Java GUI allows you to connect any circle with arrows and store

Java GUI allows you to connect any circle with arrows and store
Pass a small geometric program, the little girl is not talented, I remember thinking for a few days to get it out, O (cute _ cute) O design a GUI program, in the window, use the mouse to draw a circle (all circles are of the same size and can be stored), and drag the mouse to draw a line between the circles (the line must be a straight line of the two centers, it is a program that draws the boundary from one circle to another and has arrows.

Import javax. swing. JFrame; public class Draw {public static void main (String [] args) {JFrame frame = new JFrame ("circle"); frame. setdefaclocloseoperation (JFrame. EXIT_ON_CLOSE); frame. add (new DrawPanel (); frame. pack (); frame. setVisible (true) ;}} import javax. swing. JPanel; import java. awt. *; import java. awt. event. *; import java. util. arrayList; public class DrawPanel extends JPanel {private final int r = 50; Po Int p, p1, p2; int l1 =-1, l2 =-1; int a, B, c, d, g, h; arrayList <Point> l = new ArrayList <Point> (); ArrayList <line> al = new ArrayList <line> (); // use ArrayList to store public DrawPanel () {DrawListener listen = new DrawListener (); addMouseListener (listen); addMouseMotionListener (listen); setBackground (Color. black); setPreferredSize (new Dimension (400,700);} public void paintComponent (Graphics page) {super. paintComponen T (page); page. setColor (Color. yellow); for (Point po: l) {if (po! = Null) page. drawOval (po. x-r, po. y-r, 2 * r, 2 * r);} for (line n: al) {// core algorithm, here I used 15 and 5 in a similar program to control the size of the arrows if (n! = Null) {a = (int) (r * (n. b. x-n.a.x)/Math. sqrt (n. a. x-n. B .x) * (n. a. x-n. B .x) + (n. a. y-n. B .y) * (n. a. y-n. B .y); B = (int) (r * (n. b. y-n.a.y)/Math. sqrt (n. a. x-n. B .x) * (n. a. x-n. B .x) + (n. a. y-n. B .y) * (n. a. y-n. B .y); c = (int) (r + 15) * (n. b. x-n.a.x)/Math. sqrt (n. a. x-n. B .x) * (n. a. x-n. B .x) + (n. a. y-n. B .y) * (n. a. y-n. B .y); d = (int) (r + 15) * (n. b. y-n.a.y)/Math. sqrt (n. a. x-n. B .x) * (n. a. x-n. B .x) + (n. a. y-n. B .y) * (n. a. y-n. B .y); g = 5 * B/r; h = 5 * a/r; int Xpoint [] = new int [3]; int Ypoint [] = new int [3]; Xpoint [0] = n. b. x-c-g; Xpoint [1] = n. b. x-c + g; Xpoint [2] = n. b. x-a; Ypoint [0] = n. b. y-d + h; Ypoint [1] = n. b. y-d-h; Ypoint [2] = n. b. y-B; page. drawLine (n. a. x + a, n. a. y + B, n. b. x-a, n. b. y-B); page. fillPolygon (Xpoint, Ypoint, 3) ;}} class line {private Point a, B; line (Point p1, Point p2) {a = p1; B = p2 ;}} private class DrawListener implements MouseListener, MouseMotionLi Stener {public void mousePressed (MouseEvent event) {l2 =-1; l1 =-1; p1 = event. getPoint (); for (int I = 0; I <l. size (); I ++) {if (Math. sqrt (l. get (I ). x-p1.x) * (l. get (I ). x-p1.x + (l. get (I ). y-p1.y) * (l. get (I ). y-p1.y) <r) l1 = I;} repaint ();} public void mouseClicked (MouseEvent event) {p = event. getPoint (); int f = 1; if (l. size () = 0) {repaint (); l. add (p);} else {for (int I = 0; I <l. size (); I ++) {if (Math. sqrt (l. get (I ). x-p.x) * (L. get (I ). x-p.x + (l. get (I ). y-p.y) * (l. get (I ). y-p.y) <2 * r) f = 0;} if (f = 1) {repaint (); l. add (p) ;}} public void mouseReleased (MouseEvent event) {p2 = event. getPoint (); for (int I = 0; I <l. size (); I ++) {if (Math. sqrt (l. get (I ). x-p2.x) * (l. get (I ). x-p2.x + (l. get (I ). y-p2.y) * (l. get (I ). y-p2.y) <r) l2 = I ;}repaint (); if (l1! =-1 & l2! =-1) {al. add (new line (l. get (l1), l. get (l2);} public void mouseEntered (MouseEvent event) {} public void mouseExited (MouseEvent event) {} public void mouseMoved (MouseEvent event) {} public void mouseDragged (MouseEvent event) {p2 = event. getPoint ();}}}

Click draw circle to draw a line with a direction between any two circles!