Hello,
I’m running a TouchGFX application on LTDC Layer 2 with pixel format ARGB8888.
Underneath it, on LTDC Layer 1, I have a simple colored rectangle as a background.
I have configured the LTDC blending factors for per-pixel alpha, and the blending works — for example, when I set Layer 2’s constant alpha to zero, I can see Layer 1 correctly.
However, even when using images with transparent areas in TouchGFX, the “transparent” parts appear as solid black on the screen and completely block Layer 1. It seems that TouchGFX is filling those pixels with an opaque color (alpha 255) instead of leaving them transparent (alpha 0).
What I expect is that transparent parts of the UI would allow Layer 1 to show through, but instead they are rendered as black.
Is this the expected behavior for TouchGFX? If so, is there a supported way to make untouched areas of the framebuffer remain transparent so that hardware blending between Layer 2 and Layer 1 works as intended?
Thanks in advance.
