[Lazarus] Form position model

Graeme Geldenhuys graemeg.lists at gmail.com
Thu Apr 2 08:42:10 CEST 2009

On Thu, Apr 2, 2009 at 4:49 AM, Hans-Peter Diettrich
<DrDiettrich1 at aol.com> wrote:
> How should form positions be treated, when the project is not developed
> on the first/primary monitor?

You are raising very good questions...

> IMO we should distinguish between projects developed *for* single or
> multiple monitors, and handle somehow negative screen/desktop
> coordinates, on systems where the primary monitor is not the leftmost one.

And who said multi-monitors must be left-right. What if you have a
vertical arrangement like top-bottom?

> 1) A single-monitor project later should run on any (startup) monitor,
> regardless of the number of the monitor it was developed on. Eventually

As far as I understand how it should work.... If you start the
application on monitor three, then it should be positioned on monitor
three. LCL should also correctly handle window Position property
correctly and distinguish between poScreenCenter and poDesktopCenter.
eg: If you have four monitors 2x2 arrangement, and launch the
application in screen 4 (bottom right for example). if poScreenCenter
is applied, it should be centered in screen 4. if poDesktopCenter is
applied, it should be in the center of all four screens (overlapping
all of them).

Lazarus LCL is not the only one struggling with this. Firefox and
Thunderbird gave lots of strange issues with a 2 screen multi-monitor
setup as well. So we are not alone. :-)

  - Graeme -

fpGUI - a cross-platform Free Pascal GUI toolkit

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