object-oriented programming · object-oriented programming lecture №13 modify the example from...

Object-oriented programming Lecture №13

Sergey Aksenov


Modify the example from lecture 9 // ChildView.h : the interface of CChildView

//

#pragma once

#include "Circle.h"

#include <vector>

class CChildView : public CWnd {

. . .

//CCircle m_Circles;

//Now we need an arraay of circles

std::vector<Ccircle *> m_Objects;

//bool m_bCatched;

int m_nCatched;

CPoint m_MousePos;

//If the point is inside of a circle,

//the function will return its number, otherwise -1

int FindObject(CPoint point);

. . .

};

2


Modify the example from lecture 9 // ChildView.cpp Implementation of CChildView

. . .

CChildView::CChildView(){

m_nCatched = -1; // Initialization

}

CChildView::~CChildView()

{

// Clear the memory allocated for the circles

for(int i=0; m_Objects(); i++){

delete m_Objects[i];

}

}

. . .

3


Modify the example from lecture 9 // ChildView.cpp Implementation of CChildView . . .

void CChildView::OnPaint()

{

CPaintDC dc(this); // device context for drawing

for(int i=0; i< m_Objects.size(); i++){

m_Objects[i]->Draw(dc);

}

}

int CChildView::FindObject(CPoint point){

int nObj = -1; // if none object found, return -1

for(int i= m_Objects.size()-1; i>=0; i--){

if(m_Objects[i]->IsInside(point.x, point.y)){

nObj = i;

break;

}

}

return nObj;

}

. . .

4



. . .

void CChildView::OnLButtonDown(UINT nFlags, CPoint point){

m_nCatched =FindObject(point);

if(m_nCatched >=0 ){

m_MousePos = point;

SetCapture();

}

CWnd::OnLButtonDown(nFlags, point);

}

void CChildView::OnLButtonUp(UINT nFlags, CPoint point){

m_nCatched = -1;

ReleaseCapture();

CWnd::OnLButtonUp(nFlags, point);

}

. . .

5



. . .

void CChildView::OnMouseMove(UINT nFlags, CPoint point){

if(m_nCatched>=0){

CRect rect;

GetClientRect(&rect);

point.x = min(rect.right, max(rect.left, point.x));

point.y = min(rect.bottom, max(rect.top, point.y));

CPoint Delta = point - m_MousePos;

m_Objects[m_nCatched]->Move(Delta.x, Delta.y);

m_MousePos = point;

Invalidate();

}

CWnd::OnMouseMove(nFlags, point);

}

. . .

6


Adding of a toolbar

7

You’ll need three steps to add a toolbar to your MFC application using Visual Studio:

1. Create the toolbar resource

2. Create the toolbar itself

3. Handle the toolbar commands


Creating of the toolbar resource

• To create a new resource right click to a project *.rc file in the Resource explorer and pick “Add resource” from context menu.

8



• Pick “Toolbar” and click “Create”.

9



• The ID of the new toolbar is “IDR_TOOLBAR1”.

10


Creating the toolbar resource

• Use “Oval” tool to draw a button picture.

11



• Pick “properties” from the context menu to set the button ID.

12



• Set the button id “ID_NEWCIRCLE” in the “properties” pane and click “Save all” .

13



• Study the new ID’s automatically added to“resource.h” file

//Resource.h

//

#define IDD_ABOUTBOX 100

#define IDR_MAINFRAME 128

#define IDR_GraphAppTYPE 130

#define IDR_TOOLBAR1 310

#define ID_NEWCIRCLE 32771

// Next default values for new objects

//

#ifdef APSTUDIO_INVOKED

#ifndef APSTUDIO_READONLY_SYMBOLS

#define _APS_NEXT_RESOURCE_VALUE 312

#define _APS_NEXT_COMMAND_VALUE 32772

#define _APS_NEXT_CONTROL_VALUE 1000

#define _APS_NEXT_SYMED_VALUE 310

#endif

#endif

14


Creating of the toolbar

• Create a member variable for the toolbar in CMainFrame class

// MainFrm.h : the interphase of CMainFrame

//

#pragma once

#include "ChildView.h"

class CMainFrame : public CFrameWnd

{

. . .

CChildView m_wndView;

CToolBar m_wndToolBar; // tollbar

. . .

};

15


Creating of the toolbar • Create the toolbar in OnCreate member class

// MainFrm.cpp : implementation of CMainFrame

//

. . .

int CMainFrame::OnCreate(LPCREATESTRUCT lpCreateStruct)

{

if (CFrameWnd::OnCreate(lpCreateStruct) == -1)

return -1;

// Creating of the ToolBar

m_wndToolBar.Create(this);

m_wndToolBar.LoadToolBar(IDR_TOOLBAR1);

// Creating of the View

if (!m_wndView.Create(NULL, NULL, AFX_WS_DEFAULT_VIEW,

CRect(0, 0, 0, 0), this, AFX_IDW_PANE_FIRST, NULL)) {

TRACE0("Failed to create the view\n");

return -1;

}

return 0;

}

16


Creating of the toolbar

• After the modifications your program should look like this

17


Handling the command

• Modify the CChildView to handle the “ID_NEWCIRCLE” command: 1. Add OnNewCircle member function declaration.

// ChildView.h : the interface of CChildView

//

. . .

class CChildView : public CWnd

{

. . .

afx_msg void OnLButtonDown(UINT nFlags, CPoint point);

afx_msg void OnLButtonUp(UINT nFlags, CPoint point);

afx_msg void OnMouseMove(UINT nFlags, CPoint point);

afx_msg void OnNewCircle();

};

18



• Modify the CChildView to handle the “ID_NEWCIRCLE” command: 2. Add OnNewCircle to the Message Map to bind it with “ID_NEWCIRCLE” command.

