Re: [cc65] TGI summary

Hi!

On Mon, Oct 26, 2009 at 4:49 PM, Ullrich von Bassewitz <uz@musoftware.de> wrote:
>
> Among all the mails discussing the TGI API, I've somewhat lost track about
> what is consensus. I'm trying to write a summary, please let me know if I
> got something wrong.
>
>  * The new Atari drivers will use a black/white palette. (this one was
>    easy:-)
>
>  * Drivers must not clip lines, this will be done by the tgi_line wrapper.
>    Actually I have a prototype implementation of a line clipper already
>    running.
>
>  * The cgetc functions have to be checked not to write to the screen if the
>    cursor is switched off. Should there be a third state, "cursor on",
>    "cursor off" and "don't touch" to ease this?
>
>  * Palette and color management stays as it is. Colors are actually indices
>    into the default palette. If a programmer changes the palette, he has to
>    implement his own color names or whatever.
>
>  * It is not possible to come up with a color naming scheme that actually
>    works. Everyone (I think) agreed that using the conio color names for
>    TGI graphics is not a good idea, but defining TGI_COLOR_XX macros is
>    actually impossible, because these may be different even between two
>    drivers on the same platform. So we don't have a solution here.

I think some conventions could be enforced:

* The default palette should be (approximately) the same in all drivers:
  0 = black
  1 = white
  2 = ....

* If the driver has no palette, it can emulate the above by replacing the
  indexes in setcolor.

This should made the program output to look similar if the palette is not
changed.

> As a final note (this was not discussed): I don't know how many drivers do not
> implement OUTTEXT. Most drivers derived from the C64 driver will not have it,
> because I was too lazy at that time:-) This should be added so programs can
> rely on it.

Should a default font be included? Because, if the font is included in the
wrapper, doing outtext completely in the wrapper seems better to me.

If not, a 8x8 font size could be enforced (as standard in Atari and C64).

    Daniel.
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