Java: Rotating image around its center - java

I am new to Java programming and I am trying to rotate an image using the following code but nothing seems to be working, I searched a lot online but nothing helped. I saw people doing it using BufferedImage but don't want to use that. This code is rotating entire 2d object instead of just image which i want to rotate. I found out this by displaying rectangle as images were not aligned on top of each other. Thanks for your help.
package package3;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Rotate extends JPanel {
public static void main(String[] args) {
new Rotate().go();
}
public void go() {
JFrame frame = new JFrame("Rotate");
JButton b = new JButton("click");
MyDrawPanel p = new MyDrawPanel();
frame.add(p);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(1000, 1000);
frame.setVisible(true);
}
class MyDrawPanel extends JPanel{
#Override
protected void paintComponent(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
Image image = new ImageIcon(
getClass()
.getResource("wheel.png"))
.getImage();
g2d.drawImage(image, 0, 0, 500, 500, this);
int x = image.getHeight(this);
int y = image.getWidth(this);
g2d.rotate(1, x/2, y/2);
g2d.setBackground(Color.black);
g2d.drawImage(image, 0, 0, 500, 500, this);
g2d.setColor(Color.BLACK);
g2d.fillRect(0, 0, this.getWidth(), this.getHeight());
}
}
}
here's what output looks like

First of all, when rotating an image with a Graphics context, the rotation will occur at a "anchor" point (the top/left is default position if I recall).
So, in order to rotate an image around it's center, you need to set the anchor point to the center of the image WITHIN the context of it's container.
This would mean that the rotate call should be something like...
g2d.rotate(radians, xOffset + (image.getWidth() / 2), yOffset + (image.getHeight() / 2));
Then when you draw the image at xOffset/yOffset, the image will "appear" rotated around the anchor point (or the center of the image).
Second, transformations are compounding. That is, when you transform a graphics context, all subsequent paint operations will be transformed. If you then transform it again, the new transformation will be add to the old one (so if you rotated by 45 degrees and then rotate again by 45 degrees, the transformation would now be 90 degrees).
It's typically "easiest" to create a "copy" of the Graphics state first, apply your transformations and paint operations and then dispose of the copy, which will leave the original context in it's original (transformed) state (all painting operations applied), this way you don't to spend time trying to figure out how to undo the mess
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
JFrame frame = new JFrame();
frame.add(new MyDrawPanel());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
} catch (IOException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}
}
});
}
class MyDrawPanel extends JPanel {
private BufferedImage image;
public MyDrawPanel() throws IOException {
image = ImageIO.read(getClass().getResource("/images/MegaTokyo.png"));
}
#Override
public Dimension getPreferredSize() {
return new Dimension(1000, 1000);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (image == null) {
return;
}
Graphics2D g2d = (Graphics2D) g.create();
drawImageTopLeft(g2d);
drawImageBottomRight(g2d);
drawImageMiddle(g2d);
g2d.rotate(Math.toRadians(45), getWidth() / 2, getHeight() / 2);
g2d.setColor(Color.BLACK);
g2d.drawRect(0, 0, this.getWidth(), this.getHeight());
g2d.dispose();
}
protected void drawImageTopLeft(Graphics2D g2d) {
g2d = (Graphics2D) g2d.create();
int x = 0;
int y = 0;
g2d.rotate(Math.toRadians(135), image.getWidth() / 2, image.getHeight() / 2);
g2d.drawImage(image, x, y, this);
g2d.dispose();
}
protected void drawImageBottomRight(Graphics2D g2d) {
g2d = (Graphics2D) g2d.create();
int x = (getWidth() - image.getWidth());
int y = (getHeight() - image.getHeight());
g2d.rotate(Math.toRadians(-45), getWidth() - (image.getWidth() / 2), getHeight() - (image.getHeight() / 2));
g2d.drawImage(image, x, y, this);
g2d.dispose();
}
protected void drawImageMiddle(Graphics2D g2d) {
g2d = (Graphics2D) g2d.create();
int x = (getWidth() - image.getWidth()) / 2;
int y = (getHeight() - image.getHeight()) / 2;
g2d.rotate(Math.toRadians(45), getWidth() / 2, getHeight() / 2);
g2d.drawImage(image, x, y, this);
g2d.dispose();
}
}
}

