rgb565 bitmap exporter?

I don’t suppose anyone has already written (or knows where one is hidden in the image) a bitmap exporter that  can write rgb565 ? Pretty daft for me to faff around doing it if there is already one around. I’ve spotted assorted kinda-sorta related code but not (yet) what I need.

tim
--
tim Rowledge; [hidden email]; http://www.rowledge.org/tim
No program done by an undergrad will work after she graduates.

On 27.07.2015, at 04:31, tim Rowledge <[hidden email]> wrote:
>
> I don’t suppose anyone has already written (or knows where one is hidden in the image) a bitmap exporter that  can write rgb565 ? Pretty daft for me to faff around doing it if there is already one around. I’ve spotted assorted kinda-sorta related code but not (yet) what I need.

So what *do* you need? Which file format? Why 565? (Windows BMP supports both 555 and 565)

- Bert -

On 27-07-2015, at 8:10 AM, Bert Freudenberg <[hidden email]> wrote:

> On 27.07.2015, at 04:31, tim Rowledge <[hidden email]> wrote:
>>
>> I don’t suppose anyone has already written (or knows where one is hidden in the image) a bitmap exporter that  can write rgb565 ? Pretty daft for me to faff around doing it if there is already one around. I’ve spotted assorted kinda-sorta related code but not (yet) what I need.
>
> So what *do* you need? Which file format? Why 565? (Windows BMP supports both 555 and 565)
I need to write rgb565 to /dev/fb1 on my AstroPi :-) How else will astronauts be able to play with Scratch in orbit?


tim
--
tim Rowledge; [hidden email]; http://www.rowledge.org/tim
Computer possessed? Try DEVICE=C:\EXOR.SYS

sqUnixX11.c: copyImage16To16() should do it. If you replace the stRNMask/stRShift variables with constants it might even be reasonably efficient. ARM SIMD code would be better, obviously.

Or are you talking about Smalltalk code? A single bitblt copy with a suitable color map should do it.

- Bert -

On 28-07-2015, at 5:24 AM, Bert Freudenberg <[hidden email]> wrote:
> sqUnixX11.c: copyImage16To16() should do it. If you replace the stRNMask/stRShift variables with constants it might even be reasonably efficient. ARM SIMD code would be better, obviously.

Oh, it certainly would - indeed it does since some devious ARM simd code is hooked up on ARM platforms.

>
> Or are you talking about Smalltalk code? A single bitblt copy with a suitable color map should do it.

Since it’s only an 8x8 array of ws28-something LEDs that has to be written by opening /dev/fb*, then writing to the ‘file’, then closing the file to make it actually display, performance of the conversion is not a huge problem. Right now I can display scrolling paragraphs, arbitrary screen-grabs, whatever, and it’s now a case of deciding what people want to display rather than how to display.
I did discover to my surprise that some font glyphs are 16bpp with antialiasing that makes for really surprising displays on a physically large 8x8 display. It took a while to work out what was going on there...

tim
--
tim Rowledge; [hidden email]; http://www.rowledge.org/tim
"How many Carlos Wus does it take to change a lightbulb?”
"With an unlimited breeding licence, who needs lightbulbs?"

Quoting tim Rowledge <[hidden email]>:

> ...
> I did discover to my surprise that some font glyphs are 16bpp with  
> antialiasing that makes for really surprising displays on a  
> physically large 8x8 display. It took a while to work out what was  
> going on there...

Can you post a photograph? I would like to see that!

> tim
> --
> tim Rowledge; [hidden email]; http://www.rowledge.org/tim
> "How many Carlos Wus does it take to change a lightbulb?”
> "With an unlimited breeding licence, who needs lightbulbs?"

Cheers,
Juan Vuletich

On 29.07.2015, at 04:04, J. Vuletich (mail lists) <[hidden email]> wrote:
>
> Quoting tim Rowledge <[hidden email]>:
>
>> ...
>> I did discover to my surprise that some font glyphs are 16bpp with antialiasing that makes for really surprising displays on a physically large 8x8 display. It took a while to work out what was going on there...
>
> Can you post a photograph? I would like to see that!

http://astro-pi.org/

- Bert -

On 28-07-2015, at 7:04 PM, J. Vuletich (mail lists) <[hidden email]> wrote:

Quoting tim Rowledge <[hidden email]>:

...
I did discover to my surprise that some font glyphs are 16bpp with antialiasing that makes for really surprising displays on a physically large 8x8 display. It took a while to work out what was going on there...

Can you post a photograph? I would like to see that!