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]

Hi @Roman Schläpfer​,

Could you look around for other L8 threads? I posted some code in there to enable your DMA class to handle L8 images. Stuttering is probably related to the fact that ChromART is not being used at all right now.

Generally we enable I and D-cache on MCUs that support them and also invalidate these caches throughout (actually only D-cache) our code to ensure correct content of the framebuffer.

/Martin

[Martin KJELDSEN]

Woop! Echo Base, this is Rogue Two. I've found them. Repeat, I've found them.

https://community.st.com/s/question/0D50X0000BdgJZkSQM/is-the-l8argb8888-image-format-supported-for-shapes-widget-if-not-will-it-be-in-the-future

[Martin KJELDSEN]

I should mention that this kind of behavior when using L8 will be supported by the TouchGFX Generator as soon as we can.

/Martin

[jimmii]

Hi @Martin KJELDSEN​ 

Any news on this? Is this now supported in the 4.14.0 release or what's the ETA?

Cheers /jimmii

[jimmii]

Thanks @Martin KJELDSEN​ . Fast support, as always. I will have look at it.

Regards

[Martin KJELDSEN]

Thanks @Roman Schläpfer​, let me know how you do!

/Martin

[scottSD]

FYI this thread is related to the following one. I added new steps to utilize Martin's ChromArtDMA with newer versions of the tools:

https://community.st.com/s/question/0D53W000007XLbHSAW/why-does-animating-an-l8-image-take-significantly-longer-than-a-standard-image?t=1591218454283

[jimmii]

Thanks @scottSD​ 

[Dd.31]

What is the L8 image file format?

[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.

[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.