MagSetWindowFilterList function not remove specified window of screenshot

[flashcoder]

I had build part of this code below based in this C++ example (source file attached) where the goal is make a screenshot without the main form appear on capture.

Then i have two troubles with this following code:

1 - MagSetWindowFilterList function not remove main form (Form1).

2 - How recovery the content of "MagnifierWindow" to a image format?

My actual code is this:

Magnification.pas

Delphi-Quellcode:

unit Magnification;

{$ALIGN ON}
{$MINENUMSIZE 4}

interface

uses
  Windows;

const
  // Magnifier Class Name
  WC_MAGNIFIERA: AnsiString = 'Magnifier';
  WC_MAGNIFIERW: WideString = 'Magnifier';
  WC_MAGNIFIER = 'Magnifier';

  // Magnifier Window Styles
  MS_SHOWMAGNIFIEDCURSOR = $0001;
  MS_CLIPAROUNDCURSOR = $0002;
  MS_INVERTCOLORS = $0004;

  // Filter Modes
  MW_FILTERMODE_EXCLUDE = 0;
  MW_FILTERMODE_INCLUDE = 1;

type
  tagMAGTRANSFORM = record
    v: array[1..3, 1..3] of Single;
  end;
  MAGTRANSFORM = tagMAGTRANSFORM;
  TMagTransform = tagMAGTRANSFORM;
  PMagTransform = ^TMagTransform;

  tagMAGIMAGEHEADER = record
    width: UINT;
    height: UINT;
    format: TGUID;
    stride: UINT;
    offset: UINT;
    cbSize: UINT;
  end;
  MAGIMAGEHEADER = tagMAGIMAGEHEADER;
  TMagImageHeader = tagMAGIMAGEHEADER;
  PMagImageHeader = ^TMagImageHeader;

  tagMAGCOLOREFFECT = record
    transform: array[1..5, 1..5] of Single;
  end;
  MAGCOLOREFFECT = tagMAGCOLOREFFECT;
  TMagColorEffect = tagMAGCOLOREFFECT;
  PMagColorEffect = ^TMagColorEffect;

  TMagImageScalingCallback = function (hwnd: HWND; srcdata: Pointer;
    srcheader: MAGIMAGEHEADER; destdata: Pointer; destheader: MAGIMAGEHEADER;
    unclipped: TRect; clipped: TRect; dirty: HRGN): BOOL; stdcall;

  THWNDArray = array[0..0] of HWND;
  PHWNDArray = ^THWNDArray;

  // Public Functions
  function MagInitialize(): BOOL; stdcall;
  function MagUninitialize(): BOOL; stdcall;

  function MagSetWindowSource(hwnd: HWND; rect: TRect): BOOL; stdcall;
  function MagGetWindowSource(hwnd: HWND; var Rect: TRect): BOOL; stdcall;
  function MagSetWindowTransform(hwnd: HWND; var Transform: TMagTransform): BOOL; stdcall;
  function MagGetWindowTransform(hwnd: HWND; var Transform: TMagTransform): BOOL; stdcall;
  function MagSetWindowFilterList(hwnd: HWND; dwFilterMode: DWORD;
    count: Integer; pHWND: PHWNDArray): BOOL; stdcall;
  function MagGetWindowFilterList(hwnd: HWND; var dwFilterMode: DWORD;
    count: Integer; pHWND: PHWNDArray): Integer; stdcall;
  function MagSetImageScalingCallback(hwnd: HWND;
    MagImageScalingCallback: TMagImageScalingCallback): BOOL; stdcall;
//  MagImageScalingCallback WINAPI MagGetImageScalingCallback(HWND hwnd );
  function MagSetColorEffect(hwnd: HWND; var Effect: TMagColorEffect): BOOL; stdcall;
  function MagGetColorEffect(hwnd: HWND; var Effect: TMagColorEffect): BOOL; stdcall;

implementation

const
  MagnificationDll = 'Magnification.dll';

