Click here to Skip to main content
15,867,686 members
Articles / Desktop Programming / MFC
Article

Resizing Controls at run time

Rate me:
Please Sign up or sign in to vote.
4.75/5 (15 votes)
30 Nov 2000 133.6K   3.3K   63   18
A method to allow the user to visually resize and position any control at run time.

Sample Image - resize_at_runtime.gif

Introduction

Suppose you wanted to give the user the ability to modify the size and position on a certain control? This example shows how to implement resizing controls on a dialog box as it is done when drawing controls on a dialog template or using Visual Basic at design time.

In order to accomplish this, we can use the class CRectTracker to manage all the drawing and resizing of a rectangular frame which also has (optional) 6 resize handlers (as in the image above). First thing to do is to invoke a CRectTracker and specify given coordinates:

LPRECT rect = new RECT;
CWnd* wnd = (CWnd*)(GetDlgItem(IDC_EDIT1));
wnd->GetWindowRect(rect);
ScreenToClient(rect);
m_tracker = new CRectTracker(rect,CRectTracker::dottedLine  | 
                CRectTracker::resizeOutside | 
                CRectTracker::hatchedBorder );
m_tracker->Draw(pDC);

There are two events that are needed to be taken care of:

  1. SetCursor
    if (pWnd == this && m_tracker->SetCursor(this, nHitTest))
        return TRUE;

    This is done in order to draw the correct mouse cursors when floating the mouse pointer over the rectangle.

  2. OnLButtonDown
    m_tracker->Track(this, point, TRUE);
    Invalidate(FALSE);
    CDC* pDC = GetDC();
    m_tracker->Draw(pDC);

    This will take care of the drawing of the rectangle with resizing it.

Once you have finished, all you have to do is draw the control with the new rectangle coordinates:

LPRECT rect = new RECT;
CWnd* wnd = (CWnd*)(GetDlgItem(IDC_EDIT1));
rect = LPRECT(m_tracker->m_rect); 
wnd->MoveWindow(rect,TRUE) ;

That's it!

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here


Written By
United States United States
This member has not yet provided a Biography. Assume it's interesting and varied, and probably something to do with programming.

Comments and Discussions

 
Questiontracker is coveraged by the sibling object Pin
handsome0314-Jun-12 17:56
handsome0314-Jun-12 17:56 
GeneralActivex resize Pin
20-May-04 4:57
suss20-May-04 4:57 
GeneralActivex resize Pin
Anonymous20-May-04 4:45
Anonymous20-May-04 4:45 
Questionhow to use from c# application Pin
jbmeeh13-Feb-04 10:33
jbmeeh13-Feb-04 10:33 
QuestionHow to save the new dialog layout back to a resource? Pin
DJM5-Aug-03 1:25
DJM5-Aug-03 1:25 
AnswerRe: How to save the new dialog layout back to a resource? Pin
David Pritchard17-Nov-04 3:08
David Pritchard17-Nov-04 3:08 
GeneralCursor goes away when linked with Static Library Pin
cdsmith29-Apr-03 6:34
cdsmith29-Apr-03 6:34 
GeneralRe: Cursor goes away when linked with Static Library Pin
lesnikowski9-Jan-04 2:20
lesnikowski9-Jan-04 2:20 
GeneralRe: Cursor goes away when linked with Static Library Pin
tohichoi19-Sep-05 20:57
tohichoi19-Sep-05 20:57 
GeneralRe: Cursor goes away when linked with Static Library Pin
Artem Moroz11-Jul-08 6:56
Artem Moroz11-Jul-08 6:56 
See this article http://support.microsoft.com/kb/208856[^]

CAUSE
When an application is linked to MFC by using the static library, the MFC resources are compiled into the executable of an application. The executable of the application will include the Afxres.rc file. To check this, click Resource Includes on the View menu. The Afxres.rc file has the resources that CRectTracker uses in the MFC source code.

These resources are only included when _AFX_NO_TRACKER_RESOURCES is not defined. The BLOCKS32 project has _AFX_NO_TRACKER_RESOURCES defined. Therefore, it does not put the resources that CRectTracker requires in the executable image of the application. Therefore, none of the cursors that are used by CRectTracker will show up when you build the sample by using MFC statically.


RESOLUTION
1. On the View menu, click Resource Includes.
2. Delete the following line:

#define _AFX_NO_TRACKER_RESOURCES
AnswerRe: Cursor goes away when linked with Static Library Pin
Anthony Dunk1-Jul-09 19:34
Anthony Dunk1-Jul-09 19:34 
GeneralI have a problem Pin
BoscoW21-Feb-03 22:38
BoscoW21-Feb-03 22:38 
GeneralGreat job Pin
Synetech18-Feb-03 8:30
Synetech18-Feb-03 8:30 
GeneralNE?YO BLAD! Pin
Booooo18-Nov-02 6:12
Booooo18-Nov-02 6:12 
General<FONT COLOR="#FF0000">CRectTracker hidden when controls overlap </font> Pin
sanskypotov7-Jul-02 22:05
sanskypotov7-Jul-02 22:05 
GeneralProblem Pin
15-Jun-01 0:03
suss15-Jun-01 0:03 
GeneralRe: Problem Pin
15-Oct-01 21:38
suss15-Oct-01 21:38 
GeneralRe: Problem Pin
Member 969-Apr-02 14:10
Member 969-Apr-02 14:10 

General General    News News    Suggestion Suggestion    Question Question    Bug Bug    Answer Answer    Joke Joke    Praise Praise    Rant Rant    Admin Admin   

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.