Qt-interest Archive, August 2007
QFontDialog fitlering
Message 1 in thread
Hi All.
Sorry to take your time.
A quick question, is there any way to set an application to only show
allowed fonts to be for an application. For instance, I would like the
QFontDialog to automatically set to filter Latin fonts and not allow the
user to select any other font.
Consequently, QFontComboBox will only show the Latin fonts upon
instantiated.
Thanks.
J.
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Message 2 in thread
Hello,
Im using qt 3.3's QSocketDevice interface, and Im using it cause I'm in a
threaded environment and need it to be blocking. The problem is when using
waitForMore or readBlock, it's beginning to act strangely by not waiting the
set amount of time (something noticable like 20 seconds) and just skips over
the function. Does anyone know what the problem might be?
best regards,
Zahy
Message 3 in thread
Zahy Abou-Atme schrieb:
> Hello,
>
> Im using qt 3.3's QSocketDevice interface...
Nice to know. How does this relate to font filtering? ;) (Did you hit
the wrong button in your email client?)
Regarding the OP: I don't think there is such a functionality, IMO. Not
even the QFont class provides a method as to find out which character
set is supported, and from the QFont docs:
"When a QPainter draws a character from a font the QFont will report
whether or not it has the character; if it does not, QPainter will draw
an unfilled square."
I understand "the QFont will report whether or not is has the
character;" as "This functionality is internal to Qt": only the QPainter
(and other Qt classes) has direct access to this info (which characters
are available or not in a given font).
Else you could at least have iterated over all installed fonts
(http://doc.trolltech.com/4.3/qfontdatabase.html offers this
functionality), create a QFont object for each (costly!) and ask this
QFont whether it supports the latin1 character set (which again I don't
think is possible, at least not with the public Qt 4.3 API).
Since creating a QFont object implies loading the font data itself this
operation (iterating over ALL fonts in the system) is off course very
memory/time consuming so you would have to cache the results and update
them somehow upon user request ("Scan for new fonts") or each time the
font directory (e.g. c:\windows\fonts on Win32) has changed.
From my own experience (which is still based on Qt 3.3.x) font handling
is one of the nastier issues (and this is not Qt's fault! Even native
font handling with the win32 API is a nightmare!).
We implemented PDF export (with an external PDF library PDFlib) back
then and even simple questions like "Given a QFont, which font file is
actually used (path to truetype font)?" or "What is a suitable font
replacement for a given font (the user has chosen in the QTextWriter)
which is not able to print a given unicode (which font is REALLY used by
the font rendering library in Qt)?" turned out to be really nasty - we
had to "extend" Qt 3.3.x a bit for this (read: hack the sources, make
certain functions public etc.)
Thanks God Qt offers PDF export now on its own :)
Cheers, Oliver
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