Peter Kümmel wrote:
Abdelrazak Younes wrote:
Peter Kümmel wrote:
A other solution is to somehow handle within the views which part
of the buffer is viewed.
This is what we have already: Each LyXView (WorkArea really) has its own
unique BufferView which is a view of one part of the document. Except
for some cursor bug (the famous dEPM bug), this is working fine.
Abdel.
Ah, didn't know that. So could you describe the design a little bit
with the MVC language, I think this will help a lot of people to
read and understand the code.
Something like this:
model:
- buffer the one big buffer
view:
- WorkArea partly view of the buffer
- lyxview frontent impl of the view
OK, here is my try at it:
1) The Model: Buffer
The Buffer is the in-memory representation of a LyX file format. The
Buffer does not (should not) have any information on what part of it is
represented on screen. There is one unique Buffer per opened LyX file.
2) The Controller: BufferView/Painter
The BufferView is a tool used by the view that translates a part of the
Buffer contents into drawing routines. The BufferView asks each inset of
the Buffer to draw itself onto the screen using the Painter.
There is only Buffer loaded per BufferView. While there is the
possibility to switch Buffer inside the BufferView, the goal is to
instantiate a new BufferView on each Buffer switch.
The Painter is just a virtual interface to formalize each kind of
drawing routines (text, line, rectangle, etc).
The BufferView also contains a Cursor which may or may not be visible on
screen. The cursor is really just a bookmark to remember where the next
Buffer insertion/deletion is going to take place.
3) The View: WorkArea (and it's qt4 specialisation GuiWorkArea)
This contains the real screen area where the drawing is done by the
Painter. One WorkArea holds one unique BufferView. While it could be
possible that multiple WorkArea share one BufferView, this is not
possible right now.
The WorkArea also provide a scrollbar which position is translated into
scrolling command to the inner BufferView.
The WorkArea use the BufferView to translate each keyboard or mouse
events into terms that the Buffer can understand:
- insert/delete char
- select char
- etc.
4) The Window: LyXView (and its qt4 specialisation GuiView)
This is a full window containing a menubar, toolbars, a tabbar and a
WorkArea. One LyXView could in theory contain multiple WorkArea (ex:
with split window) but this number is limited to one only for now. In
any case, there would be only one WorkArea that gets the focus at a time.
Now, concerning the TabBar versus TabWidget issue. Right now, there is
only one WorkArea and the TabBar just used to tell the BufferView inside
the WorkArea to switch to this another Buffer.
With a TabWidget, each Tab would own its own WorkArea. Clicking on a tab
would switch a WorkArea instead of a Buffer.
That's all, I hope my English is clear enough and that helps some of you
better understand the global picture. Back to my real work.
Abdel.
