能显示文字的进度条

    这是一个比较简单的有关于进度条控制的类，它在进度框中能够显示文件名和百分比，我想读者肯定在装软件的时候看到过。这个类最重要的功能就是允许在进度条中显示文字，如下：

   void setshowtext(bool bshow);

    你可以通过这个函数来设置是否能显示文字。设置文字你可以用cwnd::setwindowtext，如果你用函数setshowtext(true)来设置能显示文字，但是你没有用cwnd::setwindowtext来设置要显示的文字是什么，那么该类就会用默认的设置，只显示进度百分比，这点大家还是要注意的。

    由于本人是菜鸟级的VC编程手，还没有完全理解其中的内容，也就是说没有看完全部的代码，我希望读者能把它读完，会更有好处。下面是其中的一些函数的功能，请大家笑纳：

void SetForeColour(colorref col)        设置进度条中的条的颜色
void SetBkColour(colorref col)          设置进度条的背景色
void SetTextForeColour(colorref col)    当进度条没有覆盖文本时，文本的颜色
void SetTextBkColour(colorref col)      当进度条覆盖文本时，文本的颜色
CORLORREF GetForeColour()               得到进度条中条的颜色
CORLORREF GetBkColour()                 得到进度条的背景色
CORLORREF GetTextForeColour()           当进度条没有覆盖文本时，得到文本的颜色
CORLORREF GetTextBkColour()             当进度条覆盖文本时，得到文本的颜色
  下面是全部的代码，包括H文件CPP文件

//以下是H文件
#if !defined(AFX_TEXTPROGRESSCTRL_H__4C78DBBE_EFB6_11D1_AB14_203E25000000__INCLUDED_)
#define AFX_TEXTPROGRESSCTRL_H__4C78DBBE_EFB6_11D1_AB14_203E25000000__INCLUDED_

#if _MSC_VER >= 1000
#pragma once
#endif // _MSC_VER >= 1000

// TextProgressCtrl.h : header file
//
// Written by Chris Maunder ([e-mail])
// Copyright 1998.
/////////////////////////////////////////////////////////////////////////////
// CTextProgressCtrl window

class CTextProgressCtrl : public CProgressCtrl
{
// Construction
public:
    CTextProgressCtrl();

// Attributes
public:

// Operations
public:
    int            SetPos(int nPos);
    int            StepIt();
    void        SetRange(int nLower, int nUpper);
    int            OffsetPos(int nPos);
    int            SetStep(int nStep);
    void        SetForeColour(COLORREF col);
    void        SetBkColour(COLORREF col);
    void        SetTextForeColour(COLORREF col);
    void        SetTextBkColour(COLORREF col);
    COLORREF    GetForeColour();
    COLORREF    GetBkColour();
    COLORREF    GetTextForeColour();
    COLORREF    GetTextBkColour();

    void        SetShowText(BOOL bShow);

// Overrides
    // ClassWizard generated virtual function overrides
    //{{AFX_VIRTUAL(CTextProgressCtrl)
    //}}AFX_VIRTUAL

// Implementation
public:
    virtual ~CTextProgressCtrl();

    // Generated message map functions
protected:
    int            m_nPos,
                m_nStepSize,
                m_nMax,
                m_nMin;
    CString        m_strText;
    BOOL        m_bShowText;
    int            m_nBarWidth;
    COLORREF    m_colFore,
                m_colBk,
                m_colTextFore,
                m_colTextBk;

    //{{AFX_MSG(CTextProgressCtrl)
    afx_msg BOOL OnEraseBkgnd(CDC* pDC);
    afx_msg void OnPaint();
    afx_msg void OnSize(UINT nType, int cx, int cy);
    //}}AFX_MSG
    afx_msg LRESULT OnSetText(UINT, LPCTSTR szText);
    afx_msg LRESULT OnGetText(UINT cchTextMax, LPTSTR szText);

    DECLARE_MESSAGE_MAP()
};

/////////////////////////////////////////////////////////////////////////////

//{{AFX_INSERT_LOCATION}}
// Microsoft Developer Studio will insert additional declarations immediately before the previous line.

#endif // !defined(AFX_TEXTPROGRESSCTRL_H__4C78DBBE_EFB6_11D1_AB14_203E25000000__INCLUDED_)

//以下是CPP文件
// TextProgressCtrl.cpp : implementation file
//
// Written by Chris Maunder ([e-mail])
// Copyright 1998.
//
// Modified : 26/05/98 Jeremy Davis, [e-mail]
//                Added colour routines
//
// TextProgressCtrl is a drop-in replacement for the standard
// CProgressCtrl that displays text in a progress control.
//
// This code may be used in compiled form in any way you desire. This
// file may be redistributed by any means PROVIDING it is not sold for
// profit without the authors written consent, and providing that this
// notice and the authors name is included. If the source code in
// this file is used in any commercial application then an email to
// the me would be nice.
//
// This file is provided "as is" with no expressed or implied warranty.
// The author accepts no liability if it causes any damage to your
// computer, causes your pet cat to fall ill, increases baldness or
// makes you car start emitting strange noises when you start it up.
//
// Expect bugs.
//
// Please use and enjoy. Please let me know of any bugs/mods/improvements
// that you have found/implemented and I will fix/incorporate them into this
// file.