Related

make image point toward specific location in java

BEFORE YOU MARK IT AS DUPLICATE
I have searched a lot in the internet for that and tried every solution, but no one does it the same way I do it. In my case the rotation is in a sperate class.
I have created a java class that inherits JLabel class, in my class I have an arrow BufferedImage which I draw using the paintComponent(Graphics g) method.
I am trying to make the arrow point to a specific point (which I get from a different method) but something goes wrong and the arrow rotates to the wrong direction.
I THINK: it doesn't calculate correctly because the imageLocation is relative to the label.
Here is my code:
package pkg1;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import java.io.*;
import javax.imageio.*;
import javax.swing.*;
public final class ImageLabel extends JLabel {
private float angle = 0.0f; // in radians
private Point imageLocation = new Point();
private File imageFile = null;
private Dimension imageSize = new Dimension(50, 50);
private BufferedImage bi;
private BufferedImage resizeImage(BufferedImage originalImage, int img_width, int img_height) {
int type = originalImage.getType() == 0 ? BufferedImage.TYPE_INT_ARGB : originalImage.getType();
BufferedImage resizedImage = new BufferedImage(img_width, img_height, type);
Graphics2D g = resizedImage.createGraphics();
g.drawImage(originalImage, 0, 0, img_width, img_height, null);
g.dispose();
return resizedImage;
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
if (bi == null) {
return;
}
imageLocation = new Point(getWidth() / 2 - bi.getWidth() / 2, getHeight() / 2 - bi.getHeight() / 2);
Graphics2D g2 = (Graphics2D) g;
g2.rotate(angle, imageLocation.x + bi.getWidth() / 2, imageLocation.y + bi.getHeight() / 2);
g2.drawImage(bi, imageLocation.x, imageLocation.y, null);
}
public void rotateImage(float angle) { // rotate the image to specific angle
this.angle = (float) Math.toRadians(angle);
repaint();
}
public void pointImageToPoint(Point target) {
calculateAngle(target);
repaint();
}
private void calculateAngle(Point target) {
// calculate the angle from the center of the image
float deltaY = target.y - (imageLocation.y + bi.getHeight() / 2);
float deltaX = target.x - (imageLocation.x + bi.getWidth() / 2);
angle = (float) Math.atan2(deltaY, deltaX);
if (angle < 0) {
angle += (Math.PI * 2);
}
}
}
Okay, so two things jump out at me...
If you take a Point from outside the context of the label, you will have to translate the point into the components coordinate context
The calculateAngle seems wrong
So starting with...
private void calculateAngle(Point target) {
// calculate the angle from the center of the image
float deltaY = target.y - (imageLocation.y + bi.getHeight() / 2);
float deltaX = target.x - (imageLocation.x + bi.getWidth() / 2);
angle = (float) Math.atan2(deltaY, deltaX);
if (angle < 0) {
angle += (Math.PI * 2);
}
}
angle = (float) Math.atan2(deltaY, deltaX); should be angle = (float) Math.atan2(deltaX, deltaY); (swap the deltas)
You will find that you need to adjust the result by 180 degrees in order to get the image to point in the right direction
angle = Math.toRadians(Math.toDegrees(angle) + 180.0);
Okay, I'm an idiot, but it works :P
I'd also make use of a AffineTransform to translate and rotate the image - personally, I find it easier to deal with.
In the example, I've cheated a little. I set the translation of the AffineTransform to the centre of the component, I then rotate the context around the new origin point (0x0). I then paint the image offset by half it's height/width, thus making it appear as the if the image is been rotated about it's centre - It's late, I'm tired, it works :P
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagLayout;
import java.awt.Point;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.LineBorder;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private ImageLabel label;
public TestPane() {
setLayout(new GridBagLayout());
label = new ImageLabel();
add(label);
addMouseMotionListener(new MouseAdapter() {
#Override
public void mouseMoved(MouseEvent e) {
label.pointImageToPoint(e.getPoint(), TestPane.this);
}
});
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
}
public final class ImageLabel extends JLabel {
private double angle = 0;
private Point imageLocation = new Point();
private File imageFile = null;
private Dimension imageSize = new Dimension(50, 50);
private BufferedImage bi;
public ImageLabel() {
setBorder(new LineBorder(Color.BLUE));
bi = new BufferedImage(50, 50, BufferedImage.TYPE_INT_ARGB);
Graphics2D g2d = bi.createGraphics();
g2d.setColor(Color.RED);
g2d.drawLine(25, 0, 25, 50);
g2d.drawLine(25, 0, 0, 12);
g2d.drawLine(25, 0, 50, 12);
g2d.dispose();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(bi.getWidth(), bi.getHeight());
}
protected Point centerPoint() {
return new Point(getWidth() / 2, getHeight() / 2);
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
if (bi == null) {
return;
}
Graphics2D g2d = (Graphics2D) g.create();
AffineTransform at = g2d.getTransform();
Point center = centerPoint();
at.translate(center.x, center.y);
at.rotate(angle, 0, 0);
g2d.setTransform(at);
g2d.drawImage(bi, -bi.getWidth() / 2, -bi.getHeight() / 2, this);
g2d.dispose();
}
public void rotateImage(float angle) { // rotate the image to specific angle
this.angle = (float) Math.toRadians(angle);
repaint();
}
public void pointImageToPoint(Point target, JComponent fromContext) {
calculateAngle(target, fromContext);
repaint();
}
private void calculateAngle(Point target, JComponent fromContext) {
// calculate the angle from the center of the image
target = SwingUtilities.convertPoint(fromContext, target, this);
Point center = centerPoint();
float deltaY = target.y - center.y;
float deltaX = target.x - center.x;
angle = (float) -Math.atan2(deltaX, deltaY);
angle = Math.toRadians(Math.toDegrees(angle) + 180.0);
repaint();
}
}
}
I just want to add that using a JLabel for this purpose is overkill, a simple JPanel or JComponent would do the same job and carry a lot less overhead with it, just saying

