[U-Boot] [PATCH v3] Add 16bpp BMP support

[Wolfgang Denk]

Dear Guennadi Liakhovetski,

In message <Pine.LNX.4.64.0901302206180.4617 at axis700.grange> you wrote:
> 
> platform-specific types and code. So, looking at this your patch - do we 
> really need the one more CONFIG_ define for CONFIG_BMP_16BPP? What are the 
> drawbacks of adding your code unconditionally? extra 100 bytes for all 
> configurations using LCD?

Yes.

> Another question - do you really need 16bpp bmp? I saw a discussion on 
> this list, that other picture formats should not be added to U-Boot - you 
> can easily convert any format to bmp. Are 256 colours really not enough 
> for you? I used a real photo today as a test image, converted to an 8-bit 
> bmp. It looked well enough on my qvga. And normally you use this lcd code 
> to display a splashscreen, which is usually a computer-generated image, so 
> 256 colours should suffice? Although, I am not an expert in graphical 
> desing.

I can understand that 8 bpp doe snot satisfy anoybode with more than
just basic graphics needs.

> If we really add more bmp formats, we also get more combinations like of 
> bmp / lcd:

Not necessarily. We can always request that bitmap images match the
"natural" color depth of the display. It makes no sense to send a 16
bpp image to a 1 bpp display, nor does it vice versa.

> BMP	LCD
> 1-bit	1-bit
> 8-bit	1-bit
> 16-bit	1-bit
> 1-bit	8-bit
> ...
> 
> if we really want to go that way, maybe better break this code into 
> several functions for different format conversions?

We do NOT want to do everything that is possible, but only what is
reasonable.

Best regards,

Wolfgang Denk

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