ARGB1555 and ARGB4444 support

[kisvegabor]

For 16 bit color depth + Alpha now only the non-standard ARGB8565 format can be used. I think it'd be great to support ARGB1555 and ARGB4444 in LVGL hence GPUs could accelerate the drawing of 16 bit ARGB images too.

So the question is how difficult would it be to add support for these formats in the converter?

If the converter supported them, I could quickly made them work in LVGL.

[embeddedt]

Sure, I think I can add support for these very easily. One thing is unclear: currently the output format is dependent on LV_COLOR_DEPTH, so how do you want these formats to be selected?

[embeddedt]

@kisvegabor Bump - just wanted to make sure my response wasn't missed.

[kisvegabor]

Sorry, I had some busy days.

currently the output format is dependent on LV_COLOR_DEPTH, so how do you want these formats to be selected?

Not always. E.g. indexed an alpha only images are exported as they are regardless to LV_COLOR_DEPTH. So I think we can list and handle these formats similarly to indexed and alpha only.

An other format request came up here. It short, in case of ARGB8565 images the pixels has 3 byte size which odd and slow to read. Instead we can have a special format for this where RGB565 pixels are written normally, and A8 pixels are written after them in the same array. We can use the image widdth/heigth to know where the alpha array starts. Can it be added with the other 2 format?

I think these names for the color format could work:

LV_IMG_CF_ARGB4444
LV_IMG_CF_ARGB1555
LV_IMG_CF_RGB565A8

[embeddedt]

I've implemented support for the RGB565A8 format now. Let me know once support is added in LVGL and I will add a snapshot test so it never breaks (in theory).

[kisvegabor]

I started to implement it, but it seems the RGB channel is always 0x00. I tested with this image

[embeddedt]

Fixed! Sorry about that; somehow I only managed to check the alpha channel during my read of the file.

[kisvegabor]

No prole, thank for the fix. It's working now.

I'm implementing the transformation of rgb565-a8 image.

[kisvegabor]

RGB565-A8 support is added here: https://github.com/lvgl/lvgl/tree/feat/rgb565a8

[GorgonMeducer]

Hi @embeddedt, I am trying to test the newly added colour format RGB565-A8, and don't know how to use the converter. For this colour format, which option should I choose?

https://lvgl.io/tools/imageconverter

Thank you.

[embeddedt]

You will need to use this link: https://lvgl.github.io/lv_img_conv/ until Gabor has a chance to update the main website. It should be the last color format in the list.

[kisvegabor]

I just updated the version on lvgl.io

[GorgonMeducer]

Thank you. I found it.

[luka177]

Hi i a am not sure if regression is related to this update but seems so. https://lvgl.io/tools/imageconverter do not output true color binary anymore.

[embeddedt]

@luka177 Could you let me know which settings you are using and what is the exact change in behavior? Thanks!

[luka177]

this settings. after clicking convert nothing happens. this is my image

[embeddedt]

@luka177 Thanks, this was indeed a regression, sorry about that (there are no unit tests on that part of the code right now). Here is a link that should work till the website is updated again: https://lvgl.github.io/lv_img_conv/

[kisvegabor]

I've updated the online converter too.

[luka177]

Thanks seems to work now.