How to use GetWindowRect

Question

Consider the following code:

LPRECT lpRect;
GetWindowRect(hwnd, lpRect);

I don't know how to get information from lpRect; please advise.

Please see: http://stackoverflow.com/questions/10851278/i-cant-get-hold-of-lprect-structure-data-what-im-doing-wrong — The Floating Brain, Aug 17 '13 at 18:03
Do you not know how to use a structure? LPRECT is just a pointer to a RECT structure, so something like lpRect->x would access a member of it. — Damon, Aug 17 '13 at 18:03
and damon so yeah i just started coding in general, and i wasn't sure. — user2662326, Aug 17 '13 at 18:04
well now that its answered im not gonna delete it, and goodgood michael that is the answer. — user2662326, Aug 17 '13 at 18:05
If you want to accept an answer you should probably go with [datenwolf's](http://stackoverflow.com/a/18291845/1889329) submission. Michael's answer does not really address your problem (writing to random memory). — IInspectable, Aug 17 '13 at 19:06
@GingerJack: I rolled back your edit, which was inappropriate for the following reasons: (1) it introduced a brand new bug -- wrong size passed to `malloc()` (2) it conflicted with existing answers (3) code in questions should only be edited to improve forwarding, never to fix a bug, because the bugs are an important part of the question. Even when a question contains unrelated code or problems outside the question being asked, cleanup/reduction to MCVE should be done only in answers. — Ben Voigt, Dec 25 '18 at 19:22

score 29 · Accepted Answer · answered Aug 17 '13 at 18:05

29

What you wrote is wrong. The Windows API uses a hideous variable and type naming convention. LPRECT means "Long Pointer to Rect", which on your usual architecture is just a RECT*. What you wrote is some uninitialized pointer variable, pointing at some arbitrary location (if you're unlucky something that when modified will crash your program).

This is what you actually require:

RECT rect;
GetWindowRect(hwnd, &rect);

RECT itself is a structure

typedef struct _RECT {
  LONG left;
  LONG top;
  LONG right;
  LONG bottom;
} RECT;

answered Aug 17 '13 at 18:05

datenwolf

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tho u super pro I didn't try it at first, then I learned the hard way. (I got "unlucky") – user2662326 Aug 19 '13 at 04:16
I use a laptop and the external display. All set 1920x1080 resolution. If I run my Delphi 7 program in the primray screen I get different RECTANGLE values like I run my program on the secondary display. [Pictures from source code](https://mega.nz/folder/Z5oREQxY#pgkh-jr7SbZ68E7UxAxZkw) – Lionking Jan 14 '21 at 15:55
@Lionking: Maybe effected by HiDPI scaling. Check if UI scaling is set to a value other than 100%. If so, set to 100% and retry if it works then. If that's the case you'll have to take that scaling into account, too: https://learn.microsoft.com/en-us/windows/win32/hidpi/high-dpi-desktop-application-development-on-windows – datenwolf Jan 14 '21 at 16:46

score 2 · Answer 2 · answered Aug 17 '13 at 18:04

2

You can get the coordinates of the window :

lpRect->left
lpRect->right
lpRect->top
lpRect->bottom

More information here : http://msdn.microsoft.com/en-us/library/windows/desktop/dd162897(v=vs.85).aspx

answered Aug 17 '13 at 18:04

Michael M.

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just so you know I liked yours better :O – user2662326 Aug 19 '13 at 04:15
Technically, it answers the question but I don't think it's what the user wanted. Passing an uninitialised pointer to `GetWindowRect` is a call for trouble. – Alexey Ivanov May 30 '23 at 16:54

score -1 · Answer 3 · answered Dec 25 '18 at 18:22

-1

Or you can just type this inside your CWnd dialog:

CRect rect;
this->GetWindowRect( &rect );

answered Dec 25 '18 at 18:22

Mil277

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The answer does not provide additional context to what is `CRect` or even `this->GetWindowRect`. I assume it refers to MFC but it doesn't answer the original question. – Alexey Ivanov May 30 '23 at 17:00

How to use GetWindowRect

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