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Painting method paints things from other components

I am trying to make a simple Java program with GUI using Java Swing.
I have painting panel (gPanel) in the center of the screen, panel with buttons (buttonSet) in the west and panel with labels (labelPanel) in the east. To paint over gPanel I use paintComponent method and since I have two buttons, which are supposed to draw different things (and change label on the right of the screen), I decided to put switch case in paintComponent method for it to choose the correct actual painting method.
When I run the program everything looks fine - program uses the first method to paint and there is a sampletext.png image shown in the middle of the screen with yellow background, as it should be. Button number 1 also uses this method to draw over gPanel, so pressing it draws the same thing.
Now Button number 2 uses the second painting method and this is where things go wrong. It draws sampleimage.png over the gPanel, but also parts of left and right panels (i.e. buttons from left buttonSet panel and orange colour that is background colour of side panels) are drawn, though it shouldn't happen. Also the whole gPanel becomes gray (I think it happens because of label on the right that becomes very long after pressing Button number 2, because when the label was shorter gPanel didn't turn gray and left the previously drawn things instead).
Pressing Button number 1 paints things from first method properly, so pressing it after pressing Button number 2 "reverts" the changes.
What do I have to do to make my second painting method work properly?
Also why adding border to buttonSet and labelPanel works but adding it to gPanel doesn't?
package com.inferjus.drawingproject;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import java.io.*;
import javax.imageio.*;
import javax.swing.border.*;
/**
*
* #author inferjus
*/
public class DrawingProject
{
private JFrame frame;
private graphicPanel gPanel;
private JPanel buttonSet;
private JPanel labelPanel;
private JLabel label;
private int painter=0;
public static void main(String[] args)
{
DrawingProject program=new DrawingProject();
program.prepareGUI();
}
public int getPainter()
{
return painter;
}
public void setPainter(int x)
{
painter=x;
}
public void prepareGUI()
{
//setting JFrame and icon
frame=new JFrame("Drawing Project");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
try { frame.setIconImage(ImageIO.read(getClass().getResource("/resources/sampleicon.png")));}
catch (IOException e) { e.printStackTrace(); }
//border for components
Border bigBlackBorder=new LineBorder(Color.black, 3);
//setting JPanel (graphicPanel) for drawing images
gPanel=new graphicPanel();
gPanel.setBorder(bigBlackBorder); // <--- why it does not work?
//setting JPanel for buttons on the left of the screen
buttonSet=new JPanel();
buttonSet.setLayout(new BoxLayout(buttonSet, BoxLayout.Y_AXIS));
buttonSet.setBorder(bigBlackBorder);
//setting JButtons
JButton buttonOne=new JButton("Button number 1");
buttonOne.addActionListener(new buttonOneListener());
buttonSet.add(buttonOne);
buttonSet.setBackground(Color.orange);
JButton buttonTwo=new JButton("Button number 2");
buttonTwo.addActionListener(new buttonTwoListener());
buttonSet.add(buttonTwo);
//setting JLabels on the right of the screen
label=new JLabel("Default label");
label.setFont(new Font("Consolas", Font.PLAIN, 20));
labelPanel=new JPanel();
labelPanel.setLayout(new BoxLayout(labelPanel, BoxLayout.Y_AXIS));
labelPanel.setBackground(Color.orange);
labelPanel.setBorder(bigBlackBorder);
JLabel popeLabelTitle=new JLabel("What does the label say?");
popeLabelTitle.setFont(new Font("Consolas", Font.BOLD, 24));
//adding JLabels to labelPanel
labelPanel.add(BorderLayout.NORTH, popeLabelTitle);
labelPanel.add(BorderLayout.CENTER, label);
//adding components to JFrame
frame.getContentPane().add(BorderLayout.CENTER, gPanel);
frame.getContentPane().add(BorderLayout.EAST, labelPanel);
frame.getContentPane().add(BorderLayout.WEST, buttonSet);
frame.setVisible(true);
}
class graphicPanel extends JPanel
{
private BufferedImage sampletext=null;
private BufferedImage sampleimage=null;
#Override
public void paintComponent(Graphics g)
{
//for Button One paint sampletext.png, for Button Two paint sampleimage.png
switch (painter)
{
case 0:
paintSampletext(g);
break;
case 1:
paintSampleimage(g);
break;
}
}
//paint yellow background and put sampletext.png in the middle
private void paintSampletext(Graphics g)
{
if (sampletext==null)
{
gPanel.setSampletextPNG();
}
g.setColor(Color.yellow);
g.fillRect(0,0, gPanel.getWidth(), gPanel.getHeight());
g.drawImage(sampletext, gPanel.getWidth()/2-sampletext.getWidth()/2, gPanel.getHeight()/2-sampletext.getHeight()/2, this);
g.setColor(Color.black);
g.drawRect(gPanel.getWidth()/2-sampletext.getWidth()/2, gPanel.getHeight()/2-sampletext.getHeight()/2, sampletext.getWidth(), sampletext.getHeight());
g.dispose();
}
//paint sampleimage.png over what is already displayed
private void paintSampleimage(Graphics g)
{
if (sampleimage==null)
{
gPanel.setSampleimagePNG();
}
int x=(int)((Math.random()*gPanel.getWidth())-sampleimage.getWidth());
int y=(int)((Math.random()*gPanel.getHeight())-sampleimage.getHeight());
g.drawImage(sampleimage, x, y, gPanel);
g.dispose();
}
public void setSampletextPNG()
{
try { sampletext=ImageIO.read(getClass().getResource("/resources/sampletext.png")); }
catch (IOException ex) { System.out.println("Image error"); }
}
public void setSampleimagePNG()
{
try { sampleimage=ImageIO.read(getClass().getResource("/resources/sampleimage.png")); }
catch (IOException ex) { System.out.println("Image error"); }
}
}
class buttonOneListener implements ActionListener
{
#Override
public void actionPerformed(ActionEvent e)
{
label.setText("Reaction to button number 1: change of label.");
setPainter(0);
gPanel.repaint();
}
}
class buttonTwoListener implements ActionListener
{
#Override
public void actionPerformed(ActionEvent e)
{
label.setText("Reaction to button number 2: change of label + drawing images over gPanel.");
setPainter(1);
gPanel.repaint();
}
}
}
Tree of my project:
DrawingProject
-JRE System Library
-src
--com.inferjus.drawingproject
---DrawingProject.java
--resources
---sampleicon.png
---sampleimage.png
---sampletext.png
what shows after running the program by default or after pressing Button One
what shows after pressing Button Two one time
what shows after pressing Button Two a few times

Introduction
Oracle has a helpful tutorial, Creating a GUI With Swing. Skip the Learning Swing with the NetBeans IDE section.
I went ahead and created the following GUI. I created two BufferedImages for the text image and the plain image so I wouldn't have to read any external files.
Explanation
When I create a Swing GUI, I use the model-view-controller pattern. This pattern allows me to separate my concerns and focus on one part of the application at a time.
Model
I created a model class to hold the button flag and the two BufferedImages. This is the class where you would read the resources.
You can add the JFrame icon back to this class.
Model classes are plain Java getter/setter classes.
View
All Swing applications must start with a call to the SwingUtilities invokeLater method. This method ensures that the Swing components are created and executed on the Event Dispatch Thread.
Class names are written in camel case and start with an upper case character. Method names are written in camel case and start with a lower case character. Field names follow the same rules as method names.
I separated the creation of the JFrame from the creation of the JPanels. This helps me to separate my concerns and makes it much easier to visually verify whether or not the code is correct. Aim to write short methods that do one thing and do it well.
You have to manually draw a border on a graphic JPanel. I added the code to your paintComponent method to paint a partial border.
Your paintComponent method should paint. Period. Nothing else. It must also start with a call to the super.paintComponent method to maintain the Swing paint chain.
I changed your JLabel in the right JPanel to a JTextArea. A JTextArea allows for longer messages to word wrap on multiple lines and not make your JFrame change size.
Controller
Your JButton controller classes were fine, except for the class names.
Code
Here's the complete runnable code. I made all the additional classes inner classes so I could post the code in one block.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import javax.swing.BorderFactory;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
public class DrawingProject implements Runnable {
public static void main(String[] args) {
SwingUtilities.invokeLater(new DrawingProject());
}
private final DrawingModel model;
private GraphicPanel graphicPanel;
private JTextArea textArea;
public DrawingProject() {
this.model = new DrawingModel();
}
#Override
public void run() {
JFrame frame = new JFrame("Drawing Project");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
graphicPanel = new GraphicPanel(model);
frame.add(createButtonPanel(), BorderLayout.WEST);
frame.add(graphicPanel, BorderLayout.CENTER);
frame.add(createTextPanel(), BorderLayout.EAST);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
private JPanel createButtonPanel() {
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
panel.setBackground(Color.orange);
panel.setBorder(BorderFactory.createLineBorder(Color.BLACK, 3));
JButton buttonOne = new JButton("Button number 1");
buttonOne.addActionListener(new ButtonOneListener());
panel.add(buttonOne);
JButton buttonTwo = new JButton("Button number 2");
buttonTwo.addActionListener(new ButtonTwoListener());
panel.add(buttonTwo);
return panel;
}
private JPanel createTextPanel() {
JPanel panel = new JPanel(new BorderLayout());
panel.setBorder(BorderFactory.createLineBorder(Color.BLACK, 3));
JLabel popeLabelTitle = new JLabel("What does the label say?");
popeLabelTitle.setFont(new Font(Font.MONOSPACED, Font.BOLD, 24));
panel.add(popeLabelTitle, BorderLayout.NORTH);
textArea = new JTextArea(4, 30);
textArea.setEditable(false);
textArea.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 20));
textArea.setText("Default label");
textArea.setLineWrap(true);
textArea.setWrapStyleWord(true);
panel.add(textArea, BorderLayout.CENTER);
return panel;
}
public class GraphicPanel extends JPanel {
private static final long serialVersionUID = 1L;
private final DrawingModel model;
public GraphicPanel(DrawingModel model) {
this.model = model;
this.setPreferredSize(new Dimension(640, 480));
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
// Paint border
int width = getWidth();
int height = getHeight();
int lineThickness = 3;
g.setColor(Color.BLACK);
g.fillRect(0, 0, width, height);
g.setColor(Color.YELLOW);
g.fillRect(0, lineThickness, width, height - 2 * lineThickness);
switch (model.getPainter()) {
case 0:
paintSampleText(g);
break;
case 1:
paintSampleImage(g);
break;
}
}
private void paintSampleText(Graphics g) {
BufferedImage image = model.getSampleText();
int x = (getWidth() - image.getWidth()) / 2;
int y = (getHeight() - image.getHeight()) / 2;
g.drawImage(image, x, y, this);
}
private void paintSampleImage(Graphics g) {
BufferedImage image = model.getSampleImage();
int x = (int) ((Math.random() * getWidth()) - image.getWidth());
int y = (int) ((Math.random() * getHeight()) - image.getHeight());
g.drawImage(image, x, y, this);
}
}
public class ButtonOneListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
textArea.setText("Reaction to button number 1: change of label.");
model.setPainter(0);
graphicPanel.repaint();
}
}
public class ButtonTwoListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
textArea.setText("Reaction to button number 2: change of label + "
+ "drawing images over gPanel.");
model.setPainter(1);
graphicPanel.repaint();
}
}
public class DrawingModel {
private int painter;
private final BufferedImage sampleText;
private final BufferedImage sampleImage;
