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JAVA中点画线算法代码 中点算法画直线代码
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如何用Java实现DDA画线算法，逐点画线算法，BRESENHAM画线算法
C++ JAVA 或其它语言, 他们的+-*/ if else while 这些都几乎一样, API和数据类型有差异, 但不影响读懂算法,还是去试着看懂吧,
而且我搜了一下, 网上有很多这些算法的文字描述, 理解起来不难;
研究算法还是自己动手吧;
LZ加油;
相关问答
Q1: java 用点画直线问题
import java.awt.*;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.ArrayList;
import java.awt.event.*;
public class TestMain1 {
public static void main(String[] args) {
FrameDraw1 fd=new FrameDraw1();
}
}
class FrameDraw1 extends Frame{
int i;
static ArrayList Point[] list =new ArrayListPoint[]();
public FrameDraw1(){
init();
this.addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);}
});
this.setBounds(20,20,400,400);
this.setVisible(true);
}
void init(){
this.addMouseListener(new Moo1(this));
}
public void paint(Graphics g){
for(int i=0;ilist.size();i++){
Point []p=(Point[])list.get(i);
int j=2;
while(p[j]!=nullj100){
g.fillOval(p[j].x,p[j].y,4,4);
j++;
}
}
}
}
class Moo1 extends MouseAdapter{
Point point;
Point points[]=new Point[100];
FrameDraw1 fd;
ArrayList Pointlist=new ArrayListPoint();
public Moo1(FrameDraw1 fd){
this.fd=fd;
}
public void mousePressed(MouseEvent e){
point=(Point)e.getPoint();
points[0]=point;//points[0]放的是起点的点坐标
}
public void mouseReleased(MouseEvent e) {
point=(Point)e.getPoint();
points[1]=point;//points[1]放的是终点的点坐标
savePoint(points[0].x,points[0].y,points[1].x,points[1].y);
fd.repaint();
// FrameDraw1.list.add(list);
}
void savePoint(int x1,int y1,int x2,int y2){
int x,y,a,b,d,d1,d2;
a=y1-y2;
b=x2-x1;
x=x1;
y=y1;
point=new Point(x,y);
d=2*a+b;d1=2*a;d2=2*(a+b);
points[2]=point;
int i;
for(i=3,x=x1;x=x2i100;x++,i++){
if(d0){y++;d+=d2;}
else{d+=d1;}
point=new Point(x,y);
points[i]=point;
}
FrameDraw1.list.add(points);
}
}
import java.awt.*;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.ArrayList;
import java.awt.event.*;
public class TestMain1 {
public static void main(String[] args) {
FrameDraw1 fd=new FrameDraw1();
}
}
class FrameDraw1 extends Frame{
int i;
static ArrayList Point[] list =new ArrayListPoint[]();
public FrameDraw1(){
init();
this.addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);}
});
this.setBounds(20,20,400,400);
this.setVisible(true);
}
void init(){
this.addMouseListener(new Moo1(this));
}
public void paint(Graphics g){
for(int i=0;ilist.size();i++){
Point []p=(Point[])list.get(i);
int j=2;
while(p[j]!=nullj100){
g.fillOval(p[j].x,p[j].y,4,4);
j++;
}
}
}
}
class Moo1 extends MouseAdapter{
Point point;
Point points[]=new Point[100];
FrameDraw1 fd;
ArrayList Pointlist=new ArrayListPoint();
public Moo1(FrameDraw1 fd){
this.fd=fd;
}
public void mousePressed(MouseEvent e){
point=(Point)e.getPoint();
points[0]=point;//points[0]放的是起点的点坐标
}
public void mouseReleased(MouseEvent e) {
point=(Point)e.getPoint();
points[1]=point;//points[1]放的是终点的点坐标
savePoint(points[0].x,points[0].y,points[1].x,points[1].y);
fd.repaint();
// FrameDraw1.list.add(list);
}
void savePoint(int x1,int y1,int x2,int y2){
int x,y,a,b,d,d1,d2;
a=y1-y2;
b=x2-x1;
x=x1;
y=y1;
point=new Point(x,y);
d=2*a+b;d1=2*a;d2=2*(a+b);
points[2]=point;
int i;
for(i=3,x=x1;x=x2i100;x++,i++){
if(d0){y++;d+=d2;}
else{d+=d1;}
point=new Point(x,y);
points[i]=point;
}
FrameDraw1.list.add(points);
}
}
Q2: 求中点画线算法的c++代码...
