Re: [ft-devel] New FreeType proofing tool: ftdiff

[Ismail Dönmez]

Hi David,
On Friday 30 March 2007 17:47:00 David Turner wrote:
> just to publicly announce that I added a new tool named "ftdiff" that
> allows you to easily compare FreeType's output with various combinations of
> hinting and rendering modes. Its window contains three columns of text,
> each one with its own settings. Press F1 to get a list of keybinding to use
> the application.
>
> It's in the CVS right now, under "ft2demos", and will be part of the next
> release, which should hopefully be imminent.
>
> Playing with the tool, several important things can be noticed:
>
>
> I. RSB/LSB Deltas rock:
> =======================
>
> we have introduced the fields lsb_delta and rsb_delta in FT_GlyphSlotRec
> several releases ago in order to allow sophisticated text layout of
> auto-hinted text. The idea is that these values record the displacement of
> left and right edge in each glyph due to auto-hinting, and this can be
> useful to correct the space between two glyph images to better respect
> their original spacing.
>
> Thanks to Owen Taylor for the original idea, which he exposed in an online
> paper I cannot find anymore. Details at the end of this e-mail
>
> Here are a few screenshots illustrating the difference it makes:
>
>   http://david.freetype.org/freetype/why-deltas-matter-1.png
>   http://david.freetype.org/freetype/why-deltas-matter-2.png
>   http://david.freetype.org/freetype/why-deltas-matter-3.png
>
> in each screenshot:
>   - the left column is unhinted text (with sub-pixel accuracy),
>   - the middle column auto-hinted text typeset using the delta adjustments
>   - the right column uses auto-hinted text without delta adjustments
>
> I now feel the urge to provide patches to many libraries and programs on
> top of FreeType so they can exhibit this *huge* improvement. However, this
> is likely to require a *lot* of work.

Very nice demo program, I tested Tahoma.ttf but using deltas doesn't seem to 
have any effect on it. Anyway thanks for the great work once again.

Regards.

-- 
Happiness in intelligent people is the rarest thing I know. (Ernest Hemingway)

Ismail Donmez ismail (at) pardus.org.tr
GPG Fingerprint: 7ACD 5836 7827 5598 D721 DF0D 1A9D 257A 5B88 F54C
Pardus Linux / KDE developer

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