  function MagInitialize; external MagnificationDll name 'MagInitialize';
  function MagUninitialize; external MagnificationDll name 'MagUninitialize';
  function MagSetWindowSource; external MagnificationDll name 'MagSetWindowSource';
  function MagGetWindowSource; external MagnificationDll name 'MagGetWindowSource';
  function MagSetWindowTransform; external MagnificationDll name 'MagSetWindowTransform';
  function MagGetWindowTransform; external MagnificationDll name 'MagGetWindowTransform';
  function MagSetWindowFilterList; external MagnificationDll name 'MagSetWindowFilterList';
  function MagGetWindowFilterList; external MagnificationDll name 'MagGetWindowFilterList';
  function MagSetImageScalingCallback; external MagnificationDll name 'MagSetImageScalingCallback';
  function MagSetColorEffect; external MagnificationDll name 'MagSetColorEffect';
  function MagGetColorEffect; external MagnificationDll name 'MagGetColorEffect';

end.

Main

Delphi-Quellcode:

var
  Form1: TForm1;

implementation

uses
  Unit3, Magnification;

{$R *.dfm}

procedure TForm1.btn1Click(Sender: TObject);
var
  desktop, hwndMag: HWND;
  desktoprect, sourceRect: TRect;
  filterList: PHWNDArray;
  m_ScreenX, m_ScreenY, m_ScreenT, m_ScreenL: Integer;
begin

  desktop := GetDesktopWindow;
  GetWindowRect(desktop, desktoprect);

  m_ScreenT := desktoprect.Top;
  m_ScreenL := desktoprect.Left;
  m_ScreenX := desktoprect.right;
  m_ScreenY := desktoprect.bottom;

  Form3 := TForm3.Create(Form3);

  SetWindowPos(Form3.Handle, 0, 0, 0, desktoprect.right, desktoprect.bottom, SWP_SHOWWINDOW);

  SetWindowLong(Form3.Handle, GWL_EXSTYLE, GetWindowLong(Form3.Handle,
    GWL_EXSTYLE) or WS_EX_LAYERED);
  SetLayeredWindowAttributes(Form3.Handle, 0, 255, LWA_ALPHA);

  if (not MagInitialize) then
  begin
    Application.MessageBox('Init magnification failed', 'Error',
      mb_Ok + mb_IconError);
    Exit;
  end;

  hwndMag := CreateWindow(WC_MAGNIFIER, 'MagnifierWindow',
    WS_CHILD {or MS_SHOWMAGNIFIEDCURSOR} or WS_VISIBLE, 0, 0, m_ScreenX,
    m_ScreenY, Form3.Handle, 0, hInstance, nil);

  if (hwndMag = 0) then
  begin
    Application.MessageBox('MagnifierWindow creation failed', 'Error',
      mb_Ok + mb_IconError);
    Exit;
  end;

  try
    filterList[0] := Handle;
  except
  end;

  if (not MagSetWindowFilterList(hwndMag, MW_FILTERMODE_EXCLUDE, 1, filterList))
  then
  begin
    Application.MessageBox('Cannot exclude main window', 'Error',
      mb_Ok + mb_IconError);
    Exit;
  end;

  sourceRect.Top := m_ScreenT;
  sourceRect.Left := m_ScreenL;
  sourceRect.right := m_ScreenX;
  sourceRect.bottom := m_ScreenY;

  if (not MagSetWindowSource(hwndMag, sourceRect)) then
  begin
    Application.MessageBox('Cannot set source to MagnifierWindow', 'Error',
      mb_Ok + mb_IconError);
    Exit;
  end;

  { if (not MagUninitialize) then
    begin
    Application.MessageBox('Finalize magnification failed', 'Error',
    mb_Ok + mb_IconError);
    Exit;
    end; }
end;

[Fukiszo]

Delphi-Quellcode:

{ Here's how you can save the screen content into a bitmapfile.
  If you don't want to include the active (Delphi-)Application
  just put easily a 'Application.Minimize;' at the beginning
  of the procedure }

uses
  Windows, Graphics, Forms;

procedure TForm1.Button1Click(Sender: TObject);
var
  DC: HDC;
  Canvas: TCanvas;
  MyBitmap: TBitmap;
begin
  Canvas := TCanvas.Create;
  MyBitmap := TBitmap.Create;
  DC := GetDC(0);

  try
    Canvas.Handle := DC;
    with Screen do
    begin
      { detect the actual height and with of the screen }
      MyBitmap.Width := Width;
      MyBitmap.Height := Height;

