Develop Reference

Trying to draw on a canvas with sliders

I am attempting to use jsliders to allow a user to pinpoint the origin of a circle to be drawn on a canvas. I am using a button to show and hide the circle. I am using paint on an inner jpanel so that paint will not write over components. However, the coordinates inside the jpanel are different than the coordinates for the entire frame. So, it is very difficult for me to get the coordinates of the jslider and then translate it to the jpanel to draw the circle. Is there an easy way to figure this out without a ton of guess and check? I am also using the custom layout miglayout. I have included the code for my GUI class as well as my custom JPanel I made so I could mess with the paint method.
public class CircleGUI extends JFrame implements ActionListener {
private MigLayout layout = new MigLayout();
private CustomPanel innerpanel;
private JSlider x,y;
private JColorChooser colorpick;
private JButton state;
private boolean bstate;
CircleGUI() {
initialize();
}
private void initialize() {
Border blackline = BorderFactory.createLineBorder(Color.black);
bstate = false;
x = new JSlider(JSlider.HORIZONTAL,650,325);
x.setPaintTicks(true);
x.setPaintLabels(true);
x.setPreferredSize(new Dimension(650,0));
y = new JSlider(JSlider.HORIZONTAL,650,325);
y.setPaintTicks(true);
y.setPaintLabels(true);
y.setInverted(true);
y.setOrientation(JSlider.VERTICAL);
y.setPreferredSize(new Dimension (0,600));
colorpick = new JColorChooser();
state = new JButton("Show");
state.addActionListener(e -> {
if(!bstate) {
int positionx = x.getValue() - 80;
int positiony = y.getValue();
Color c = colorpick.getColor();
innerpanel.setColor(c);
innerpanel.setX(positionx);
innerpanel.setY(positiony);
innerpanel.repaint();
state.setText("Hide");
bstate = true;
} else {
Color transparent = new Color(0,0,0,0);
innerpanel.setColor(transparent);
innerpanel.repaint();
state.setText("Show");
bstate = false;
}
});
JPanel outerpanel = new JPanel(layout);
innerpanel = new CustomPanel();
innerpanel.setPreferredSize(new Dimension(600,600));
innerpanel.setBorder(blackline);
outerpanel.add(x,"wrap");
outerpanel.add(y,"split 2");
outerpanel.add(innerpanel);
outerpanel.add(state,"wrap");
outerpanel.add(colorpick);
this.setSize(1000, 1000);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.add(outerpanel);
}
#Override
public void actionPerformed(ActionEvent e) {
}
}
public class CustomPanel extends JPanel implements ActionListener {
private Color c;
private int x;
private int y;
public CustomPanel() {
c = null;
}
#Override
public void actionPerformed (ActionEvent e) {
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setPaint(c);
g2.fill(new Ellipse2D.Double(x, y, 100, 100));
}
public void setColor(Color c) {
this.c = c;
}
public void setX(int x) {
this.x = x;
}
public void setY(int y) {
this.y = y;
}
}

