Find specific window and retrieve it's content (windows VISTA)
lazarus / 39-Graphics

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--Dynamic-Pascal-- · 2010-09-23 08:45

Hi!

1. I want to find a visible window from a running process.

2. Make a copy of its bitmap (content) in memory (array or other
structure) where I can access each pixel fast.

3. Repeat 2. 1-3 times/sec (even if the window is resized or moved).

--------

I have struggled with this problem enough (months...   ), and I need
code examples that works.

/anders

(Lazarus IDE v0.9.29)

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theo · 2010-09-23 09:27

Quote from: --Dynamic-Pascal-- on September 23, 2010, 10:45:23 amI
have struggled with this problem enough (months...   ), and I need
code examples that works.

What did you try so far (in all those months) and where's the problem?

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--Dynamic-Pascal-- · 2010-09-23 09:48

I have tried getting the main window:

Code: [Select]var
  ScreenDC: HDC;
  Bitmap: TBitmap;
begin
  Bitmap := TBitmap.Create;
  try
    ScreenDC := GetDC(0);
    Bitmap.LoadFromDevice(ScreenDC);
    ReleaseDC(0, ScreenDC);
    Canvas.Draw(0, 0, Bitmap);
  finally
    Bitmap.Free;
  end;
end;
and it works fine. I could extract the window I want from this bitmap.
I get in trouble if my target window is moved or resized.

Another attempt getting the foreground window:

Code: [Select]MyBitmap := TBitmap.Create;
hWin := GetForegroundWindow;
and I get my Lazarus window (as expected).

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theo · 2010-09-23 10:28

And this?

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TForm1.Button1Click(Sender: TObject);var  wnd: HWnd;  aDC:HDC;begin 
wnd := FindWindow('Notepad',nil);  if wnd>0 then  begin   
aDC:=GetDC(wnd);    if aDC>0 then     
Image1.Picture.Bitmap.LoadFromDevice(aDC);  end;end;

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--Dynamic-Pascal-- · 2010-09-23 14:46

It works for Notepad (swedish "Anteckningar"), but not other programs.
I guess that I have figured out how to put it all together within this
year...

BTW: how to get posted code Pascal-formated?

/anders

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theo · 2010-09-23 20:38

Quote from: --Dynamic-Pascal-- on September 23, 2010, 04:46:10 pmIt
works for Notepad (swedish "Anteckningar"), but not other programs. I
guess that I have figured out how to put it all together within this
year...

BTW: how to get posted code Pascal-formated?

/anders

This is pure Win-API.
Please read in MSDN how things work.
For example:
http://msdn.microsoft.com/en-us/library/ms633499%28VS.85%29.aspx

BTW: replace code with code=pascal manually.

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--Dynamic-Pascal-- · 2010-09-23 20:57

Thank You for your answers.

I will try to get it working and then post a short example here if
that's OK.

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--Dynamic-Pascal-- · 2010-09-25 17:00

I came up with a solution where i use the "BitBtn" in the Form as a
pointer to retrieve the mouse position. I use that position to get the
windows handler.

When you click the "BitBtn" the Form is hidden and a snapshot of the
visible window is taken (don't try it on Lazarus' windows!).

Source code is included in "FindWindow.zip".

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
[tt][size=8pt]unit Unit1; {$mode objfpc}{$H+} interface uses  Windows,
Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, 
StdCtrls, ExtCtrls, Buttons; type  { TForm1 }  TForm1 = class(TForm) 
 BitBtn1: TBitBtn;    Image1: TImage;    Label1: TLabel;    Label2:
TLabel;    procedure BitBtn1Click(Sender: TObject);  private    {
private declarations }  public    { public declarations }  end;  var 
 Form1: TForm1; implementation {$R *.lfm}//procedure
FindTheWindow;procedure TForm1.BitBtn1Click(Sender: TObject);var 
 wnd: HWnd;   aDC:HDC;   coord: tpoint; begin     coord :=
Mouse.CursorPos;     Form1.Label1.Caption := ('X=' +
IntToStr(coord.X));     Form1.Label2.Caption := ('Y=' +
IntToStr(coord.Y));     Form1.Label1.Show;     Form1.Label2.Show;   
 Form1.Hide;     Sleep(300);     wnd := WindowFromPoint(coord);     if
wnd>0 then     begin          aDC:=GetDC(wnd);          if aDC>0 then 
        Form1.Image1.Picture.Bitmap.LoadFromDevice(aDC);         
form1.Show;     end;end; end.[/size] [/tt]

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captian jaster · 2010-09-25 22:24

Quote from: --Dynamic-Pascal-- on September 25, 2010, 07:00:00 pmI
came up with a solution where i use the "BitBtn" in the Form as a
pointer to retrieve the mouse position. I use that position to get the
windows handler.

When you click the "BitBtn" the Form is hidden and a snapshot of the
visible window is taken (don't try it on Lazarus' windows!).

Source code is included in "FindWindow.zip".

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
[tt][size=8pt]unit Unit1; {$mode objfpc}{$H+} interface uses  Windows,
Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, 
StdCtrls, ExtCtrls, Buttons; type  { TForm1 }  TForm1 = class(TForm) 
 BitBtn1: TBitBtn;    Image1: TImage;    Label1: TLabel;    Label2:
TLabel;    procedure BitBtn1Click(Sender: TObject);  private    {
private declarations }  public    { public declarations }  end;  var 
 Form1: TForm1; implementation {$R *.lfm}//procedure
FindTheWindow;procedure TForm1.BitBtn1Click(Sender: TObject);var 
 wnd: HWnd;   aDC:HDC;   coord: tpoint; begin     coord :=
Mouse.CursorPos;     Form1.Label1.Caption := ('X=' +
IntToStr(coord.X));     Form1.Label2.Caption := ('Y=' +
IntToStr(coord.Y));     Form1.Label1.Show;     Form1.Label2.Show;   
 Form1.Hide;     Sleep(300);     wnd := WindowFromPoint(coord);     if
wnd>0 then     begin          aDC:=GetDC(wnd);          if aDC>0 then 
        Form1.Image1.Picture.Bitmap.LoadFromDevice(aDC);         
form1.Show;     end;end; end.[/size] [/tt]
OFFTOPIC:
All that is used from the windows unit?
Were can I find out more of the windows unit types/procedures and
functions?
the rtl doesn't say
ONTopic:
Nice code

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typo · 2010-09-25 22:50

QuoteWere can I find out more of the windows unit types/procedures and
functions?
Put the cursor on the word "windows" in editor and choose Open File
from the popup menu.

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captian jaster · 2010-09-26 02:25

thanks again typo