public DrawingModel() {
this.painter = 0;
this.sampleText = createBufferedImage(Color.BLUE);
this.sampleImage = createBufferedImage(Color.MAGENTA);
}
private BufferedImage createBufferedImage(Color color) {
BufferedImage image = new BufferedImage(64, 64,
BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
g.setColor(color);
g.fillRect(0, 0, image.getWidth(), image.getHeight());
g.dispose();
return image;
}
public int getPainter() {
return painter;
}
public void setPainter(int painter) {
this.painter = painter;
}
public BufferedImage getSampleText() {
return sampleText;
}
public BufferedImage getSampleImage() {
return sampleImage;
}
}
}
Update
In order to paint multiple images, you have to save the origin of the images in a List. I've modified the application model to hold a List of origin Point instances. I also corrected the code to create a random point.
Here's the GUI with multiple images.
Here's the modified code
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import java.util.List;
import javax.swing.BorderFactory;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
public class DrawingProject implements Runnable {
public static void main(String[] args) {
SwingUtilities.invokeLater(new DrawingProject());
}
private final DrawingModel model;
private GraphicPanel graphicPanel;
private JTextArea textArea;
public DrawingProject() {
this.model = new DrawingModel();
}
#Override
public void run() {
JFrame frame = new JFrame("Drawing Project");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
graphicPanel = new GraphicPanel(model);
frame.add(createButtonPanel(), BorderLayout.WEST);
frame.add(graphicPanel, BorderLayout.CENTER);
frame.add(createTextPanel(), BorderLayout.EAST);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
private JPanel createButtonPanel() {
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
panel.setBackground(Color.orange);
panel.setBorder(BorderFactory.createLineBorder(Color.BLACK, 3));
JButton buttonOne = new JButton("Button number 1");
buttonOne.addActionListener(new ButtonOneListener());
panel.add(buttonOne);
JButton buttonTwo = new JButton("Button number 2");
buttonTwo.addActionListener(new ButtonTwoListener());
panel.add(buttonTwo);
return panel;
}
private JPanel createTextPanel() {
JPanel panel = new JPanel(new BorderLayout());
panel.setBorder(BorderFactory.createLineBorder(Color.BLACK, 3));
JLabel popeLabelTitle = new JLabel("What does the label say?");
popeLabelTitle.setFont(new Font(Font.MONOSPACED, Font.BOLD, 24));
panel.add(popeLabelTitle, BorderLayout.NORTH);
textArea = new JTextArea(4, 30);
textArea.setEditable(false);
textArea.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 20));
textArea.setText("Default label");
textArea.setLineWrap(true);
textArea.setWrapStyleWord(true);
panel.add(textArea, BorderLayout.CENTER);
return panel;
}
public class GraphicPanel extends JPanel {
private static final long serialVersionUID = 1L;
private final DrawingModel model;
public GraphicPanel(DrawingModel model) {
this.model = model;
this.setPreferredSize(new Dimension(640, 480));
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
paintMyBorder(g);
if (model.getPainter() == 1) {
createSampleImage(g);
}
paintSampleText(g);
BufferedImage image = model.getSampleImage();
List<Point> origin = model.getImageOrigin();
for (Point point : origin) {
g.drawImage(image, point.x, point.y, this);
}
}
private void paintMyBorder(Graphics g) {
int width = getWidth();
int height = getHeight();
int lineThickness = 3;
g.setColor(Color.BLACK);
g.fillRect(0, 0, width, height);
g.setColor(Color.YELLOW);
g.fillRect(0, lineThickness, width, height - 2 * lineThickness);
}
private void paintSampleText(Graphics g) {
BufferedImage image = model.getSampleText();
int x = (getWidth() - image.getWidth()) / 2;
int y = (getHeight() - image.getHeight()) / 2;
g.drawImage(image, x, y, this);
}
private void createSampleImage(Graphics g) {
BufferedImage image = model.getSampleImage();
int x = (int) (Math.random() * (getWidth() - image.getWidth()));
int y = (int) (Math.random() * (getHeight() - image.getHeight()));
model.addNewImageOrigin(new Point(x, y));
}
}
public class ButtonOneListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
textArea.setText("Reaction to button number 1: change of label.");
model.setPainter(0);
graphicPanel.repaint();
}
}
public class ButtonTwoListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
textArea.setText("Reaction to button number 2: change of label + "
+ "drawing images over gPanel.");
model.setPainter(1);
graphicPanel.repaint();
}
}
public class DrawingModel {
private int painter;
private final BufferedImage sampleText;
private final BufferedImage sampleImage;
private final List<Point> imageOrigin;
public DrawingModel() {
this.painter = 0;
this.sampleText = createBufferedImage(Color.BLUE);
this.sampleImage = createBufferedImage(Color.MAGENTA);
this.imageOrigin = new ArrayList<>();
}
private BufferedImage createBufferedImage(Color color) {
BufferedImage image = new BufferedImage(64, 64,
BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
g.setColor(color);
g.fillRect(0, 0, image.getWidth(), image.getHeight());
g.dispose();
return image;
}
public void addNewImageOrigin(Point point) {
this.imageOrigin.add(point);
}
public int getPainter() {
return painter;
}
public void setPainter(int painter) {
this.painter = painter;
}
public BufferedImage getSampleText() {
return sampleText;
}
public BufferedImage getSampleImage() {
return sampleImage;
}
public List<Point> getImageOrigin() {
return imageOrigin;
}
}
}

