On Mon, 5 Apr 2010, Hans-Peter Diettrich wrote:
Michael Van Canneyt schrieb:
In Delphi, you can make dock zones along the edges of your
form by dropping 4 panels and aligning them along the edges of the form. If
autosize=true, then they have size 0 when the app is run (not when
designed), but you can dock controls on them, since there is a "fuzzy" zone
of 10 pixels.
Such DockSites should work without AutoSize, because their extent is
determined by the DockManager - which is not involved in autosizing. The free
extent of an elastic docksite should be user-adjustable, by means of an
splitter. They worked until now, at least with the Win32 and gtk2 widgetsets.
The influence rectangle of a docksite is the control's rectangle, extended by
10 pixels in every direction. It it used only in the determination of the
target site, not in the layout.
I know. That is why setting
No code is needed, and you can then dock toolbars etc. along the edges of
the form.
Code is needed to extend and shrink the sites - also in Delphi.
Not at all. I have a counter-example on my disk here.
I didn't test docking 2 controls on it, but when docking only 1 control,
you don't need any code whatsoever in Delphi.
The docked
size of the controls is not normally useful to determine the extent of a
docksite, instead the DockManager controls the layout of the site, by
adjusting all docked controls to the given extent of the site.
And this is not so in delphi when the panel has autosize=true.
Unless someone has a better idea for dock zones around the edge of a form
without having to write code...
I already asked for an (user selectable) layout manager some time ago. Such a
manager would replace or include docking managers, that essentially control
the *layout* of a docksite, while docking itself is only a minor addition.
Then AutoSize should be handled by the applicable layout manager, and anchor
docking will become just another layout manager. A stable algorithm and
protocol (API) has to be established, that allows all layout managers to work
together.
I have been thinking about layout managers. I think that this should be an
add-on
to the currently existing layouting (to preserve delphi compatibility):
I imagine a component that one drops on a form.
One sets the 'target' control (control whose children should be managed) and some
properties.
Depending on the layout one wants, a different component must be dropped:
TLayout
+- TAbsoluteLayout
+- THBoxLayout
+- TVBoxLayout
+- TTableLayout
+- TBorderLayout
...
Each descendent has different properties. Changing the layout just means
dropping another component; something that can be done run-time.
Something like this exists in ExtJS, and it works very well.
The only thing I am unsure about is whether TControl should be made
TLayout-aware.
As far as I understand, a layouter only needs to be able to handle rectangles,
within some restrictions (some callbacks to get min/max rectangles).
It need not know anything about TControl or it's properties, and as such could
be implemented totally independent of the LCL.
I discussed this idea once with Mattias Gaertner, but he seems to disagree
on the TControl-unawareness, if I recall correctly.
Maybe the planned Lazarus day in the netherlands would be a good place to
discuss this and settle things once and for all :-)
Michael.
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