Using Graphics2D, how can I take a black and white image, and use to define what should and what shouldn't rendered on another image?
E.g if I had an image of say, a field, and on that field is a cow, and on another image of the same dimensions I draw a white box on a black background, at the same coordinates of the cow, when rendered in Java the image would be all black, apart from the cow where I had the white box?
EDIT: Based on a long discussion in the chat, it became clear that there was a misunderstanding about the intention, and the original question suffered from the XY-Problem: The question of how to compose an image with a masking image was only about one solution attempt for the actual problem - namely painting some shadow/light effects on a tile map. The original versions of the post can be seen in the revision history.
The actual goal was obviously to add a "light effect" over the image. Here is an example of how this can be achieved:
The original image is painted in the background
A "shadow image" is painted over the image.
The "shadow image" is initially a nearly opaqe, nearly black image. The lights are painted into this image, with a RadialGradientPaint. The colors for this paint are chosen so that they make the shadow image less opaque and less black at the places where the lights should be. This causes these areas to appear lighted, while the other parts remain dark.
import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.MultipleGradientPaint.CycleMethod;
import java.awt.Point;
import java.awt.RadialGradientPaint;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import java.awt.geom.Point2D;
import java.awt.image.BufferedImage;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class LightEffectTest2
{
public static void main(String args[])
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new LightEffectTest2();
}
});
}
public LightEffectTest2()
{
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().add(new LightEffectPanel2());
f.setSize(600,600);
f.setVisible(true);
}
}
class LightEffectPanel2 extends JPanel implements MouseMotionListener
{
private Point point = new Point(0,0);
private BufferedImage image;
private BufferedImage shadow;
public LightEffectPanel2()
{
image = createExampleImage(600,600);
shadow = new BufferedImage(image.getWidth(), image.getHeight(),
BufferedImage.TYPE_INT_ARGB);
addMouseMotionListener(this);
}
private static BufferedImage createExampleImage(int w, int h)
{
BufferedImage image = new BufferedImage(w, h,
BufferedImage.TYPE_INT_ARGB);
Graphics g = image.getGraphics();
Random random = new Random(0);
for (int i=0; i<200; i++)
{
int x = random.nextInt(w);
int y = random.nextInt(h);
Color c = new Color(
random.nextInt(255),
random.nextInt(255),
random.nextInt(255));
g.setColor(c);
g.fillOval(x-20, y-20, 40, 40);
}
g.dispose();
return image;
}
#Override
protected void paintComponent(Graphics gr)
{
super.paintComponent(gr);
Graphics2D g = (Graphics2D)gr;
g.drawImage(image, 0,0,null);
drawLights();
g.drawImage(shadow, 0,0, null);
}
private void drawLights()
{
Graphics2D g = shadow.createGraphics();
g.setComposite(AlphaComposite.Src);
g.setColor(new Color(0,0,16,240));
g.fillRect(0,0,getWidth(),getHeight());
drawLight(g, new Point(100,100));
drawLight(g, point);
g.dispose();
}
private void drawLight(Graphics2D g, Point pt)
{
float radius = 100;
g.setComposite(AlphaComposite.DstOut);
Point2D center = new Point2D.Float(pt.x, pt.y);
float[] dist = {0.0f, 1.0f};
Color[] colors = {new Color(255,255,255,255), new Color(0,0,0,0) };
RadialGradientPaint p =
new RadialGradientPaint(
center, radius, dist, colors, CycleMethod.NO_CYCLE);
g.setPaint(p);
g.fillOval(pt.x-(int)radius,pt.y-(int)radius,(int)radius*2,(int)radius*2);
}
#Override
public void mouseDragged(MouseEvent e) {
}
#Override
public void mouseMoved(MouseEvent e) {
point = e.getPoint();
repaint();
}
}
(late) EDIT For the request in the comments:
To add another shadow (regardless of the existing lights), one can create a drawShadow method that re-applies the shadows after the lights have been drawn. It basically uses another RadialGradientPaint that partially "restores" the original, opaqe, dark shadow image.