JComponents with Graphics.draw

I am trying to make a simple game using JPanel.
I am using Graphics Draw to display all information, including text, but I need to add user input.
I was thinking about using JTextField with absolute positioning to make it work with what is being drawn, but I have heard that absolute positioning is not a good way set up a JPanel.
Is there a better way to use both graphics paint and JComponents in the same panel?

Solution: use layout managers
Why not simply have the drawing JPanel held by another JPanel, one that uses BorderLayout and held in the BorderLayout.CENTER position. You can then place JTextFields or other control components in the outer JPanel in other positions.
You can also add a layout manager to the drawing JPanel and then add components onto this using the layout. Just remember that if you add any JPanels on top of the drawing JPanel, the added JPanels should be transparent, that is myPanel.setOpaque(false) should be called on them so that the drawing underneath shows through.
For example -- run this program to see what I mean:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import javax.swing.*;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class GradientPaintEg extends JPanel {
private DrawingPanel drawingPanel = new DrawingPanel();
private JSlider hue1Slider = new JSlider(0, 100, 0);
private JSlider hue2Slider = new JSlider(0, 100, 0);
public GradientPaintEg() {
Color color = drawingPanel.getColor1();
float[] hsb = Color.RGBtoHSB(color.getRed(), color.getGreen(), color.getBlue(), null);
int value = (int) (hsb[0] * 100);
hue1Slider.setValue(value);
color = drawingPanel.getColor2();
hsb = Color.RGBtoHSB(color.getRed(), color.getGreen(), color.getBlue(), null);
value = (int) (hsb[0] * 100);
hue2Slider.setValue(value);
hue1Slider.setMajorTickSpacing(20);
hue1Slider.setMinorTickSpacing(5);
hue1Slider.setPaintTicks(true);
hue1Slider.setPaintLabels(true);
hue1Slider.setPaintTrack(true);
hue1Slider.addChangeListener(new SliderListener(hue1Slider, drawingPanel, true));
hue1Slider.setOpaque(false);
hue2Slider.setMajorTickSpacing(20);
hue2Slider.setMinorTickSpacing(5);
hue2Slider.setPaintTicks(true);
hue2Slider.setPaintLabels(true);
hue2Slider.setPaintTrack(true);
hue2Slider.addChangeListener(new SliderListener(hue2Slider, drawingPanel, false));
hue2Slider.setOpaque(false);
JPanel sliderPanel = new JPanel(new GridLayout(0, 1, 4, 4));
sliderPanel.add(hue1Slider);
sliderPanel.add(hue2Slider);
sliderPanel.setOpaque(false);
setLayout(new BorderLayout());
// if you want to add the slider panel to the main JPanel:
// add(sliderPanel, BorderLayout.PAGE_START);
add(drawingPanel);
// if you want to add the sliderPanel to the drawing JPanel
drawingPanel.setLayout(new BorderLayout());
drawingPanel.add(sliderPanel, BorderLayout.PAGE_START);
}
private class SliderListener implements ChangeListener {
private JSlider slider;
private DrawingPanel drawingPanel;
private boolean color1Listener;
public SliderListener(JSlider slider, DrawingPanel drawingPanel, boolean color1Listener) {
this.slider = slider;
this.drawingPanel = drawingPanel;
this.color1Listener = color1Listener;
}
#Override
public void stateChanged(ChangeEvent e) {
int value = slider.getValue();
float hue = value / 100f;
Color c = Color.getHSBColor(hue, 1f, 1f);
if (color1Listener) {
drawingPanel.setColor1(c);
} else {
drawingPanel.setColor2(c);
}
}
}
private static void createAndShowGui() {
GradientPaintEg mainPanel = new GradientPaintEg();
JFrame frame = new JFrame("GradientPaintEg");
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());
}
}
class DrawingPanel extends JPanel {
private static final int PREF_W = 600;
private static final int PREF_H = PREF_W;
private static final float X2 = 20;
private static final float Y2 = X2;
private Color color1 = Color.RED;
private Color color2 = Color.BLUE;
public Color getColor1() {
return color1;
}
public void setColor1(Color color1) {
this.color1 = color1;
repaint();
}
public Color getColor2() {
return color2;
}
public void setColor2(Color color2) {
this.color2 = color2;
repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setPaint(new GradientPaint(0, 0, color1, X2, Y2, color2, true));
g2.fillRect(0, 0, getWidth(), getHeight());
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
}
In this code example, I have a JPanel that draws, called class DrawingPanel and use within another main JPanel, the GradientPaintEg class:
public class GradientPaintEg extends JPanel {
private DrawingPanel drawingPanel = new DrawingPanel();
If I want to add components to the DrawingPanel, I first give it a layout, and then add the component(s). For instance, there is a JPanel that holds JSliders called sliderPanel that I add to the DrawingPanel instance using BorderLayout:
drawingPanel.setLayout(new BorderLayout());
drawingPanel.add(sliderPanel, BorderLayout.PAGE_START);
This adds the sliderPanel to the top of the drawingPanel.
But also note that I have to make sliderPanel non-opaque first:
JPanel sliderPanel = new JPanel(new GridLayout(0, 1, 4, 4));
sliderPanel.add(hue1Slider);
sliderPanel.add(hue2Slider);
sliderPanel.setOpaque(false);
I've also made the JSliders themselves non-opaque so that the underlying drawing shows through:
// ......
hue1Slider.setOpaque(false);
// ......
hue2Slider.setOpaque(false);

