刚刚看了个CroundButton类,注释不够清楚,图像处理的函数一点都没头绪
在这里个大家贴出来,有心人给我理理来龙去脉哈
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#if !defined(AFX_ROUNDBUTTON_H__5254170E_59CF_11D1_ABBA_00A0243D1382__INCLUDED_)
#define AFX_ROUNDBUTTON_H__5254170E_59CF_11D1_ABBA_00A0243D1382__INCLUDED_
#if _MSC_VER >= 1000
#pragma once
#endif // _MSC_VER >= 1000
// RoundButton.h : header file
//
// Round buttons!
//
// Written by Chris Maunder (
chrismaunder@codeguru.com)
// Copyright (c) 1998.
//
// This code may be used in compiled form in any way you desire. This
// file may be redistributed unmodified 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 a simple email woulod 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.
//
/////////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////
// CRoundButton window
class CRoundButton : public CButton
{
// Construction
public:
CRoundButton();
// Attributes
public:
// Operations
public:
// Overrides
// ClassWizard generated virtual function overrides
//{{AFX_VIRTUAL(CRoundButton)
public:
virtual void DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct);
protected:
virtual void PreSubclassWindow();
//}}AFX_VIRTUAL
// Implementation
public:
virtual ~CRoundButton();
CRgn m_rgn;
CPoint m_ptCentre;
int m_nRadius;
BOOL m_bDrawDashedFocusCircle;
// Generated message map functions
protected:
//{{AFX_MSG(CRoundButton)
//}}AFX_MSG
DECLARE_MESSAGE_MAP()
};
/////////////////////////////////////////////////////////////////////////////
//{{AFX_INSERT_LOCATION}}
// Microsoft Developer Studio will insert additional declarations immediately before the previous line.
#endif // !defined(AFX_ROUNDBUTTON_H__5254170E_59CF_11D1_ABBA_00A0243D1382__INCLUDED_)
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// RoundButton.cpp : implementation file
//
// Round Buttons!
//
// Written by Chris Maunder (
chrismaunder@codeguru.com)
// Copyright (c) 1997,1998.
//
// Modified: 2 Feb 1998 - Fix vis problem, CRgn resource leak,
// button reposition code redone. CJM.
//
// This code may be used in compiled form in any way you desire. This
// file may be redistributed unmodified 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 a simple email 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 "math.h"
#include "RoundButton.h"
#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif
// prototypes
COLORREF GetColour(double dAngle, COLORREF crBright, COLORREF crDark);
void DrawCircle(CDC* pDC, CPoint p, LONG lRadius, COLORREF crColour, BOOL bDashed = FALSE);
void DrawCircle(CDC* pDC, CPoint p, LONG lRadius, COLORREF crBright, COLORREF crDark);
// Calculate colour for a point at the given angle by performing a linear
// interpolation between the colours crBright and crDark based on the cosine
// of the angle between the light source and the point.
//
// Angles are measured from the +ve x-axis (i.e. (1,0) = 0 degrees, (0,1) = 90 degrees )
// But remember: +y points down!
COLORREF GetColour(double dAngle, COLORREF crBright, COLORREF crDark)
{
#define Rad2Deg 180.0/3.1415
#define LIGHT_SOURCE_ANGLE -2.356 // -2.356 radians = -135 degrees, i.e. From top left
ASSERT(dAngle > -3.1416 && dAngle < 3.1416);
double dAngleDifference = LIGHT_SOURCE_ANGLE - dAngle;
if (dAngleDifference < -3.1415) dAngleDifference = 6.293 + dAngleDifference;
else if (dAngleDifference > 3.1415) dAngleDifference = 6.293 - dAngleDifference;
double Weight = 0.5*(cos(dAngleDifference)+1.0);
