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IDProjectCategoryView StatusLast Update
0016782LazarusLCLpublic2010-06-28 20:30
ReporterEugen Bolz Assigned ToPaul Ishenin  
Status closedResolutionfixed 
OSWindows 7 
Product Version0.9.29 (SVN) 
Fixed in Version0.9.29 (SVN) 
Summary0016782: Anchordock: Draging a Window is slow on Windows Vista/7

if you drag a window, it is very slow, it only happens when aero is on...


I've already searched for a solution: this may helps, but I couldn't implement it, because the OnStartDock-Event don't get called :( ...
TagsNo tags attached.
Fixed in Revision26309
Attached Files


José Mejuto

2010-06-24 00:07

reporter   ~0038777

The problem is that direct writes to screen (desktop screen) are now disabling composition, paint and reenable composition, which renders to a brutal CPU power needed.

There are 2 basic solutions:

1) Use a window with alpha transparency to simulate the rect. Selecting zones of same color as window could be a visual problem.

2) Using the same technique as Microsoft MFC. Relevant code can be found in the last message of this thread: It requires a bit of CPU more than (1).

2010-06-25 16:27


dragdockalphablend.pas (1,295 bytes)

Eugen Bolz

2010-06-25 16:31

reporter   ~0038807

Hey :)

I have implemented Solution 1).

Using this Patch for AnchorDock: 0016789 and the Unit: dragdockalphablend.pas.

Now we just have to create a Custom TDragDockObject with the TForm.OnStartDock-Event.

procedure TForm1.FormStartDock(Sender: TObject;
  var DragObject: TDragDockObject);
   DragObject := TDragDockObjectEx_AlphaBlend.Create(TControl(Sender));
   // TForm(Sender) would create an exception

Now I can dock all without have a stupid slow focus rect :)

Paul Ishenin

2010-06-28 10:23

manager   ~0038849

Please test and close if ok.

Eugen Bolz

2010-06-28 20:30

reporter   ~0038857

It is working now, thanks :)

0016789 can be closed now too :)

Issue History

Date Modified Username Field Change
2010-06-23 20:35 Eugen Bolz New Issue
2010-06-23 20:35 Eugen Bolz Widgetset => Win32/Win64
2010-06-24 00:07 José Mejuto Note Added: 0038777
2010-06-25 16:27 Eugen Bolz File Added: dragdockalphablend.pas
2010-06-25 16:31 Eugen Bolz Note Added: 0038807
2010-06-27 14:17 Mattias Gaertner Status new => assigned
2010-06-27 14:17 Mattias Gaertner Assigned To => Mattias Gaertner
2010-06-27 14:20 Mattias Gaertner Assigned To Mattias Gaertner => Paul Ishenin
2010-06-28 10:23 Paul Ishenin Fixed in Revision => 26309
2010-06-28 10:23 Paul Ishenin LazTarget => -
2010-06-28 10:23 Paul Ishenin Status assigned => resolved
2010-06-28 10:23 Paul Ishenin Fixed in Version => 0.9.29 (SVN)
2010-06-28 10:23 Paul Ishenin Resolution open => fixed
2010-06-28 10:23 Paul Ishenin Note Added: 0038849
2010-06-28 20:30 Eugen Bolz Status resolved => closed
2010-06-28 20:30 Eugen Bolz Note Added: 0038857