Direct2D (7) : 空间变换

{相关方法} 

TDirect2DCanvas.RenderTarget.SetTransform();

TDirect2DCanvas.RenderTarget.GetTransform();



{相关结构}

TD2DMatrix3x2F (或D2D_MATRIX_3X2_F) //因第三列的值在这里是固定的(0,0,1)，所以这里用的是 3*2 的矩阵；该结构重载了 * 运算符



{TD2DMatrix3x2FHelper 为 TD2DMatrix3x2F 提供的方法(多为 class 方法)}

Identity();     //初始化 TD2DMatrix3x2F，默认值：_11、_22 为 1.0，其它是 0

Translation();  //平移

Scale();        //放缩

Rotation();     //旋转

Skew();         //斜切

Determinant();  //计算行列式

IsInvertible(); //是否可逆

Invert();       //逆向运算

SetProduct();   //乘



{相关全局函数}

D2D1MakeRotateMatrix();   //旋转

D2D1MakeSkewMatrix();     //斜切

D2D1IsMatrixInvertible(); //是否可逆

D2D1InvertMatrix();       //逆向运算

---

测试代码：

---

uses Direct2D, D2D1;



procedure TForm1.FormPaint(Sender: TObject);

var

  cvs: TDirect2DCanvas;

  pts: array[0..2] of TPoint;

  matrix: TD2DMatrix3x2F;

begin

  pts[0] := Point(ClientWidth div 2, ClientHeight div 2);

  pts[1] := Point(ClientWidth div 5, ClientHeight div 2);

  pts[2] := Point(ClientWidth div 2, ClientHeight div 5);



  cvs := TDirect2DCanvas.Create(Canvas, ClientRect);

  cvs.BeginDraw;

  cvs.Brush.Style := bsClear;



  {原始}

  cvs.Pen.Color := clSilver;

  cvs.Pen.Width := 9;

  cvs.Polygon(pts);



  cvs.Pen.Width := 2;



  {平移}

  matrix := TD2DMatrix3x2F.Translation(90, 50);

  cvs.RenderTarget.SetTransform(matrix);

  cvs.Pen.Color := clRed;

  cvs.Polygon(pts);



  {放缩}

  matrix := TD2DMatrix3x2F.Scale(1.5, 0.5, pts[0]);

  cvs.RenderTarget.SetTransform(matrix);

  cvs.Pen.Color := clBlue;

  cvs.Polygon(pts);



  {旋转}

  matrix := TD2DMatrix3x2F.Rotation(90, pts[0]);

//  D2D1MakeRotateMatrix(90, pts[0], @matrix); //同上一行

  cvs.RenderTarget.SetTransform(matrix);

  cvs.Pen.Color := clGreen;

  cvs.Polygon(pts);



  {斜切}

  matrix := TD2DMatrix3x2F.Skew(60, 0, pts[0]);

//  D2D1MakeSkewMatrix(60, 10, pts[0], @matrix); //同上一行

  cvs.RenderTarget.SetTransform(matrix);

  cvs.Pen.Color := clPurple;

  cvs.Polygon(pts);



  cvs.EndDraw;

  cvs.Free;

end;



procedure TForm1.FormResize(Sender: TObject);

begin

  Repaint;

end;

---

效果图：

---