Using MFC to realize the midpoint circle algorithm in graphics course

1. Go to Resource View, new dialog, edit Modify caption or id attribute

Right-click the dialog box to add the class base class to CDialog

Named as: Mycircledialog

Using the Class Wizard, select the Mycircledialog class, select the member variable to add the variable value type int

M_radius setting variable value ranges

M_circlex

M_circlex

2. Add the menu, set the ID to Id_mycirclemenu and add the message map function through the Class wizard

Select the class name C***view

Find ID id_mycirclemenu, map OnCommand message

C***view

3. Add a variable and initialize it in the constructor

C***view.h

Public:int M_vradius;    int M_vcirclex; int M_vcircley;

C***view.cpp

M_vradius = 0;    M_vcirclex = 0; M_vcircley = 0;

Add Mycircledialog header File

#include "MyCircleDialog.h"

4. Adding code to the message handler to get input data with dialog interaction

Cmfccircledialogdemoview Message handler void Cmfccircledialogdemoview::onmycirclemenu () {///TODO:  Add Command handler code here Mycircledialog dlg; Defines a dialog box object if (dlg.   DoModal () = = IDOK)//Display dialog box {M_vradius = Dlg.m_radius;m_vcirclex = Dlg.m_circlex;m_vcircley = Dlg.m_circley; Receive and store edit box data invalidate (); Refresh View}}

Cmfctestview Drawing

5. Add drawing code in OnDraw (cancel cdc* parameter comment, use all device environment base class CDC paint,

The

can also define the use of other device environment classes such as CCLIENTDC, etc.)  

Void cmfccircledialogdemoview::ondraw (CDC*&NBSP;PDC) {cmfccircledialogdemodoc* pdoc =  GetDocument (); Assert_valid (PDOC);if  (!pdoc) return;// todo:  here to add drawing code for native data/* To determine the center of the circle, draw a Cartesian coordinate system */crect rect; GetWindowRect (rect); Int center_x = rect. Width ()/2;int center_y = rect. Height ()/2; cpen mypen; //Create Brush Mypen.createstockobject (black_pen);  //Set brush Properties Pdc->selectobject (&myPen);  //bind brush Handle Pdc->moveto (center_x,0);pD C->lineto (center_x, rect. Height ());pD C->moveto (0,center_y);pD C->lineto (rect. Width (), center_y);/********************* Draw Circle ****************///Logical Center coordinate/*int m_vradius = 50;int  m_vcirclex = -70; int m_vcircley = 100;*///into the center coordinate of the canvas center_x =  Center_x + m_vcirclex;center_y = center_y - m_vcircley;pdc->setpixel (center_x , Center_y+m_vradius,rgb (125,125,125));//Draw Center point Pdc->ellipse (center_x-3,center_y-3,center_x+3, center_y+3);  //draw a small circle to determine the center position int p=5/4-m_vradius;                                        //the initial value of the key value Int x=0;int y=m_ vradius;        //using the midpoint circle algorithm to draw a circle   while (x<y) {x++;if (p<0) {p= P+2*x+3;pdc->setpixel (Center_x+x,center_y+y,rgb (125,125,125));pD C->setpixel (Center_x+y,center_y+x,rgb ( 125,125,125));pD C->setpixel (Center_x+y,center_y-x,rgb (125,125,125));pD C->setpixel (Center_x+x,center_y-y, RGB (125,125,125));pD C->setpixel (Center_x-x,center_y-y,rgb (125,125,125));pD C->setpixel (center_x-y,center_ Y-x,rgb (125,125,125));pD C->setpixel (Center_x-y,center_y+x,rgb (125,125,125));pD C->setpixel (Center_x-x, Center_y+y,rgb (125,125,125))           //complete the drawing of the circle in a symmetrical way}else{ y--;p =p+2*x+3-2*y-2;pdc-> SetPixel (Center_x+x,center_y+y,rgb (125,125,125));pD C->setpixel (Center_x+y,center_y+x,rgb (125,125,125));pD C- >setpixel (Center_x+y,center_y-x,rgb (125,125,125));pD C->setpixel (Center_x+x,center_y-y,rgb (125,125,125)); Pdc->setpixel (Center_x-x,center_y-y,rgb (125,125,125));pD C->setpixel (Center_x-y,center_y-x,rgb ( 125,125,125));pD C->setpixel (Center_x-y,center_y+x,rgb (125,125,125));pD C->setpixel (Center_x-x,center_y+y, RGB (125,125,125));              //complete the drawing of the circle in a symmetrical way   }sleep (20);}}

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Using MFC to realize the midpoint circle algorithm in graphics course