复合几何对象包括 ID2D1GeometryGroup 和 ID2D1TransformedGeometry,它们都继承自 ID2D1Geometry。
ID2D1TransformedGeometry 只是包含了 2D 变换的 ID2D1Geometry。
uses Direct2D, D2D1; procedure TForm1.FormPaint(Sender: TObject); var cvs: TDirect2DCanvas; iTransformedGeometry: ID2D1TransformedGeometry; iRectangleGeometry: ID2D1RectangleGeometry; iGeometry: ID2D1Geometry; R: TRect; begin {建立一个矩形的 ID2D1Geometry} R := Bounds((ClientWidth-100) div 2, (ClientHeight-100) div 2, 100, 100); D2DFactory.CreateRectangleGeometry(R, iRectangleGeometry); {建立 ID2D1TransformedGeometry} D2DFactory.CreateTransformedGeometry( iRectangleGeometry, TD2DMatrix3x2F.Rotation(45, ClientWidth/2, ClientHeight/2), iTransformedGeometry ); cvs := TDirect2DCanvas.Create(Canvas, ClientRect); cvs.BeginDraw; {绘制原始矩形} cvs.Pen.Color := clGreen; cvs.Pen.Width := 11; cvs.DrawGeometry(iRectangleGeometry); {绘制 ID2D1TransformedGeometry} cvs.Brush.Color := clGreen; cvs.FillGeometry(iTransformedGeometry); {绘制从 ID2D1TransformedGeometry 再次获取的 iGeometry} cvs.Pen.Color := clWhite; cvs.Pen.Width := 1; iTransformedGeometry.GetSourceGeometry(iGeometry); cvs.DrawGeometry(iGeometry); cvs.EndDraw; cvs.Free; end; procedure TForm1.FormResize(Sender: TObject); begin Repaint; end;
效果图: