6

我添加了一个比原始插件晚 3 年发布的代码，但它仍然返回错误...

代码是直截了当的恕我直言......但我仍然很可能错过某些方面......

请参阅此代码：

{
        nsScreenshot NSIS Plugin
        (c) 2003: Leon Zandman (leon@wirwar.com)

        Re-compiled by: Linards Liepins (linards.liepins@gmail.com)
        Code by: http://www.delphitricks.com/source-code/forms/make_a_desktop_screenshot.html
        (e) 2012.
}
library nsScreenshot;

uses
  nsis in './nsis.pas',
  Windows,
  Jpeg,
  graphics,
  types,
  SysUtils;

const
  USER32 = 'user32.dll';

type
  HWND = type LongWord;
  {$EXTERNALSYM HWND}
  HDC = type LongWord;
  {$EXTERNALSYM HDC}
  BOOL = LongBool;
  {$EXTERNALSYM BOOL}

{$EXTERNALSYM GetDesktopWindow}
function GetDesktopWindow: HWND; stdcall; external USER32 name 'GetDesktopWindow';
{$EXTERNALSYM GetWindowDC}
function GetWindowDC(hWnd: HWND): HDC; stdcall; external USER32 name 'GetWindowDC';
{$EXTERNALSYM GetWindowRect}
function GetWindowRect(hWnd: HWND; var lpRect: TRect): BOOL; stdcall; external USER32 name 'GetWindowRect';
{$EXTERNALSYM ReleaseDC}
function ReleaseDC(hWnd: HWND; hDC: HDC): Integer; stdcall; external user32 name 'ReleaseDC';

function GetScreenshot(Filename: string; Hwnd: HWND; var Width: integer; var Height: integer): boolean; forward;
function ScreenShot(Bild: TBitMap; hWnd: HWND): boolean; forward;


function Grab_FullScreen(hwndParent: HWND; string_size: integer; variables: PChar; stacktop: pointer):integer; cdecl;
var
  buf: array[0..1024] of char;
  W,H: integer;
begin
  Result := 0;
  // set up global variables
  Init(hwndParent,string_size,variables,stacktop);

  // Get filename to save to
  PopString;//(@buf);

  // Get a full-screen screenshot
  if GetScreenShot(buf,GetDesktopWindow,W,H) then begin
    // Everything went just fine...

    // Push image dimensions onto stack
    PushString(PChar(IntToStr(H)));
    PushString(PChar(IntToStr(W)));

    // Push result onto stack
    PushString(PChar('ok'));
    Result := 1;
  end else begin
    // Something went wrong...
    PushString(PChar('error'));
  end;
end;

function Grab(hwndParent: HWND; string_size: integer; variables: PChar; stacktop: pointer):integer; cdecl;
var
  buf: array[0..1024] of char;
  grabWnd: HWND;
  Filename: string;
  W,H: integer;
begin
  Result := 0;
  // set up global variables
  Init(hwndParent,string_size,variables,stacktop);

  try
    // Get filename to save to
    PopString;//(@buwf);
    Filename := buf;

    // Get window handle of window to grab
    PopString;//(@buf);
    grabWnd := StrToInt(buf);
  except
    PushString(PChar('error'));
    exit;
  end;

  // Get screenshot of parent windows (NSIS)
  if GetScreenShot(Filename,grabWnd,W,H) then begin
    // Everything went just fine...

    // Push image dimensions onto stack
    PushString(PChar(IntToStr(H)));
    PushString(PChar(IntToStr(W)));

    // Push result onto stack
    PushString(PChar('ok'));
    Result := 1;
  end else begin
    // Something went wrong...
    PushString(PChar('error'));
  end;
end;

function GetScreenshot(Filename: string; Hwnd: HWND; var Width: integer; var Height: integer): boolean;
var
  bmp: TBitmap;
begin
  Result := false;

  // Get screenshot
  bmp := TBitmap.Create;
  try
    try
      if ScreenShot(bmp,Hwnd) then begin
        Width  := bmp.Width;
        Height := bmp.Height;
        bmp.SaveToFile(Filename);
        Result := true;
      end;
    except
      // Catch exception and do nothing (function return value remains 'false')
    end;
  finally
    bmp.Free;
  end;
end;

function ScreenShot(Bild: TBitMap; hWnd: HWND): boolean;
var
  c: TCanvas;
  r, t: TRect;
  h: THandle;
begin
  Result := false;

  c := TCanvas.Create;
  c.Handle := GetWindowDC(GetDesktopWindow);

  h := hWnd;
  if h <> 0 then begin
    GetWindowRect(h, t);
    try
      r := Rect(0, 0, t.Right - t.Left, t.Bottom - t.Top);
      Bild.Width  := t.Right - t.Left;
      Bild.Height := t.Bottom - t.Top;
      Bild.Canvas.CopyRect(r, c, t);
    finally
      ReleaseDC(0, c.Handle);
      c.Free;
    end;
    Result := true;
  end;
end;

function GetScreenToFile(FileName: string; Quality: Word; Percent: Word): boolean;
var
  Bmp: TBitmap;
  Jpg: TJpegImage;
begin
  Bmp := TBitmap.Create;
  Jpg := TJpegImage.Create;
  try
    Bmp.Width := GetDeviceCaps(GetDc(0), 8) * Percent div 100;
    Bmp.Height := GetDeviceCaps(GetDc(0), 10) * Percent div 100;
    SetStretchBltMode(Bmp.Canvas.Handle, HALFTONE);
    StretchBlt(Bmp.Canvas.Handle, 0, 0, Bmp.Width, Bmp.Height, GetDc(0), 0, 0, GetDeviceCaps(GetDc(0), 8), GetDeviceCaps(GetDc(0), 10), SRCCOPY);
    Jpg.Assign(Bmp);
    Jpg.CompressionQuality := Quality;
    Jpg.SaveToFile(FileName);
  finally
    Jpg.free;
    Bmp.free;
  end;
end;

function ScreenToFile(hwndParent: HWND; string_size: integer; variables: PChar; stacktop: pointer):integer; cdecl;
var
  buf: array[0..1024] of char;
  grabWnd: HWND;
  Filename: string;
  W,H: integer;
begin
  Result := 0;
  Init(hwndParent,string_size,variables,stacktop);
  try
    PopString;
    Filename := buf;
    PopString;
    grabWnd := StrToInt(buf);
  except
    PushString(PChar('error'));
    exit;
  end;
  if GetScreenToFile(Filename,W,H) then
  begin
    PushString(PChar('ok'));
    Result := 1;
  end else
  begin
    PushString(PChar('error'));
  end;
end;

  //ScreenToFile('SHOT.JPG', 50, 70);

exports Grab_FullScreen,
        Grab,
        ScreenToFile;

begin
end.

搜索ScreenToFile。

感谢您的任何意见，。该插件对于安装程序文档生成自动化至关重要。

4

3 回答 3

7

1. NSIS插件核心单元问题：

1.1。关于错误的字符串：

从您自己的答案帖子中得出您正在使用 NSIS 的 ANSI 版本。由于您在 Delphi XE 中编译的库代码中使用了string和Char映射PChar到 Unicode 字符串，因此您在 NSIS 设置应用程序和库之间传递了错误数据。

1.2. 关于核心插件单元的另一种观点：

我检查了您稍作修改的插件核心单元NSIS.pas，并且存在一些问题，这会阻止您的插件正常工作。然而，当我看到这个单元时，我首先想到的是将独立的过程和函数包装到一个类中。这就是我所做的。

1.3. NSIS.pas v2.0：

由于您目前只使用了原始核心单元中的 3 个函数，因此your code我简化了仅使用这些函数的类（还有一个用于显示消息框的额外函数）。所以这里是修改后的插件核心单元的代码。我不是数据操作专家，所以也许可以简化以下代码，但它至少在我测试过的 Delphi XE2 和 Delphi 2009 中有效。这是代码：

unit NSIS;

interface

uses
  Windows, CommCtrl, SysUtils;

type
  PParamStack = ^TParamStack;
  TParamStack = record
    Next: PParamStack;
    Value: PAnsiChar;
  end;
  TNullsoftInstaller = class
  private
    FParent: HWND;
    FParamSize: Integer;
    FParameters: PAnsiChar;
    FStackTop: ^PParamStack;
  public
    procedure Initialize(Parent: HWND; ParamSize: Integer; Parameters: PAnsiChar;
      StackTop: Pointer);
    procedure PushString(const Value: string = '');
    function PopString: string;
    function MessageDialog(const Text, Caption: string; Buttons: UINT): Integer;
  end;

var
  NullsoftInstaller: TNullsoftInstaller;

implementation

procedure TNullsoftInstaller.Initialize(Parent: HWND; ParamSize: Integer;
  Parameters: PAnsiChar; StackTop: Pointer);
begin
  FParent := Parent;
  FParamSize := ParamSize;
  FParameters := Parameters;
  FStackTop := StackTop;
end;

procedure TNullsoftInstaller.PushString(const Value: string = '');
var
  CurrParam: PParamStack;
begin
  if Assigned(FStackTop) then
  begin
    CurrParam := PParamStack(GlobalAlloc(GPTR, SizeOf(TParamStack) + FParamSize));
    StrLCopy(@CurrParam.Value, PAnsiChar(AnsiString(Value)), FParamSize);
    CurrParam.Next := FStackTop^;
    FStackTop^ := CurrParam;
  end;
end;

function TNullsoftInstaller.PopString: string;
var
  CurrParam: PParamStack;
begin
  Result := '';
  if Assigned(FStackTop) then
  begin
    CurrParam := FStackTop^;
    Result := String(PAnsiChar(@CurrParam.Value));
    FStackTop^ := CurrParam.Next;
    GlobalFree(HGLOBAL(CurrParam));
  end;
end;

function TNullsoftInstaller.MessageDialog(const Text, Caption: string;
  Buttons: UINT): Integer;
begin
  Result := MessageBox(FParent, PChar(Text), PChar(Caption), Buttons);
end;

initialization
  NullsoftInstaller := TNullsoftInstaller.Create;
finalization
  if Assigned(NullsoftInstaller) then
    NullsoftInstaller.Free;

end.

1.4. 修改后的插件核心单元的用法：

如您所见，NullsoftInstaller声明了全局变量，它允许您使用我包装过您之前使用过的函数的类。这个变量中的对象实例的使用通过初始化和结束部分被简化，当库被加载和释放时，这个对象实例被创建并分配给这个变量。

所以你唯一需要在你的代码中做的就是NullsoftInstaller像这样使用这个全局变量：

uses
  NSIS;

function ScreenToFile(Parent: HWND; ParamSize: Integer; Parameters: PAnsiChar;
  StackTop: Pointer): Integer; cdecl;
var
  InputString: string;
begin
  Result := 0;

  // this is not necessary, if you keep the NullsoftInstaller object instance 
  // alive (and there's even no reason to free it, since this will be done in 
  // the finalization section when the library is unloaded), so the following
  // statement has no meaning when you won't free the NullsoftInstaller
  if not Assigned(NullsoftInstaller) then
    NullsoftInstaller := TNullsoftInstaller.Create;

  // this has the same meaning as the Init procedure in the original core unit
  NullsoftInstaller.Initialize(Parent, ParamSize, Parameters, StackTop);
  // this is the same as in the original, except that returns a native string
  InputString := NullsoftInstaller.PopString;
  NullsoftInstaller.MessageDialog(InputString, 'PopString Result', 0);
  // and finally the PushString method, this is also the same as original and
  // as well as the PopString supports native string for your Delphi version
  NullsoftInstaller.PushString('ok');
end;

