Mega Code Archive
How to AlphaBlend your forms with a component!
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Title: How to AlphaBlend your forms with a component!
Question: Do you like the AlphaBlending of Windows 2000 menus? Use that and you'll implement in your applications.
Answer:
Unit uAlphaWindow;
Interface
Uses
Windows, Messages, Classes, Controls, Forms;
Type
TAlphaPercent = 0..100;
TAlphaWindow =
Class( TComponent )
Protected
User32 : HModule;
Public
Constructor Create( AOwner : TComponent ); OverRide;
Destructor Destroy; OverRide;
Procedure SetTransparentHWND( HWnd : THandle; Percent : TAlphaPercent );
Procedure SetTransparent( Percent : TAlphaPercent );
Procedure SetOpaqueHWND( HWnd : THandle );
Procedure SetOpaque;
End;
Procedure Register;
Implementation
Const
LWA_ALPHA = $2;
GWL_EXSTYLE = -20;
WS_EX_LAYERED = $80000;
WS_EX_TRANSPARENT = $20;
Var
SetLayeredWindowAttributes : Function( HWnd : LongInt; crKey : Byte; bAlpha : Byte; dwFlags : LongInt ) : LongInt; StdCall;
Constructor TAlphaWindow.Create( AOwner : TComponent );
Begin
Inherited;
User32 := LoadLibrary( 'USER32.DLL' );
If ( User32 0 ) Then
@SetLayeredWindowAttributes := GetProcAddress( User32, 'SetLayeredWindowAttributes' )
Else
SetLayeredWindowAttributes := NIL;
End;
Destructor TAlphaWindow.Destroy;
Begin
If ( User32 0 ) Then FreeLibrary( User32 );
Inherited;
End;
Procedure TAlphaWindow.SetOpaqueHWND( HWnd : THandle );
Var
Old : THandle;
Begin
If ( IsWindow( HWnd ) ) Then Begin
Old := GetWindowLongA( HWnd, GWL_EXSTYLE );
SetWindowLongA( HWnd, GWL_EXSTYLE, Old And ( ( Not 0 ) - WS_EX_LAYERED ) );
End;
End;
Procedure TAlphaWindow.SetOpaque;
Begin
Self.SetOpaqueHWND( ( Self.Owner As TWinControl ).Handle );
End;
Procedure TAlphaWindow.SetTransparentHWND( HWnd : THandle; Percent : TAlphaPercent );
Var
Old : THandle;
Begin
If ( ( User32 0 ) And ( Assigned( SetLayeredWindowAttributes ) ) And ( IsWindow( HWnd ) ) ) Then
If ( Percent = 0 ) Then
SetOpaqueHWND( HWnd )
Else Begin
Percent := 100 - Percent;
Old := GetWindowLongA( HWnd, GWL_EXSTYLE );
SetWindowLongA( HWnd, GWL_EXSTYLE, Old Or WS_EX_LAYERED );
SetLayeredWindowAttributes( HWnd, 0, ( 255 * Percent ) Div 100, LWA_ALPHA );
End;
End;
Procedure TAlphaWindow.SetTransparent( Percent : TAlphaPercent );
Begin
Self.SetTransparentHWND( ( Self.Owner As TForm ).Handle, Percent );
End;
Procedure Register;
Begin
RegisterComponents( 'Christian', [ TAlphaWindow ] );
End;
End.
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