Your problem is you are trying to make a one-to-one mapping between the value of the JSlider and the coordinate in your CustomPanel. You should use the JSlider value as a percentage, i.e. minimum value zero and maximum value 100. If you want the circle to appear in the middle of the CustomPanel so you place both JSliders in their mid-points, i.e. both at 50%. Then you calculate 50% of the corresponding dimension to get the coordinate. If the width of CustomPanel is 600, then 50% of 600 is 300 so positionx needs to be 300.
The only thing I changed in your code is the calculation of positionx and positiony.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Ellipse2D;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JColorChooser;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.border.Border;
import net.miginfocom.swing.MigLayout;
public class CircleGUI extends JFrame implements ActionListener {
private MigLayout layout = new MigLayout();
private CustomPanel innerpanel;
private JSlider x,y;
private JColorChooser colorpick;
private JButton state;
private boolean bstate;
CircleGUI() {
initialize();
}
private void initialize() {
Border blackline = BorderFactory.createLineBorder(Color.black);
bstate = false;
// x = new JSlider(JSlider.HORIZONTAL, 650, 325);
x = new JSlider(0, 100, 10);
x.setPaintTicks(true);
x.setPaintLabels(true);
x.setPreferredSize(new Dimension(650, 0));
// y = new JSlider(JSlider.HORIZONTAL, 650, 325);
y = new JSlider(0, 100, 10);
y.setPaintTicks(true);
y.setPaintLabels(true);
y.setInverted(true);
y.setOrientation(JSlider.VERTICAL);
y.setPreferredSize(new Dimension(0, 600));
colorpick = new JColorChooser();
state = new JButton("Show");
state.addActionListener(e -> {
if (!bstate) {
int positionx = Math.round(x.getValue() / 100.0f * innerpanel.getSize().width) - 50;
int positiony = Math.round(y.getValue() / 100.0f * innerpanel.getSize().height) - 50;
Color c = colorpick.getColor();
innerpanel.setColor(c);
innerpanel.setX(positionx);
innerpanel.setY(positiony);
innerpanel.repaint();
state.setText("Hide");
bstate = true;
}
else {
Color transparent = new Color(0, 0, 0, 0);
innerpanel.setColor(transparent);
innerpanel.repaint();
state.setText("Show");
bstate = false;
}
});
JPanel outerpanel = new JPanel(layout);
innerpanel = new CustomPanel();
innerpanel.setPreferredSize(new Dimension(600, 600));
innerpanel.setBorder(blackline);
outerpanel.add(x, "wrap");
outerpanel.add(y, "split 2");
outerpanel.add(innerpanel);
outerpanel.add(state, "wrap");
outerpanel.add(colorpick);
this.setSize(1000, 1000);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.add(outerpanel);
}
#Override
public void actionPerformed(ActionEvent e) {
}
public static void main(String[] args) {
EventQueue.invokeLater(() -> {
CircleGUI cg = new CircleGUI();
cg.setVisible(true);
});
}
}
class CustomPanel extends JPanel implements ActionListener {
private Color c;
private int x;
private int y;
public CustomPanel() {
c = null;
}
#Override
public void actionPerformed(ActionEvent e) {
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setPaint(c);
g2.fill(new Ellipse2D.Double(x, y, 100, 100));
}
public void setColor(Color c) {
this.c = c;
}
public void setX(int x) {
this.x = x;
}
public void setY(int y) {
this.y = y;
}
}

Add a JComponent via Child to Parent

I want to accomplish something very similar to the image a Rectangle whit a Selector Line.
Basically, I have a Rectangle and I want to have a selector line all around it.
For that, I wanted to create an additional JComponent.
At the moment I can only draw the Rectangle. How could I get the parentPanel JPanel inside the Rectangle class, so that I could add the selector?
public class TestPanel extends JFrame {
public class Rectangle extends JComponent {
public Rectangle(){
setBounds(x1, y1, x2, y2);
JPanel Selector = new JPanel();
//Adds Selector to parentPanel within Rectangle
//setBounds(x1-1, y1-1, x2+1, y2+1)
//!Problem parent is initially null! cant even a use property
//Life hacks?
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawRect(0, 0, getWidth(), getHeight());
}
}
public TestPanel() {
Rectangle Rectangle = new Rectangle();
JPanel parentFrame = new JPanel();
parentFrame.add(Rectangle);
setSize(200, 200);
setVisible(true);
}
public static void main(String[] args) {
new TestPanel();
}
}
If I try to add the selector inside the rectangle, it will get out of the drawing area. If I resize the drawing area, it won't be scalable for later development.
If possible I would avoid dual binding like:
public TestPanel() {
Rectangle Rectangle = new Rectangle();
JPanel parentPanel = new JPanel();
parentPanel.add(Rectangle);
Rectangle.addParent(parentPanel)
...
}

