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

[Guennadi Liakhovetski]

On Tue, 27 Jan 2009, Mark Jackson wrote:

> This patch adds 16bpp BMP support to the common lcd code.
> 
> Use CONFIG_BMP_16BPP and set LCD_BPP to LCD_COLOR16 to enable the code.
> 
> At the moment it's only been tested on the MIMC200 AVR32 board, but extending 
> this to other platforms should be a simple task !!
> 
> Signed-off-by: Mark Jackson <mpfj at mimc.co.uk>

It is a pity I didn't notice these patches earlier, and I didn't notice 
them, because it's only today that I realized that I needed to change this 
code too. But - for the other case  8 bit bmp on a 16 bit lcd without a 
colourmap support. I have implemented that, it works now, a patch will 
follow, but while working on it I noticed how this generic code is 
difficult to work with due to all the ifdefs and especially 
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?

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.

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

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?

Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.

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