Solved

Does window width equal (xmax - xmin) or (xmax - xmin  + 1)?

Posted on 2003-11-18
2
213 Views
Last Modified: 2013-11-20
I am confused as to what the meaning of a window is in regards to the Windows SDK.
Some functions like SetWindowPos() require the window width and height as parmeters and other function like GetWindowRect() pass back the left, right, top, and bottom positions.  I am trying to understand exactly how they relate.

I keep coming across code that says width = xmax - xmin.  For example in Microsoft Knowledge Base #68556 it has a call to GetWindowRect(hDlg, &rect) followed by a call to SetWindowPos() in which the fourth parameter for the width is the following:

        rect.right - rect.left,     // Based on the values returned by
                                    // GetWindowRect, calculate the new
                                    // width of the main window.

I would think that the width would be rect.right - rect.left + 1.  If the window is 3 pixels wide and placed at the upper right corner wouldn't there be pixels at horizontal screen locations 0, 1, and 2?  Therefore right - left would be 2 - 0 which is only 2 (not 3)

Could someone please explain to me the logic of whether or not you add 1 to the right - left calculation to figure out window width?

Thanks,
Mark

0
Comment
Question by:kaplan1
2 Comments
 
LVL 9

Accepted Solution

by:
Priyesh earned 500 total points
ID: 9775838
If the window is 3 pixels wide, and you place it at top left corner, it would span from 0 to 3

Try this code:

      HWND hWnd = CreateWindow("EDIT", "", WS_CHILD|WS_VISIBLE, 0, 0, 3, 3, m_hWnd, NULL, AfxGetInstanceHandle(), NULL) ;

      RECT rc ;
      ::GetClientRect(hWnd, &rc) ;//see rect = {0, 0, 3, 3}

So, the answer would be width = right - left. not right - left +1
0
 
LVL 44

Expert Comment

by:AndyAinscow
ID: 9776823
If rect is a CRect then it has a function rect.Width().
Also note there is a NormalizeRect function which forces a positive width and height of the rect.  (think of left = 90, right=60, unnormalised width= -30, rect.right-rect.left=-30 but if you normalise it the width is then 30).
Why could the left be bigger than the right?
eg. Use the mouse to select an area but start at the bottom right first.  If the programmer was lazy you would end up with that situation.
0

Featured Post

Live: Real-Time Solutions, Start Here

Receive instant 1:1 support from technology experts, using our real-time conversation and whiteboard interface. Your first 5 minutes are always free.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Is it possible to combine several text files into one big one? (redhat v5 enterprise) 4 91
if loop in java 3 139
fizzArray2 challenge 1 78
Fibonacci challenge 11 120
In this article, I'll describe -- and show pictures of -- some of the significant additions that have been made available to programmers in the MFC Feature Pack for Visual C++ 2008.  These same feature are in the MFC libraries that come with Visual …
Introduction: Load and Save to file, Document-View interaction inside the SDI. Continuing from the second article about sudoku.   Open the project in visual studio. From the class view select CSudokuDoc and double click to open the header …
This video will show you how to get GIT to work in Eclipse.   It will walk you through how to install the EGit plugin in eclipse and how to checkout an existing repository.
Windows 10 is mostly good. However the one thing that annoys me is how many clicks you have to do to dial a VPN connection. You have to go to settings from the start menu, (2 clicks), Network and Internet (1 click), Click VPN (another click) then fi…

813 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

16 Experts available now in Live!

Get 1:1 Help Now