Re: How to resize an Custom class derived from CEdit when it reaches its max text limit?

From:
sujeet27kulk@gmail.com
Newsgroups:
microsoft.public.vc.mfc
Date:
Fri, 11 Apr 2008 02:09:43 -0700 (PDT)
Message-ID:
<c55769a8-b192-4ee8-ac72-0ffd0f9953b5@u12g2000prd.googlegroups.com>
On Apr 11, 12:51 am, Joseph M. Newcomer <newco...@flounder.com> wrote:

See below...

On Thu, 10 Apr 2008 10:46:06 -0700 (PDT), sujeet27k...@gmail.com wrote:

On Apr 10, 6:23 pm, Joseph M. Newcomer <newco...@flounder.com> wrote:

In the OnUpdate handler:

CClientDC dc(this);
CFont * f = GetFont();
dc.SelectObject(f);
CString s;
GetWindowText(s);
CSize sz = dc.GetTextExtent(s);
CRect r;
GetClientRect(&r);
if(r.right > sz.cx)
   r.right = sz.cx;
if(r.right < MY_MIN_SIZE)
    r.right = MY_MIN_SIZE;
r.right += MY_MINIMUM_RIGHT_PADDING;
CalcWindowRect(&r);

CRect w;
GetWindowRect(&w);
if(r.Width() != w.Width())
    SetWindowPos(NULL, 0, 0, r.Width(), r.Height(), SWP_NOMOVE | SW=

P_NOZORDER);

This should do the job. I'm typing this in off the top of my head, b=

ut its probably

pretty close to what you will need.
                                joe

On Thu, 10 Apr 2008 01:55:25 -0700 (PDT), sujeet27k...@gmail.com wrote:=

Hi, I have a class derrived from CEdit. I need to resize it when it
reaches its max text limit in order to accomodate the new character.


****
Max text limit is not an issue; maximum width of the edit control is what =

this is testing

*****

But if I incremant it by a fixed size there is a problem. As each
character is taking different space. like 'l' , '.' and '2' wiil
require different space. So a constant number doesen't fit the bill.
Also when I press backspace the Edit control should decreament by
exact size required by the chartacter (I fill this is somewhat more
difficult as you need to know the size of a character) back space is
going to delete.Please help if anybody has the solution.


Joseph M. Newcomer [MVP]
email: newco...@flounder.com
Web:http://www.flounder.com
MVP Tips:http://www.flounder.com/mvp_tips.htm


Hi, Thanks for posting but I am not getting how this will increse the
size of CEdit control when it reaches the max limit.


****
See above coment on max limit.
****>As I think update

will never occur. I tried this out but its not working .


****
Update *always* occurs when you change the contents. This would have to=

 be a reflected

method of the edit control (=EN_UPDATE) which I forgot to mention
****>Now I am getting width of character through GetCharWidth32()

****
There is no need to call GetCharWidth32(), and in any case CDC::GetTextExt=

ent is what you

need to use. What you are doing is not correct.
****>and

increasing Size of CEdit control in OnEnMaxtext()


****
EN_MAXTEXT is sent when the maximum number of characters that can be typed=

 is reached, but

this has nothing to do with your problem.
****> but still the

character width is more than the actual space required and also not in
a proper ratio(for various characters).


****
I have no idea what you just said.
****>And when user presses the

backspace the problem of decreasing the size is remains.


****
The algorithm I gave should work no matter what the size is. But it has=

 a couple bugs.

Below is the corrected code
****>And second

thing is my CEdit boxes are floating so if first ncreases in size
second should be moved.


****
Well, that's something you have to account for; I just showed how to incre=

ase one. How

you do your geometry management of multiple controls is up to you.
                                joe
****
// Note: to make this work, you must set AutoHScroll to FALSE

// ExtensibleEdit.h
#pragma once

// CExtensibleEdit

class CExtensibleEdit : public CEdit
{
        DECLARE_DYNAMIC(CExtensibleEdit)

public:
        CExtensibleEdit();
        virtual ~CExtensibleEdit();

protected:
        DECLARE_MESSAGE_MAP()
        int MinSize;
protected:
        afx_msg void OnEnUpdate();
protected:
        virtual void PreSubclassWindow();

};

// ExtensibleEdit.cpp : implementation file
//

#include "stdafx.h"
#include "ExtensibleEdit.h"

// CExtensibleEdit

IMPLEMENT_DYNAMIC(CExtensibleEdit, CEdit)

CExtensibleEdit::CExtensibleEdit()
{

}

CExtensibleEdit::~CExtensibleEdit()
{

}

BEGIN_MESSAGE_MAP(CExtensibleEdit, CEdit)
        ON_CONTROL_REFLECT(EN_UPDATE, &CExtensibleEdit::OnEnUpdate=

)

END_MESSAGE_MAP()

// CExtensibleEdit message handlers

void CExtensibleEdit::OnEnUpdate()
   {
    CClientDC dc(this);
    CFont * f = GetFont();
    dc.SelectObject(f);

    //****************************************************************=

    // |<---------GetWindowRect().Width()---------->|_________
    // BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB ^
    // B+------------------------------------------+B |
    // B| *** =

     * * |B |

    // B| * * =

    ** ** |B |

    // B| ***** =

   * * * |B GetWindowRect().Height()

    // B| * * =

    * * |B |

    // B| * * =

    * * |B |

    // B+------------------------------------------+B |
    // BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB_____V___
    //-->| |<--LOWORD(margins) -->| =

|<--HIWORD(margins)

    // | |<------dc.GetTextExtent().cx------>| |
    //
    // The border is indicated by B
    //****************************************************************=

    int padding = dc.GetTextExtent(_T(" ")).cx;

    DWORD margins = GetMargins();
    int margin = LOWORD(margins) + HIWORD(margins);

    CString s;
    GetWindowText(s);
    CSize sz = dc.GetTextExtent(s);

    // Compute the desired space for the string, and extend the space =

so it has extra

space

    sz.cx += margin + padding;
    if(sz.cx < MinSize)
       sz.cx = MinSize;

    CRect r;
    GetClientRect(&r);

    r.right = sz.cx;
    r.right += padding;
    CalcWindowRect(&r);

    CRect w;
    GetWindowRect(&w);
    int width = w.Width();
    if(r.Width() != width)
       SetWindowPos(NULL, 0, 0, r.Width(), w.Height(), SWP_NOMOVE =

| SWP_NOZORDER);

   }

void CExtensibleEdit::PreSubclassWindow()
{
        ASSERT( (GetStyle() & ES_AUTOHSCROLL) == 0);
        CEdit::PreSubclassWindow();
        CRect w;
        GetClientRect(&w);
        DWORD margins = GetMargins();
        int margin = LOWORD(margins) + HIWORD(margins);

        MinSize = w.Width() - margin;

}

Joseph M. Newcomer [MVP]
email: newco...@flounder.com
Web:http://www.flounder.com
MVP Tips:http://www.flounder.com/mvp_tips.htm- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -


Thanks.Its working.

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