Positioning a control
lazarus / 31-LCL

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Bart · 2019-01-23 18:07

Hi,

I'm trying to position a control so that it's top is the same as the
top of another control.
The controls are on different containers, so I can't use anchors for
that.

btnCopy is on a TPanel, the panel has Align = alLeft.
btnStartCopy is on a TTabSheet, which is on a TPageControl, which has
Align = alClient and has ShowTabs = False.

I tried with this 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   P :=
Classes.Point(btnCopy.Left, btnCopy.Top);  P := ClientToScreen(P);
//transform to screen-coördinates  btnStartCopy.Top :=
ScreenToClient(P).y;
Obviously this is the wrong approach, since on screen the Top of
btnStartCopyis a few pizels below the Top of btnCopy (see attached
image).

Note that when I calculate ClientToScreen() on both buttons (after
executing the code above), Top for both will be the same.

How to do it the right way?

Bart

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ASerge · 2019-01-23 18:30

Quote from: Bart on January 23, 2019, 07:07:47 pmObviously this is the
wrong approach, since on screen the Top of btnStartCopyis a few pizels
below the Top of btnCopy (see attached image).
Note that when I calculate ClientToScreen() on both buttons (after
executing the code above), Top for both will be the same.
Try this
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
btnStartCopy.Top :=
btnStartCopy.Parent.ScreenToClient(btnCopy.ClientToScreen(Point(0,
0))).Y;

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Bart · 2019-01-23 21:25

Quote from: ASerge on January 23, 2019, 07:30:21 pmTry this
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
btnStartCopy.Top :=
btnStartCopy.Parent.ScreenToClient(btnCopy.ClientToScreen(Point(0,
0))).Y;
Yeah, that works.
But why (and why did my previous code not)?

Bart

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ASerge · 2019-01-23 22:23

Quote from: Bart on January 23, 2019, 10:25:45 pmBut why (and why did
my previous code not)?
Parent.ScreenToClient not Form.ScreenToClient

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Bart · 2019-01-23 22:32

I think I see it now.
I solved it as follows (a bit more readable to me):
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   P1 := btn
Copy.Parent.ClientToScreen(Classes.Point(btnCopy.Left,btnCopy.Top)); 
P2 := btnStartCopy.Parent.ScreenToClient(P1);  btnStartCopy.Top :=
P2.y;
Thanks for the help (your mentioned in my svn log now).

Bart

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jamie · 2019-01-23 23:17

Don't forget that in Trunk the Screen/Client functions no longer add
the Scrollbar offset to the return values
for something that is sitting on a TScrollingWinControl, you must add
this offset if you have scrollbars.

 This is Delphi and windows compliant