[softwarelist] Re: File problems
- From: David Boddie <david@xxxxxxxxxxxxx>
- To: davidpilling@xxxxxxxxxxxxx
- Date: Tue, 12 Dec 2006 18:20:59 +0100
[Dredging up an old post from November to add comments]
On Mon, 20 Nov 2006 10:40:52 +0000, Tony van der Hoff wrote in
message <gemini.j90z0407xx7k003s2.tony@xxxxxxxxxxxxxx>
> On 19 Nov at 22:17 David Pilling <flist@xxxxxxxxxxxxxxxxxxx> wrote in
> message <Ya4eEkAefNYFFwdB@xxxxxxxxxxxxxxxxxxx>
[Tony discusses DTP on Linux]
> The only DTP of any significance is Scribus, and whilst free, is highly
> ideosyncratic, and offers only a tiny fraction of what OP can do. I believe
> there is room for a 'killer' DTP app on Linux, and that OP could well be
> that package. But <shrug>, what do I know?
I was hoping to use Scribus as a target for my Impression document
conversion efforts but, despite its Free (as in Freedom) nature and
XML-based file format, it didn't appear to support the features that
were required. Although Scribus is written using Qt, and although I'm
fairly familiar with Qt, I didn't really have the time to pitch in to
improve the situation. :-(
In the end, I used Skencil (http://www.skencil.org) as a rendering
engine instead, though I still have the Impression to XML convertor I
wrote in the process. :-)
> > As to QT... the problem is that DTP depends very intimately on the
> > operating system. Although OP was written for RISC OS with no thoughts of
> > portability, moving it to Windows would not have been much work - except
> > for how close one has to get to Windows.
> >
> Now there I have no immediate answer. My feeling is that, given OP renders
> quite nicely under wine, a native implementation can only do better. I also
> rather suspect that the work you've put in to the Windows port (Presumably
> Visual Studio) will be very helpful in a Linux port.
The commercial version of Qt for Windows (as opposed to the GNU GPL version
for Windows) includes support for Visual Studio, so it might even be
possible to develop using that, though you would need to think about the
licensing situation if you also wanted to deploy closed source applications
on multiple platforms.
> > For example you can't just paint text on screen, if you do it looks awful,
> > you've got to start fiddling with how many pixels appear between
> > characters - that is just one example it goes on and on.
> >
> > So does QT offer the sort of control that is needed?
> >
> No, QT is just a set of GUI libraries. It's benefit is providing the
> necessary infrastructure of windows, system calls, etc for the desktop
> system. There are other libraries out there to facilitate graphics
> programming, which may help provide the necessary control over screen
> rendering.
I think you underestimate what Qt provides! Additionally, support for
fonts and text handling in Qt is improving all the time. Even if you
bypass the higher level rich text handling features and paint everything
yourself, there are plenty of low level features available that give you
a lot of control over how text is rendered, whether you're displaying it
on screen or preparing output for a printer.
> You have the advantage of intimate knowledge of the application and its
> requirements, and my inclination would be to let you get on with the job you
> have magnificantly performed over the years. However, with all respect, you
> appear to have become, I hope only temporarily, stalled for various reasons.
> I also believe that having built a machine, and installed Linux, is a far
> step from porting a major application to it, even for a man of your
> undoubted ability. I believe it would take at least a year of quite intense
> use of the system to become sufficiently familiar with it to contemplate
> such a project.
I don't know about that. Qt isn't difficult to learn, and should be simple
to get to grips with for an experienced (C++) developer. You (David) should
get in touch with Jonathan Marten (of DrawPlus and Vector fame) and ask him
about his experiences with writing DrawView:
http://www.keelhaul.me.uk/acorn/drawview/
From the perspective of Ovation Pro, you should note that that point
in the Compatibility section of that page that talks about non-integer
point sizes is slightly misleading - font sizes can be specified with
floating point precision:
http://doc.trolltech.com/4.2/qfont.html
> So, with no knowledge of the internals of OP, but with some years experience
> of developing for GNU/Linux, I'm offering you a helping hand. I really don't
> know how successful it'll be, but I'm prepared to give it a try.
I think it would be interesting to see it running on Linux, especially as
an open source or Free Software application.
> I must own up to not being entirely altruistic.
I'm not being entirely altruistic either. I have a professional interest
in Qt, and I use the Python bindings (PyQt) in my spare time.
> Secondly, I would expect some quid-pro-quo, over which I'll go to
> private email. Thirdly, This would be an ideal project for my next step into
> the depths of Linux application programming.
I'd be interested to hear from either of you if you take this any further.
David
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