Again, I'm not 100% clear on what you're trying to achieve. If what you wish to create is a user-created dashed line, one that can change with mouse press/drag/release, then you don't need to create a new component but rather use a MouseAdapter as a MouseListener and MouseMotionListener, all to help you create the Rectangle, and then simply draw the Rectangle with a dashed line using an appropriate Stroke, as per this answer.
For example, something like would create a dashed line that is user-selectable:
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.Stroke;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.*;
public class SelectorPanel extends JPanel {
private static final int PREF_W = 800;
private static final int PREF_H = 650;
private static final Stroke DASHED_STROKE = new BasicStroke(2, BasicStroke.CAP_BUTT,
BasicStroke.JOIN_BEVEL, 0, new float[] { 5 }, 0);
private static final Color DASHED_COLOR = Color.LIGHT_GRAY;
private Rectangle rectangle = null;
public SelectorPanel() {
MyMouse myMouse = new MyMouse();
addMouseListener(myMouse);
addMouseMotionListener(myMouse);
}
private class MyMouse extends MouseAdapter {
private Point p1 = null;
#Override
public void mousePressed(MouseEvent e) {
p1 = e.getPoint();
rectangle = null;
}
#Override
public void mouseDragged(MouseEvent e) {
if (p1 != null) {
createRectangle(e);
}
}
#Override
public void mouseReleased(MouseEvent e) {
if (p1 != null) {
createRectangle(e);
p1 = null;
}
}
private void createRectangle(MouseEvent e) {
Point p2 = e.getPoint();
int x = Math.min(p1.x, p2.x);
int y = Math.min(p1.y, p2.y);
int width = Math.abs(p1.x - p2.x);
int height = Math.abs(p1.y - p2.y);
rectangle = new Rectangle(x, y, width, height);
repaint();
}
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (rectangle != null) {
Graphics2D g2 = (Graphics2D) g.create();
g2.setColor(DASHED_COLOR);
g2.setStroke(DASHED_STROKE);
g2.draw(rectangle);
g2.dispose();
}
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
private static void createAndShowGui() {
SelectorPanel mainPanel = new SelectorPanel();
JFrame frame = new JFrame("SelectorPanel");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}

drawImage error when trying to draw a sprite onto a JFrame

I have this really crappy sprite sheet that I made, which is basically just a bunch of circles and ovals so I can grasp Sprite animation.
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.Timer;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.*;
public class CircleSprite extends JFrame implements ActionListener, Runnable{
BufferedImage circles;
BufferedImage[] test;
Timer timer;
int cycle = 0;
Graphics g = getGraphics();
public void asd(){
setSize(500,500);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
try {
circles = ImageIO.read(new File("CircleTest.png"));
} catch (IOException e) {
e.printStackTrace();
}
final int width = 206;
final int height = 206;
final int rows= 2;
final int columns = 3;
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
test = new BufferedImage[rows * columns];
try{
for(int i = 0; i < rows; i++)
for(int j = 0;j<columns;j++)
{
test[i*columns + j] = circles.getSubimage(j * width, i * height, width, height);
}
}catch(Exception e){
e.printStackTrace();
}
timer = new Timer(500, this);
setVisible(true);
}
public void actionPerformed(ActionEvent e){
//0, 1, 2, 3, 4, 5, 4, 3, 2, 1, 0, 1, 2, etc.
repaint();
g.drawImage(test[cycle], 25, 25, null);
if(cycle >= 5){
cycle--;
}
if(cycle <=0){
cycle++;
}
}
public void run(){
asd();
while(timer.isRunning() == false && this.isVisible() == true){
timer.start();
try {
CircleSpriteRun.t1.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
The error occurs here: g.drawImage(test[cycle], 25, 25, null);
At first I though it had to do with the ImageObserver being null, and looking further into it, I was wrong. Now, I think it might be because of the timer, but I don't really know too much about Timers, let alone the swing one.
This all runs on a Thread being executed in another class, and it could also have to do with the while statement in the run method, since that also involves the timer.

