GdiPlus[47]: IGPMatrix 矩阵(二)

IGPMatrix 的属性与方法:

---

//方法

IGPMatrix.Reset;              { 重置 Matrix 得到单位矩阵(斜对角线是1其他是0) }

IGPMatrix.Translate();        { 平移 }

IGPMatrix.Scale();            { 放缩 }

IGPMatrix.Rotate();           { 旋转(沿(0,0)点, 顺时针) }

IGPMatrix.RotateAt();         { 沿指定点, 顺时针旋转 }

IGPMatrix.Shear();            { 剪切(或叫错切、斜切) }

IGPMatrix.Invert;             { 反转 }

IGPMatrix.Multiply();         { 与指定的 Matrix 相乘 }

IGPMatrix.TransformPoint();   { 对指定点应用此 Matrix 变换 }

IGPMatrix.TransformPoints();  { 对点数组应用此 Matrix 变换 }

IGPMatrix.TransformVector();  { 对指定点应用此 Matrix 变换中的缩放和旋转变换 }

IGPMatrix.TransformVectors(); { 对点数组应用此 Matrix 变换中的缩放和旋转变换 }

IGPMatrix.SetElements();      { 设置 Matrix 各元素 }

IGPMatrix.Clone;              { 克隆副本 }

IGPMatrix.Equals();           { 判断是否相等 }



//属性

IGPMatrix.Elements;           { 获取 Matrix 各元素构成的数组 }

IGPMatrix.OffsetX;            { 获取 Matrix.Elements.DX }

IGPMatrix.OffsetY;            { 获取 Matrix.Elements.DY }

IGPMatrix.IsInvertible;       { 判断 Matrix 是否可逆转 }

IGPMatrix.IsIdentity;         { 判断 Matrix 是否是单位矩阵(斜对角线是1其他是0) }


 
   

下面的例子用到了其中的 Reset、Translate、Scale、Rotate、Shear、Invert 方法:

---

代码:

---

unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls;



type

  TForm1 = class(TForm)

    Button1: TButton;

    Button2: TButton;

    Button3: TButton;

    Button4: TButton;

    Button5: TButton;

    Button6: TButton;

    Memo1: TMemo;

    procedure FormCreate(Sender: TObject);

    procedure FormPaint(Sender: TObject);

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

    procedure Button3Click(Sender: TObject);

    procedure Button4Click(Sender: TObject);

    procedure Button5Click(Sender: TObject);

    procedure Button6Click(Sender: TObject);



  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



uses

  GdiPlus;



var

  Matrix: IGPMatrix;



//用字符串的形式返回 Matrix 数据, 用于查看

function ViewMatrix(Matrix: IGPMatrix): string;

const

  fmt = '%f'#9'%f'#9'0'#13#10#13#10'%f'#9'%f'#9'0'#13#10#13#10'%f'#9'%f'#9'1';

begin

  Result := Format(fmt, [Matrix.Elements.M11,

                         Matrix.Elements.M12,

                         Matrix.Elements.M21,

                         Matrix.Elements.M22,

                         Matrix.Elements.DX,

                         Matrix.Elements.DY]);

end;



//初识化

procedure TForm1.FormCreate(Sender: TObject);

begin

  Button1.Caption := '重置 (Reset)';

  Button2.Caption := '反转 (Invert)';

  Button3.Caption := '平移 (Translate)';

  Button4.Caption := '比例 (Scale)';

  Button5.Caption := '旋转 (Rotate)';

  Button6.Caption := '错切 (Shear)';

  Matrix := TGPMatrix.Create;

end;



//绘图

procedure TForm1.FormPaint(Sender: TObject);

var

  Image: IGPImage;

  Graphics: IGPGraphics;

  Rect: TGPRect;

begin

  Image := TGPImage.Create('C:\GdiPlusImg\Apple.gif');

  Rect.Initialize(20, 20, 80, 80);

  Graphics := TGPGraphics.Create(Handle);

  Graphics.MultiplyTransform(Matrix);

  Graphics.DrawImage(Image, Rect);

  Graphics.DrawRectangle(TGPPen.Create($FFFF0000, 2), Rect);

end;



//重置到单位矩阵

procedure TForm1.Button1Click(Sender: TObject);

begin

  Matrix.Reset;

  Memo1.Text := ViewMatrix(Matrix);

  Repaint;

end;



//反转变换

procedure TForm1.Button2Click(Sender: TObject);

begin

  Matrix.Invert;

  Memo1.Text := ViewMatrix(Matrix);

  Repaint;

end;



//平移变换

procedure TForm1.Button3Click(Sender: TObject);

begin

  Matrix.Translate(1.5, 3);

  Memo1.Text := ViewMatrix(Matrix);

  Repaint;

end;



//比例变换

procedure TForm1.Button4Click(Sender: TObject);

begin

  Matrix.Scale(0.75, 1.5);

  Memo1.Text := ViewMatrix(Matrix);

  Repaint;

end;



//旋转变换

procedure TForm1.Button5Click(Sender: TObject);

begin

  Matrix.Rotate(15);

  Memo1.Text := ViewMatrix(Matrix);

  Repaint;

end;



//错切变换

procedure TForm1.Button6Click(Sender: TObject);

begin

  Matrix.Shear(0.2, 0.5);

  Memo1.Text := ViewMatrix(Matrix);

  Repaint;

end;



end.


 
   

窗体:

---

object Form1: TForm1

  Left = 0

  Top = 0

  Caption = 'Form1'

  ClientHeight = 200

  ClientWidth = 377

  Color = clBtnFace

  Font.Charset = DEFAULT_CHARSET

  Font.Color = clWindowText

  Font.Height = -11

  Font.Name = 'Tahoma'

  Font.Style = []

  OldCreateOrder = False

  OnCreate = FormCreate

  OnPaint = FormPaint

  PixelsPerInch = 96

  TextHeight = 13

  object Button1: TButton

    Left = 185

    Top = 8

    Width = 90

    Height = 25

    Caption = 'Button1'

    TabOrder = 0

    OnClick = Button1Click

  end

  object Button2: TButton

    Left = 281

    Top = 8

    Width = 90

    Height = 25

    Caption = 'Button2'

    TabOrder = 1

    OnClick = Button2Click

  end

  object Button3: TButton

    Left = 185

    Top = 39

    Width = 90

    Height = 25

    Caption = 'Button3'

    TabOrder = 2

    OnClick = Button3Click

  end

  object Button4: TButton

    Left = 281

    Top = 39

    Width = 90

    Height = 25

    Caption = 'Button4'

    TabOrder = 3

    OnClick = Button4Click

  end

  object Button5: TButton

    Left = 185

    Top = 70

    Width = 90

    Height = 25

    Caption = 'Button5'

    TabOrder = 4

    OnClick = Button5Click

  end

  object Memo1: TMemo

    Left = 185

    Top = 111

    Width = 181

    Height = 81

    Lines.Strings = (

      'Memo1')

    TabOrder = 5

  end

  object Button6: TButton

    Left = 281

    Top = 70

    Width = 90

    Height = 25

    Caption = 'Button6'

    TabOrder = 6

    OnClick = Button6Click

  end

end