Re: Add a test showing that GDI should not scale bitmap font metrics

[Huw D M Davies]

On Wed, Sep 01, 2004 at 05:44:19PM +0900, Dmitry Timoshkov wrote:
> Hello,
>
> I had a wild guess whether GDI actually scales or not metrics for
> a bitmap font if a requested font size is not available and wrote
> a test case for it. No, GDI *does not* scale bitmap font metrics.

Well it does do integer scaling.  So if you request System (whose
normal size is 16) with 32 <= lfHeight < 48 you'll get a double sized
font with all the metrics scaled by a factor of two.  Wine doesn't do
this yet.  Your test shows that gdi doesn't do fractional scaling which
is indeed correct.

Huw.
-- 
Huw Davies
huw(a)codeweavers.com

Add a test showing that GDI should not scale bitmap font metrics

[Dmitry Timoshkov]

"Huw D M Davies" <h.davies1(a)physics.ox.ac.uk> wrote:
> > I had a wild guess whether GDI actually scales or not metrics for
> > a bitmap font if a requested font size is not available and wrote
> > a test case for it. No, GDI *does not* scale bitmap font metrics.
>
> Well it does do integer scaling.  So if you request System (whose
> normal size is 16) with 32 <= lfHeight < 48 you'll get a double sized
> font with all the metrics scaled by a factor of two.  Wine doesn't do
> this yet.  Your test shows that gdi doesn't do fractional scaling which
> is indeed correct.

Thanks for pointing this out. A quick addition to the submitted test
case (attached) confirms that win2k does integer scaling. But it does
it in a somewhat inconsistent manner. For instance GetTextExtentPoint32
scales only height but not width, and GetCharWidth does not scale width
either. I'm a bit confused, is that a bug or a feature?

-- 
Dmitry.

Add a test showing that GDI should not scale bitmap font metrics

[Huw D M Davies]

On Wed, Sep 01, 2004 at 06:49:14PM +0900, Dmitry Timoshkov wrote:
> "Huw D M Davies" <h.davies1(a)physics.ox.ac.uk> wrote:
> > > I had a wild guess whether GDI actually scales or not metrics for
> > > a bitmap font if a requested font size is not available and wrote
> > > a test case for it. No, GDI *does not* scale bitmap font metrics.
> >
> > Well it does do integer scaling.  So if you request System (whose
> > normal size is 16) with 32 <= lfHeight < 48 you'll get a double sized
> > font with all the metrics scaled by a factor of two.  Wine doesn't do
> > this yet.  Your test shows that gdi doesn't do fractional scaling which
> > is indeed correct.
>
> Thanks for pointing this out. A quick addition to the submitted test
> case (attached) confirms that win2k does integer scaling. But it does
> it in a somewhat inconsistent manner. For instance GetTextExtentPoint32
> scales only height but not width, and GetCharWidth does not scale width
> either. I'm a bit confused, is that a bug or a feature?

Try setting lfWidth to 0, that should then scale the font
isotropically - setting a non-zero lfWidth can result in different
scaling factors in the x and y directions.  So for example if you
leave width set to the normal width and only multiply up the height
then the font will only be scaled in the y direction.

Huw.
-- 
Huw Davies
huw(a)codeweavers.com

Add a test showing that GDI should not scale bitmap font metrics

[Dmitry Timoshkov]

"Huw D M Davies" <h.davies1(a)physics.ox.ac.uk> wrote:
> Try setting lfWidth to 0, that should then scale the font
> isotropically - setting a non-zero lfWidth can result in different
> scaling factors in the x and y directions.  So for example if you
> leave width set to the normal width and only multiply up the height
> then the font will only be scaled in the y direction.

That worked. Thanks again for teaching me :-)

-- 
Dmitry.