Question about GetWindowRect

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upsurt

Joined: 14 Jan 2014
Posts: 51

upsurt 28 Jul 2014, 13:24

Hi

I try to get the position and the height/width of an window with GetWindowRect.

rc RECT
hwnd dd 0
left dq 0
top dq 0
width dq 0
height dq 0

invoke GetWindowRect,[hwnd],rc
mov dword[left],rc.left
mov dword[top],rc.top
mov dword[width],rc.right-rc.left
mov dword[height],rc.bottom-rc.top

while [rc.left], [rc.right], [rc.top] and [rc.bottom] contain the correct data, [left], [top], [width] and [height] contain complete sensless data.

I'm sure it's my fault and that I mess sth up with the data types. Can someone please point me the direction?
What I need is width and height of the window.

New to ASM and didn't find an usefull explanation of data types in ASM by now.

Thank you very much!

Last edited by upsurt on 28 Jul 2014, 13:27; edited 1 time in total

28 Jul 2014, 13:24

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20409
Location: In your JS exploiting you and your system

revolution 28 Jul 2014, 13:26

You need to load the value from the structure:

Code:

mov eax,[rc.left]
mov [left],eax

28 Jul 2014, 13:26

upsurt

Joined: 14 Jan 2014
Posts: 51

upsurt 28 Jul 2014, 13:29

I did this before, but I get an "operand sizes do not match (mov [left],eax)" error.

28 Jul 2014, 13:29

upsurt

Joined: 14 Jan 2014
Posts: 51

upsurt 28 Jul 2014, 13:39

Ok, I got it working with your help! Thank you, revolution.

Code:

  invoke GetWindowRect,[hwnd],rc
  ;x
  mov eax,[rc.left]
  mov dword[left],eax
  ;y
  mov eax,[rc.top]
  mov dword[top],eax
  ;width
  mov eax,[rc.right]
  mov dword[width],eax
  mov eax,[rc.left]
  sub dword[width],eax
  ;height
  mov eax,[rc.bottom]
  mov dword[height],eax
  mov eax,[rc.top]
  sub dword[height],eax

now I get the correct data in dword[left], dword[top], dword[width] and dword[height]

But is this the correct way to do it, or is there a better way?

28 Jul 2014, 13:39

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20409
Location: In your JS exploiting you and your system

revolution 28 Jul 2014, 14:01

You can use the matching size for the values then you don't need the 'dword' overrides:

Code:

left dd ?

28 Jul 2014, 14:01

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