[hatari-devel] User selectable threshold for window zooming

Eero Tamminen eerot at users.berlios.de
Thu Feb 11 22:13:04 CET 2010


Hi,

Thomas, could you give an opinion on automatic Falcon mode vertical &
horizontal doubling based on the appropriate Videl registers? (see below)

	- Eero

On Sunday 31 January 2010, Eero Tamminen wrote:
> 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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