<Swing Dev> Fixing font sizes in GTKLookAndFeel

[Phil Race]

There's two public API changes in here and you can get away without 
either of them.
So I believe you wouldn't need the changes in SunFontManager, 
FontUIResource, or Font.java

Eg in PangoFonts you can write something like :

Font f = new Font(family, style, ((int)dsize+0.5));
f = f.deriveFont((float)dsize); // already public API
FontUIResource fuir = new FontUIResource(f); // already public API

And something similar would need to be done in FontUtilities

The two extra font objects that are created really will not matter as a Font
is a small object and its lazily mapped to a real font.

-phil.

On 8/5/2010 2:20 PM, Omair Majid wrote:
> Hi,
>
> A while ago a user pointed out the issue that font sizes between GTK 
> programs and Swing programs using the GTKLookAndFeel can be 
> inconsistent. Digging through the code, here is a comment I found in
> com.sun.java.swing.plaf.gtk.PangoFonts:
>
> [snip]
>     * Finally this DPI is used to calculate the nearest Java 2D font
>     * 72 dpi font size.
>     * There are cases in which JDK behaviour may not exactly mimic
>     * GTK native app behaviour :
> [snip]
>     * 3) Because of rounding errors sizes may differ very slightly
>     * between JDK and GTK. To fix that would at the very least require
>     * Swing to specify floating pt font sizes.
>     * Eg "10 pts" for GTK at 96 dpi to get the same size at Java 2D's
>     * 72 dpi you'd need to specify exactly 13.33.
> [snip]
>
> As it turns out, Swing is fine with floating point font sizes: I can 
> use affine transforms to scale the font. I also noticed that the Font 
> class supports setting floating point font sizes (through a private 
> constructor). I have created a patch that makes PangoFont avoid 
> converting the size to integer units. The webrev is available at: 
> http://cr.openjdk.java.net/~omajid/webrevs/gtk-floating-point-font-size-support/webrev.00/ 
>
>
> Any comments and ideas are appreciated.
>
> Thanks,
> Omair