Re: Video subsystem draft

[Marco Gerards <mgerards@xs4all.nl>]

Vesa Jääskeläinen <chaac@nic.fi> writes:

> Vincent Pelletier wrote:
>> By the way, I think we should start a discussion on the API common to
>> all architectures for framebuffer handling.
>
> Currently there is a terminal implementation that uses video subsystem
> to render screen. So basicly in every arch there must be a video driver
> if you want graphical console.
>
> You can see my current idea how to use video driver in grub wiki:
> http://grub.enbug.org/VideoSubsystem

As I still can't log in on the wiki, I better reply here :-)

First of all I'd like to see some double buffering feature.  Will that
be somehow possible?  In that case we need functions like:

- Switching to a buffer, making it visible.
- Selecting which buffer is used for output.
What is the emulation you talk about for set palette?

Why are viewports needed?

Have you thought about how to load bitmaps?

I don't like using grub_uint*_t for parameters.  Just use normal
integers instead.  These types just have to be used for ABIs and
network and disk access.  In the case of APIs such types should be
avoided.

So better use "int height" instead of "grub_uint32_t height".  This is
especially important for portability and it serves no purpose.

Is it possible to pass parameters like depth to grub_video_setup?

Will it be possible for other users than the terminal to use these
functions?  I think that would be nice.  But in that case a function
should be used to redraw the screen.

How would scrolling work if a background picture was used?

Thanks,
Marco