BYTE Red = (BYTE) (Weight*GetRValue(crBright) + (1.0-Weight)*GetRValue(crDark));
BYTE Green = (BYTE) (Weight*GetGValue(crBright) + (1.0-Weight)*GetGValue(crDark));
BYTE Blue = (BYTE) (Weight*GetBValue(crBright) + (1.0-Weight)*GetBValue(crDark));
//TRACE("LightAngle = %0.0f, Angle = %3.0f, Diff = %3.0f, Weight = %0.2f, RGB %3d,%3d,%3d\n",
// LIGHT_SOURCE_ANGLE*Rad2Deg, dAngle*Rad2Deg, dAngleDifference*Rad2Deg, Weight,Red,Green,Blue);
return RGB(Red, Green, Blue);
}
void DrawCircle(CDC* pDC, CPoint p, LONG lRadius, COLORREF crColour, BOOL bDashed)
{
const int nDashLength = 1;
LONG lError, lXoffset, lYoffset;
int nDash = 0;
BOOL bDashOn = TRUE;
//Check to see that the coordinates are valid
ASSERT( (p.x + lRadius <= LONG_MAX) && (p.y + lRadius <= LONG_MAX) );
ASSERT( (p.x - lRadius >= LONG_MIN) && (p.y - lRadius >= LONG_MIN) );
//Set starting values
lXoffset = lRadius;
lYoffset = 0;
lError = -lRadius;
do {
if (bDashOn) {
pDC->SetPixelV(p.x + lXoffset, p.y + lYoffset, crColour);
pDC->SetPixelV(p.x + lXoffset, p.y - lYoffset, crColour);
pDC->SetPixelV(p.x + lYoffset, p.y + lXoffset, crColour);
pDC->SetPixelV(p.x + lYoffset, p.y - lXoffset, crColour);
pDC->SetPixelV(p.x - lYoffset, p.y + lXoffset, crColour);
pDC->SetPixelV(p.x - lYoffset, p.y - lXoffset, crColour);
pDC->SetPixelV(p.x - lXoffset, p.y + lYoffset, crColour);
pDC->SetPixelV(p.x - lXoffset, p.y - lYoffset, crColour);
}
//Advance the error term and the constant X axis step
lError += lYoffset++;
//Check to see if error term has overflowed
if ((lError += lYoffset) >= 0)
lError -= --lXoffset * 2;
if (bDashed && (++nDash == nDashLength)) {
nDash = 0;
bDashOn = !bDashOn;
}
} while (lYoffset <= lXoffset); //Continue until halfway point
}
void DrawCircle(CDC* pDC, CPoint p, LONG lRadius, COLORREF crBright, COLORREF crDark)
{
LONG lError, lXoffset, lYoffset;
//Check to see that the coordinates are valid
ASSERT( (p.x + lRadius <= LONG_MAX) && (p.y + lRadius <= LONG_MAX) );
ASSERT( (p.x - lRadius >= LONG_MIN) && (p.y - lRadius >= LONG_MIN) );
//Set starting values
lXoffset = lRadius;
lYoffset = 0;
lError = -lRadius;
do {
const double Pi = 3.141592654,
Pi_on_2 = Pi * 0.5,
Three_Pi_on_2 = Pi * 1.5;
COLORREF crColour;
double dAngle = atan2(lYoffset, lXoffset);
//Draw the current pixel, reflected across all eight arcs
crColour = GetColour(dAngle, crBright, crDark);
pDC->SetPixelV(p.x + lXoffset, p.y + lYoffset, crColour);
crColour = GetColour(Pi_on_2 - dAngle, crBright, crDark);
pDC->SetPixelV(p.x + lYoffset, p.y + lXoffset, crColour);
crColour = GetColour(Pi_on_2 + dAngle, crBright, crDark);
pDC->SetPixelV(p.x - lYoffset, p.y + lXoffset, crColour);
crColour = GetColour(Pi - dAngle, crBright, crDark);
pDC->SetPixelV(p.x - lXoffset, p.y + lYoffset, crColour);
crColour = GetColour(-Pi + dAngle, crBright, crDark);
pDC->SetPixelV(p.x - lXoffset, p.y - lYoffset, crColour);
crColour = GetColour(-Pi_on_2 - dAngle, crBright, crDark);
pDC->SetPixelV(p.x - lYoffset, p.y - lXoffset, crColour);
crColour = GetColour(-Pi_on_2 + dAngle, crBright, crDark);
pDC->SetPixelV(p.x + lYoffset, p.y - lXoffset, crColour);
crColour = GetColour(-dAngle, crBright, crDark);
pDC->SetPixelV(p.x + lXoffset, p.y - lYoffset, crColour);
//Advance the error term and the constant X axis step
lError += lYoffset++;
//Check to see if error term has overflowed
if ((lError += lYoffset) >= 0)
lError -= --lXoffset * 2;
