[hatari-devel] User selectable threshold for window zooming

Eero Tamminen eerot at users.berlios.de
Sat Jan 30 23:11:54 CET 2010


Hi,

On Friday 29 January 2010, Eero Tamminen wrote:
> On Friday 29 January 2010, Eero Tamminen wrote:
> > Except for the ST-medrez case in screen.c, I was just wondering why one
> > would want to zoom vertical and horizontal directions by different
> > amounts?   Does it make sense for Falcon?
>
> Answering myself... Yes, it has interlace mode.  But I would like this
> zoom-only-vertically thing to be done on Falcon only when it make
> sense like it's done on ST medrez.
>
> So, how do I know in hostscreen.c whether Falcon is using an interlaced
> screen mode?

Again answering myself (I'm talking to myself, should I be worried?)...

$FF82C2, the Video Control register tells this.  I tested what changes
happen to it when toggling the TOS4 video options.

On Hatari RGB monitor emu:
- On the 320x200 default res, none of the bits are set.
- Changing from 40  to 80 columns mode sets the Half pixel width bit 2.
- Enabling the interlace option, sets the Interlace bit 1.

On Hatari VGA monitor emu:
- On the 320x200 default res, the Half pixel width bit 2 and
  Line doubling bit 0 are both set (TOS4 says "line doubling=on).
- Changing from 40  to 80 columns mode clears the Half pixel width bit 2
  and sets the Quarter pixel bit 3.  Vertical resolution increases from 200
  to 480, more than double (interlace doubled the res exactly).  Why?
- Changing line doubling to off, clears bit 0.

So, I can catch them.   But should Hatari really double vertical and
horizontal resolution differently when some of these bits are set, and
if yes, for which of them?


> > Attached is a patch that makes the desired target window resolution
> > selectable from the configuration file.  If resolution would still fit
> > to that size when doubled, it will be doubled in both directions.
>
> Any comments on the patch?  Only thing missing from it is the GUI
> code for letting user to specify the target/max window size for doubling
> and having a command line option for that + doc updates.
>
> It will prevent Hatari from trying to use a resolution (e.g.
> borders+doubling) that can be larger than what user wants it to use.

Attached is a new patch and screenshots of the Screen dialog which
I split in the patch into separate (Atari) Monitor and (Hatari) Window
dialogs.

The window dialog has user configurable Max size for doubled resolutions
(doubling won't be used if it would make window larger in either direction
than the given max size).

Enabling doubling means now just that you specify your screen resolution,
or leave it at default values (800x600) if you don't have a larger monitor
or don't want larger Falcon resolutions to be scaled too.

If you want to temparily disable doubling completely, that will now be more
awkward (one needs to set the max resolution low enough that screen
will be never doubled), but is that really a problem?


	- Eero
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