再学 GDI+[95]: TGPImage(15) 颜色的旋转变换

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:

---

代码文件:

---

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