1. MFC GUI 编程

2. Greetings

3. Hello, World! class CGreetingsDoc : public CDocument {
protected: // create from serialization only
char *m_pMessage;
// Attributes
public:
char *GetGreetings()
return m_pMessage; } …
CGreetingsDoc::CGreetingsDoc()
m_pMessage = "Hello, world!";

4. void CGreetingsView::OnDraw(CDC* pDC){
CGreetingsDoc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
RECT ClientRect;
GetClientRect(&ClientRect);
pDC->DrawText( pDoc->GetGreetings(), -1, &ClientRect, DT_CENTER ); }

5. Button void CGreetingsView::OnButtongreetings() {
AfxMessageBox("Hello, world!"); }

6. MiniDraw

7. MiniDraw
用户可以画不同的图形元素
Line, rectangle, ellipse, polygon…
demo

8. 1. 用鼠标画线

9. Member Variables class CMiniDrawView : public CView { private:
int m_Dragging;
CPoint m_PointOld;
CPoint m_PointOrigin; }
CMiniDrawView::CMiniDrawView()
m_Dragging = 0;

10. 响应消息
ClassWizard (^W)

11. WM_LBUTTONDOWN
void CMiniDrawView::OnLButtonDown(UINT nFlags, CPoint point) {
//AfxMessageBox("button down");
m_PointOrigin = point;
m_PointOld = point;
m_Dragging = 1;
CView::OnLButtonDown(nFlags, point); }

12. WM_MOUSEMOVE
void CMiniDrawView::OnMouseMove(UINT nFlags, CPoint point) {
if( !m_Dragging )
return;
CClientDC ClientDC( this );
ClientDC.SetROP2( R2_NOT );
ClientDC.MoveTo( m_PointOrigin );
ClientDC.LineTo( m_PointOld );
ClientDC.LineTo( point );
m_PointOld = point;
CView::OnMouseMove(nFlags, point); }

13. WM_LBUTTONUP
void CMiniDrawView::OnLButtonUp(UINT nFlags, CPoint point) {
if( !m_Dragging )
return ;
CClientDC ClientDC( this );
ClientDC.SetROP2( R2_NOT );
ClientDC.MoveTo( m_PointOrigin );
ClientDC.LineTo( m_PointOld );
ClientDC.SetROP2( R2_COPYPEN );
ClientDC.LineTo( point );
m_Dragging = 0;
CView::OnLButtonUp(nFlags, point); }

14. Problem
窗口更新后线段消失了
原因？
没有存储数据

15. 2. 存储数据

16. 线段数据结构 class CLine { private: int m_X1, m_Y1, m_X2, m_Y2; public:
CLine(int X1, int Y1, int X2, int Y2 )
m_X1 = X1;
m_Y1 = Y1;
m_X2 = X2;
m_Y2 = Y2; }
void Draw( CDC *pDC )
pDC->MoveTo( m_X1, m_Y1 );
pDC->LineTo( m_X2, m_Y2 ); };

17. 保存线段的数组 class CMiniDrawView : public CView {
vector<CLine *> m_LineArray; … }
#include <vector>
using namespace std;

18. 保存线段数据 void CMiniDrawView::OnLButtonUp(UINT nFlags, CPoint point) {
// TODO: Add your message handler code here and/or call default
if( m_Dragging )
CClientDC ClientDC( this );
ClientDC.SetROP2( R2_NOT );
ClientDC.MoveTo( m_PointOrigin );
ClientDC.LineTo( m_PointOld );
ClientDC.SetROP2( R2_COPYPEN );
ClientDC.LineTo( point );
m_Dragging = 0;
CLine *pLine = NULL;
pLine = new CLine(m_PointOrigin.x, m_PointOrigin.y,
point.x, point.y );
m_LineArray.push_back( pLine ); }

19. 重画所有线段 void CMiniDrawView::OnDraw(CDC* pDC) {
CMiniDrawDoc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
// TODO: add draw code for native data here
for( int i=0; i<m_LineArray.size(); i++)
m_LineArray.at(i)->Draw(pDC); }

20. 如何检测有无内存泄漏
Debug information

21. 释放空间 CMiniDrawView::~CMiniDrawView() {
for( int i=0; i<m_LineArray.size(); i++)
SAFEDELETE ( m_LineArray.at(i) ); }
#define SAFEDELETE(p) {if(p){delete p; p=NULL;}}

22. 3. 更多图形元素
不同类型图形元素如何存储？
如何组织它们之间的关系？

23. 椭圆图形及数据结构 class CEllipse { private: int m_X1, m_Y1, m_X2, m_Y2;
public:
CEllipse(int X1, int Y1, int X2, int Y2 )
m_X1 = X1;
m_Y1 = Y1;
m_X2 = X2;
m_Y2 = Y2; }
void Draw( CDC *pDC )
pDC->Ellipse( m_X1, m_Y1, m_X2, m_Y2 ); };