直线方程:a*x+b*y+c=0, p1(x1,y1), p2(x2,y2)== a=y1-y2;b=x2-x1.
点到直线的距离：distance=|a*x0-b*y0+c|/sqrt(a*a + b*b)
设directionX,directionY分别为从(x1,y1)==(x2,y2)的单位变化量（+/-1）
当直线偏向X轴时，当前象素为（xk， yk），下一个象素可能为：(xk+directionX, yk)或者(xk+directionX,yk+directionY)这两点到直线的距离分别为：
d1=|a*xk+b*yk+c+a*directionX|/sqrt(a*a + b*b);
d2=|a*xk+b*yk+c+a*directionX+b*directonY|/sqrt(a*a + b*b);
便于运算，定义:f(xk,yk)= d2 * d2 - d1 * d1 (将d1和d2的分母去掉了的)
= b*b + 2*b*directonY*(a*xk+b*yk+c+a*directionX) ;
当f(xk,yk)0的时候，下一个点为(xk+directionX,yk+directionY):
f(xk+directionX,yk+directionY)=f(xk,yk) +2*b*b+2*a*b*directionX*directionY ;
当f(xk,yk)=0的时候，下一个点为(xk+directionX, yk) :
f(xk+directionX, yk) = f(xk,yk) + 2*a*b*directionX*directionY ;
当直线偏向Y轴时，当前象素为（xk， yk），下一个象素可能为：(xk, yk+directionY)或者(xk+directionX,yk+directionY)这两点到直线的距离分别为：
d1=|a*xk+b*yk+c+b*directionY|/sqrt(a*a + b*b);
d2=|a*xk+b*yk+c+b*directionY+a*directonX|/sqrt(a*a + b*b);
便于运算，定义:f(xk,yk)= d2 * d2 - d1 * d1 (将d1和d2的分母去掉了的)
= a*a + 2*a*directonX*(a*xk+b*yk+c+b*directionY) ;
当f(xk,yk)0的时候，下一个点为(xk+directionX,yk+directionY):
f(xk+directionX,yk+directionY)=f(xk,yk) +2*a*a+2*a*b*directionX*directionY ;
当f(xk,yk)=0的时候，下一个点为(xk+directionX, yk) :
f(xk+directionX, yk) = f(xk,yk) + 2*a*b*directionX*directionY ;
/*
* 中点画线算法
*/
void LineMLDA(HDC hdc, POINT ptSrc, POINT ptDec, COLORREF cr)
{
int a, b ;
a = ptSrc.y - ptDec.y ;
b = ptDec.x - ptSrc.x ;
int iDirectionX, iDirectionY ;
iDirectionX = iDirectionY = 1 ;
if(b0)
iDirectionX = -1 ;
if(a0)
iDirectionY = -1 ;
int iDistance,
iDeltaSmall, iDeltaBig ,
iCurrX, iCurrY ;
int iStep ;
iDeltaSmall = 2*a*b*iDirectionX*iDirectionY ;
iCurrX = ptSrc.x ;
iCurrY = ptSrc.y ;
if(abs(b) abs(a))
{
iDeltaBig = 2*b*b + iDeltaSmall ;
iDistance = b*b + iDeltaSmall ;
iStep = abs(b) ;
while (iStep-- 0)
{
SetPixel(hdc, iCurrX, iCurrY, cr) ;
iCurrX += iDirectionX ;
if(iDistance 0)
{
iCurrY += iDirectionY ;
iDistance += iDeltaBig ;
}
else
{
iDistance += iDeltaSmall ;
}
}
}
else
{
iDeltaBig = 2*a*a + iDeltaSmall ;
iDistance = a*a + iDeltaSmall ;
iStep = abs(a) ;
while (iStep-- 0)
{
SetPixel(hdc, iCurrX, iCurrY, cr) ;
iCurrY += iDirectionY ;
if(iDistance 0)
{
iCurrX += iDirectionX ;
iDistance += iDeltaBig ;
}
else
{
iDistance += iDeltaSmall ;
}
}
}
SetPixel(hdc, ptDec.x, ptDec.y, cr) ;
}