Here is a basic mcve of combining user input in JTextfield and painting, on a panel using a layout manager:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;
class DrawingPanel extends JPanel {
private final JButton update;
private final JTextField input;
private final static int W = 300, H = 350, RADIUS = 100, GAP = 50;
private String text;
public DrawingPanel() {
setPreferredSize(new Dimension(W, H));
setOpaque(false);
setLayout(new BorderLayout());
update = new JButton("Update");
update.addActionListener(e->update());
add(update, BorderLayout.PAGE_START);
input = new JTextField();
add(input, BorderLayout.PAGE_END);
text = "Enter text and press button";
}
private void update() {
text = input.getText();
input.setText("");
repaint();
}
#Override
public void paintComponent(final Graphics g) {
super.paintComponents(g);
final int width = getWidth();
final int height = getHeight();
g.setColor(Color.RED);
g.fillOval(width/2 - RADIUS, height/2 - RADIUS, RADIUS*2, RADIUS*2);
g.setColor(Color.BLUE);
g.drawString(text, height/2 - RADIUS - GAP, GAP);
}
public static void main(final String[] args) {
SwingUtilities.invokeLater(()->makeGui());
}
private static void makeGui() {
JFrame frame = new JFrame();
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.add(new DrawingPanel());
frame.pack();
frame.setVisible(true);
}
}

Java: How to control JPanel aspect ratio?

I have a JPanel which I want to remain a square however I want it to size so that it fills the maximum amount of space possible in its parent JFrame but remains square i.e. it takes the shortest side of the JFrame as the square width.
I've searched the net, checked all layout managers and none seem to have a simple solution to this very simple problem.

import java.awt.*;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
public class YouAreSoSquare {
private static JPanel createPanel() {
// GBL is important for the next step..
JPanel gui = new JPanel(new GridBagLayout());
JPanel squareComponent = new JPanel() {
private static final long serialVersionUID = 1L;
#Override
public Dimension getPreferredSize() {
// Relies on being the only component
// in a layout that will center it without
// expanding it to fill all the space.
Dimension d = this.getParent().getSize();
int newSize = d.width > d.height ? d.height : d.width;
newSize = newSize == 0 ? 100 : newSize;
return new Dimension(newSize, newSize);
}
};
squareComponent.setBackground(Color.RED);
gui.add(squareComponent);
return gui;
}
public static void main(String[] args) {
Runnable r = new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception useDefault) {
}
JFrame mainFrame = new JFrame("..So Square");
mainFrame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
mainFrame.setLocationByPlatform(true);
mainFrame.add(createPanel());
mainFrame.pack();
mainFrame.setMinimumSize(mainFrame.getSize());
mainFrame.setVisible(true);
}
};
SwingUtilities.invokeLater(r);
}
}

You may use a GridBagLayout and ComponentListener,
For example: (inspired from: https://community.oracle.com/thread/1265752?start=0&tstart=0)
public class AspectRatio {
public static void main(String[] args) {
final JPanel innerPanel = new JPanel();
innerPanel.setBackground(Color.YELLOW);
final JPanel container = new JPanel(new GridBagLayout());
container.add(innerPanel);
container.addComponentListener(new ComponentAdapter() {
#Override
public void componentResized(ComponentEvent e) {
resizePreview(innerPanel, container);
}
});
final JFrame frame = new JFrame("AspectRatio");
frame.getContentPane().add(container);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(600, 600);
frame.setVisible(true);
}
private static void resizePreview(JPanel innerPanel, JPanel container) {
int w = container.getWidth();
int h = container.getHeight();
int size = Math.min(w, h);
innerPanel.setPreferredSize(new Dimension(size, size));
container.revalidate();
}
}

Here's my take for a most reusable solution, which use the Swing Layout concept. So that you can use it simply by copy/pasting this Layout class and set the layout on your Swing Containers.
I was surprised not to find it already done on the net, so here it is ! A main method is included, it creates a JFrame similar to the screenshots by
Andrew Thompson
import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Insets;
import java.awt.LayoutManager;
import javax.swing.JFrame;
import javax.swing.JPanel;
//#Slf4j
/**
* A Swing Layout that will shrink or enlarge keep the content of a container while keeping
* it's aspect ratio. The caveat is that only a single component is supported or an exception
* will be thrown.
* This is the component's {#link Component#getPreferredSize()} method that must return the
* correct ratio. The preferredSize will not be preserved but the ratio will.
*
* #author #francoismarot
* #see https://gist.github.com/fmarot/f04346d0e989baef1f56ffd83bbf764d
*/
public class SingleComponentAspectRatioKeeperLayout implements LayoutManager {
/** Will be used for calculus in case no real component is in the parent */
private static Component fakeComponent = new JPanel();
public SingleComponentAspectRatioKeeperLayout() {
fakeComponent.setPreferredSize(new Dimension(0, 0));
}
#Override
public void addLayoutComponent(String arg0, Component arg1) {
}
#Override
public void layoutContainer(Container parent) {
Component component = getSingleComponent(parent);
Insets insets = parent.getInsets();
int maxWidth = parent.getWidth() - (insets.left + insets.right);
int maxHeight = parent.getHeight() - (insets.top + insets.bottom);
Dimension prefferedSize = component.getPreferredSize();
Dimension targetDim = getScaledDimension(prefferedSize, new Dimension(maxWidth, maxHeight));
double targetWidth = targetDim.getWidth();
double targetHeight = targetDim.getHeight();
double hgap = (maxWidth - targetWidth) / 2;
double vgap = (maxHeight - targetHeight) / 2;
// Set the single component's size and position.
component.setBounds((int) hgap, (int) vgap, (int) targetWidth, (int) targetHeight);
}
private Component getSingleComponent(Container parent) {
int parentComponentCount = parent.getComponentCount();
if (parentComponentCount > 1) {
throw new IllegalArgumentException(this.getClass().getSimpleName()
+ " can not handle more than one component");
}
Component comp = (parentComponentCount == 1) ? parent.getComponent(0) : fakeComponent;
return comp;
}
private Dimension getScaledDimension(Dimension imageSize, Dimension boundary) {
double widthRatio = boundary.getWidth() / imageSize.getWidth();
double heightRatio = boundary.getHeight() / imageSize.getHeight();
double ratio = Math.min(widthRatio, heightRatio);
return new Dimension((int) (imageSize.width * ratio), (int) (imageSize.height * ratio));
}
#Override
public Dimension minimumLayoutSize(Container parent) {
return preferredLayoutSize(parent);
}
#Override
public Dimension preferredLayoutSize(Container parent) {
return getSingleComponent(parent).getPreferredSize();
}
#Override
public void removeLayoutComponent(Component parent) {
}
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel(); // the panel we want to keep it's aspect ratio
panel.setPreferredSize(new Dimension(300, 600));
panel.setBackground(Color.ORANGE);
JPanel wrapperPanel = new JPanel(new SingleComponentAspectRatioKeeperLayout());
wrapperPanel.add(panel);
frame.getContentPane().add(wrapperPanel);
frame.setSize(450, 450);
frame.setVisible(true);
}
}

How to force component in JScrollPane to show

I have a problem with showing specific component placed in JScrollPane. I have horizontal JScrollPane with GridLayout(1,0) and it contains variable number of JPanels - each containing image. It's like a preview of frames in GIF image. I use button to move among these JPanels (by changing borders and keeping index of chosen one), but I don't know how to force JScrollPane to show me JPanel if it's chosen (and center it if possible).
So I want this
force to do this:
Thanks in advance!
EDIT: almost working code with scrollRectToVisible() method
public class MiniatursPanel extends JPanel{
private int indexOfChosenFrame = 0;
private ArrayList<JPanel> frames;
private JScrollPane scrollPane;
private JPanel innerPanel;
public MiniatursPanel(){
setBorder(BorderFactory.createCompoundBorder(BorderFactory.createRaisedBevelBorder(),BorderFactory.createLoweredBevelBorder()));
setPreferredSize(new Dimension(1200,170));
setLayout(null);
}
public void initialize(){
int width = GifImageStats.getInstance().getWidth();
int height = GifImageStats.getInstance().getHeight();
int numberOfFrames = GifImageStats.getInstance().getNumberOfFrames();
frames = new ArrayList(numberOfFrames);
for (int i = 0; i < numberOfFrames; i++) {
JPanel frameBox = new JPanel();
frameBox.setLayout(new FlowLayout(FlowLayout.CENTER));
JButton button = new JButton(String.valueOf(i+1));
button.setPreferredSize(new Dimension(2*width,2*height));
button.setBackground(Color.white);
button.setFocusable(false);
frameBox.add(button);
frames.add(frameBox);
}
innerPanel = new JPanel();
innerPanel.setLayout(new GridLayout(1,0,10,10));
for (JPanel button : frames) {
innerPanel.add(button);
}
scrollPane = new JScrollPane(innerPanel);
scrollPane.setBounds(10, 10, 1180, 145);
scrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_NEVER);
highlightFrame(frames.get(0));
add(scrollPane);
}
public void nextFrame(){
if (indexOfChosenFrame == frames.size() - 1) {
unhighlightFrame(frames.get(indexOfChosenFrame));
indexOfChosenFrame = 0;
highlightFrame(frames.get(0));
}else{
unhighlightFrame(frames.get(indexOfChosenFrame));
indexOfChosenFrame++;
highlightFrame(frames.get(indexOfChosenFrame));
}
}
public void previousFrame(){
if (indexOfChosenFrame == 0) {
unhighlightFrame(frames.get(0));
indexOfChosenFrame = frames.size()-1;
highlightFrame(frames.get(indexOfChosenFrame));
}else{
unhighlightFrame(frames.get(indexOfChosenFrame));
indexOfChosenFrame--;
highlightFrame(frames.get(indexOfChosenFrame));
}
}
private void highlightFrame(JPanel frame){
Rectangle rect = frame.getBounds();
rect.setBounds(frame.getX()-550, frame.getY(), frame.getWidth()+1050, frame.getHeight());
innerPanel.scrollRectToVisible(rect);
frame.setBorder(BorderFactory.createLineBorder(Color.red,2));
}
private void unhighlightFrame(JPanel frame){
frame.setBorder(null);
}

