擷取程式大表徵圖方案

擷取檔案的表徵圖

在win7的檔案狀態列中能顯示最大256x256的程式應用表徵圖。

在XP下測試無法正常擷取256的巨型表徵圖

Shell提供了一個函數 SHGetFileInfo 可以擷取檔案資訊，在使用此函數有需要處理Icon控制代碼的釋放（DestroyIcon），否則每次會有3個GDI控制代碼泄漏問題。

使用此函數後會一次性產生47個GDI控制代碼，只要Icon控制代碼釋放，就不會再增長。現在還未找到處理多處理啊的調用所產生的這些GDI控制代碼。

 

注意：

  GHGetFileInfo 和 DestoryIcon 成對調用。

 

測試環境

   Win7 and XE2

 

 

View Code

unit Unit4;interfaceuses  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;type  TForm4 = class(TForm)    btn1: TButton;    procedure btn1Click(Sender: TObject);  private    { Private declarations }  public    { Public declarations }  end;var  Form4: TForm4;implementationuses  ShellApi, Commctrl, ShlObj;{$R *.dfm}const  SHIL_LARGE     = $00;  //The image size is normally 32x32 pixels. However, if the Use large icons option is selected from the Effects section of the Appearance tab in Display Properties, the image is 48x48 pixels.  SHIL_SMALL     = $01;  //These images are the Shell standard small icon size of 16x16, but the size can be customized by the user.  SHIL_EXTRALARGE= $02;  //These images are the Shell standard extra-large icon size. This is typically 48x48, but the size can be customized by the user.  SHIL_SYSSMALL  = $03;  //These images are the size specified by GetSystemMetrics called with SM_CXSMICON and GetSystemMetrics called with SM_CYSMICON.  SHIL_JUMBO     = $04;  //Windows Vista and later. The image is normally 256x256 pixels.  IID_IImageList: TGUID= '{46EB5926-582E-4017-9FDF-E8998DAA0950}';function GetImageListSH(SHIL_FLAG:Cardinal): HIMAGELIST;type  _SHGetImageList = function (iImageList: integer; const riid: TGUID; var ppv: Pointer): hResult; stdcall;var  Handle        : THandle;  SHGetImageList: _SHGetImageList;begin  Result:= 0;  Handle:= LoadLibrary('Shell32.dll');  if Handle<> S_OK then  try    SHGetImageList:= GetProcAddress(Handle, PChar(727));    if Assigned(SHGetImageList) and (Win32Platform = VER_PLATFORM_WIN32_NT) then      SHGetImageList(SHIL_FLAG, IID_IImageList, Pointer(Result));  finally    FreeLibrary(Handle);  end;end;procedure GetIconFromFile(aFile:String; var aIcon : TIcon;SHIL_FLAG:Cardinal);var  aImgList    : HIMAGELIST;  SFI         : TSHFileInfo;Begin    //Get the index of the imagelist    SHGetFileInfo(PChar(aFile), FILE_ATTRIBUTE_NORMAL, SFI,                 SizeOf( TSHFileInfo ), SHGFI_ICON or SHGFI_LARGEICON or SHGFI_SHELLICONSIZE or                 SHGFI_SYSICONINDEX or SHGFI_TYPENAME or SHGFI_DISPLAYNAME );    if not Assigned(aIcon) then    aIcon:= TIcon.Create;    //get the imagelist    aImgList:= GetImageListSH(SHIL_FLAG);    //extract the icon handle    aIcon.Handle:= ImageList_GetIcon(aImgList, Pred(ImageList_GetImageCount(aImgList)), ILD_NORMAL);    DestroyIcon(SFI.hIcon);    ImageList_Destroy(aImgList);end;procedure TForm4.btn1Click(Sender: TObject);var  icon:TIcon;begin  icon := TIcon.Create;  try    GetIconFromFile(ParamStr(0), icon, SHIL_JUMBO);    canvas.Draw(10, 100, icon);    Canvas.TextOut(10, 80, inttostr(icon.Handle));    GetIconFromFile(ParamStr(0), icon, SHIL_SYSSMALL);    canvas.Draw(10+ 280 , 100, icon);    Canvas.TextOut(10 + 280, 80, inttostr(icon.Handle));    GetIconFromFile(ParamStr(0), icon, SHIL_EXTRALARGE);    canvas.Draw(10+ 280 + 150 , 100, icon);    Canvas.TextOut(10+ 280 + 150, 80, inttostr(icon.Handle));    GetIconFromFile(ParamStr(0), icon, SHIL_LARGE);    canvas.Draw(10+ 280 + 150 +50 , 100, icon);    Canvas.TextOut(10+ 280 + 150 +50, 80, inttostr(icon.Handle));    GetIconFromFile(ParamStr(0), icon, SHIL_SMALL);    canvas.Draw(10+ 280 + 150 +50 +40, 100, icon);    Canvas.TextOut(10+ 280 + 150 +50 +40, 80, inttostr(icon.Handle));  finally    icon.Free;  end;end;end.

 

詳細內容可以看

http://www.codeproject.com/Articles/2532/Obtaining-and-managing-file-and-folder-icons-using

有比較詳細的使用說明