Rotating BufferedImage in Java without change size

I am trying to rotating a BufferedImage in Java without changing size.
width = 232 height = 174
width = 232 height = 174
I using this code but my image don`t rotate:
AffineTransform at = new AffineTransform();
at.translate(four2.getWidth() / 2, four2.getHeight() / 2);
at.rotate(Math.PI/2);
at.scale(0.5, 0.5);
at.translate(-four2.getWidth()/2, -four2.getHeight()/2);
Graphics2D g2d = (Graphics2D) four2.getGraphics();
g2d.drawImage(four2, at, null);
g2d.dispose();
Rotating a non-square image within the same boundaries will crop the image.
You could change the Graphics clipping bounds, but this is dangerous, as you could actually end up painting outside of the visible bounds available to the Graphics context, which results in some very weird and generally not welcomed results.
A simpler solution might be to just generate a new image from the original and rotate it within it's own confines, for example...
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
try {
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
} catch (IOException iOException) {
iOException.printStackTrace();
}
}
});
}
public class TestPane extends JPanel {
private BufferedImage master;
private BufferedImage rotated;
public TestPane() throws IOException {
master = ImageIO.read(new File("/Volumes/Disk02/Dropbox/MegaTokyo/issue142.jpg"));
rotated = new BufferedImage(master.getWidth(), master.getHeight(), BufferedImage.TYPE_INT_ARGB);
Graphics2D g2d = rotated.createGraphics();
AffineTransform at = new AffineTransform();
at.rotate(Math.PI / 2, master.getWidth() / 2, master.getHeight() / 2);
g2d.setTransform(at);
g2d.drawImage(master, 0, 0, this);
g2d.dispose();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(master.getWidth() * 2, master.getHeight());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
int x = (getWidth() - (master.getWidth() * 2)) / 2;
int y = (getHeight() - master.getHeight()) / 2;
g2d.drawImage(master, x, y, this);
g2d.drawImage(rotated, x + master.getWidth(), y, this);
g2d.dispose();
}
}
}

How to Draw a Transparent Background?

