[plt-scheme] Make a grid / table control in GUI

http://upload.wikimedia.org/wikipedia/commons/a/a6/Gnucash_2_screenshot.png
the gnucash screenshot shows a pretty full featured 'widget' including;
- resizable columns
- twisties
- images

s.


On Tue, Sep 8, 2009 at 6:09 PM, Stephen De Gabrielle <
spdegabrielle at gmail.com> wrote:

> How would you implement that?
>
>
>
> Another  iteration
>
>
> #lang scheme/gui
>
> (define grid-pasteboard%
>   (class pasteboard%
>     (init-field w h)
>     (define/override (insert snip r c) (super insert snip (* c w) (* r h)))
>     (super-new)))
>
>
> ;; accepts data-grid (list of columns)
> (define data-grid-pasteboard%
>   (class pasteboard%
>     (init-field data-grid
>                 (col-widths '(75 55 65))
>                 (row-height 16)
>                 )
>
>     ;; create new list that is the cumulative sum of the source list
>     (define (cumulative-sums offsets)
>       (foldl (lambda (offset cum-list)
>                (append cum-list (list (+ offset (last cum-list)))))
>              (list 0) ; start from 0
>              offsets))
>     ;; column widths -> col offsets
>     (define (column-offsets col-widths)
>       (cumulative-sums (drop-right col-widths 1)))
>     ;;
>
>     (define col-offset
>       (let ((offsets (column-offsets col-widths)))
>         (lambda (col) (list-ref offsets col))))
>     ;; rows are all the same height
>     (define (row-offset row)
>       (* row row-height))
>     ;; initialise pasteboard
>
>     (define/override (insert snip row col)
>       (super insert snip (col-offset col) (row-offset row)))
>     (define (grid-ref datagrid row col)
>       (list-ref (list-ref datagrid col) row)
>       )
>     (super-new)
>     (for ([col (in-range (length data-grid))])
>       (for ([row (in-range (length (car data-grid)))])
>         (insert (make-object string-snip% (grid-ref data-grid row col))
>                 row col)
>         ))
>
>     ))
> (define f (new frame% [label "Simple Edit"]
>                [width 200]
>                [height 200]))
> (define c (new editor-canvas% [parent f]))
> (define t (new  grid-pasteboard% (w 66) (h 16)))
> (send t insert (make-object string-snip% "at23") 2 3)
> (send t insert (make-object string-snip% "at23") 2 2)
> (send t insert (make-object string-snip% "at23") 3 2)
> (send t insert (make-object string-snip% "at23") 1 1)
> (send t insert (make-object string-snip% "at23") 0 0)
> (send c set-editor t)
> (send f show #t)
>
> ;;
>
> (define f2 (new frame% [label "Simple Edit"]
>                 [width 200]
>                 [height 200]))
> (define c2 (new editor-canvas% [parent f2]))
> (define t2 (new data-grid-pasteboard%
>                 (data-grid
>                  '(("name" "Stephen" "Patrick")
>                    ("age" "39" "38")
>                    ("eye-colour" "green" "blue")
>                    ))))
> (send c2 set-editor t2)
> (send f2 show #t)
>
>
>
> On Tue, Sep 8, 2009 at 2:01 PM, praimon <praimon at gmail.com> wrote:
>
>> Hi,
>> Thanks for your work. It seems we have this conversation every year or
>> two.
>> One of the most important features of the directory-table widget is the
>> ability
>> to manually resize the columns. Otherwise, either some of the data will be
>> hidden/lost or the table needs to be too large (so as to accomodate
>> any conceivable
>> data entry).
>> regards,
>> praimon
>>
>> On Tue, Sep 8, 2009 at 2:15 AM, Stephen De
>> Gabrielle<spdegabrielle at gmail.com> wrote:
>> > Hi, people have asked about a data grid on this list a few times.
>> >
>> > This is the simplest possible approach. I've tried and abandoned other
>> > approaches when I realised they were too much work for my available free
>> > time.
>> >
>> > Comments appreciated.
>> >
>>
>
>
>
> --
>
> --
> Stephen De Gabrielle
> stephen.degabrielle at acm.org
> Telephone +44 (0)20 85670911
> Mobile        +44 (0)79 85189045
> http://www.degabrielle.name/stephen
>
>


-- 

--
Stephen De Gabrielle
stephen.degabrielle at acm.org
Telephone +44 (0)20 85670911
Mobile        +44 (0)79 85189045
http://www.degabrielle.name/stephen
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