#include "stdafx.h"
#include "TextProgressCtrl.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif


#ifndef _MEMDC_H_
//////////////////////////////////////////////////
// CMemDC - memory DC
//
// Author: Keith Rule
// Email:  [e-mail]
// Copyright 1996-1997, Keith Rule
//
// You may freely use or modify this code provided this
// Copyright is included in all derived versions.
//
// History - 10/3/97 Fixed scrolling bug.
//                   Added print support.
//
// This class implements a memory Device Context

class CMemDC : public CDC
{
public:

    // constructor sets up the memory DC
    CMemDC(CDC* pDC) : CDC()
    {
        ASSERT(pDC != NULL);

        m_pDC = pDC;
        m_pOldBitmap = NULL;
        m_bMemDC = !pDC->IsPrinting();
              
        if (m_bMemDC)    // Create a Memory DC
        {
            pDC->GetClipBox(&m_rect);
            CreateCompatibleDC(pDC);
            m_bitmap.CreateCompatibleBitmap(pDC, m_rect.Width(), m_rect.Height());
            m_pOldBitmap = SelectObject(&m_bitmap);
            SetWindowOrg(m_rect.left, m_rect.top);
        }
        else        // Make a copy of the relevent parts of the current DC for printing
        {
            m_bPrinting = pDC->m_bPrinting;
            m_hDC       = pDC->m_hDC;
            m_hAttribDC = pDC->m_hAttribDC;
        }
    }
    
    // Destructor copies the contents of the mem DC to the original DC
    ~CMemDC()
    {
        if (m_bMemDC)
        {    
            // Copy the offscreen bitmap onto the screen.
            m_pDC->BitBlt(m_rect.left, m_rect.top, m_rect.Width(), m_rect.Height(),
                          this, m_rect.left, m_rect.top, SRCCOPY);

            //Swap back the original bitmap.
            SelectObject(m_pOldBitmap);
        } else {
            // All we need to do is replace the DC with an illegal value,
            // this keeps us from accidently deleting the handles associated with
            // the CDC that was passed to the constructor.
            m_hDC = m_hAttribDC = NULL;
        }
    }

    // Allow usage as a pointer
    CMemDC* operator->() {return this;}
        
    // Allow usage as a pointer
    operator CMemDC*() {return this;}

private:
    CBitmap  m_bitmap;      // Offscreen bitmap
    CBitmap* m_pOldBitmap;  // bitmap originally found in CMemDC
    CDC*     m_pDC;         // Saves CDC passed in constructor
    CRect    m_rect;        // Rectangle of drawing area.
    BOOL     m_bMemDC;      // TRUE if CDC really is a Memory DC.
};

#endif



/////////////////////////////////////////////////////////////////////////////
// CTextProgressCtrl

CTextProgressCtrl::CTextProgressCtrl()
{
    m_nPos            = 0;
    m_nStepSize        = 1;
    m_nMax            = 100;
    m_nMin            = 0;
    m_bShowText        = TRUE;
    m_strText.Empty();
    m_colFore        = ::GetSysColor(COLOR_HIGHLIGHT);
    m_colBk            = ::GetSysColor(COLOR_WINDOW);
    m_colTextFore    = ::GetSysColor(COLOR_HIGHLIGHT);
    m_colTextBk        = ::GetSysColor(COLOR_WINDOW);

    m_nBarWidth = -1;
}

CTextProgressCtrl::~CTextProgressCtrl()
{
}

BEGIN_MESSAGE_MAP(CTextProgressCtrl, CProgressCtrl)
    //{{AFX_MSG_MAP(CTextProgressCtrl)
    ON_WM_ERASEBKGND()
    ON_WM_PAINT()
    ON_WM_SIZE()
    //}}AFX_MSG_MAP
    ON_MESSAGE(WM_SETTEXT, OnSetText)
    ON_MESSAGE(WM_GETTEXT, OnGetText)
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CTextProgressCtrl message handlers