I am trying to make a piece of a JPanel transparent, but I cannot quite get it to work. Is it possible to do this?
import java.awt.*;
import javax.swing.*;
public class ClearPanel extends JPanel{
public static void main(String[] args) {
ClearPanel c = new ClearPanel();
c.setPreferredSize(new Dimension(200, 200));
c.setOpaque(false);
JPanel backPanel = new JPanel();
backPanel.setBackground(Color.CYAN);
backPanel.add(c);
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setContentPane(backPanel);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.fillOval(0, 0, 200, 200);
g.clearRect(45, 45, 50, 50);
Graphics2D g2 = (Graphics2D) g;
g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.0f));
g2.fillRect(75, 75, 50, 50);
}
}
The oval should be opaque, but the rectangles I would like to be transparent. By transparent, I mean that I should be able to see the panel behind the ClearPanel.
Going off of MadProgrammer's answer, is there any way to make that gray box draw where it is outside of the area, but remain transparent where it is in the area?
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Rectangle fill = new Rectangle(getWidth(), getHeight());
Graphics2D g2d = (Graphics2D) g.create();
Rectangle hole = new Rectangle(0, 0, 100, 100);
Area area = new Area(fill);
area.subtract(new Area(hole));
g2d.setColor(getBackground());
g2d.fill(area);
g2d.setColor(Color.RED);
g2d.setComposite(AlphaComposite.SrcOver.derive(0.0f));
g2d.fill(hole);
g2d.setComposite(AlphaComposite.SrcOver.derive(1.0f));
g2d.setColor(Color.DARK_GRAY);
if(area.contains(0,0,100,200))
g2d.fillRect(0, 0, 100, 200);
g2d.dispose();
}
The problem you have is, by default, JPanel is opaque, meaning that the repaint will NOT paint anything under it.
You need to set the the panel to transparent and then take over the painting of the background.
Now, the real trick begins. If you simply fill the component and then try and paint transparent section over the top of it, you will simply be painting a transparent section over a opaque background...not very helpful.
What you need to do is not fill the area you want to remain transparent.
You can accomplish this by using a Area shape, which has a neat trick of been able to append/add and remove shapes from it.
import java.awt.AlphaComposite;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.geom.Area;
import java.awt.geom.Ellipse2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class TransparentPane {
public static void main(String[] args) {
new TransparentPane();
}
public TransparentPane() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException ex) {
} catch (InstantiationException ex) {
} catch (IllegalAccessException ex) {
} catch (UnsupportedLookAndFeelException ex) {
}
BackgroundPane backgroundPane = new BackgroundPane();
backgroundPane.setBackground(Color.RED);
backgroundPane.setLayout(new BorderLayout());
backgroundPane.add(new TranslucentPane());
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(backgroundPane);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class BackgroundPane extends JPanel {
private BufferedImage bg;
public BackgroundPane() {
try {
bg = ImageIO.read(new File("/path/to/your/image.jpg"));
} catch (IOException ex) {
ex.printStackTrace();
}
}
#Override
public Dimension getPreferredSize() {
return bg == null ? super.getPreferredSize() : new Dimension(bg.getWidth(), bg.getHeight());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (bg != null) {
int width = getWidth() - 1;
int height = getHeight() - 1;
int x = (width - bg.getWidth()) / 2;
int y = (height - bg.getHeight()) / 2;
g.drawImage(bg, x, y, this);
}
}
}