} while (lYoffset <= lXoffset); //Continue until halfway point
}
/////////////////////////////////////////////////////////////////////////////
// CRoundButton
CRoundButton::CRoundButton()
{
m_bDrawDashedFocusCircle = TRUE;
}
CRoundButton::~CRoundButton()
{
m_rgn.DeleteObject();
}
BEGIN_MESSAGE_MAP(CRoundButton, CButton)
//{{AFX_MSG_MAP(CRoundButton)
//}}AFX_MSG_MAP
END_MESSAGE_MAP()
/////////////////////////////////////////////////////////////////////////////
// CRoundButton message handlers
void CRoundButton::PreSubclassWindow()
{
CButton::PreSubclassWindow();
ModifyStyle(0, BS_OWNERDRAW);
CRect rect;
GetClientRect(&rect);
// Resize the window to make it square
rect.bottom = rect.right = min(rect.bottom,rect.right);
// Get the vital statistics of the window
m_ptCentre = rect.CenterPoint();
m_nRadius = rect.bottom/2-1;
// Set the window region so mouse clicks only activate the round section
// of the button
m_rgn.DeleteObject();
SetWindowRgn(NULL, FALSE);
m_rgn.CreateEllipticRgnIndirect(rect);
SetWindowRgn(m_rgn, TRUE);
// Convert client coords to the parents client coords
ClientToScreen(rect);
CWnd* pParent = GetParent();
if (pParent) pParent->ScreenToClient(rect);
// Resize the window
MoveWindow(rect.left, rect.top, rect.Width(), rect.Height(), TRUE);
}
void CRoundButton::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct)
{
ASSERT(lpDrawItemStruct != NULL);
CDC* pDC = CDC::FromHandle(lpDrawItemStruct->hDC);
CRect rect = lpDrawItemStruct->rcItem;
UINT state = lpDrawItemStruct->itemState;
UINT nStyle = GetStyle();
int nRadius = m_nRadius;
int nSavedDC = pDC->SaveDC();
pDC->SelectStockObject(NULL_BRUSH);
pDC->FillSolidRect(rect, ::GetSysColor(COLOR_BTNFACE));
// Draw the focus circle around the button
if ((state & ODS_FOCUS) && m_bDrawDashedFocusCircle)
DrawCircle(pDC, m_ptCentre, nRadius--, RGB(0,0,0));
// Draw the raised/sunken edges of the button (unless flat)
if (nStyle & BS_FLAT) {
DrawCircle(pDC, m_ptCentre, nRadius--, RGB(0,0,0));
DrawCircle(pDC, m_ptCentre, nRadius--, ::GetSysColor(COLOR_3DHIGHLIGHT));
} else {
if ((state & ODS_SELECTED)) {
DrawCircle(pDC, m_ptCentre, nRadius--,
::GetSysColor(COLOR_3DDKSHADOW), ::GetSysColor(COLOR_3DHIGHLIGHT));
DrawCircle(pDC, m_ptCentre, nRadius--,
::GetSysColor(COLOR_3DSHADOW), ::GetSysColor(COLOR_3DLIGHT));
} else {
DrawCircle(pDC, m_ptCentre, nRadius--,
::GetSysColor(COLOR_3DHIGHLIGHT), ::GetSysColor(COLOR_3DDKSHADOW));
DrawCircle(pDC, m_ptCentre, nRadius--,
::GetSysColor(COLOR_3DLIGHT), ::GetSysColor(COLOR_3DSHADOW));
}
}
// draw the text if there is any
CString strText;
GetWindowText(strText);
if (!strText.IsEmpty())
{
CRgn rgn;
rgn.CreateEllipticRgn(m_ptCentre.x-nRadius, m_ptCentre.y-nRadius,
m_ptCentre.x+nRadius, m_ptCentre.y+nRadius);
pDC->SelectClipRgn(&rgn);
CSize Extent = pDC->GetTextExtent(strText);
CPoint pt = CPoint( m_ptCentre.x - Extent.cx/2, m_ptCentre.x - Extent.cy/2 );
if (state & ODS_SELECTED) pt.Offset(1,1);
pDC->SetBkMode(TRANSPARENT);
if (state & ODS_DISABLED)
pDC->DrawState(pt, Extent, strText, DSS_DISABLED, TRUE, 0, (HBRUSH)NULL);
else
pDC->TextOut(pt.x, pt.y, strText);
pDC->SelectClipRgn(NULL);
rgn.DeleteObject();
}
// Draw the focus circle on the inside of the button
if ((state & ODS_FOCUS) && m_bDrawDashedFocusCircle)
DrawCircle(pDC, m_ptCentre, nRadius-2, RGB(0,0,0), TRUE);
pDC->RestoreDC(nSavedDC);
}
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重点讲解cpp中的函数的来龙去脉啊