2 problems: GetObjectAPI and GetCurrentObject

[CVMichael]

OK, i'm posting here, since no one seems to look at my thread in the API forum...

Problem 1:

Debug.Print "HDC " & GetDCEx(GetForegroundWindow, 0, DCX_WINDOW)
    Debug.Print "HDC " & GetDCEx(GetDesktopWindow, 0, DCX_WINDOW)
    
    Debug.Print "OBJ " & GetCurrentObject(GetDCEx(GetForegroundWindow, 0, DCX_WINDOW), OBJ_BITMAP)
    Debug.Print "OBJ " & GetCurrentObject(GetDCEx(GetDesktopWindow, 0, DCX_WINDOW), OBJ_BITMAP)

This is what the previous code returns (on my computer):

HDC 2097221708
HDC 1610680699
OBJ 17104950
OBJ 17104950

How come the GetCurrentObject API returns the same object as the GetDesktopWindow's bitmap object ??

When I get the picture of the ForegroundWindow, it is actually the DesktopWindow, how come ?


Problem 2:

Dim dBitmap As Long, dBMP As BITMAP, HDC As Long, ret As Long
    
    HDC = GetDC(GetForegroundWindow)
    dBitmap = GetCurrentObject(HDC, OBJ_BITMAP)
    
    If dBitmap <> 0 Then
        ret = GetObjectAPI(dBitmap, Len(dBMP), dBMP)
        Debug.Print ret, dBMP.bmHeight, dBMP.bmWidth
 
' .... the rest of the ode...

The GetObjectAPI ALWAYS returns 0, and dBMP variables are 0 also, how come ?

[Shawn N]

Maybe

Declare Function GetActiveWindow Lib "user32" Alias "GetActiveWindow" () As Long

or

Declare Function GetFocus Lib "user32" Alias "GetFocus" () As Long

instead.

[CVMichael]

same thing for both...

With GetActiveWindow API:
HDC -1509881489
HDC 1107363695
OBJ 17104950
OBJ 17104950

With GetFocus API:
HDC 872483951
HDC 1342245950
OBJ 17104950
OBJ 17104950

[CVMichael]

When you try it on your computer, do you get the same thing ?
I just wanna know if it's something wrong on my computer, or that's how it's supposed to be.

Here are the declarations, so you don't have to look for them.

Public Const DCX_WINDOW = &H1&
Public Const OBJ_BITMAP = 7
 
Public Declare Function GetCurrentObject Lib "gdi32" (ByVal HDC As Long, ByVal uObjectType As Long) As Long
Public Declare Function GetDCEx Lib "user32" (ByVal hwnd As Long, ByVal hrgnclip As Long, ByVal fdwOptions As Long) As Long
Public Declare Function GetDesktopWindow Lib "user32" () As Long
Public Declare Function GetForegroundWindow Lib "user32" () As Long
Public Declare Function GetActiveWindow Lib "user32" () As Long
Public Declare Function GetFocus Lib "user32" () As Long

[Shawn N]

I'm getting different results.

Private Const DCX_WINDOW As Long = &H1&
Private Const OBJ_BITMAP As Long = 7
 
Private Declare Function GetCurrentObject Lib "gdi32" ( _
     ByVal hdc As Long, _
     ByVal uObjectType As Long) As Long
 
Private Declare Function GetDCEx Lib "user32" ( _
     ByVal hwnd As Long, _
     ByVal hrgnclip As Long, _
     ByVal fdwOptions As Long) As Long
 
Private Declare Function GetDesktopWindow Lib "user32" () As Long
 
Private Declare Function GetForegroundWindow Lib "user32" () As Long
 
Private Declare Function GetActiveWindow Lib "user32" () As Long
 
Private Declare Function GetFocus Lib "user32" () As Long
 
Option Explicit
 
Private Sub Form_Load()
 
    Debug.Print "GetForegroundWindow HDC " & GetDCEx(GetForegroundWindow, 0, DCX_WINDOW)
    Debug.Print "GetDesktopWindow HDC " & GetDCEx(GetDesktopWindow, 0, DCX_WINDOW)
    Debug.Print "GetActiveWindow HDC " & GetDCEx(GetDesktopWindow, 0, DCX_WINDOW)
    Debug.Print
    Debug.Print "GetForegroundWindow OBJ " & GetCurrentObject(GetDCEx(GetForegroundWindow, 0, DCX_WINDOW), OBJ_BITMAP)
    Debug.Print "GetDesktopWindow OBJ " & GetCurrentObject(GetDCEx(GetDesktopWindow, 0, DCX_WINDOW), OBJ_BITMAP)
    Debug.Print "GetActiveWindow OBJ " & GetCurrentObject(GetDCEx(GetActiveWindow, 0, DCX_WINDOW), OBJ_BITMAP)
 
    Unload Me
    
End Sub

GetForegroundWindow HDC 0
GetDesktopWindow HDC 318838164
GetActiveWindow HDC 234951952

GetForegroundWindow OBJ 0
GetDesktopWindow OBJ 17104950
GetActiveWindow OBJ 0

Is "GetDCEx" necessary? Maybe just a plain old "GetDC" would fix something.

[CVMichael]

yea, because GetDC returns only the client area of the window (the part that starts under the menu, up to the bottom of the window), and GetDCEx returns the whole window, with the menu and the title bar...

[CVMichael]

I just noticed you have 0 on some returns

Don't output while you debug, and don't put it in form_Load(), or at least put Me.Show right after the Form_Load() line...

Then you will get the proper values

[Shawn N]

Yea OK. Put it in Click event and results are different.

GetForegroundWindow HDC -1325329018
GetDesktopWindow HDC -922675887
GetActiveWindow HDC 1929450204

GetForegroundWindow OBJ 17104950
GetDesktopWindow OBJ 17104950
GetActiveWindow OBJ 17104950

I dunno then...

[CVMichael]

You have the same values as me: 17104950

Strange....

Also, it seems that GetCurrentObject returns the object for the GetDesktopWindow whever the HDC is a VALID hdc, that's all it cares about...


How about my second problem, do you know what's wrong there ?

[Shawn N]

You have pretty much the same thing from API-Guide. I can't see anything wrong with it other than that dBitmap might be screwy.

Dim PicInfo As BITMAP
GetObject Picture1.Image, Len(PicInfo), PicInfo

[CVMichael]

"dBitmap might be screwy" you mean the structure is not the right length ? (cuz that's all it needs to return actually, just a buffer of 24 bytes length)

Public Type BITMAP '24 bytes
    bmType As Long
    bmWidth As Long
    bmHeight As Long
    bmWidthBytes As Long
    bmPlanes As Integer
    bmBitsPixel As Integer
    bmBits As Long
End Type

And I can't use Picture1.Image, because in my function I only get the HDC, and from it I get the object, and even there, I have problems...

Ahhh... i'm starting to hate this API thing, that don't even do what their supposed to do !!

[CVMichael]

Anyone ?

[Shawn N]

I was reading about GetObject on Dan Appleman's API book. It says "The bmBits field of the BITMAP data structure is not valid when retrieving information for a bitmap; however, the bmBitrs field within the BITMAP structure contained in a DIBSECTINO structure will be valid."

Not sure if that helps you or not.

[CVMichael]

I knew that bmBits field is not valid, but the others should be, the bmWidth, and bmHeight

And what did you write after the however ? (i don't get that part)

[Shawn N]

Yea, kind of confusing. Took me 3 passes to understand.

DIBSECTION

The DIBSECTION type contains a BITMAP structure member. So I guess it's like "DIBSECTION_VARIABLE.BITMAP_MEMBER.bmBits" will be valid for use on the GetObject function.

Now how to get that loaded...

[CVMichael]

The DIBSECTION does not work also, I get the same results (or no results i should say) as with BITMAP...

I don't understand why no on else than Shawn N wants to help on this thread...

Did anyone try the code I pasted earlier ? do you get the same results ?
I am curious if it's a problem with my computer, or everyone has the same output ?

[Shawn N]

Originally posted by CVMichael
I don't understand why no on else than Shawn N wants to help on this thread...

Cause I'm extremely cool.

Anyways, think you could explain exactly what it is you're trying to do? Maybe there's another way to go about it...