The relevant method here is JComponent#scrollRectToVisible(Rectangle). It has to be called on the component that is in the viewport of the scroll pane. (In your case, this is the panel with the grid layout, which contains the other sub-panels).
The rectangle that is passed to this method can be the bounds of one sub-panel. In this case, the scoll pane will do the "minimum" scrolling that is necessary to make the given rectangle visible. If you want to make sure that the respective sub-panel is in the center, then you can increase the size of this rectangle - that is, you define a rectangle in a way that the desired sub-panel will be in the center.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.Rectangle;
import java.util.ArrayList;
import java.util.List;
import javax.swing.BorderFactory;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSpinner;
import javax.swing.SpinnerNumberModel;
import javax.swing.SwingConstants;
import javax.swing.SwingUtilities;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class ScrollToVisible
{
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
#Override
public void run()
{
createAndShowGUI();
}
});
}
private static void createAndShowGUI()
{
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
int n = 20;
final JPanel panel = new JPanel(new GridLayout(1,0));
final List<JComponent> components = new ArrayList<JComponent>();
for (int i=0; i<n; i++)
{
JComponent component = new JLabel(String.valueOf(i), SwingConstants.CENTER);
component.setPreferredSize(new Dimension(100,100));
component.setBorder(BorderFactory.createLineBorder(Color.BLACK));
components.add(component);
panel.add(component);
}
final JScrollPane scrollPane = new JScrollPane(panel);
final JSpinner spinner = new JSpinner(new SpinnerNumberModel(0, 0, n-1, 1));
spinner.addChangeListener(new ChangeListener()
{
JComponent selectedComponent = components.get(0);
#Override
public void stateChanged(ChangeEvent e)
{
selectedComponent.setBorder(BorderFactory.createLineBorder(Color.BLACK));
int index = (Integer)spinner.getValue();
JComponent component = components.get(index);
Rectangle bounds = component.getBounds();
// This would make the component "just" visible:
//panel.scrollRectToVisible(bounds);
// This will center the component:
int cx = bounds.x + bounds.width / 2;
int w = scrollPane.getViewport().getWidth();
Rectangle r = new Rectangle(cx-w/2, bounds.y, w, bounds.height);
panel.scrollRectToVisible(r);
selectedComponent = component;
selectedComponent.setBorder(BorderFactory.createLineBorder(Color.RED));
}
});
f.getContentPane().setLayout(new BorderLayout());
f.getContentPane().add(scrollPane, BorderLayout.CENTER);
f.getContentPane().add(spinner, BorderLayout.NORTH);
f.setSize(800, 300);
f.setLocationRelativeTo(null);
f.setVisible(true);
}
}
EDIT: You should NOT use setLayout(null), and you should not do manual calls to setBounds, and you should rarely use setPreferredSize. And... when you post code that already is so close to a https://stackoverflow.com/help/mcve (or even was created from a runnable example of another post) then you should make it really runnable. It's annoying to re-insert the boilerplate code and waste some time with debugging until you realize that initialize() is not called at all...
However, change the code according to this:
private void highlightFrame(JPanel frame){
Rectangle rect = frame.getBounds();
int c = rect.x + rect.width / 2;
int w = scrollPane.getViewport().getWidth();
int x = c-w/2;
rect.setBounds(x, rect.y, w, rect.height);
innerPanel.scrollRectToVisible(rect);
frame.setBorder(BorderFactory.createLineBorder(Color.red,2));
}
private void unhighlightFrame(JPanel frame){
frame.setBorder(BorderFactory.createEmptyBorder(2, 2, 2, 2));
}
The most important thing is to make sure that the size of the components is correct, by setting an empty border with the same size as the "highlighting" border.