public class TranslucentPane extends JPanel {
public TranslucentPane() {
setOpaque(false);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Rectangle fill = new Rectangle(getWidth(), getHeight());
Graphics2D g2d = (Graphics2D) g.create();
int width = getWidth() - 1;
int height = getHeight() - 1;
int radius = Math.min(width, height) / 2;
int x = (width - radius) / 2;
int y = (height - radius) / 2;
Ellipse2D hole = new Ellipse2D.Float(x, y, radius, radius);
Area area = new Area(fill);
area.subtract(new Area(hole));
g2d.setColor(getBackground());
g2d.fill(area);
g2d.setColor(Color.RED);
g2d.setComposite(AlphaComposite.SrcOver.derive(0.25f));
g2d.fill(hole);
g2d.dispose();
}
}
}
Update
Well, that took a little longer the I expected...
Basically, we need to create a mask of the shape that subtracts the hole from the rectangle we want to display, then subtract that result from the rectangle we want to diplay
import java.awt.AlphaComposite;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.geom.Area;
import java.awt.geom.Ellipse2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class TransparentPane {
public static void main(String[] args) {
new TransparentPane();
}
public TransparentPane() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException ex) {
} catch (InstantiationException ex) {
} catch (IllegalAccessException ex) {
} catch (UnsupportedLookAndFeelException ex) {
}
BackgroundPane backgroundPane = new BackgroundPane();
backgroundPane.setBackground(Color.RED);
backgroundPane.setLayout(new BorderLayout());
backgroundPane.add(new TranslucentPane());
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(backgroundPane);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class BackgroundPane extends JPanel {
private BufferedImage bg;
public BackgroundPane() {
try {
bg = ImageIO.read(new File("/Users/swhitehead/Dropbox/MegaTokyo/Evil_Small.jpg"));
} catch (IOException ex) {
ex.printStackTrace();
}
}
#Override
public Dimension getPreferredSize() {
return bg == null ? super.getPreferredSize() : new Dimension(bg.getWidth(), bg.getHeight());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (bg != null) {
int width = getWidth() - 1;
int height = getHeight() - 1;
int x = (width - bg.getWidth()) / 2;
int y = (height - bg.getHeight()) / 2;
g.drawImage(bg, x, y, this);
}
}
}
public class TranslucentPane extends JPanel {
public TranslucentPane() {
setOpaque(false);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Rectangle fill = new Rectangle(getWidth(), getHeight());
Graphics2D g2d = (Graphics2D) g.create();
int width = getWidth() - 1;
int height = getHeight() - 1;
int radius = Math.min(width, height) / 2;
int x = (width - radius) / 2;
int y = (height - radius) / 2;
Ellipse2D hole = new Ellipse2D.Float(x, y, radius, radius);
Area area = new Area(fill);
area.subtract(new Area(hole));
g2d.setColor(getBackground());
g2d.fill(area);
g2d.setColor(Color.RED);
g2d.setComposite(AlphaComposite.SrcOver.derive(0.0f));
g2d.fill(hole);
g2d.dispose();
g2d = (Graphics2D) g.create();
// Basically, we create an area that is subtraction of the window/rectangle
// from the whole. This leaves us with a rectangle (with a hole in it)
// that doesn't include the area where the whole is...
Rectangle win = new Rectangle(
x + (radius / 2),
y + (radius / 2), radius, (radius / 4));
area = new Area(win);
area.subtract(new Area(hole));
// Then we create a area that is a subtraction of the original rectangle
// from the one with a "hole" in it...
Area actual = new Area(win);
actual.subtract(area);
g2d.setColor(Color.BLUE);
g2d.setComposite(AlphaComposite.SrcOver.derive(0.5f));
g2d.fill(actual);
g2d.dispose();
}
}
}

