Not sure if last post worked, so doing it again... 
 
Original Message: 
----------------- 
From: rwlbuis@xs4all.nl rwlbuis@xs4all.nl 
Date: Wed, 7 May 2003 14:20:03 -0400 
To: rwlbuis@xs4all.nl 
Subject: Re: karbon/umbrello 
 
 
Hi again,  
  
>so it sounds like there's a need for a general purpose vector drawing   
>framework that works with some kind of painter. this could be used for, 
say,   
>umbrello, kivio, karbon or just about anything that needs to display 
create   
>and display vector graphics. excellent.  
  
It basically boils down to that :)  
  
>i really like the V* object hierarchy... it certainly seems like the right 
 
>direction. even more, i also i like the usage of base objects as 
interfaces   
  
Keep in mind though that not every class that starts with a V will be 
appropriate  
outside karbon ;) For instance we have vselection which may be useless 
outside  
karbon, and vfillrule.h, which may be overkill on its own and could be 
moved to  
kpainter perhaps.  
Another unclear area are things like VGradient, VPattern. The unclear thing 
atm  
is whether such a thing should be in shared lib, kpainter or both...  
  
>for managing certain components of objects. unless i'm completely   
>misinterpreting the code, i see a potential problem involving multiple   
>inheritance - granted, it can be eliminated via virtual inheritance. the   
>other thing might be to introduce QObject as a base of VObject - i know 
its a   
>little heavy, but it does grant signal/slot capabilities to objects in the 
 
>canvas.  
  
I dont see the MI problem? Probably I am overlooking something, you may  
reuse the classes in another way I imagined or so...  
  
>there are some KOffice refactoring issues - like eliminating any 
dependencies   
>on KOffice. not that KO is bad, its probably just a little heavy for 
smaller   
  
Well IIRC Lenny wanted to make a core path lib not limited to karbon. So 
that would  
probably imply not using things like KoRect and other koffice structures.  
  
>applications to link against and it would be nice to have this as stand 
alone   
>as possible. for this, i think KPainter would be an excellent replacement 
for   
>VKoPainter - they're basically the same thing anyway (built on top of   
>libart). we might even be able to package KPainter as the default painter 
for   
  
They are close, but with a slightly different philosophy. KPainter tries to 
stick  
to QPainter/QPaintDevice abstraction (so KPainter and QPainter should be  
interchangeable), whereas VKoPainter was just something I hacked up 
quickly.  
  
>the object hierarchy - that means there wouldn't need to be any massive   
>rewriting for karbon (that i can forsee).  
  
Phew :)  
  
>the canvas is probably going to be a little harder. i think it might be   
>worthwhile to try and provide an abstract canvas interface and then 
provide a   
>default implementation as with KPainter/VPainter stuff i suggested. the 
same   
>should go for VDocument. that provides a lot of interesting opportunities 
for   
>people down the road, should the need arise.  
  
Right. I have no idea yet how common VDocument can be for the three apps...

BTW load/save as it is now could have some implications. ATM for instance  
karbon VComposite saves/loads svg path data. In general for karbon the file 
format  
has gone into the direction of OO Draw. Please have a think how applicable 
this is  
to umbrello, and whether there are opportunities for extending the format. 
OTOH  
you can derive and implement your own load/save routines, but that would be 
a slight  
waste of code.  
  
>question: if people are serious about proceeding with this, where does it 
go?   
>i'd suggest KPainter, but the name might be a little misleading because 
we'd   
>be providing alot more than just KPainter (and alot less than Karbon :).   
>actually, what would be a good name for this thing?  
  
KPainter should be restricted to painting :) I am not very good at coming 
up with  
names, but vector should probably be in it :)  
  
>anyway, depending on what my advisor needs me to do for research this 
summer   
>(hopefully not too much), i'm going to have tons of free time starting 
next   
>week. being that i'd love to see this get used for umbrello2 i suppose 
i'll   
>have to do some work getting stuff started... this should be fun :)  
  
I really hope you have lots of time. Ofcourse I am interested a lot in this 
stuff and  
willing to help as much as time permits.  
Cheers,  
  
Rob.  
 
 
 
 

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