Since you didn't provide a runnable example, I created one to show how to properly code a Swing application.
First, you must start a Swing application with the SwingUtilities.invokeLater method. Here's how I started the CircleSprite class.
public static void main(String[] args) {
SwingUtilities.invokeLater(new CircleSprite());
}
Second, you should use a JPanel for drawing, not a JFrame. Here's the DrawingPanel I created. My version of CircleSprite draws a circle in a random location every 2 seconds.
public class DrawingPanel extends JPanel {
private static final long serialVersionUID = -4603711384104715819L;
private int x;
private int y;
private BufferedImage image;
public DrawingPanel(BufferedImage image) {
this.image = image;
this.x = 0;
this.y = 0;
setPreferredSize(new Dimension(500, 500));
}
public void setPoint(int x, int y) {
this.x = x;
this.y = y;
repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, x, y, null);
}
}
Third, you create the Swing GUI before you do anything with the Swing GUI. Here's the run method from the CircleSprite class. I create the GUI, then I start the thread that does the random drawing.
public void run() {
circle = createCircle();
frame = new JFrame("Circle Sprite");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
drawingPanel = new DrawingPanel(circle);
frame.add(drawingPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
new Thread(new RandomDraw(drawingPanel)).start();
}
Fourth, you only extend a Swing component when you want to override a method, like I did in the DraawingPanel class. You use Swing Components otherwise.
Here's the entire, runnable, CircleSprite class. You can use this as a model for future Swing applications.
package com.ggl.testing;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class CircleSprite implements Runnable {
private BufferedImage circle;
private DrawingPanel drawingPanel;
private JFrame frame;
#Override
public void run() {
circle = createCircle();
frame = new JFrame("Circle Sprite");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
drawingPanel = new DrawingPanel(circle);
frame.add(drawingPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
new Thread(new RandomDraw(drawingPanel)).start();
}
private BufferedImage createCircle() {
BufferedImage image = new BufferedImage(100, 100,
BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
g.setColor(Color.WHITE);
g.fillRect(0, 0, 100, 100);
g.setColor(Color.BLUE);
g.fillOval(10, 10, 80, 80);
g.dispose();
return image;
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new CircleSprite());
}
public class DrawingPanel extends JPanel {
private static final long serialVersionUID = -4603711384104715819L;
private int x;
private int y;
private BufferedImage image;
public DrawingPanel(BufferedImage image) {
this.image = image;
this.x = 0;
this.y = 0;
setPreferredSize(new Dimension(500, 500));
}
public void setPoint(int x, int y) {
this.x = x;
this.y = y;
repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, x, y, null);
}
}
public class RandomDraw implements Runnable {
private DrawingPanel drawingPanel;
private Random random;
public RandomDraw(DrawingPanel drawingPanel) {
this.drawingPanel = drawingPanel;
this.random = new Random();
}
#Override
public void run() {
while (true) {
sleep();
int x = random.nextInt(400);
int y = random.nextInt(400);
drawingPanel.setPoint(x, y);
}
}
private void sleep() {
try {
Thread.sleep(2000L);
} catch (InterruptedException e) {
}
}
}
}