Internal padding for JTextArea with background Image

My ultimate goal is to have a JTextArea with a background image. I found code online that showed me how to do this, but now I'm having an issue with the text being on top of the image.
This Is what I mean:
Is there any way I can add a sort of inward indent so that the text is not overlapping the edges of the image?
Here is the raw comment bubble image.
Here is the code:
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.Image;
import javax.swing.GrayFilter;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
public class myBackgroundSample {
String file;
public myBackgroundSample(String i) {
file = i;
setItUp();
}
public void setItUp() {
final ImageIcon imageIcon = new ImageIcon(file);
JTextArea textArea = new JTextArea() {
Image image = imageIcon.getImage();
public void paint(Graphics g) {
setOpaque(false);
g.drawImage(image, 0, 0, this);
super.paint(g);
}
};
JFrame frame = new JFrame("Background Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JScrollPane scrollPane = new JScrollPane(textArea);
Container content = frame.getContentPane();
content.add(scrollPane, BorderLayout.CENTER);
frame.setSize(400, 400);
frame.setVisible(true);
}
public static void main(String[] args) {
// TODO Auto-generated method stub
String right = "chat1.jpg";
myBackgroundSample temp = new myBackgroundSample(right);
}
}

Use a custom border that extends AbstractBorder. Something like this:
Getting the exact shape & color is left as an exercise for the reader. :)
import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;
import javax.swing.border.AbstractBorder;
class TextBubbleBorder extends AbstractBorder {
private Color color;
private int thickness = 4;
private int radii = 8;
private int pointerSize = 7;
private Insets insets = null;
private BasicStroke stroke = null;
private int strokePad;
private int pointerPad = 4;
RenderingHints hints;
TextBubbleBorder(
Color color) {
new TextBubbleBorder(color, 4, 8, 7);
}
TextBubbleBorder(
Color color, int thickness, int radii, int pointerSize) {
this.thickness = thickness;
this.radii = radii;
this.pointerSize = pointerSize;
this.color = color;
stroke = new BasicStroke(thickness);
strokePad = thickness/2;
hints = new RenderingHints(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
int pad = radii + strokePad;
int bottomPad = pad + pointerSize + strokePad;
insets = new Insets(pad,pad,bottomPad,pad);
}
#Override
public Insets getBorderInsets(Component c) {
return insets;
}
#Override
public Insets getBorderInsets(Component c, Insets insets) {
return getBorderInsets(c);
}
#Override
public void paintBorder(
Component c,
Graphics g,
int x, int y,
int width, int height) {
Graphics2D g2 = (Graphics2D)g;
int bottomLineY = height-thickness-pointerSize;
RoundRectangle2D.Double bubble = new RoundRectangle2D.Double(
0+strokePad,
0+strokePad,
width-thickness,
bottomLineY,
radii,
radii
);
Polygon pointer = new Polygon();
// left point
pointer.addPoint(
strokePad+radii+pointerPad,
bottomLineY);
// right point
pointer.addPoint(
strokePad+radii+pointerPad+pointerSize,
bottomLineY);
// bottom point
pointer.addPoint(
strokePad+radii+pointerPad+(pointerSize/2),
height-strokePad);
Area area = new Area(bubble);
area.add(new Area(pointer));
g2.setRenderingHints(hints);
Area spareSpace = new Area(new Rectangle(0,0,width,height));
spareSpace.subtract(area);
g2.setClip(spareSpace);
g2.clearRect(0,0,width,height);
g2.setClip(null);
g2.setColor(color);
g2.setStroke(stroke);
g2.draw(area);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JLabel l = new JLabel(
"The quick brown fox jumped over the lazy dog!");
l.setBorder(new TextBubbleBorder(Color.MAGENTA.darker(),2,4,0));
l.setOpaque(true);
l.setBackground(Color.BLACK);
JOptionPane.showMessageDialog(null, l);
}
});
}
}

You should use an Border for that, more specifictly you should use BorderFactory.createEmptyBorder(int top, int left, int bottom, int right):
textArea.setBorder(BorderFactory.createEmptyBorder(10,10,15,10));
You should also override paintComponent instead of paint. Also, use setRows() and setColumns() to set the size of the textArea, then you can use pack() instead of setSize(400,400) which is not recommended. See this example:
import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextArea;
public class Test extends JFrame {
class MyTextArea extends JTextArea {
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
g2.setColor(Color.PINK);
g2.setStroke(new BasicStroke(4));
g2.drawRoundRect(3, 3, getWidth()-7, getHeight()-7, 5, 5);
}
}
public Test() {
JPanel panel = new JPanel(new BorderLayout());
JTextArea textArea = new MyTextArea();
textArea.setRows(3);
textArea.setColumns(25);
textArea.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
panel.add(textArea, BorderLayout.NORTH);
add(panel);
pack();
setDefaultCloseOperation(EXIT_ON_CLOSE);
setVisible(true);
}
public static void main(String[] args) {
new Test();
}
}

To post code, indent every line by four spaces.
I assume you are overriding paintComponent()* for your JTextArea. If you are, make sure that it is transparent by adding
setOpaque(false);
*This also works if you override paint(), but as trashgod correctly states, that would interfere with paintBorder().

A better version of TextBubbleBorder.
https://gist.github.com/wenerme/6940534
pointer padding control
pointer side control
dynamic change