Hi Jocelyn (et al)
Your concern about using a nest of widgets vs a single paintbox (aka
pixmap) is well founded. I have tried both and the difference in
performance can be shocking. If you only want a few items, it's not
bad, but the event overhead alone on a redraw will get very bad very
quickly.
If you (boxer41a) really really want to do this sort of thing, it's not
impossible. I'd use an EV_VERTICAL_BOX inside an EV_VIEWPORT. EV_FIXED
will let you set item sizes, but it's less forgiving that a box, so I'd
stick wth the box.
You'll need a kind of 'new_item' function (disable_item_expand calls in
it) that will ensure that items don't expand too badly and end up
looking really ugly.
Getting the columns to line up will require disabling expand as well,
using cell or box per item in each row, and that means to support column
resizing, you have some mouse events to capture and process. A very
primitive multi-column list of widgets is doable this way, but the
closer you want to come to a real grid, the more you'll realize that
it's not worth it.
R
==================================================
Roger F. Osmond
-------- Original Message --------
Subject: Re: [eiffel_software] Re: Can an EV_TREE display complex
widgets?
From: Jocelyn <
[hidden email]>
Date: Thu, September 03, 2009 2:53 pm
To:
[hidden email]
Note that EV_GRID is more or less a PIXMAP
EV_GRID_LABEL_ITEM is an item where the grid draws the "text"
EV_GRID_EDITABLE_ITEM is a kind of EV_GRID_LABEL_ITEM ... but when you
click on it, it will display in a popup window (without border) an
EV_TEXT_FIELD ... but it is just display over the underlying
EV_GRID_ITEM.
So, if ever one want to have an EV_WIDGET ... this would means ... when
even the underlying grid/pixmap is redrawn
your application should display this widget with similar "trick", maybe
using a EV_FIXED would help but I think this would not be that trivial
to achieve.
And I am not sure about the performance.
Maybe others have idea or comment on this.
boxer41a wrote:
> Now that my exuberance has worn off I have a wish list. For Christmas I would like an EV_GRID_ITEM that contains an EV_CELL so that more complex widgets such as an EV_HORIZONTAL_BOX can be placed in each row item in the tree.
>
> I must complement the author of the in instructions in the description of EV_GRID.
>
>
>
> --- In
[hidden email], "boxer41a" <boxer41a@...> wrote:
>
>> Yes! Thank you.
>>
>> --- In
[hidden email], Jocelyn <eiffel@> wrote:
>>
>>> I guess you are talking about EV_GRID which contains EV_GRID_ITEM (and
>>> descendant)
>>>
>>> -- Jocelyn
>>>
>>> boxer41a wrote:
>>>
>>>> I thought I read recently that there was a new EV_TREE-like widget that could hold nodes which contained other widgets, so the nodes could display more than just one text field.
>>>>
>>>> Is this right? If so what are the classes involved?
>>>>
>>>> Thanks,
>>>>
>>>> jjj
>>>>
>>>>
>>>>
>>>>
>>>>
>
>
>
