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This article will explain in detail how to use MFC to achieve the midpoint circle algorithm in the graphics course. The editor thinks it is very practical, so I share it with you as a reference. I hope you can get something after reading this article.

1. Go to the resource view, create a new dialog box, and edit and modify Caption or ID properties

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

Named: MyCircleDialog

Using the class wizard, select the MyCircleDialog class, select the member variable to add the variable value type int

M_radius sets the range of variables

M_circlex

M_circlex

two。 Add a menu, set ID to ID_MyCircleMenu and add a message mapping function through the class wizard

Select the class name C***View

Find ID ID_MyCircleMenu, map ONCOMMAND messages

C***View

3. Add a variable and initialize it in the constructor

C***View.h

Public: int massively radius; int massively vcirclex; int m_vcircley

C***View.cpp

M_vradius = 0; m_vcirclex = 0; m_vcircley = 0

Add MyCircleDialog header file

# include "MyCircleDialog.h"

4. Add the code that interacts with dialog to get input data in the message handler

/ / CMFCCircleDialogDemoView message handler void CMFCCircleDialogDemoView::OnMycirclemenu () {/ / TODO: add the command handler code MyCircleDialog dlg; / / define a dialog object if (dlg.DoModal () = = IDOK) / / display the 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 to OnDraw (uncomment CDC* parameters and draw with all device environment base classes CDC

You can also define the use of other device environment classes such as CClientDC)

Void CMFCCircleDialogDemoView::OnDraw (CDC* pDC) {CMFCCircleDialogDemoDoc* pDoc = GetDocument (); ASSERT_VALID (pDoc); if (! pDoc) return; / / TODO: add drawing code for native data here / * determine the center of the circle, draw the 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); pDC- > LineTo (center_x, rect.Height ()); pDC- > MoveTo (0dcentery) PDC- > LineTo (rect.Width (), center_y); / * draw circle * / / logical center coordinates / * int m_vradius = 50; int m_vcirclex =-70 Int m_vcircley = 100; * / convert to the center coordinate of the canvas center_x = center_x + masked vCirclex; center_y = center_y-massively vcircley; pDC- > SetPixel (center_x,center_y+m_vradius,RGB (125125125)) / / draw the point of the center of the circle pDC- > Ellipse (center_x-3,center_y-3,center_x+3,center_y+3); / / draw a small circle to determine the position of the center of the circle, and determine the position of the center of the circle; / / the initial value of the key value int x = 0; int y=m_vradius / / use midpoint circle algorithm to draw circles while (xSetPixel (center_x+y,center_y+x,RGB (125125125)); pDC- > SetPixel (center_x+y,center_y-x,RGB (125125125)); pDC- > SetPixel (center_x+x,center_y-y,RGB (125125125)) PDC- > SetPixel (center_x-x,center_y-y,RGB (125125125)); pDC- > SetPixel (center_x-y,center_y-x,RGB (125125125)); pDC- > SetPixel (center_x-y,center_y+x,RGB (125125125)) PDC- > SetPixel (center_x-x,center_y+y,RGB (125125125)); / / complete the drawing of circles in a symmetrical way} else {ymurmuri; p=p+2*x+3-2*y-2 PDC- > SetPixel (center_x+x,center_y+y,RGB (125125125)); pDC- > SetPixel (center_x+y,center_y+x,RGB (125125125)); pDC- > SetPixel (center_x+y,center_y-x,RGB (125125125)) PDC- > SetPixel (center_x+x,center_y-y,RGB (125125125)); pDC- > SetPixel (center_x-x,center_y-y,RGB (125125125)); pDC- > SetPixel (center_x-y,center_y-x,RGB (125125125)) PDC- > SetPixel (center_x-y,center_y+x,RGB (125125125)); pDC- > SetPixel (center_x-x,center_y+y,RGB (125125125)); / / complete circle drawing in a symmetrical way} Sleep (20) }} this is the end of the article on "how to use MFC to implement the midpoint circle algorithm in graphics courses". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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