常見圖象格式轉換技術
作者:lyboy99
e-mail:lyboy99@sina.com  
url: http://hnh.126.com

給大家提供幾個常用的圖象格式轉換方法和其轉換函數
希望可以對你有幫助
1. ICO圖標轉換BMP格式
2. 32x32 BMP格式圖象轉換為 ICO格式
3.轉換BMP->JPEG文件格式
4.JPEG 轉換為BMP函數
5.Bmp轉換為JPEG文件格式函數
-------------------------------------------------------------------------------------------------------------------------
1.Chinese : ICO圖標轉換BMP格式
English :(Conversion from ICO to BMP)
--------------------------------------------------------

  var
    Icon   : TIcon;
    Bitmap : TBitmap;
  begin
     Icon   := TIcon.Create;
     Bitmap := TBitmap.Create;
     Icon.LoadFromFile('c:picture.ico');
     Bitmap.Width := Icon.Width;
     Bitmap.Height := Icon.Height;
     Bitmap.Canvas.Draw(0, 0, Icon );
     Bitmap.SaveToFile('c:picture.bmp');
     Icon.Free;
     Bitmap.Free;
===================================
2.Chinese: 32x32 BMP格式圖象轉換為 ICO格式
English :32x32 bit Bitmaps to ICO's
-----------------------------------
unit main;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls,
  Forms,Dialogs,ExtCtrls, StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Image1: TImage;
    Image2: TImage;
    PRocedure Button1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.Button1Click(Sender: TObject);
var winDC, srcdc, destdc : HDC;
    oldBitmap : HBitmap;
    iinfo : TICONINFO;
begin
    GetIconInfo(Image1.Picture.Icon.Handle, iinfo);

    WinDC := getDC(handle);
    srcDC := CreateCompatibleDC(WinDC);
    destDC := CreateCompatibleDC(WinDC);
    oldBitmap := SelectObject(destDC, iinfo.hbmColor);
    oldBitmap := SelectObject(srcDC, iinfo.hbmMask);

    BitBlt(destdc, 0, 0, Image1.picture.icon.width,
     Image1.picture.icon.height,
           srcdc, 0, 0, SRCPAINT);
    Image2.picture.bitmap.handle := SelectObject(destDC, oldBitmap);
    DeleteDC(destDC);
    DeleteDC(srcDC);
    DeleteDC(WinDC);

 image2.Picture.Bitmap.savetofile(ExtractFilePath(application.ExeName)
          + 'myfile.bmp');
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  image1.picture.icon.loadfromfile('c:myicon.ico');
end;

end.
==================================================================
3. Chinese:轉換BMP->JPEG文件格式
Englsh:convert the bitmap into a JPEG file format
------------------------------------------------------------------
var
  MyJpeg: TJpegImage;
  Image1: TImage;
begin
  Image1:= TImage.Create;
  MyJpeg:= TJpegImage.Create;
  Image1.LoadFromFile('TestImage.BMP');  // 讀取Bitmap文件
  MyJpeg.Assign(Image1.Picture.Bitmap); 
object
  MyJpeg.SaveToFile('MyJPEGImage.JPG'); //保存JPEG
end;

--------------------------------------------------------------------
4.JPEG 轉換為BMP函數

procedure Jpg2Bmp(const source,dest:string);
var
  MyJpeg: TJpegImage;
  bmp: Tbitmap;
begin
bmp:=tbitmap.Create;
MyJpeg:= TJpegImage.Create;
try
  myjpeg.LoadFromFile(source);
  bmp.Assign(myjpeg);
  bmp.SaveToFile(dest);
finally
  bmp.free;
  myjpeg.Free;
end;
end;

----------------------------------------------------------
5.Bmp轉換為JPEG文件格式函數
----------------------------------------------------------
procedure Bmp2Jpg(const source,dest:string;const scale:byte);
var
  MyJpeg: TJpegImage;
  Image1: TImage;
begin
Image1:= TImage.Create(application);
MyJpeg:= TJpegImage.Create;
try
  Image1.Picture.Bitmap.LoadFromFile(source);
  MyJpeg.Assign(Image1.Picture.Bitmap);
  MyJpeg.CompressionQuality:=scale;
  MyJpeg.Compress;
  MyJpeg.SaveToFile(dest);
finally
  image1.free;
  myjpeg.Free;
end;
end;
-----------------------------------------------------------------------