Re: FreeType - A TrueType engine

[Guido Flohr <gufl0000@stud.uni-sb.de>]

Hi!

On Sat, Nov 14, 1998 at 04:11:50AM +0100, Johan Klockars wrote:
> > of course platform-specific.  I've written a driver for the
> > AES/VDI but I'm not sure if everything works with every thinkable
> 
> I did that too about half a year ago to see if there would be any
> problems integrating it with fVDI.

Could you send me your driver source?  I'm sure your's is better
than mine.

On the other hand I've set up configure.in, config.guess and config.sub
correctly so that future versions of FreeType will compile out
of the box ("configure && make install") with MiNT/AES.

> > I think FreeType could be particularly interesting for those
> > guys that are working on that free VDI.  FreeType
> 
> That has been planned all along.

Fine.

A propos displaying bitmaps on arbitrary screens...  While
writing that driver I recognized one more time that I'm really
far from being an expert in that area.  I've already seen that
my driver will definitely crash on 24-bit graphics cards.

Am I particularly stupid or are these things really particularly
complicated on the Atari?  The next thing I need is the xpm
library for MiNT and I have the same problem to write portable
routines to display bitmaps.

I've been looking around for free code that handles this stuff
but I couldn't find any.  Have I missed something?

What I would really like is a library that performs all the nice
stuff the graphics gurus do in their programs (blitting images,
dithering in various qualities, color management...) but don't
like to talk about.  In fact I've already started with such a library.
I try to design an API which is sufficiently similar
to the Xlib (to allow easy porting of graphics software) but
still handles all the peculiarities of the Atari resp. the
VDI.

If this library shall ever run stable I will most probably need
help.  The biggest problem I currently have is the interleaved
format of some resolutions.  Am I right that this format is
only used for color depths of (1), 2, 4, and 8 bits (i.e. the
standard ST and TT resolutions)?  Has anybody
got (preferably fast) code that converts bitmaps from the
"default" (i.e. packed pixels) format to these plane-oriented
formats?

Another thing I've come across:  The Xlib specification distinguishes
between "TrueColor" and "DirectColor" visuals.  Can anybody
explain the difference to me?

Last but not least, the xbios functions EgetShift() and EgetGray().
My edition of Julian's "Profibuch" reads that these functins are
reserved for TT hardware.  What about newer machines, Falcon,
Milan, Hades etc.?  And - with grayscale mode switched on -
how can I calculate the real rgb values from what the VDI returns?
I had expected that:

	int rgb[3] = { 0, 1000, 0 };
	
	vs_color (v_handle, index, rgb);
	vq_color (v_handle, index, 1, rgb);

would always return equal values in the rgb array.  This is the case
for NVDI but not for the TT's built-in VDI.  The built-in
version still returns { 0, 1000, 0 }.  From what I understand
of my hardware docs I would say that the graylevel is simply
0.5 green + 0.5 blue and red is completely ignored.  Thus cyan would
be white in grayscale mode, correct?

Help is really welcome.

Ciao

Guido

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