Andy J. :
I am creating an application that draws 5 random triangles of different random colors. The random drawing of triangles work but for some reason the triangles are all the same color, sometimes having different colors where the triangles intersect. Here is a picture:
image of what the application creates
Does anyone know how to fix this issue and make it so that each triangle will be a different color?
TrianglesJPanel.java:
import javax.swing.JPanel;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.GeneralPath;
import java.util.Random;
public class TrianglesJPanel extends JPanel
{
public void paintComponent(Graphics g) {
//call superclass's paintComponent
super.paintComponent(g);
Random random = new Random();
Graphics2D g2 = (Graphics2D) g;
GeneralPath triangle = new GeneralPath(); //create general path object
//get the height and width
int height = this.getHeight();
int width = this.getWidth();
int[] x = new int[3];
int[] y = new int[3];
//draw 5 random triangles in application frame that can be adjusted
for (int i = 0; i < 5; i++) {
//get random points on the panel
for (int j = 0; j < 3; j++) {
x[j] = random.nextInt(width + 1); //random number from 0 to width
y[j] = random.nextInt(height + 1); //random number from 0 to height
//Ex. Frame 500x500: x could be from 0 to 500, y from 0 to 500
}
triangle.moveTo(x[0], y[0]); //start pos
triangle.lineTo(x[1], y[1]); //2nd point
triangle.lineTo(x[2], y[2]); //3rd point
triangle.lineTo(x[0], y[0]); //back to start pos
triangle.closePath(); //close the triangle
System.out.println(g2.getColor());
//set random color for triangle
g2.setColor(new Color(random.nextInt(256), random.nextInt(256), random.nextInt(256)));
g2.fill(triangle); //draw filled triangle
}
}
}
Triangle.java:
import java.awt.Color;
import javax.swing.JFrame;
public class Triangles
{
public static void main(String args[]) {
//choose title
JFrame frame = new JFrame("Drawing random triangles");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//drawing done on JPanel, embedded in a JFrame
TrianglesJPanel triangle = new TrianglesJPanel();
frame.add(triangle); //add the triangles to frame
frame.setBackground(Color.WHITE); //set background of frame to white color
frame.setSize(500,500); //set frame size to 500x500
frame.setVisible(true); //display frame
}
}
Hovercraft Full Of Eels :
All Triangles share the same GeneralPath object, and it is being filled with the last color used. To solve this you need a new GeneralPath object for each triangle
so:
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
// GeneralPath triangle = new GeneralPath(); //create general path object
int height = this.getHeight();
int width = this.getWidth();
int[] x = new int[3];
int[] y = new int[3];
for (int i = 0; i < 5; i++) {
for (int j = 0; j < 3; j++) {
x[j] = random.nextInt(width + 1); //random number from 0 to width
y[j] = random.nextInt(height + 1); //random number from 0 to height
}
GeneralPath triangle = new GeneralPath();
triangle.moveTo(x[0], y[0]); //start pos
triangle.lineTo(x[1], y[1]); //2nd point
triangle.lineTo(x[2], y[2]); //3rd point
triangle.lineTo(x[0], y[0]); //back to start pos
triangle.closePath(); //close the triangle
System.out.println(g2.getColor());
g2.setColor(new Color(random.nextInt(256), random.nextInt(256), random.nextInt(256)));
g2.fill(triangle); //draw filled triangle
}
}
Guess you like
Origin http://43.154.161.224:23101/article/api/json?id=334691&siteId=1