
  • LCD layers?
  • driver?

My CPU is Samsung Exynos4412,Linux standard fb driver.Here is the config file for my lvgl project.
lv_conf.h (21.8 KB)

The problem has been solved. It is an LCD display layer problem.Thank you for your help.

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Hi, i got the same issue, could you tell how to fixed this issue?

Could you share how you made your LVGL application display transparent on top of a background image? I’ve been trying to do the same thing.