Change the JSlider look and feel

I have gone through this website Change look and feel of JSlider
but except for Slider.altTrackColor nothing else is working. I want to do something like shown in pic1 any suggestion would be of great help. I'm working on JDK 1.6.
UIDefaults defaults = UIManager.getDefaults();
defaults.put("Slider.altTrackColor", Color.red);
defaults.put("Slider.thumb", Color.red);
I have also tried this:
WindowUtilities.setNativeLookAndFeel();
// WindowUtilities.setNimbuzzLookAndFeel();
// WindowUtilities.setJavaLookAndFeel();
WindowUtilities is class that tells the system to use native look and feel, as in previous releases. Metal (Java) LAF is the default otherwise.
public static void setNativeLookAndFeel() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch(Exception e) {
System.out.println("Error setting native LAF: " + e);
}
Here is a full example of working UI that shown on 1st image:
(no magic - just a bit of work with graphics and basic UI knowledge)
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Stroke;
import java.awt.geom.GeneralPath;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JSlider;
import javax.swing.SwingConstants;
import javax.swing.plaf.basic.BasicSliderUI;
/**
*
* #see http://stackoverflow.com/a/12297384/714968
*/
public class CustomSliderUI extends BasicSliderUI {
private BasicStroke stroke = new BasicStroke(1f, BasicStroke.CAP_ROUND,
BasicStroke.JOIN_ROUND, 0f, new float[]{1f, 2f}, 0f);
public CustomSliderUI(JSlider b) {
super(b);
}
#Override
public void paint(Graphics g, JComponent c) {
Graphics2D g2d = (Graphics2D) g;
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
super.paint(g, c);
}
#Override
protected Dimension getThumbSize() {
return new Dimension(12, 16);
}
#Override
public void paintTrack(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
Stroke old = g2d.getStroke();
g2d.setStroke(stroke);
g2d.setPaint(Color.BLACK);
if (slider.getOrientation() == SwingConstants.HORIZONTAL) {
g2d.drawLine(trackRect.x, trackRect.y + trackRect.height / 2,
trackRect.x + trackRect.width, trackRect.y + trackRect.height / 2);
} else {
g2d.drawLine(trackRect.x + trackRect.width / 2, trackRect.y,
trackRect.x + trackRect.width / 2, trackRect.y + trackRect.height);
}
g2d.setStroke(old);
}
#Override
public void paintThumb(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
int x1 = thumbRect.x + 2;
int x2 = thumbRect.x + thumbRect.width - 2;
int width = thumbRect.width - 4;
int topY = thumbRect.y + thumbRect.height / 2 - thumbRect.width / 3;
GeneralPath shape = new GeneralPath(GeneralPath.WIND_EVEN_ODD);
shape.moveTo(x1, topY);
shape.lineTo(x2, topY);
shape.lineTo((x1 + x2) / 2, topY + width);
shape.closePath();
g2d.setPaint(new Color(81, 83, 186));
g2d.fill(shape);
Stroke old = g2d.getStroke();
g2d.setStroke(new BasicStroke(2f));
g2d.setPaint(new Color(131, 127, 211));
g2d.draw(shape);
g2d.setStroke(old);
}
public static void main(String[] args) {
JFrame frame = new JFrame();
JSlider slider = new JSlider(0, 100);
slider.setPaintTicks(true);
slider.setPaintLabels(true);
slider.setMinorTickSpacing(5);
slider.setMajorTickSpacing(25);
slider.setUI(new CustomSliderUI(slider));
frame.add(slider);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
}
You can easily modify the thumb (gripper) size by changing the returned bounds. The thumb painting will adapt to any size. And you can also easily customize painting of any other slider part.
Here is the final view by the way:
P.S. I did not adapt UI for vertical sliders, but that shouldn't take too long.

How do I use graphics2D in paint or is there a better way to do this?

I want to use graphics2D but I can't get I get it to display my graphics. Is there a better way to go about this that would allow me to use repaint()? Eventually I want to make have a image set as a background and be able to draw on it then save the contents of the frame as a image.
import java.awt.image.*;
import javax.imageio.ImageIO;
import javax.swing.*;
import java.io.File;
import java.io.IOException;
import java.net.URL;
import javax.swing.JApplet;
import java.awt.*;
// assume that the drawing area is 150 by 150
public class test extends JApplet
{
final int radius = 25;
int width = 200, height = 200;
BufferedImage img = new BufferedImage(
width, height, BufferedImage.TYPE_INT_ARGB);
public void paint ( )
{
Graphics2D g = img.createGraphics();
g.setColor( Color.orange );
g.fillRect( 0, 0, 150, 150 );
g.setColor( Color.black );
g.drawOval( (150/2 - radius), (150/2 - radius), radius*2, radius*2 );
}
}
Ok so,
You have public void paint( ) what the hell is this doing lol? You need a graphics object. public void paint(Graphics g) is like the default method which gets called automatically when your applet is initialised.
You have Graphics2D g = img.createGraphics(); when you need to use your default Graphics g object and cast it into a Graphics2D object like so Graphics2D g2d = (Graphics2D) g;
You should search for a little more information on double buffering too :)
anyway... This code works so take from it what you want :)
P.S Note how I implemented Runnable; You do not need to do this if you only want to use the Graphics2D code. It is just making the class a thread and is used for game frame rates :)
Hope this helped.
import java.applet.*;
import java.awt.*;
public class Test extends Applet implements Runnable{
public boolean isRunning = false;
public int radius = 25;
public void start() {
isRunning = true;
new Thread(this).start();
}
public void stop() {
isRunning = false;
}
public void paint(Graphics g) {
//Create Graphics2D object, cast g as a Graphics2D
Graphics2D g2d = (Graphics2D) g;
g2d.setColor(Color.ORANGE);
g2d.fillRect(0, 0, 150, 150);
g2d.setColor(Color.BLACK);
g2d.drawOval((150/2 - radius), (150/2 - radius), radius * 2, radius * 2);
}
public void run() {
while (isRunning) {
repaint();
try {
Thread.sleep(17);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}

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