// ChildView.cpp the implementation of CChildView

. . .

BEGIN_MESSAGE_MAP(CChildView, CWnd)

ON_WM_PAINT()

ON_WM_LBUTTONDOWN()

ON_WM_LBUTTONUP()

ON_WM_MOUSEMOVE()

ON_COMMAND(ID_NEWCIRCLE, OnNewCircle)

END_MESSAGE_MAP()

. . .

19



• Modify the CChildView to handle the “ID_NEWCIRCLE” command:

3. Add the OnNewCircle implementation. // ChildView.cpp the implementation of CChildView

. . .

void CChildView::OnNewCircle(){

CRect rect;


m_Objects.push_back(new CCircle(rand()%rect.Width(), rand()%rect.Height(), 10));

Invalidate();

}

. . .

20



• Now your program will respond on clicking the toolbar button by creating a new circle.

21


Create CGrpObject class // GrpObject.h : the interphase of CGrpObject

#pragma once

class CGrpObject

{

public:

CGrpObject(void){}

virtual void Draw(CDC &dc)=0;

virtual bool IsInside(double x, double y)=0;

virtual void Move(double dx, double dy){

m_dCenterX += dx;

m_dCenterY += dy;

}

virtual ~CGrpObject(void){}

protected:

double m_dCenterX;

double m_dCenterY;

};

22


Inherit the CCircle from CGrpObject // Circle.h : the interphase of CCircle

#pragma once

#include "GrpObject.h"

class CCircle : public CGrpObject{

public:

CCircle(double x, double y, double R);

~CCircle(void);

public:

void Draw(CDC &dc);

bool IsInside(double x, double y);

//The Move(…) member function is now implemented in the base class

protected:

double m_dRadius;

//We don't need the m_dCentreX and m_dCentreY members now

//they are declared in the base class

};

23


Modify the CChildView // ChildView.h : the interface of CChildView

#pragma once


#include <vector>

class CChildView : public CWnd

{

. . .

std::vector<CGrpObject *> m_Objects;

. . .

};

________________________________________________________________________________________

• Circle.h should be included to ChildView.cpp in order to create the CCircle

objects in OnNewCircle member function

// ChildView.cpp Implementation of CChildView

. . .

#include "Circle.h"

. . .

24


New derived class

• Create a new class derived from

CGrpObject

//Square.h : the interphase of CSquare

#pragma once


class CSquare : public CGrpObject{

public:

CSquare(double x, double y, double a);

~CSquare(void);

public:

void Draw(CDC &dc);

bool IsInside(double x, double y);

protected:

double m_dA;

};

25


New derived class //Square.cpp : the implementation of CSquare

#include "stdafx.h"

#include "Square.h"

#include <math.h>

CSquare::CSquare(double x, double y, double a){

m_dCenterX = x;

m_dCenterY = y;

m_dA = a;

}

CSquare::~CSquare(void){}

void CSquare::Draw(CDC &dc){

dc.FillSolidRect( m_dCenterX-m_dA*0.5, m_dCenterY-m_dA*0.5,

m_dA, m_dA, RGB(255,255,255));

dc.Draw3dRect(m_dCenterX-m_dA*0.5, m_dCenterY-m_dA*0.5, m_dA, m_dA, 0, 0);

}

bool CSquare::IsInside(double x, double y){

return fabs(x - m_dCenterX) <= m_dA*0.5 && fabs(y - m_dCenterY) <= m_dA*0.5;

}

26


Creating “AddSquare” button

• Add a new button with to the toolbar as it was described in the slides 12-13.

• Rename the ID of the new button to “ID_NEWSQUARE”

• Implement the ID_NEWSQUARE command handler in the CChildView similar as it was shown in slides 18-20.

27


Get rid of the flickering • How to get rid of the flickering during the object dragging?

– 1. Add WM_ERASEBKGND message holder // ChildView.h : the interface of CChildView . . . class CChildView : public CWnd{ . . . afx_msg BOOL OnEraseBkgnd(CDC* pDC); }; ___________________________________________________________________________ // ChildView.cpp Implementation of CChildView . . . BEGIN_MESSAGE_MAP(CChildView, CWnd) . . . ON_WM_ERASEBKGND() END_MESSAGE_MAP() . . . BOOL CChildView::OnEraseBkgnd(CDC* pDC) { //Don’t call base class implementation //return CWnd::OnEraseBkgnd(pDC); return true;//Just return true. }

– 2. Implement double buffering in OnPaint

28


Double buffering when drawing

void CChildView::OnPaint()

{

CPaintDC dc(this); // device context for drawing

CDC dcMem;

dcMem.CreateCompatibleDC(&dc);

CRect rect;


CBitmap bmp;

bmp.CreateCompatibleBitmap(&dcMem, rect.Width(), rect.Height());

CBitmap *pOldBmp = dcMem.SelectObject(&bmp);

dcMem.FillSolidRect(0,0,rect.Width(), rect.Height(), 0xFFFFFF);

//0x FFFFFF is similar to RGB(255, 255, 255)

for(int i=0; i<m_Objects.size(); i++){

m_Objects[i]->Draw(dcMem);

}

dc.BitBlt(0,0, rect.Width(), rect.Height(), &dcMem, 0,0,SRCCOPY);

dcMem.SelectObject(pOldBmp);

}

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object-oriented programming · object-oriented programming lecture №13 modify the example from...

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