Re: [ft] ugly output with freetype and gtk

[suzuki toshiya]

Hi,

Hmm, if ftview could not reproduce the noise pixel, the
next library to be checked would be Pango (text rendering
engine of GTK+) or Cairo (the vector graphic engine used
by Pango, under some configuration).

However, yet I don't know which display subsystem is used
in your embedded systems (e.g. X window, DirectFB, or anything
else?), I cannot give detailed comments.

Regards,
mpsuzuki

Jochen Jägers wrote:
> Hi,
> thank your for your fast answer.
>
> With ftview everthing looks fine so it seems to be a gtk problem.
>
> The noise pixels are exactly reproduceable. After reboot and also after
> reinstalling the whole system the noise pixels are at the same position.
> only by changing fontconfig parameters like hinting the pixels change
> their positions.
>
> Are there any ideas where to look for more information or where to ask
> for further help?
>
> Greetings,
> Jochen Jägers
>
> Am Dienstag, den 17.01.2012, 14:57 +0100 schrieb suzuki toshiya:
> > Hi,
> >
> > Thank you for reporting with illustrative screenshot.
> >
> > Your screenshot does not seem to be hinting issue, rather,
> > it looks like something wrong in the rasterization itself,
> > forced to say, integer overflow etc. The noise pixel on
> > glyph "d" seem to lack reasonable cause in hinting.
> >
> > I want to know if any smallest rasterization program, like,
> > ftview (a demo program in freetype2-demos) can show same
> > issue or not. If you cannot execute such program on your
> > embedded system, please let me know what kind of testing
> > progam can be executed on your system.
> >
> > Also I'm interested in the noise pixels are exactly
> > reproduceable, or, they appear at different positions
> > when you reboot the system.
> >
> > Talking about my personal experience, some old rogue
> > FreeType2 client breaks the cached glyph bitmap, so
> > same glyphs shown in one execution have constant noises
> > (in your screenshot, "e", "g", "n", "u" have constant
> > noise pixels), but when I terminate/restart the program,
> > the noise pixels appear differently.
> >
> > Regards,
> > mpsuzuki
> >
> > Jochen Jägers wrote:
> > > Hello,
> > >
> > > i'm developing an embedded system for home automation based on
> > > gnu/linux.
> > >
> > > The userinterface is build in HTML/Javascript displayed in a fullscreen
> > > browser based on webkit-gtk with freetype as font-backend.
> > >
> > > I get ugly output on some glyphs. I've made a screenshot to illustrate
> > > this ugly output. 
> > >
> > > http://tinypic.com/r/4uwbkl/5
> > >
> > > Look at "Standort" for example. The "d" has two pixels in the top left
> > > corner. I get this ugly output with different types and different file
> > > formats. The text in other gtk-based applications look ugly too.
> > >
> > > I've tryed many things i found on the internet like different settings
> > > for hinting, lcdfilter and subpixels but nothing worked.
> > >
> > > I've also tryed different versions of freetype (2.4.4 and 2.4.8) with
> > > the same ugly result.
> > >
> > > At the moment I've no idea to solve this problem.
> > > Do you have any idea what i can try?
> > >
> > > Greetings
> > > Jochen Jägers
> > >
> > >
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