Re: How to get there from Here.

From: Andrew Dunbar (hippietrail@yahoo.com)
Date: Tue Apr 23 2002 - 07:30:33 EDT

  • Next message: Andrew Dunbar: "Re: selections and combining characters"

     --- Martin Sevior
    <msevior@mccubbin.ph.unimelb.edu.au> wrote: > Ok the
    final email on these new classes is a
    > strategy for
    > migrating our code base to use the new layout
    > engine. Here is my
    > proposal.
    >
    > When we're happy that we've reached consesus the way
    > we want to
    > go,

    At this point I want to point out my RFE for vertical
    text:
    http://bugzilla.abisource.com/show_bug.cgi?id=3186

    It sounds scarier than it is, at least for the back
    end. But it would have some impact.

    > 1. Hub creates new CVS modules abi-1.2,
    > abiword-plugins-1.2 which
    > are initially just a copy of the current modules.
    >
    > 2. We implement the fp_Container class heiracy and
    > make the
    > current code work for the new heiracy with fp_Lines
    > as
    > fp_ContainerObjects etc. We generalize
    > fb_LineBreaker to break any
    > fp_ContainerObjects into horizontally laid out
    > lines.
    >
    > Once the new class heiracy works with existing
    > documents we go to
    > stage 3.
    >
    > 3. We implement the new Layout class heiracy with
    > fl_BLockLayout
    > and fl_SectionLayout as subclasses of
    > fl_ContainerLayout. The
    > fl_ContainerLayout abstract base class is fully
    > defined. We create
    > the new fb_SectionBreaker class to layout any
    > collection of
    > objects vertically. Once we've made this new heiracy
    > work with our
    > existing code we go to stage 4.
    >
    > 4. Put the new struxes into the piecetable and
    > investigate the
    > properties we need them to define. I suggest we use
    > RTF as a model
    > here. RTF version 1.6 is basically a blueprint on
    > how MS Word 2000
    > works.
    >
    > 5. Now the fun really starts. We implement the new
    > fp_Container
    > classes, then the fl_Section classes and connect
    > them to the
    > piecetable via fl_Doclistener. Once this is done we
    > define the new
    > tags needed for our AbiWord_2 importer/exporter.
    > This is actually
    > very easy. We just invent tag names for our new
    > struxes and
    > include them in the "case" statements.
    >
    > 6. Steal/invent a fast Table layout tool.
    >
    > 7. Once we can import/export
    > tables/footnotes/endnotes to *.abw we
    > begin work on the Table/footnote/endnote/positioned
    > object UI.
    >
    > IMHO MS Word provides a base from which to work
    > here. In my
    > opinion this is still rather cumbersome so I'd love
    > to get some
    > help for how to do a better Table UI.

    I wouldn't try to create a "draw tables" UI at this
    stage. I would like an initial dialog asking the
    number of columns and rows, and nice ways to add and
    remove columns and rows.

    > We will definately needed to rework how to do
    > selections and how
    > to keep the cursor inside a container. The latter
    > can be done with
    > a generalization of getEdittableBounds().
    >
    > In the case of the former may not want to draw a
    > selection over
    > footnotes/endnotes and positioned object's.
    >
    > For deletions that cross cell boundaries we will
    > want
    > to pop up a little window to ask above deleting
    > cells/rows/columns
    > etc the way Gnumeric/excell/MS Word does now. It
    > should not be
    > hard to trigger this. Just put a hook into in to
    > detect attempts
    > to delete Table or cell struxes.

    I think once the selection crosses a cell boundary
    that the entirety of both cells should be selected.
    I don't think trying to select half of one cell and
    half of the next cell is a worthwhile case to try to
    support.

    > This strategy allows us several checkpoints to make
    > sure we're on
    > the right track to a much more sophisticated layout
    > engine.
    >
    > Cheers!
    >
    > Martin
    >
    > PS. There are details that I haven't talked about
    > like how to map clicks
    > on the document window to a location in the
    > document. This particualr item
    > is straight foward. As we do now, find the container
    > containing the click,
    > scan the container until a run intercepts the x,y
    > location of the click.
    > Feel free to ask about other details. I might have
    > overlooked something
    > vital.

    I always have lots of trouble trying to select an
    entier table in Word. I also have trouble trying to
    select certain rows or columns. I hope we can avoid
    this.

    Andrew Dunbar.

    =====
    http://linguaphile.sourceforge.net http://www.abisource.com

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