Location of background image is wrong

I am trying to create a BackgroundImage class that has the purpose of creating a background with several image layers, I am using a JLayeredPane to achieve the layers.
The background image will hold a permanent base image and will have methods that allows me(hopefully) to fade in and out images upon this base image.
Right now i'm stuck at the base image being located wrong.
Here is a image that shows the problem:
As you can see in the image, there is a slight grey area above the image that is not supposed to be there. I would like the base image to take all the space.
Here is a MCVE:
BackgroundTest class
import java.awt.*;
import javax.swing.*;
final class BackgroundTest extends JFrame {
public static void main(String[] args) {
new BackgroundTest();
}
BackgroundTest() {
JPanel contentPanel = new JPanel();
BackgroundImage bgImage = new BackgroundImage(contentPanel);
add(contentPanel);
setSize(getScreenDimension());
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
setVisible(true);
}
public static Dimension getScreenDimension() {
GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
Rectangle bounds = ge.getMaximumWindowBounds();
return new Dimension((int) bounds.getWidth(), (int) bounds.getHeight());
}
}
BackgroundImage class
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.*;
import org.imgscalr.Scalr;
class BackgroundImage {
private final BaseImage baseImage;
private final JPanel targetPanel;
private final JLayeredPane layeredPane;
BackgroundImage(JPanel targetPanel) {
this.targetPanel = targetPanel;
layeredPane = new JLayeredPane();
Dimension screenDimension = BackgroundTest.getScreenDimension();
layeredPane.setPreferredSize(screenDimension);
layeredPane.setMaximumSize(screenDimension);
layeredPane.setMinimumSize(screenDimension);
baseImage = new BaseImage();
layeredPane.add(baseImage, new Integer(0));
targetPanel.add(layeredPane);
}
public void addCharacterImageToBase(int characterIdentifier) {
}
public void replaceCurrentCharacterImage(int characterIdentifier) {
}
private class BaseImage extends JComponent {
private ImageIcon imageIcon;
private int imageWidth, imageHeight;
BaseImage() {
BufferedImage backgroundImage;
try {
Dimension screenSize = BackgroundTest.getScreenDimension();
imageWidth = screenSize.width;
imageHeight = screenSize.height;
setBounds(0, 0, imageWidth, imageHeight);
backgroundImage = ImageIO.read(getClass().getResource("/images/background/sky.jpg"));
if (imageWidth > 0 && imageHeight > 0) {
backgroundImage = Scalr.resize(backgroundImage, Scalr.Method.QUALITY, Scalr.Mode.FIT_EXACT, imageWidth, imageHeight, Scalr.OP_ANTIALIAS);
}
imageIcon = new ImageIcon(backgroundImage);
} catch (IOException e) {
Main.getLogger().log(java.util.logging.Level.INFO, e.getMessage(), e);
}
}
public int getImageWidth() {
return imageWidth;
}
public int getImageHeight() {
return imageHeight;
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(imageIcon.getImage(), 0, 0, imageWidth, imageHeight, this);
}
}
private class CharacterImage extends JComponent {
CharacterImage(int currentLevelNumber) {
}
}
}
Thank you for your time.

The answer is that your JPanel has a BorderLayout by default and its hgap and vgap are not 0.
You need this:
JPanel contentPanel = new JPanel(new BorderLayout(0,0));

Overlapping AWT lines and Swing JLabels

I have a problem in my application using line primitives and JLables. I try to explain it:
I have to draw a vehicle route using lines to represent roads and JLabels to represent cities. I need the use of JLabels because each JLabel has a Listener that shows a dialog with information about the city.
I redefine paint() method of my main JPanel. In that method I first in invoke the super.paint(), then I draw the lines and finally I add the Labels to the JPanel.
The problem is that the lines overlap the labels regardless the matter the order of painting them. Is there any suggestion?

You can also override paintComponent() or paintChildren() methods of the JPanel.
In the paintChildren() call your lines drawing and then super to draw JLabels.

