Image format L8 performance

[jimmii]

Hi there

Today I wanted to try the L8 image format. After generating the assets I flashed the STM32H750-DK.

I have a startupscreen with a fade transistion. Now with the L8 image format the screen is stuttering a lot. I also have a scroll list, which is not usable because of the delay.

I this behaviour to be expected?

Is there anything to be done to use L8 image format?

One side note: I have deactivated caching until our development is finished. When D-Cache is activated, the performance is a lot better.

Thanks for your help @Martin KJELDSEN​ =)

[Martin KJELDSEN]

Check out this article on L8:

Using the L8 Image Format to Reduce Memory Consumption | TouchGFX Documentation

[Dd.31]

This is just the explanation about L8 principle.

I need the L8 PNG file format.

[Martin KJELDSEN]

Okay. Wasn't clear. Still not 100% clear, but here's some more info that will get me closer =)

Why do you need to know the format? Do you want to write your own image converter? We support four different 8-bit framebuffer formats . When using LTDC the CLUT for each format is programmed directly and is not a part of the image. This is handled by the generator.

ARGB2222

RGBA2222

BGRA2222

ABGR2222

/Martin

[Dd.31]

Yes,I want to write imageconverter.

Like the PNG image file,it has the standard format,like IHDR block,IDAT block and chunk and so on.I need these info.

I saw the chapter "Using L8 Images in TouchGFX Designer",the TouchGFX will generate a L8 format image,and is this image saved as a L8 image file?What is the file format?If it is not file,how does the L8 image been stored?

[Martin KJELDSEN]

You can probably just inspect one of the generated pngs =) Just pick one of the L8_ image formats from the designer and look inside the TouchGFX/generated/assets/images/ folder. The color lookup table is provided on the side.