24. ??? vector<CLine *> m_LineArray;
vector<CEllipse *> m_EllipseArray; …

25. 4. 父类和继承 class CFigure { public:
virtual void Draw( CDC *pDC ) {} //虚函数 };
class CLine: public CFigure
class CEllipse: public CFigure

26. 5. 图形数组 class CMiniDrawView : public CView {
vector<CFigure *> m_FigArray;
UINT m_CurrentTool; //图形类型 }
//数据初始化
CMiniDrawView::CMiniDrawView()
m_CurrentTool = ID_BUTTONLINE;
替换m_LineArraym_FigArray
CFigure *pFigure = NULL;
pFigure = new CLine (m_PointOrigin.x, m_PointOrigin.y,
point.x, point.y );
m_FigArray.push_back( pFigure );

27. 图形类型 void CMiniDrawView::OnButtonline() {
m_CurrentTool = ID_BUTTONLINE; }
void CMiniDrawView::OnButtonellipse()
m_CurrentTool = ID_BUTTONELLIPSE;

28. OnMouseMove void CMiniDrawView::OnMouseMove(UINT nFlags, CPoint point){
if( !m_Dragging )
return ;
CClientDC ClientDC( this );
ClientDC.SelectStockObject (NULL_BRUSH);
switch (m_CurrentTool)
case ID_BUTTONLINE:
ClientDC.SetROP2( R2_NOT );
ClientDC.MoveTo( m_PointOrigin );
ClientDC.LineTo( m_PointOld );
ClientDC.LineTo( point );
break;
case ID_BUTTONELLIPSE:
ClientDC.SetROP2 (R2_NOT);
ClientDC.Ellipse (m_PointOrigin.x, m_PointOrigin.y, m_PointOld.x, m_PointOld.y );
ClientDC.Ellipse (m_PointOrigin.x, m_PointOrigin.y, point.x, point.y ); }
m_PointOld = point;
CView::OnMouseMove(nFlags, point);

29. OnLButtonUp void CMiniDrawView::OnLButtonUp(UINT nFlags, CPoint point){
if( !m_Dragging )
return;
CClientDC ClientDC( this );
ClientDC.SelectStockObject (NULL_BRUSH);
CFigure *pFigure = NULL;
switch (m_CurrentTool)
case ID_BUTTONLINE:
ClientDC.SetROP2( R2_NOT );
ClientDC.MoveTo( m_PointOrigin );
ClientDC.LineTo( m_PointOld );
pFigure = new CLine(m_PointOrigin.x, m_PointOrigin.y,
point.x, point.y );
break;
case ID_BUTTONELLIPSE:
ClientDC.SetROP2 (R2_NOT);
ClientDC.Ellipse (m_PointOrigin.x, m_PointOrigin.y, m_PointOld.x, m_PointOld.y );
pFigure = new CEllipse (m_PointOrigin.x, m_PointOrigin.y, point.x, point.y); }
ClientDC.SetROP2 (R2_COPYPEN);
pFigure->Draw (&ClientDC);
m_FigArray.push_back( pFigure );
m_Dragging = 0;
CView::OnLButtonUp(nFlags, point);

30. 6. 多态性 void CMiniDrawView::OnDraw(CDC* pDC) {
CMiniDrawDoc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
// TODO: add draw code for native data here
pDC->SelectStockObject (NULL_BRUSH);
for( int i=0; i<m_FigArray.size(); i++)
m_FigArray.at(i)->Draw(pDC); }

31. 线框画图模式 CMiniDrawView:: OnMouseMove() CMiniDrawView::OnLButtonUp()
CClientDC ClientDC( this );
ClientDC.SelectStockObject (NULL_BRUSH);
CMiniDrawView::OnDraw()
pDC->SelectStockObject (NULL_BRUSH);

32. 类的分离
Figure.h/cpp

33. 总结
STL vector
GDI画图
鼠标交互
消息响应（鼠标） 按钮
类的继承和多态

34. 作业3--MiniDraw 完善MiniDraw画图程序
写一个画图小程序MiniDraw，要求画直线(Line)，椭圆(Ellipse)，矩形(Rectangle)，多边形(Polygon)等图形元素(图元)
每种图元需用一个类（对象）来封装，如CLine, CEllipse, CRect, CPolygon, CFreehand；
各种图元从一个父类CFigure来继承；
学习类的继承和多态

35. 要求
至少完成直线(Line)，椭圆(Ellipse)，矩形(Rectangle)，多边形(Polygon) ，自由手绘线(Freehand)等图形元素
Deadline: 9:30a.m. April 6, 2011

36. 如何学好VC 需要有好的C/C++基础 理解Windows的消息机制，窗口句柄和其他GUI句柄的含义和用途 多使用Online Help
记住一些常用的消息名称和参数的意义
学会看别人的代码
多练习，在实践中成长！

37. References
VC入门级书籍
Windows编程
《MFC深入浅出》

38. Q&A