Re: [ft] ugly output with freetype and gtk
suzuki toshiya <mpsuzuki <at> hiroshima-u.ac.jp>
2012-01-17 16:18:35 GMT
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.
Jochen Jägers wrote:
> 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?
> Jochen Jägers
> Am Dienstag, den 17.01.2012, 14:57 +0100 schrieb suzuki toshiya:
>> 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.
>> Jochen Jägers wrote:
>>> i'm developing an embedded system for home automation based on
>>> 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.
>>> 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?
>>> Jochen Jägers
>>> Freetype mailing list
>>> Freetype <at> nongnu.org
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