2. Aero 合成窗口截图

这是我尝试的屏幕截图过程，TakeScreenshotin 代码。它需要一个额外的参数DropShadow，当启用 Aero 合成时，它应该截取包括窗口阴影在内的屏幕截图。但是，我找不到一种与将假窗口放在捕获的窗口后面不同的方法来做到这一点。它有一个很大的弱点；有时会发生捕获完成后假窗口未完全显示的情况，因此它会在捕获的窗口周围截取当前桌面的屏幕截图，而不是后面的白色假窗口（尚未显示）。所以设置DropShadow为 True 现在只是在实验阶段。

当DropShadowFalse （没有投影的屏幕截图）时，它可以正常工作。我的猜测是，由于上述 Unicode Delphi 与 ANSI NSIS 问题，您传递了错误的参数。

library nsScreenshot;

uses
  Windows, SysUtils, Types, Graphics, DwmApi, Forms, JPEG, NSIS;

procedure CalcCloseCrop(Bitmap: TBitmap; const BackColor: TColor;
  out CropRect: TRect);
var
  X: Integer;
  Y: Integer;
  Color: TColor;
  Pixel: PRGBTriple;
  RowClean: Boolean;
  LastClean: Boolean;
begin
  LastClean := False;
  CropRect := Rect(Bitmap.Width, Bitmap.Height, 0, 0);
  for Y := 0 to Bitmap.Height-1 do
  begin
    RowClean := True;
    Pixel := Bitmap.ScanLine[Y];
    for X := 0 to Bitmap.Width - 1 do
    begin
      Color := RGB(Pixel.rgbtRed, Pixel.rgbtGreen, Pixel.rgbtBlue);
      if Color <> BackColor then
      begin
        RowClean := False;
        if X < CropRect.Left then
          CropRect.Left := X;
        if X + 1 > CropRect.Right then
          CropRect.Right := X + 1;
      end;
      Inc(Pixel);
    end;
    if not RowClean then
    begin
      if not LastClean then
      begin
        LastClean := True;
        CropRect.Top := Y;
      end;
      if Y + 1 > CropRect.Bottom then
        CropRect.Bottom := Y + 1;
    end;
  end;
  with CropRect do
  begin
    if (Right < Left) or (Right = Left) or (Bottom < Top) or 
      (Bottom = Top) then
    begin
      if Left = Bitmap.Width then
        Left := 0;
      if Top = Bitmap.Height then
        Top := 0;
      if Right = 0 then
        Right := Bitmap.Width;
      if Bottom = 0 then
        Bottom := Bitmap.Height;
    end;
  end;
end;

procedure TakeScreenshot(WindowHandle: HWND; const FileName: string;
  DropShadow: Boolean);
var
  R: TRect;
  Form: TForm;
  Bitmap: TBitmap;
  Target: TBitmap;
  DeviceContext: HDC;
  DesktopHandle: HWND;
  ExtendedFrame: Boolean;
const
  CAPTUREBLT = $40000000;
begin
  ExtendedFrame := False;
  if DwmCompositionEnabled then
  begin
    DwmGetWindowAttribute(WindowHandle, DWMWA_EXTENDED_FRAME_BOUNDS, @R,
      SizeOf(TRect));
    if DropShadow then
    begin
      ExtendedFrame := True;
      R.Left := R.Left - 30;
      R.Top := R.Top - 30;
      R.Right := R.Right + 30;
      R.Bottom := R.Bottom + 30;
    end;
  end
  else
    GetWindowRect(WindowHandle, R);

