Computer graphics linear anti-aliasing Wu algorithm (4)

Ching

Original address: http://blog.csdn.net/qingdujun/article/details/40048285

In this paper, a complete example is presented to illustrate the linear anti-aliasing Wu algorithm.

1) Create CP2 class

Header file: P2.h

P2.h:interface for the CP2 class.////////////////////////////////////////////////////////////////////////#if! Defined (afx_p2_h__dd23884f_7f62_48e8_a906_65c4558de4eb__included_) #define Afx_p2_h__dd23884f_7f62_48e8_a906_ 65c4558de4eb__included_#if _msc_ver > 1000#pragma once#endif//_msc_ver > 1000//Two-dimensional point class  CP2    {  Public:      CP2 ();      CP2 (double x,double y);      Virtual ~cp2 ();  Public:         //easy access, directly defined as a total of      double X;      Double y;  };    #endif//!defined (AFX_P2_H__DD23884F_7F62_48E8_A906_65C4558DE4EB__INCLUDED_)

implementation file: P2.cpp

P2.cpp:implementation of the CP2 class.////////////////////////////////////////////////////////////////////////# Include "stdafx.h" #include "WuLine.h" #include "P2.h" #ifdef _debug#undef this_filestatic Char this_file[]=__file__;# Define New debug_new#endif////////////////////////////////////////////////////////////////////////Construction/ Destruction//////////////////////////////////////////////////////////////////////cp2::cp2 () {}CP2::~CP2 () {}

2) Create Cwuanti class

Header file: WuAnti.h

Wuanti.h:interface for the Cwuanti class./////////////////////////////////////////////////////////////////////// /#if!defined (afx_wuanti1_h__2c2d354f_c8aa_4f64_81cc_56195dee5704__included_) #define Afx_wuanti1_h__2c2d354f_ c8aa_4f64_81cc_56195dee5704__included_#if _msc_ver > 1000#pragma once#endif//_msc_ver > 1000#include "P2.h" Class Cwuanti  {Public:cwuanti (); virtual ~cwuanti (); void MoveTo (CP2 p0)              ; Moves to the specified position      void MoveTo (Double x, double y);      void LineTo (CP2 p1, CDC *PDC);    Plots Wu Anti-aliasing line with no end point      void LineTo (Double x, double y, CDC *PDC), private:      CP2 P0;      Beginning      CP2 P1;      end}; #endif//!defined (AFX_WUANTI1_H__2C2D354F_C8AA_4F64_81CC_56195DEE5704__INCLUDED_)

implementation file: WuAnti.cpp

WuAnti.cpp:implementation of the Cwuanti class.///////////////////////////////////////////////////////////////// #include "stdafx.h" #include "WuLine.h" #include "WuAnti.h" #include <math.h> #define ROUND (d) Int (Floor (d+ 0.5)//Rounding macro definition #ifdef _debug#undef this_filestatic char this_file[]=__file__; #define NEW debug_new#endif///////////// construction/destruction/////////////////////////// Cwuanti::cwuanti () {}cwuanti::~cwuanti () {}void Cwuanti::moveto (CP2 p0)  Record line start function {p0=p0;      } void Cwuanti::moveto (Double x, double y) {p0.x = x;  P0.y = y;      } void Cwuanti::lineto (Double x, double y, CDC *PDC)//Draw {CP2 p;      p.x = x;        P.y = y;  LineTo (P, PDC);      } void Cwuanti::lineto (CP2 p1, CDC *pdc) {p1=p1;  CP2 p,t;    Double k,e;  The intersection of P (U) and P (d) is f (i), E is f (i) to P (U) and the distance colorref clr = RGB (0,0,0); Black Pixel point if (fabs (p0.x-p1.x) <1e-6)    Draw the vertical line (no antialiasing required) {if (P0.Y&GT;P1.Y)//swap vertices so that the starting point is below the endpoint {t=p0; P0=P1;          p1=t;              } for (p=p0;p.y<p1.y;p.y++)//execute draw, fill pixel dot {pdc->setpixelv (Round (p.x), Round (P.Y), CLR); }} else {k= (P1.Y-P0.Y)/(p1.x-p0.x);//slope if (p0.x>p1.x) {t=p0; P0=P1;  p1=t; } if (k>=0)//Draw 13 Quadrant line {for (p=p0,e=0;p.x<p1.x;p.x++) {Pdc->setpixelv                (Round (p.x), Round (P.Y), RGB (e*255,e*255,e*255));            Pdc->setpixelv (Round (p.x), Round (p.y+1), RGB ((1-E) *255, (1-E) *255, (1-E) *255)); E+=k;if (e>=1.0) {p.y++;e--;} }} if (k<0)//Draw 24 Quadrant line {for (p=p0,e=0;p.x<p1.x;p.x++) {Pdc-&gt ;                Setpixelv (Round (p.x), Round (P.Y), RGB (e*255,e*255,e*255));            Pdc->setpixelv (Round (p.x), Round (p.y+1), RGB ((1-E) *255, (1-E) *255, (1-E) *255)); E+=k;if (e<=-1.0) {p.y--;e--;}       }   }} P0=P1;   Assign the end point to the start}

3) OnDraw function

void Cwulineview::ondraw (cdc* pDC) {cwulinedoc* PDoc = GetDocument (); Assert_valid (PDOC);//Todo:add Draw code for native data Herecwuanti *line=new cwuanti;//dynamically creates a line drawing class object      line-> MoveTo (100,100);      Line->lineto (500,500, PDC);  }

4) Operation effect (magnification 25 times times)

Original address: http://blog.csdn.net/qingdujun/article/details/40048285

Reference: Basic Computer Graphics tutorial (Visual C + + Edition) (2nd edition) Konglingde

Computer graphics linear anti-aliasing Wu algorithm (4)