How to access the framebuffer currently on display

Question

Hi

We are trying a screen capure feature by saving the framebuffer data to file. It works fine sometimes but other times the capured image is from a previous screen. I am guessing this is because the previous framebuffer is used. How can I access the current framebuffer on display in Embedded Wizard? Currently Embedded Wizard is responsible for the UI but is not directly involved in saving the framebuffer data.

Thanks and regards

Steven

Answer 1

Hello Steven,

I assume your system is working in double-buffering mode. If you are reading the framebuffer content for your screen capture feature always from the same address, you will read sometimes the frontbuffer (= the current screen content) and sometimes the backbuffer (= the previous screen content).

In order to access always the currently visible framebuffer, please have a look into the module ew_bsp_display.c which you will find in the subdirectory /TargetSpecific of our Build Environments.

The variable CurrentFramebufferAddress contains the start address you are looking for - it is updated via the function EwBspSetFramebufferAddress() after the screen has been redrawn.

Best regards,

Manfred.

Comments

Hello Manfred

Thanks for your answer. The codes is modified to make use of CurrentFramebuffer and screen capture is working fine now.
Yes the system is working in double-buffer mode.

Thanks and regards
Steven