LRESULT CTextProgressCtrl::OnSetText(UINT, LPCTSTR szText)
{
    LRESULT result = Default();

    if ( (!szText && m_strText.GetLength()) ||
         (szText && (m_strText != szText))   )
    {
        m_strText = szText;
        Invalidate();
    }

    return result;
}

LRESULT CTextProgressCtrl::OnGetText(UINT cchTextMax, LPTSTR szText)
{
    if (!_tcsncpy(szText, m_strText, cchTextMax))
        return 0;
    else
        return min(cchTextMax, (UINT) m_strText.GetLength());
}

BOOL CTextProgressCtrl::OnEraseBkgnd(CDC* /*pDC*/)
{    
     return TRUE;
}

void CTextProgressCtrl::OnSize(UINT nType, int cx, int cy)
{
    CProgressCtrl::OnSize(nType, cx, cy);
    
    m_nBarWidth    = -1;   // Force update if SetPos called
}

void CTextProgressCtrl::OnPaint()
{
    if (m_nMin >= m_nMax)
        return;

    CRect LeftRect, RightRect, ClientRect;
    GetClientRect(ClientRect);

    double Fraction = (double)(m_nPos - m_nMin) / ((double)(m_nMax - m_nMin));

    CPaintDC PaintDC(this); // device context for painting
    CMemDC dc(&PaintDC);
    //CPaintDC dc(this);    // device context for painting (if not double buffering)

    LeftRect = RightRect = ClientRect;

    LeftRect.right = LeftRect.left + (int)((LeftRect.right - LeftRect.left)*Fraction);
    dc.FillSolidRect(LeftRect, m_colFore);

    RightRect.left = LeftRect.right;
    dc.FillSolidRect(RightRect, m_colBk);

    if (m_bShowText)
    {
        CString str;
        if (m_strText.GetLength())
            str = m_strText;
        else
            str.Format("%d%%", (int)(Fraction*100.0));

        dc.SetBkMode(TRANSPARENT);

        CRgn rgn;
        rgn.CreateRectRgn(LeftRect.left, LeftRect.top, LeftRect.right, LeftRect.bottom);
        dc.SelectClipRgn(&rgn);
        dc.SetTextColor(m_colTextBk);

        dc.DrawText(str, ClientRect, DT_CENTER | DT_VCENTER | DT_SINGLELINE);

        rgn.DeleteObject();
        rgn.CreateRectRgn(RightRect.left, RightRect.top, RightRect.right, RightRect.bottom);
        dc.SelectClipRgn(&rgn);
        dc.SetTextColor(m_colTextFore);

        dc.DrawText(str, ClientRect, DT_CENTER | DT_VCENTER | DT_SINGLELINE);
    }
}

void CTextProgressCtrl::SetForeColour(COLORREF col)
{
    m_colFore = col;
}

void CTextProgressCtrl::SetBkColour(COLORREF col)
{
    m_colBk = col;
}

void CTextProgressCtrl::SetTextForeColour(COLORREF col)
{
    m_colTextFore = col;
}

void CTextProgressCtrl::SetTextBkColour(COLORREF col)
{
    m_colTextBk = col;
}

COLORREF CTextProgressCtrl::GetForeColour()
{
    return m_colFore;
}

COLORREF CTextProgressCtrl::GetBkColour()
{
    return m_colBk;
}

COLORREF CTextProgressCtrl::GetTextForeColour()
{
    return m_colTextFore;
}

COLORREF CTextProgressCtrl::GetTextBkColour()
{
    return m_colTextBk;
}
/////////////////////////////////////////////////////////////////////////////
// CTextProgressCtrl message handlers

void CTextProgressCtrl::SetShowText(BOOL bShow)
{
    if (::IsWindow(m_hWnd) && m_bShowText != bShow)
        Invalidate();

    m_bShowText = bShow;
}


void CTextProgressCtrl::SetRange(int nLower, int nUpper)
{
    m_nMax = nUpper;
    m_nMin = nLower;
}

int CTextProgressCtrl::SetPos(int nPos)
{    
    if (!::IsWindow(m_hWnd))
        return -1;

    int nOldPos = m_nPos;
    m_nPos = nPos;

    CRect rect;
    GetClientRect(rect);

    double Fraction = (double)(m_nPos - m_nMin) / ((double)(m_nMax - m_nMin));
    int nBarWidth = (int) (Fraction * rect.Width());

    if (nBarWidth != m_nBarWidth)
    {
        m_nBarWidth = nBarWidth;
        RedrawWindow();
    }

    return nOldPos;
}

int CTextProgressCtrl::StepIt()
{    
   return SetPos(m_nPos + m_nStepSize);
}

int CTextProgressCtrl::OffsetPos(int nPos)
{
    return SetPos(m_nPos + nPos);
}

int CTextProgressCtrl::SetStep(int nStep)
{
    int nOldStep = nStep;
    m_nStepSize = nStep;
    return nOldStep;
}