## 介绍

The Line2D class states a line segment in (x,y) coordinate space.

## 类声明

Following is the declaration for java.awt.geom.Line2D class:

public abstract class Line2D   extends Object      implements Shape, Cloneable

## 类的构造函数

S.N.Constructor & Description
1protected Line2D() () This is an abstract class that cannot be instantiated directly.

## 类方法

S.N.Method & Description
1Object clone() Creates a new object of the same class as this object.
2boolean contains(double x, double y) Tests if a specified coordinate is inside the boundary of this Line2D.
3boolean contains(double x, double y, double w, double h) Tests if the interior of this Line2D entirely contains the specified set of rectangular coordinates.
4boolean contains(Point2D p) Tests if a given Point2D is inside the boundary of this Line2D.
5boolean contains(Rectangle2D r) Tests if the interior of this Line2D entirely contains the specified Rectangle2D.
6Rectangle getBounds() Returns an integer Rectangle that completely encloses the Shape.
7abstract Point2D getP1() Returns the start Point2D of this Line2D.
8abstract Point2D getP2() Returns the end Point2D of this Line2D.
9PathIterator getPathIterator(AffineTransform at) Returns an iteration object that defines the boundary of this Line2D.
10PathIterator getPathIterator(AffineTransform at, double flatness) Returns an iteration object that defines the boundary of this flattened Line2D.
11abstract double getX1() Returns the X coordinate of the start point in double precision.
12abstract double getX2() Returns the X coordinate of the end point in double precision.
13abstract double getY1() Returns the Y coordinate of the start point in double precision.
14abstract double getY2() Returns the Y coordinate of the end point in double precision.
15boolean intersects(double x, double y, double w, double h) Tests if the interior of the Shape intersects the interior of a specified rectangular area.
16boolean intersects(Rectangle2D r) Tests if the interior of the Shape intersects the interior of a specified Rectangle2D.
17boolean intersectsLine(double x1, double y1, double x2, double y2) Tests if the line segment from (x1,y1) to (x2,y2) intersects this line segment.
18boolean intersectsLine(Line2D l) Tests if the specified line segment intersects this line segment.
19static boolean linesIntersect(double x1, double y1, double x2, double y2, double x3, double y3, double x4, double y4) Tests if the line segment from (x1,y1) to (x2,y2) intersects the line segment from (x3,y3) to (x4,y4).
20double ptLineDist(double px, double py) Returns the distance from a point to this line.
21static double ptLineDist(double x1, double y1, double x2, double y2, double px, double py)Returns the distance from a point to a line.
22double ptLineDist(Point2D pt)Returns the distance from a Point2D to this line.
23double ptLineDistSq(double px, double py)Returns the square of the distance from a point to this line.
24static double ptLineDistSq(double x1, double y1, double x2, double y2, double px, double py)Returns the square of the distance from a point to a line.
25double ptLineDistSq(Point2D pt)Returns the square of the distance from a specified Point2D to this line.
26double ptSegDist(double px, double py) Returns the distance from a point to this line segment.
27static double ptSegDist(double x1, double y1, double x2, double y2, double px, double py)Returns the distance from a point to a line segment.
28double ptSegDist(Point2D pt) Returns the distance from a Point2D to this line segment.
29double ptSegDistSq(double px, double py) Returns the square of the distance from a point to this line segment.
30static double ptSegDistSq(double x1, double y1, double x2, double y2, double px, double py)Returns the square of the distance from a point to a line segment.
31double ptSegDistSq(Point2D pt) Returns the square of the distance from a Point2D to this line segment.
32int relativeCCW(double px, double py) Returns an indicator of where the specified point (px,py) lies with respect to this line segment.
33static int relativeCCW(double x1, double y1, double x2, double y2, double px, double py)Returns an indicator of where the specified point (px,py) lies with respect to the line segment from (x1,y1) to (x2,y2).
34int relativeCCW(Point2D p)Returns an indicator of where the specified Point2D lies with respect to this line segment.
35abstract void setLine(double x1, double y1, double x2, double y2) Sets the location of the end points of this Line2D to the specified double coordinates.
36void setLine(Line2D l)Sets the location of the end points of this Line2D to the same as those end points of the specified Line2D.
37void setLine(Point2D p1, Point2D p2)Sets the location of the end points of this Line2D to the specified Point2D coordinates.

## 方法继承

This class inherits methods from the following classes:

• java.lang.Object

## Line2D Example

Create the following java program using any editor of your choice in say D:/ > AWT > com > tutorialspoint > gui >AWTGraphicsDemo.java

package com.tutorialspoint.gui; import java.awt.*;import java.awt.event.*;import java.awt.geom.*; public class AWTGraphicsDemo extends Frame {    public AWTGraphicsDemo(){      super("Java AWT Examples");      prepareGUI();   }    public static void main(String[] args){      AWTGraphicsDemo  awtGraphicsDemo = new AWTGraphicsDemo();        awtGraphicsDemo.setVisible(true);   }    private void prepareGUI(){      setSize(400,400);      addWindowListener(new WindowAdapter() {         public void windowClosing(WindowEvent windowEvent){            System.exit(0);         }              });    }        @Override   public void paint(Graphics g) {      Line2D shape = new Line2D.Double();      shape.setLine(250D,250D,150D,150D);        Graphics2D g2 = (Graphics2D) g;       g2.draw (shape);      Font font = new Font("Serif", Font.PLAIN, 24);      g2.setFont(font);      g.drawString("Welcome to TutorialsPoint", 50, 70);      g2.drawString("Line2D.Line", 100, 120);     }}

Compile the program using command prompt. Go to D:/ > AWT and type the following command.

D:\AWT>javac com\tutorialspoint\gui\AWTGraphicsDemo.java

If no error comes that means compilation is successful. Run the program using following command.

D:\AWT>java com.tutorialspoint.gui.AWTGraphicsDemo

Verify the following output