Left value of the maximized form
lazarus / 31-LCL

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krzynio · 2023-11-21 12:13

Hi. Why Left parameter of maximized form is not zero but -8? Border
size is zero.
Tested on Windows 11 with Lazarus 2.2.6

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Handoko · 2023-11-21 12:54

Can you provide a demo?

I tested it on my Lazarus 2.2.6 Ubuntu Mate 23.10, it showed zero,
this is my code:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TForm1.Button1Click(Sender: TObject);var  i: Integer;begin 
WindowState := wsMaximized;  for i := 1 to 100 do   
Application.ProcessMessages;  Caption := Left.ToString;end;
The for-loop is used for making some delays so the Left property can
have correct value.

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krzynio · 2023-11-21 13:15

Thank you for your interest. Could you try this please?
1. start a new project
2. put a button on from and write a procedure onbuttonclick:
showmessage(IntToStr(Form1.Left))
3. Run the program and click the button. The Left should have a
positive value, i.e. 861
4. Maximize the form and press the button again. Now Left is -8 ???
what I do not understand.

I have to add that I work on virtual machine. Maybe this helps.

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Handoko · 2023-11-21 13:42

I could be wrong. But I believe Windows consider the form style border
as part of the form position. For example you can see the thick border
of the form that run on WinXP from the screenshot below, it gave me -4
px when maximized. I opened and zoomed it using GIMP, and I could
clearly see the thickness of the border is 4px.

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krzynio · 2023-11-21 17:17

I think the same, probably in Windows 11 the frame is invisible but
still exists.
It looks strange but there is some logic in this.
When window is maximized the frame is outside of the desktop and you
cannot catch it for windows resizing.

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Martin_fr · 2023-11-21 20:10

I am on Windows 10

Maximizing the form, and left = -1448 => But then that is on a monitor
that starts at -1440

On a normal monitor, I get -8 too

That seems to go back for some time => Lazarus 1.8 has that too.

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ASerge · 2023-11-21 20:34

Quote from: krzynio on November 21, 2023, 01:13:09 pmHi. Why Left
parameter of maximized form is not zero but -8? Border size is zero.
Starting with Windows 8, Microsoft has added transparent shadows to
the window for beauty. Unfortunately, the company did not make the
appropriate changes to the Windows API, as a result, many applications
had to be changed to take into account these additional boundaries.