anothe way should be
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.Ellipse2D;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
public class AddVertexDemo {
public AddVertexDemo() {
}
private static void createAndShowUI() {
JFrame frame = new JFrame("AddVertexDemo");
frame.getContentPane().add(new Gui().getMainPanel());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
createAndShowUI();
}
});
}
}
class DrawingPanel extends JPanel {
private static final int RADIUS = 6;
private static final long serialVersionUID = 1L;
private List<Shape> vertexList = new ArrayList<Shape>();
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
if (vertexList.size() > 1) {
Shape s0 = vertexList.get(0);
Shape s1 = null;
for (int i = 0; i < vertexList.size(); i++) {
s1 = vertexList.get(i);
drawConnectingLine(g, s0, s1);
s0 = s1;
}
s1 = vertexList.get(0);
//drawConnectingLine(g2, s0, s1);
}
for (Shape shape : vertexList) {
g2.setColor(Color.blue);
g2.fill(shape);
g2.setColor(Color.blue.darker().darker());
g2.draw(shape);
}
}
private void drawConnectingLine(Graphics g, Shape s0, Shape s1) {
Rectangle r0 = s0.getBounds();
Rectangle r1 = s1.getBounds();
int x0 = r0.x + r0.width / 2;
int y0 = r0.y + r0.height / 2;
int x1 = r1.x + r1.width / 2;
int y1 = r1.y + r1.height / 2;
g.drawLine(x0, y0, x1, y1);
}
public void addVertex(Point p) {
int x = p.x - RADIUS;
int y = p.y - RADIUS;
int w = 2 * RADIUS;
int h = w;
vertexList.add(new Ellipse2D.Double(x, y, w, h));
repaint();
}
public void removeVertex(Point p) {
if (vertexList.size() > 0) {
for (int i = vertexList.size() - 1; i >= 0; i--) {
if (vertexList.get(i).contains(p)) {
vertexList.remove(i);
repaint();
return;
}
}
}
}
}
class Gui {
private static final Dimension DRAWING_PANEL_SIZE = new Dimension(600, 500);
private JPanel mainPanel = new JPanel(new BorderLayout());
private DrawingPanel drawingPanel = new DrawingPanel();
private JToggleButton addVertexBtn = new JToggleButton("Add Vertex");
private JToggleButton removeVertexBtn = new JToggleButton("Remove Vertex");
Gui() {
JPanel buttonPanel = new JPanel();
buttonPanel.add(addVertexBtn);
buttonPanel.add(removeVertexBtn);
DrawPanelMouseListener mouseListener = new DrawPanelMouseListener();
mouseListener.setDrawingPanel(drawingPanel);
mouseListener.setGui(this);
drawingPanel.addMouseListener(mouseListener);
drawingPanel.setPreferredSize(DRAWING_PANEL_SIZE);
drawingPanel.setBorder(BorderFactory.createLineBorder(Color.black));
mainPanel.add(drawingPanel, BorderLayout.CENTER);
mainPanel.add(buttonPanel, BorderLayout.SOUTH);
}
public JPanel getMainPanel() {
return mainPanel;
}
public boolean isAddingVertex() {
return addVertexBtn.isSelected();
}
public boolean isRemovingVertex() {
return removeVertexBtn.isSelected();
}
public void setAddingVertex(boolean addingVertex) {
addVertexBtn.setSelected(addingVertex);
}
public void setRemovingVertex(boolean removingVertex) {
removeVertexBtn.setSelected(removingVertex);
}
}
class DrawPanelMouseListener extends MouseAdapter {
private DrawingPanel drawingPanel;
private Gui gui;
public DrawPanelMouseListener() {
}
public void setGui(Gui gui) {
this.gui = gui;
}
public void setDrawingPanel(DrawingPanel drawingPanel) {
this.drawingPanel = drawingPanel;
}
#Override
public void mousePressed(MouseEvent me) {
if (gui.isAddingVertex() && gui.isRemovingVertex()) {
gui.setAddingVertex(false);
gui.setRemovingVertex(false);
return;
}
if (gui.isAddingVertex()) {
drawingPanel.addVertex(me.getPoint());
gui.setAddingVertex(false);
}
if (gui.isRemovingVertex()) {
drawingPanel.removeVertex(me.getPoint());
gui.setRemovingVertex(false);
}
}
}

I'm not sure that this is the right way to do this but you can try this:
Create 2 panels. One for drawing lines and another for drawing buildings(labels).
Add both panels in LayeredPane of JFrame. Add panel with line in lower layer then panel with labels.
You can use LayeredPanes in other ways also to solve your problem. Learn more here: How to use Layered Panes in java