  SetForegroundWindow(WindowHandle);
  Bitmap := TBitmap.Create;
  try
    Bitmap.PixelFormat := pf24bit;
    Bitmap.SetSize(R.Right - R.Left, R.Bottom - R.Top);
    if ExtendedFrame then
    begin
      DesktopHandle := GetDesktopWindow;
      DeviceContext := GetDC(GetDesktopWindow);
      Form := TForm.Create(nil);
      try
        Form.Color := clWhite;
        Form.BorderStyle := bsNone;
        Form.AlphaBlend := True;
        Form.AlphaBlendValue := 0;
        ShowWindow(Form.Handle, SW_SHOWNOACTIVATE);
        SetWindowPos(Form.Handle, WindowHandle, R.Left, R.Top, 
          R.Right - R.Left, R.Bottom - R.Top, SWP_NOACTIVATE);
        Form.AlphaBlendValue := 255;
        BitBlt(Bitmap.Canvas.Handle, 0, 0, R.Right - R.Left, R.Bottom - R.Top,
          DeviceContext, R.Left, R.Top, SRCCOPY or CAPTUREBLT);
      finally
        Form.Free;
        ReleaseDC(DesktopHandle, DeviceContext);
      end;
      Target := TBitmap.Create;
      try
        CalcCloseCrop(Bitmap, clWhite, R);
        Target.SetSize(R.Right - R.Left, R.Bottom - R.Top);
        Target.Canvas.CopyRect(Rect(0, 0, R.Right - R.Left, R.Bottom - R.Top),
          Bitmap.Canvas, R);
        Target.SaveToFile(FileName);
      finally
        Target.Free;
      end;
    end
    else
    begin
      DeviceContext := GetWindowDC(WindowHandle);
      try
        BitBlt(Bitmap.Canvas.Handle, 0, 0, R.Right - R.Left, R.Bottom - R.Top,
          DeviceContext, 0, 0, SRCCOPY or CAPTUREBLT);
      finally
        ReleaseDC(WindowHandle, DeviceContext);
      end;
      Bitmap.SaveToFile(FileName);
    end;
  finally
    Bitmap.Free;
  end;
end;

function ScreenToFile(Parent: HWND; ParamSize: Integer; Params: PAnsiChar;
  StackTop: Pointer): Integer; cdecl;
var
  I: Integer;
  FileName: string;
  DropShadow: Boolean;
  Parameters: array[0..1] of string;
begin
  Result := 0;
  if not Assigned(NullsoftInstaller) then
    NullsoftInstaller := TNullsoftInstaller.Create;

  NullsoftInstaller.Initialize(Parent, ParamSize, Params, StackTop);

  for I := 0 to High(Parameters) do
    Parameters[I] := NullsoftInstaller.PopString;
  FileName := Parameters[1];
  if not DirectoryExists(ExtractFilePath(FileName)) or
    not TryStrToBool(Parameters[0], DropShadow) then
  begin
    NullsoftInstaller.PushString('error');
    NullsoftInstaller.PushString('Invalid parameters!');
    Exit;
  end;

  try
    TakeScreenshot(Parent, FileName, DropShadow);
    NullsoftInstaller.PushString('ok');
    Result := 1;
  except
    on E: Exception do
    begin
      NullsoftInstaller.PushString('error');
      NullsoftInstaller.PushString(E.Message);
      NullsoftInstaller.MessageDialog(E.Message, 'Error', 0);
    end;
  end;
end;

exports
  ScreenToFile;

begin

end.
于 2012-08-05T11:42:06.813 回答
3

GetDesktopWindow可能应该是，GetDesktopWindow()但通常你可以（并且应该）使用 NULL 而不是 GetDesktopWindow()。此外，一个函数使用 GetDC，另一个函数使用 GetWindowDC ...

于 2012-06-29T10:22:15.730 回答
3

经过一番搜索，我发现以下代码适用于以下 SO 问题：

如何在 Delphi 中截取活动窗口的屏幕截图？

包含 NSIS 的所有其他选项导致 BitBtl 函数崩溃，可能是因为 Aero 及其相关的 DWM 雾...

另外，建议使用此功能。没有经过喷气测试...

http://msdn.microsoft.com/en-us/library/dd162869.aspx

尽管如此，还是有一些问题：

  • 玻璃框架被绘制为透明的
  • NSIS 的文件名被转换为有点损坏的宽字符串......
  • 如果您更改页面（使用 nsdialogs 和 MUI2 ），则可以仅通过对话框背景颜色绘制文件...
于 2012-07-28T12:28:05.473 回答