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jamesa · Guest

I intercepted onPaint event to draw in the form surface. I use
offscreen buffer to avoid flicker.

But why if I set the form to transparent (TransparentColor := TRUE),
the flicker occured ?

Is this normal? That something I must live with?

I need to use transparent form, but I dont want flicker.

Any idea for workaround ?

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls,
Forms,
Dialogs;

type
TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
procedure FormPaint(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
OffScreen: TBitmap;
BG: TBitmap;
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
Form1.Color := clMaroon;
Form1.TransparentColorValue := clMaroon;
Form1.TransparentColor := TRUE;

OffScreen := TBitmap.Create;
OffScreen.Width := Form1.ClientWidth;
OffScreen.Height := Form1.ClientHeight;

BG := TBitmap.Create;
BG.LoadFromFile('BG.bmp');
end;

procedure TForm1.FormPaint(Sender: TObject);
var
x, y: integer;
begin
// Draw something in the off screen buffer
y := 0;
While y < ClientHeight DO
Begin
x := 0;
While x < ClientWidth Do
Begin
BitBlt(OffScreen.Canvas.Handle, x, y, BG.Width, BG.Height,
BG.Canvas.Handle, 0, 0, SRCCOPY);
Inc (x, BG.Width);
End;
Inc (y, BG.Height);
// This sleep is to see the flicker
Sleep(300);
End;

// copy it into form surface
BitBlt(Canvas.Handle, 0, 0, ClientWidth, ClientHeight,
OffScreen.Canvas.Handle, 0, 0, SRCCOPY);
end;

end.

Oisin · Guest

[email]meerkapot (AT) yahoo-dot-com (DOT) no-spam.inva[/email]lid (jamesa) wrote in message news:<42286467$1 (AT) newsgroups (DOT) borland.com>...