      { copy the screen content to the bitmap }
      MyBitmap.Canvas.CopyRect(Rect(0, 0, Width, Height), Canvas,
                               Rect(0, 0, Width, Height));
      { stream the bitmap to disk }
      MyBitmap.SaveToFile('c:\windows\desktop\screen.bmp');
    end;

  finally
    { free memory }
    ReleaseDC(0, DC);
    MyBitmap.Free;
    Canvas.Free
  end;
end;

[flashcoder]

Zitat von Fukiszo:

Delphi-Quellcode:

{ Here's how you can save the screen content into a bitmapfile.
  If you don't want to include the active (Delphi-)Application
  just put easily a 'Application.Minimize;' at the beginning
  of the procedure }

uses
  Windows, Graphics, Forms;

procedure TForm1.Button1Click(Sender: TObject);
var
  DC: HDC;
  Canvas: TCanvas;
  MyBitmap: TBitmap;
begin
  Canvas := TCanvas.Create;
  MyBitmap := TBitmap.Create;
  DC := GetDC(0);

  try
    Canvas.Handle := DC;
    with Screen do
    begin
      { detect the actual height and with of the screen }
      MyBitmap.Width := Width;
      MyBitmap.Height := Height;

      { copy the screen content to the bitmap }
      MyBitmap.Canvas.CopyRect(Rect(0, 0, Width, Height), Canvas,
                               Rect(0, 0, Width, Height));
      { stream the bitmap to disk }
      MyBitmap.SaveToFile('c:\windows\desktop\screen.bmp');
    end;

  finally
    { free memory }
    ReleaseDC(0, DC);
    MyBitmap.Free;
    Canvas.Free
  end;
end;

The main Form not must be minimized in my situation.
I really need of help to fix code that was posted on question.

[Fukiszo]

use this command wherever you need
this will hide a window by its handle

Code:

 ShowWindow(EnterHandle, SW_HIDE); // Enter Handle of Window wich needs to become invisible

or

 ShowWindow(FindWindow(EnterClassName,nil), SW_HIDE); // EnterClassName can be something like TForm1 etc, adjust to your 

or

 ShowWindow(FindWindow(nil,'Enter Forms Caption'), SW_HIDE); // self explaining

replace SW_HIDE with SW_SHOW to bring it back

use this code careful, it can be used to also tweak control (in and outside of your program)

[Zacherl]

Hiding / minimizing a window to exclude it from a screenshot is an invasive operation and I as an user would not like it (even if it's only for a split second).

Zitat von flashcoder:

1 - MagSetWindowFilterList function not remove main form (Form1).

You should not declare your filterList as PHWNDArray . Just use a normal THWNDArray as variable declaration and pass it like this: MagSetWindowFilterList(hwndMag, MW_FILTERMODE_EXCLUDE, 1, @filterList[0]) . You could even use plain HWND as type for filterList (in case there's always only one handle in your "list").

Zitat von flashcoder:

2 - How recovery the content of "MagnifierWindow" to a image format?

I never used the magnification API, but the linked article shows a way by using the so called MagImageScalingCallback .

[flashcoder]

@Zacherl,

thank you very much, your suggestion about MagSetWindowFilterList worked fine.
I will try translate the part of save content of hwndmag to a image format.

I tried the suggestion of @Fukiszo but not worked see:

Delphi-Quellcode:

Canvas := TCanvas.Create;
  MyBitmap := TBitmap.Create;
  DC := GetWindowDC(hwndMag);

  GetWindowRect(hwndMag, r);

  try
    Canvas.Handle := DC;

      MyBitmap.Width := r.Width;
      MyBitmap.Height := r.Height;

      MyBitmap.Canvas.CopyRect(Rect(0, 0, MyBitmap.Width, MyBitmap.Height), Canvas,
                               Rect(0, 0, r.Width, r.Height));

      MyBitmap.SaveToFile('c:\screen.bmp');

  finally
    ReleaseDC(0, DC);
    MyBitmap.Free;
    Canvas.Free
  end;

But if someone know a way in Delphi and that works, i will accept.