Re: custom treeview cell renderer advice

[Kim Adil <ksadil bigpond net au>]

Sorry about the visuals. Here is the question again with better spacing of example data.

I would like to write a custom cell renderer for a treeview and would
appreciate any advice you may offer. I want to be able to hide any
repeats cells that follow one another, with a few extra features. If
standard rendering of sample data in a treeview of fruit classifications
shows:

Color        | Size            | Variety
Red          |  1              |  a
Red          |  1              |  b
Green        |  1              |  a
Green        |  2              |  a
Green        |  2              |  b
Yellow       |  1              |  a


then my new cell renderer would render it as:

Color        | Size           | Variety
Red          |  1             |  a
             |                |  b
Green        |  1             |  a
             |  2             |  a
             |                |  b
Yellow       |  1             |  a

But then if the user scrolls down one row it would look like:

Color        | Size           | Variety
Red          |  1             |  b
Green        |  1             |  a
             |  2             |  a
             |                |  b
Yellow       |  1             |  a

So the very top row always shows the the value in the  list store.
Subsequent rows hide duplicate cells that are the same as cells
immediately above, unless the column to the left changes. It has the
effect of de-cluttering a table full of sorted/grouped data.

It is essentially what most database report writers (crystal & access)
do with a "hide duplicates" option
.
My initial thoughts are that I would have to maintain a few extra
columns based on:
(1) what row is at the top of the treeview,
(2) has the cell to the left of the cell being considered, changed from
last row to this row, and
(3) is the cell above a duplicate of the cell being considered.

Ideas and considered opinions would be much appreciated.

Thanks Kim



Kim Adil wrote:
> I would like to write a custom cell renderer for a treeview and would
> appreciate any advice you may offer. I want to be able to hide any
> repeats cells that follow one another, with a few extra features. If
> standard rendering of sample data in a treeview of fruit classifications
> shows:
>
> Color        | Size           | Variety
> Red           |  1              |  a
> Red           |  1              |  b
> Green        |  1              |  a
> Green        |  2              |  a
> Green        |  2              |  b
> Yellow      |  1              |   a
>
>
> then my new cell renderer would render it as:
>
> Color        | Size           | Variety
> Red           |  1              |  a
>                  |                  |  b
> Green        |  1              |  a
>                  |  2              |  a
>                  |                  |  b
> Yellow      |  1              |   a
>
> But then if the user scrolls down one cell it would look like:
>
> Color        | Size           | Variety
> Red           |  1              |  b
> Green        |  1              |  a
>                  |  2              |  a
>                  |                  |  b
> Yellow      |  1              |   a
>
> So the very top row always shows the the value in the  list store.
> Subsequent rows hide duplicate cells that are the same as cells
> immediately above, unless the column to the left changes. It has the
> effect of de-cluttering a table full of sorted/grouped data.
>
> It is essentially what most database report writers (crystal & access)
> do with a "hide duplicates" option
> .
> My initial thoughts are that I would have to maintain a few extra
> columns based on:
> (1) what row is at the top of the treeview,
> (2) has the cell to the left of the cell being considered, changed from
> last row to this row, and
> (3) is the cell above a duplicate of the cell being considered.
>
> Ideas and considered opinions would be much appreciated.
>
> Thanks Kim
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