颜色的旋转变换

文章出处：http://www.cnblogs.com/del/archive/2008/07/06/1237038.html

我通过做此例同时证实了 GDI+ 可以直接显示 png、gif、tif 格式的透明图片.

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//红色与绿色绕蓝色旋转(r 是弧度)

ColorMatrix: TColorMatrix = (

  (Cos(r),   Sin(r), 0.0,  0.0,  0.0),

  (-Sin(r),  Cos(r), 0.0,  0.0,  0.0),

  (0.0,      0.0,    1.0,  0.0,  0.0),

  (0.0,      0.0,    0.0,  1.0,  0.0),

  (0.0,      0.0,    0.0,  0.0,  1.0));



//绿色与蓝色绕红色旋转(r 是弧度)

ColorMatrix: TColorMatrix = (

  (0.0,  0.0,     0.0,     0.0,  0.0),

  (0.0,  Cos(r),  Sin(r),  0.0,  0.0),

  (0.0,  -Sin(r), Cos(r),  0.0,  0.0),

  (0.0,  0.0,     0.0,     1.0,  0.0),

  (0.0,  0.0,     0.0,     0.0,  1.0));



//红色与蓝色绕绿色旋转(r 是弧度)

ColorMatrix: TColorMatrix = (

  (Cos(r),   0.0,  Sin(r),  0.0,  0.0),

  (-Sin(r),  0.0,  Cos(r),  0.0,  0.0),

  (0.0,      0.0,  1.0,     0.0,  0.0),

  (0.0,      0.0,  0.0,     1.0,  0.0),

  (0.0,      0.0,  0.0,     0.0,  1.0));


  
    

本例效果图:

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代码文件:

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unit Unit1;



interface



uses

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

  Dialogs, StdCtrls, ComCtrls, ExtCtrls;



type

  TForm1 = class(TForm)

    TrackBar1: TTrackBar;

    RadioGroup1: TRadioGroup;

    procedure FormCreate(Sender: TObject);

    procedure FormPaint(Sender: TObject);

    procedure CheckBox1Click(Sender: TObject);

    procedure TrackBar1Change(Sender: TObject);

    procedure RadioGroup1Click(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



uses GDIPOBJ, GDIPAPI;



const

  Matrix: TColorMatrix = (

    (1.0, 0.0, 0.0, 0.0, 0.0),

    (0.0, 1.0, 0.0, 0.0, 0.0),

    (0.0, 0.0, 1.0, 0.0, 0.0),

    (0.0, 0.0, 0.0, 1.0, 0.0),

    (0.0, 0.0, 0.0, 0.0, 1.0));



procedure TForm1.FormCreate(Sender: TObject);

begin

  TrackBar1.Height := 23;

  TrackBar1.ShowSelRange := False;

  TrackBar1.Min := -180;

  TrackBar1.Max := 180;

  TrackBar1.Position := 0;



  with RadioGroup1.Items do

  begin

    Add('红色与绿色绕蓝色旋转');

    Add('红色与蓝色绕绿色旋转');

    Add('绿色与蓝色绕红色旋转');

  end;

  RadioGroup1.ItemIndex := 0;



  DoubleBuffered := True;

end;



procedure TForm1.FormPaint(Sender: TObject);

var

  g: TGPGraphics;

  img: TGPImage;

  ImageAttributes: TGPImageAttributes;

  r: Single;

  ColorMatrix: TColorMatrix;

begin

  g := TGPGraphics.Create(Canvas.Handle);

  img := TGPImage.Create('c:\temp\test.png');



  ImageAttributes := TGPImageAttributes.Create;



  r := TrackBar1.Position * pi / 180; {根据角度算出弧度}

  ColorMatrix := Matrix;              {回复默认值}

  case RadioGroup1.ItemIndex of

    0: begin {红色与绿色绕蓝色旋转}

      ColorMatrix[0,0] := Cos(r);

      ColorMatrix[0,1] := Sin(r);

      ColorMatrix[1,0] := -Sin(r);

      ColorMatrix[1,1] := Cos(r);

    end;

    1: begin {红色与蓝色绕绿色旋转}

      ColorMatrix[0,0] := Cos(r);

      ColorMatrix[0,2] := Sin(r);

      ColorMatrix[2,0] := -Sin(r);

      ColorMatrix[2,2] := Cos(r);

    end;

    2: begin {绿色与蓝色绕红色旋转}

      ColorMatrix[1,1] := Cos(r);

      ColorMatrix[1,2] := Sin(r);

      ColorMatrix[2,1] := -Sin(r);

      ColorMatrix[2,2] := Cos(r);

    end;

  end;



  ImageAttributes.SetColorMatrix(ColorMatrix);



  g.DrawImage(img,

              MakeRect(4, 4, img.GetWidth, img.GetHeight),

              0,

              0,

              img.GetWidth,

              img.GetHeight,

              UnitPixel,

              ImageAttributes

              );



  ImageAttributes.Free;

  img.Free;

  g.Free;

end;



procedure TForm1.RadioGroup1Click(Sender: TObject);

begin

  Repaint;

end;



procedure TForm1.TrackBar1Change(Sender: TObject);

begin

  Repaint;

end;



procedure TForm1.CheckBox1Click(Sender: TObject);

begin

  Repaint;

end;



end.


  
    

窗体文件:

---

object Form1: TForm1

  Left = 0

  Top = 0

  Caption = 'Form1'

  ClientHeight = 290

  ClientWidth = 208

  Color = clBtnFace

  Font.Charset = DEFAULT_CHARSET

  Font.Color = clWindowText

  Font.Height = -11

  Font.Name = 'Tahoma'

  Font.Style = []

  OldCreateOrder = False

  Position = poDesktopCenter

  OnCreate = FormCreate

  OnPaint = FormPaint

  PixelsPerInch = 96

  TextHeight = 13

  object TrackBar1: TTrackBar

    Left = 3

    Top = 170

    Width = 202

    Height = 22

    TabOrder = 0

    OnChange = TrackBar1Change

  end

  object RadioGroup1: TRadioGroup

    Left = 8

    Top = 198

    Width = 190

    Height = 83

    Caption = 'RadioGroup1'

    TabOrder = 1

    OnClick = RadioGroup1Click

  end

end