[Pmwiki-users] Re: Re: PmWikiDraw and multiple editors?

[mistyfire]

On Saturday 25 December 2004 16:24, Ciaran wrote:
> But how would this allow you to modify 'previous' layers as you put it
> ? I can see how this would allow concurrent annotation of a drawing,
> but it wouldn't allow you to modify the drawing in its present form?
yes, now modifying the downloaded drawing will not be needed as....
> Thanks
> - Ciaran
TO start with,
Once the server managed basetime is resolved (as suggested by pm,
1.  The user clicks on an edit drawing link and DRAW starts
2.  DRAW downloads the drawing and notes the drawing's time ("basetime")
3.  The user modifies the LAYER drawing and presses save
3a. Assuming that full drawing capability at the client side, the draw 
program saves the LAYER as well as the Original Drawing as separate drawings 
on the client itself(how it would be saved is a matter of implementation) and 
merges the LAYER together onto the drawing(most layer capable progs can do 
it).
4.  DRAW sends the "Merged" updated drawing and its basetime to the server.
5.  The server checks the timestamp of the current drawing against the
    basetime sent by DRAW.  If the timestamp is not the same as the 
    basetime, then the drawing changed while the client was editing it, and 
    5a.  The server sends a message back to DRAW indicating
         the drawing changed.
    5aa. The message send would SAY "Drawing changed....etc...etc.." and gives
           the user following option..... 
           (i) Redownload Latest Image and open the saved Layer on top of it,
           (ii) Save Current Layer as user defined file and EXIT, 
           (iii) Overwrite with the one client has,
                i.e old merged drawing (Dangerous), 
           (iv) Abort
    5b.  If (i) DRAW downloads the latest version of the drawing from the
         server and notes the time as its new basetime
    5c.  ---merged in 5aa--
    5d.  Go back to step 3 above
6.  Otherwise, the server stores the new drawing and all is well.

Apart from the above capability LAYERs open whole lot of new functionalities
eg. Client can keep the LAYER(changes) that he has modified, which can help in 
a. Keeping track of his changes
b. Undo-ing "HIS" changes if UNDO is not build in yet.
>
> On Sat, 25 Dec 2004 04:40:33 +0530, mistyfire <mistyfire at autograf.pl> wrote:
> > Hi,
> > I was wondering if LAYER's could be a better solution to multiple
> > editor's problem? Though it might not be a complete one.
> >
> > By LAYER I mean every client downldoads the drawing for editing and on
> > top of it an "Invisible Drawing Layer" is created for the user to draw,
> > having the same canvas size as the original drawing.
> >
> > Please note that I am completely unaware of whether LAYER can be
> > implemented in JAVA draw programme..... and I would humbly state that the
> > following idea is only theoritical, me having no working idea of the
> > PmWikiDraw.
> >
> > I kinda got this idea from:
> > http://ktown.kde.org/kimdaba/kimdaba-doc/en/doc-multi-page/chp-viewer.htm
> >l#drawing-on-images ....and
> > from how MS-Reader and some of the PDF readers that allow you to
> > underline and highlight on the documents itself which is NOT stored on
> > the original document.
> >
> > I have a rough idea as how this could potentially solve the multiple
> > editors problem..Apart from whole new functionality this can lead
> > into.... .. but not sure if LAYER functionality can be implemented or
> > not.
> >
> > V Krishn
> >
> > --
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