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| type
TForm1 = class(TForm)
Timer1: TTimer;
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
procedure FormPaint(Sender: TObject);
procedure Timer1Timer(Sender: TObject);
private
Image :TBitmap;
Angle :extended;
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.FormCreate(Sender: TObject);
var
i :integer;
p :PRGBQuad;
begin
Image := TBitmap.Create;
Image.LoadFromFile('d:\temp\Image.bmp');
//Couche alpha
Image.PixelFormat := pf32bit;
p := Image.ScanLine[Image.Height -1];
for i := 0 to Image.Width *Image.Height -1 do
begin
if dword(p^) <> clWhite then
p.rgbReserved := $FF;
inc(p);
end;
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
Image.Free;
end;
procedure TForm1.FormPaint(Sender: TObject);
var
XF :tagXForm;
const
Blend :TBlendFunction = (BlendOp:AC_SRC_OVER; BlendFlags:0; SourceConstantAlpha:255; AlphaFormat:AC_SRC_ALPHA);
begin
with XF do
begin
eM11 := cos(Angle);
eM12 := sin(Angle);
eM21 := -eM12;
eM22 := eM11;
eDX := Width div 2 -eM11 *(Image.Width div 2) +eM12 *(Image.Height div 2);
eDY := Height div 2 -eM12 *(Image.Width div 2) -eM11 *(Image.Height div 2);
end;
SetGraphicsMode(Canvas.Handle, GM_Advanced);
SetWorldTransform(Canvas.Handle, XF);
Windows.AlphaBlend(Canvas.Handle, 0, 0, Image.Width, Image.Height, Image.Canvas.Handle, 0, 0, Image.Width, Image.Height, Blend);
ModifyWorldTransform(Canvas.Handle, XF, MWT_IDENTITY);
end;
procedure TForm1.Timer1Timer(Sender: TObject);
begin
Angle := pi;//Angle +0.1;
Invalidate;
end; |
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