Direct2D (4) : DrawGeometry() 與 FillGeometry()

原始的 Direct2D 只提供了幾種簡單圖形(直線、矩形、圓角矩形、橢圓)的繪製與填充，更多集合圖形或路徑的描繪要使用 DrawGeometry() 和 FillGeometry()。

既然能繪製更複雜的圖形，當然也能繪製基本圖形，先試下使用 DrawGeometry()、FillGeometry() 實現矩形、圓角矩形和橢圓。

方法的參數是 ID2D1Geometry 介面，ID2D1RectangleGeometry、ID2D1RoundedRectangleGeometry、ID2D1EllipseGeometry 都是它的子介面。
ID2D1Factory 提供了實現這三個介面的方法，從 D2DFactory() 可擷取 ID2D1Factory 介面。

測試代碼：

uses Direct2D, D2D1;procedure TForm1.FormPaint(Sender: TObject);var  cvs: TDirect2DCanvas;  fPt: TD2DPoint2f;  fLeft,fTop: Single;  iEllipse: ID2D1EllipseGeometry;  iRectangle: ID2D1RectangleGeometry;  iRoundedRectangle: ID2D1RoundedRectangleGeometry;  iFactory: ID2D1Factory;begin  fPt := D2D1PointF(ClientWidth / 2, ClientHeight / 2);  fLeft := ClientWidth / 4;  fTop := ClientHeight / 4;  iFactory := D2DFactory();  iFactory.CreateRectangleGeometry(D2D1RectF(fLeft, fTop, fLeft*3, fTop*3), iRectangle);  iFactory.CreateRoundedRectangleGeometry(D2D1RoundedRect(D2D1RectF(fLeft, fTop, fLeft*3, fTop*3), 32, 32), iRoundedRectangle);  iFactory.CreateEllipseGeometry(D2D1Ellipse(fPt, fLeft, fTop), iEllipse);  cvs := TDirect2DCanvas.Create(Canvas, ClientRect);  cvs.BeginDraw;  cvs.Pen.Color := clRed;  cvs.Brush.Color := clBlack;  cvs.FillGeometry(iRectangle);  cvs.Brush.Color := clGreen;  cvs.FillGeometry(iRoundedRectangle);  cvs.Brush.Color := clBlue;  cvs.FillGeometry(iEllipse);  cvs.DrawGeometry(iRectangle);  cvs.DrawGeometry(iRoundedRectangle);  cvs.DrawGeometry(iEllipse);  cvs.EndDraw;  cvs.Free;end;procedure TForm1.FormResize(Sender: TObject);begin  Repaint;end;