dll.dpr

一个关于Delphi获取摄像头视频的例子

library Dll;

{ Important note about DLL memory management: ShareMem must be the
  first unit in your library's USES clause AND your project's (select
  Project-View Source) USES clause if your DLL exports any procedures or
  functions that pass strings as parameters or function results. This
  applies to all strings passed to and from your DLL--even those that
  are nested in records and classes. ShareMem is the interface unit to
  the BORLNDMM.DLL shared memory manager, which must be deployed along
  with your DLL. To avoid using BORLNDMM.DLL, pass string information
  using PChar or ShortString parameters. }

{$IMAGEBASE $57800000}

uses
  Windows, madCodeHook;

var
  capCreateCaptureWindowANext: function(
    lpszWindowName: PChar;
    dwStyle: DWord;
    x, y: Integer;
    nWidth, nHeight: Integer;
    hwndParent: THandle;
    nID: Integer): THandle; stdcall;

  capCreateCaptureWindowWNext: function(
    lpszWindowName: PWideChar;
    dwStyle: DWord;
    x, y: Integer;
    nWidth, nHeight: Integer;
    hwndParent: THandle;
    nID: Integer): THandle; stdcall;


function IsAllowed(lpszWindowNameA: PChar;lpszWindowNameW: PWideChar): boolean;
var
  FileName: array[0..1023] of char;
begin
  GetModuleFileName(0, FileName, sizeof(FileName));
  if lpszWindowNameA<>nil then
  Result := MessageBox(0, Pchar('程序"' + FileName + '"欲调用API函数capCreateCaptureWindowA创建摄像头窗口进行捕获,摄像头窗口名称:"'+lpszWindowNameA+'"是否允许?'), '信息', MB_ICONQUESTION + MB_YESNO + MB_TOPMOST) = ID_YES
  else
  Result := MessageBox(0, Pchar('程序"' + FileName + '"欲调用API函数capCreateCaptureWindowW创建摄像头窗口进行捕获,摄像头窗口名称:"'+WideCharToString(lpszWindowNameW)+'"是否允许?'), '信息', MB_ICONQUESTION + MB_YESNO + MB_TOPMOST) = ID_YES;
end;

function capCreateCaptureWindowACallback(
  lpszWindowName: PChar;
  dwStyle: DWord;
  x, y: Integer;
  nWidth, nHeight: Integer;
  hwndParent: THandle;
  nID: Integer): THandle; stdcall;
begin
  if not IsAllowed(lpszWindowName,nil) then
  begin
    // the user doesn't like this capCreateCaptureWindow call, so we block it
    result := 0;
    SetLastError(ERROR_ACCESS_DENIED);
  end else
  begin
    // this capCreateCaptureWindow call is okay
    result := capCreateCaptureWindowANext(lpszWindowName,
      dwStyle,
      x, y,
      nWidth, nHeight,
      hwndParent,
      nID);
    // capCreateCaptureWindow hooks are used very often, so to be sure we renew the hook
    RenewHook(@capCreateCaptureWindowANext);
  end;
end;

function capCreateCaptureWindowWCallback(
  lpszWindowName: PWideChar;
  dwStyle: DWord;
  x, y: Integer;
  nWidth, nHeight: Integer;
  hwndParent: THandle;
  nID: Integer): THandle; stdcall;
begin
  if not IsAllowed(nil,lpszWindowName) then
  begin
    // the user doesn't like this capCreateCaptureWindow call, so we block it
    result := 0;
    SetLastError(ERROR_ACCESS_DENIED);
  end
  else
  begin
    // this capCreateCaptureWindow call is okay
    result := capCreateCaptureWindowWNext(lpszWindowName,
      dwStyle,
      x, y,
      nWidth, nHeight,
      hwndParent,
      nID);
    // capCreateCaptureWindow hooks are used very often, so to be sure we renew the hook
    RenewHook(@capCreateCaptureWindowWNext);
  end;
end;

begin
  HookAPI('AVICAP32.dll', 'capCreateCaptureWindowA', @capCreateCaptureWindowACallback, @capCreateCaptureWindowANext);
  HookAPI('AVICAP32.dll', 'capCreateCaptureWindowW', @capCreateCaptureWindowWCallback, @capCreateCaptureWindowWNext);
end.