[Solved] How to lock/unlock control repainting (to eliminate flicker)?

[AlexTP]

On Delphi I was able to use some WIn32 API (with word "Update"? I dont recall)
which was blocking all control repainting. And then unlock too.

How to do it here?
I need it for CudaText, where changing grouping mode makes FLICKER: new groups (child panels) appear, old groups resize...

[jamie]

Control.Invalidate;
---
Also, the canvas has ClipRect;;

Canvvas.ClipRect := TREct(?,?,?,?); Canvas.Clipping := true;

----
You can assign a clear brush to the background of the parent if you are going to repaint the background yourself.

Also the use of ExcludeClipRect can disallow a rect to not be painted.


There are many ways..

[lucamar]

I'm not really sure but, doesn't TForm's BeginFormUpdate/EndFormUpdate do what you want?

[balazsszekely]

On Delphi I was able to use some WIn32 API (with word "Update"? I dont recall)
which was blocking all control repainting. And then unlock too.

API LockWindowUpdate?

Code: Pascal  [Select][+][-]

1. LockWindowUpdate(Control.Handle);
2. try
3.   //...
4. finally
5.   LockWindowUpdate(0);
6. end;

[AlexTP]

Thanks! i used your tip and have fixed it:

Code: Pascal  [Select][+][-]

1. type
2.   TFormHack = class(TForm);
3.  
4. procedure DoControlLock(Ctl: TWinControl);
5. begin
6.   if Application.MainForm<>nil then
7.     TFormHack(Application.MainForm).BeginFormUpdate;
8. end;
9.  
10. procedure DoControlUnlock(Ctl: TWinControl);
11. begin
12.   if Application.MainForm<>nil then
13.     TFormHack(Application.MainForm).EndFormUpdate;
14. end;
15.  

[User137]

That's not crossplatform. Are you sure the invalidate and begin/endupdate things weren't enough? Set form doublebuffering true?

[AlexTP]

Corrected the code: it is cross platform.