Get control screenshot as bitmap

[Zedna]

Purpose is to get bitmap screenshot of nonstandard statusbar from another application and later compare it with saved bitmap to see state of application.

Now I have working script but only if I capture bitmap (and save it as BMP file) from my own AutoIt's GUI control (StatusBar):

expandcollapse popup

#include <GUIConstants.au3>
#include <GDIPlus.au3>
#Include <WinAPI.au3>
#include <GUIStatusBar.au3>
#include <ButtonConstants.au3>
#include <GUIConstantsEx.au3>
#include <StatusBarConstants.au3>
#include <WindowsConstants.au3>

$Form1_1 = GUICreate("Form1", 593, 453, 193, 115)
$StatusBar1 = _GUICtrlStatusBar_Create($Form1_1)
_GUICtrlStatusBar_SetSimple($StatusBar1)
_GUICtrlStatusBar_SetText($StatusBar1, "Optimizing F:\ks\sybaz7\az-los.pbl ...")
$MyButton1 = GUICtrlCreateButton("Get Status as image", 224, 176, 140, 30, 0)
GUISetState(@SW_SHOW)

While 1
    $nMsg = GUIGetMsg()
    Switch $nMsg
        Case $GUI_EVENT_CLOSE
            Exit
        Case $MyButton1
            GetStatusImage()
    EndSwitch
WEnd


Func GetStatusImage()
$hWnd = ControlGetHandle("Form1","","msctls_statusbar321")
$pos = ControlGetPos("Form1","","msctls_statusbar321")

_GDIPlus_StartUp()
$Width = $pos[2]
$Height = $pos[3]

;~ MsgBox(0,'Image size', $Width & 'x' & $Height)

$hDC = _WinAPI_GetDC($hWnd)
$memDC = _WinAPI_CreateCompatibleDC($hDC)
$memBmp = _WinAPI_CreateCompatibleBitmap($hDC, $Width, $Height)
_WinAPI_SelectObject ($memDC, $memBmp)
;~ Func _WinAPI_BitBlt($hDestDC, $iXDest, $iYDest, $iWidth, $iHeight, $hSrcDC, $iXSrc, $iYSrc, $iROP)
_WinAPI_BitBlt($memDC, 0, 0, $Width, $Height, $hDC, 0, 0, $SRCCOPY)

$hImage = _GDIPlus_BitmapCreateFromHBITMAP ($memBmp)
_GDIPlus_ImageSaveToFile($hImage, 'status.bmp')
    _GDIPlus_ImageDispose ($hImage)
_WinAPI_ReleaseDC($hWnd, $hDC)
_WinAPI_DeleteDC($memDC)
_WinAPI_DeleteObject ($memBmp)

_GDIPlus_ShutDown()
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Here is screenshot from my first working example:

Can somebody help me with this weird behaviour?

status.bmp

[smashly]

Hi,

The window needs to be active or in view from what I can see..

Add

WinActivate("Form1")

to the top of "2) Capture part" of the code and it works like it should.

Cheers

[Zedna]

Hi,

The window needs to be active or in view from what I can see..

Add

WinActivate("Form1")

to the top of "2) Capture part" of the code and it works like it should.

Cheers

OK. Thanks for the answer smashly.

In my original script I tested MouseGetCursor() = 15 in While loop so it was dependent on active status too.

So if somebody switched to another application cursor (hourglass) changed and my logic was gone.

I'm rewriting my script to check some inner states inside my target application so it will not be dependent on active status.

I thought this will work also on non-active windows/controls.

So now new question:

How can I do that (bitmap screenshot of control) also with non-active window (it's control)?

AutoIt can do such things also with non-active/minimized windows as far as I know.

What's the trick?

[Zedna]

I discovered the

WinActivate("Form1","")
WinWaitActive("Form1","")

must be called before (not after) BitBlt API call.

So problem is in BitBlt API. It needs to have active windows.

But on MSDN I see no note about such behaviour/limitation

http://msdn.microsoft.com/en-us/library/ms532278(VS.85).aspx

The BitBlt function performs a bit-block transfer of the color data corresponding to a rectangle of pixels from the specified source device context into a destination device context.

Edited May 19, 2008 by Zedna

[smashly]

I'm not sure as of yet how to get an image of a window/control that's not showing.

I know it's not what you want to hear or be asked, but can't you use ControlGetText() instead?

At least it works on minimized and non focused windows.

[smashly]

In regards to the msdn link you posted, it's sorta whack that it states in the dwRop descriptions...

CAPTUREBLT Windows 98/Me, Windows 2000/XP: Includes any windows that are layered on top of your window in the resulting image. By default, the image only contains your window. Note that this generally cannot be used for printing device contexts.

So the default isn't really working as a default then is it?

[Zedna]

I know it's not what you want to hear or be asked, but can't you use ControlGetText() instead?

At least it works on minimized and non focused windows.

Really No.

My target application is PowerBuilder and it uses non-standard StatusBar control (ClassName PBHELP801) and I can't see any text from it in Au3Info tool.

So I really can't use standard controls' functions.

[Zedna]

I googled for that problem and here is result:

http://www.fengyuan.com/article/wmprint.html

In short: Instead of BitBlt use WM_PRINT or WM_PRINTCLIENT API

[Siao]

Yea, the subject was discussed before http://www.autoitscript.com/forum/index.php?showtopic=55564 and the same article quoted.

All the kiddies around here probably would be overjoyed, as this would be kind of a breakthrough moment in game botting with AutoIt. And therefore I'm not sure if it's really good idea.

[Zedna]

I have found another nice topic about that

http://www.xtremevbtalk.com/t238494.html

http://support.microsoft.com/kb/230502/EN-US/

I will test it and I will post result later.

Edited May 19, 2008 by Zedna

[Zedna]

I wasn't successfull

I replaced

_WinAPI_BitBlt($memDC, 0, 0, $Width, $Height, $hDC, 0, 0, $SRCCOPY)

by

$ret = _SendMessage($hWnd, $WM_PRINT, $memDC,  BitOR($PRF_CHILDREN , $PRF_CLIENT, $PRF_NONCLIENT))

I tested all combinations of PRF constants:

Const $WM_PRINT = 0x317
Const $PRF_CLIENT = 0x4  ; Draw the window's client area.
Const $PRF_NONCLIENT = 0x2
Const $PRF_CHILDREN = 0x10; Draw all visible child windows.
Const $PRF_OWNED = 0x20  ; Draw all owned windows.

But resulting bitmap was always black. It was black also if I commented WM_PRINT line.

I noticed on MSDN at WM_PAINT:

http://msdn.microsoft.com/en-us/library/ms534901(VS.85).aspx

The WM_PAINT message is generated by the system and should not be sent by an application. To force a window to draw into a specific device context, use the WM_PRINT or WM_PRINTCLIENT message. Note that this requires the target window to support the WM_PRINTCLIENT message. Most common controls support the WM_PRINTCLIENT message.

So if somebody can tell me what else must be done to do the trick I will be glad. Edited May 21, 2008 by Zedna

[Zedna]

I'm curious why but now it works (also previous code):

$ret = _SendMessage($hWnd, $WM_PRINT, $memDC, BitOR($PRF_CHILDREN , $PRF_CLIENT, $PRF_NONCLIENT, $PRF_ERASEBKGND ))

thanks ptrex - his post is here:

http://www.autoitscript.com/forum/index.ph...st&p=568428

[martin]

I'm curious why but now it works (also previous code):

$ret = _SendMessage($hWnd, $WM_PRINT, $memDC, BitOR($PRF_CHILDREN , $PRF_CLIENT, $PRF_NONCLIENT, $PRF_ERASEBKGND ))

thanks ptrex - his post is here:

http://www.autoitscript.com/forum/index.ph...st&p=568428

I cannot get anything but a black area if I use $PRF_CLIENT. If I add a menu then the menu appears in the jpg but the client area, apart from the menu, is black and no controls are shown. How do you do that? Edited August 27, 2008 by martin

[Zedna]

I cannot get anything but a black area if I use $PRF_CLIENT. If I add a menu then the menu appears in the jpg but the client area, apart from the menu, is black and no controls are shown. How do you do that?

It works for me on WIN98.

Tomorrow I will test it also on WINXP ...

EDIT: On WINXP it really doesn't work (only WIN98). So problem still not solved

Edited August 28, 2008 by Zedna