(The shadow is given a somewhat sharper border here, to make the effect more visible)
import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.MultipleGradientPaint.CycleMethod;
import java.awt.Point;
import java.awt.RadialGradientPaint;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import java.awt.geom.Point2D;
import java.awt.image.BufferedImage;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class LightEffectTest3
{
public static void main(String args[])
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new LightEffectTest3();
}
});
}
public LightEffectTest3()
{
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().add(new LightEffectPanel3());
f.setSize(600,600);
f.setVisible(true);
}
}
class LightEffectPanel3 extends JPanel implements MouseMotionListener
{
private Point point = new Point(0,0);
private BufferedImage image;
private BufferedImage shadow;
public LightEffectPanel3()
{
image = createExampleImage(600,600);
shadow = new BufferedImage(image.getWidth(), image.getHeight(),
BufferedImage.TYPE_INT_ARGB);
addMouseMotionListener(this);
}
private static BufferedImage createExampleImage(int w, int h)
{
BufferedImage image = new BufferedImage(w, h,
BufferedImage.TYPE_INT_ARGB);
Graphics g = image.getGraphics();
Random random = new Random(0);
for (int i=0; i<200; i++)
{
int x = random.nextInt(w);
int y = random.nextInt(h);
Color c = new Color(
random.nextInt(255),
random.nextInt(255),
random.nextInt(255));
g.setColor(c);
g.fillOval(x-20, y-20, 40, 40);
}
g.dispose();
return image;
}
#Override
protected void paintComponent(Graphics gr)
{
super.paintComponent(gr);
Graphics2D g = (Graphics2D)gr;
g.drawImage(image, 0,0,null);
drawLights();
g.drawImage(shadow, 0,0, null);
}
private void drawLights()
{
Graphics2D g = shadow.createGraphics();
g.setComposite(AlphaComposite.Src);
g.setColor(new Color(0,0,16,240));
g.fillRect(0,0,getWidth(),getHeight());
drawLight(g, new Point(200,200));
drawLight(g, point);
drawShadow(g, new Point(250,250));
g.dispose();
}
private void drawLight(Graphics2D g, Point pt)
{
float radius = 150;
g.setComposite(AlphaComposite.DstOut);
Point2D center = new Point2D.Float(pt.x, pt.y);
float[] dist = {0.0f, 1.0f};
Color[] colors = {new Color(255,255,255,255), new Color(0,0,0,0) };
RadialGradientPaint p =
new RadialGradientPaint(
center, radius, dist, colors, CycleMethod.NO_CYCLE);
g.setPaint(p);
g.fillOval(pt.x-(int)radius,pt.y-(int)radius,
(int)radius*2,(int)radius*2);
}
private void drawShadow(Graphics2D g, Point pt)
{
float radius = 75;
g.setComposite(AlphaComposite.DstOver);
Point2D center = new Point2D.Float(pt.x, pt.y);
float[] dist = {0.0f, 0.7f, 1.0f};
Color[] colors = {
new Color(0,0,0,200),
new Color(0,0,0,150),
new Color(255,255,255,0) };
RadialGradientPaint p =
new RadialGradientPaint(
center, radius, dist, colors, CycleMethod.NO_CYCLE);
g.setPaint(p);
g.fillOval(pt.x-(int)radius,pt.y-(int)radius,
(int)radius*2,(int)radius*2);
}
#Override
public void mouseDragged(MouseEvent e) {
}
#Override
public void mouseMoved(MouseEvent e) {
point = e.getPoint();
repaint();
}
}
Related
I really need some help with that.
I'm trying to crop an image into a circle and it's fine but the pixels outside the circle stay white. How can I put them transparent?
My code it's:
static ColorImage Circulo(ColorImage img, int radius) {
for (int x=0; x < img.getWidth(); x++ ) {
for(int y=0; y < img.getHeight(); y++) {
if((x - (img.getWidth()/2)) * (x - (img.getWidth()/2)) + (y - (img.getHeight()/2) )* (y - (img.getHeight()/2)) <= (radius*radius)) {
img.setColor(x, y, img.getColor(x, y));
}else {
Color c = new Color (255, 255, 255);
img.setColor(x, y, c );
}
}
}
return img;
}
Try this. This will paint the image on the screen inside a circle. If you want to create a new image, get the Graphics context from a BufferedImage and write the image to that instead of the graphics context in paintComponent. Any image format will work as this does not rely on any transparency mode of the graphics image.
The main idea behind this is setting the clip region to that of a circle. Then whatever you paint will only appear in that region.
In this example, I made the diameter of the circle the minimum of the width and height of the image. This way, the entire circle will fit in a rectangle.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.geom.Ellipse2D;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class ImageInCircle extends JPanel {
JFrame f = new JFrame();
Image img;
int width;
int height;
static String imgFile =
"location/of/image/img.gif";
public static void main(String[] args) {
SwingUtilities.invokeLater(()->new ImageInCircle().start());
}
#Override
public Dimension getPreferredSize() {
return new Dimension(width, height);
}
public ImageInCircle () {
f.add(this);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public void start() {
try {
img = ImageIO.read(new File(imgFile));
} catch (IOException fne) {
fne.printStackTrace();
}
width = img.getWidth(null);
height = img.getHeight(null);
revalidate();
f.setVisible(true);
f.pack();
f.setLocationRelativeTo(null);
repaint();
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
setBackground(Color.white);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
int circleDiameter = Math.min(width,height);
Ellipse2D.Double circle = new Ellipse2D.Double(0,0,circleDiameter,circleDiameter);
g2.setClip(circle);
g2.drawImage(img,0,0,this);
}
}
Im working on a simple game engine using java.
Im want to make some light in the game and I want to use RadialGradientPaint.
Here is my light class
package engine.graphics;
import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RadialGradientPaint;
import java.awt.geom.Point2D;
import engine.Main;
import engine.maths.Vector2f;
public class Light
{
private Vector2f pos;
private int radius;
public Light(Vector2f pos, int radius)
{
this.pos = pos;
this.radius = radius;
}
public void render(Graphics g)
{
Graphics2D g2d = (Graphics2D)g;
Point2D center = new Point2D.Float(pos.x, pos.y);
float[] dist = {0.9f, 1.0f};
Color[] color = {new Color(0.0f, 0.0f, 0.0f, 0.1f), new Color(0, 0, 0, 255)};
RadialGradientPaint p = new RadialGradientPaint(center, radius, dist, color);
g2d.setPaint(p);
g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, .95f));
g2d.fillRect(0, 0, Main.WIDTH, Main.HEIGHT);
g2d.dispose();
}
}
The problem that i found is that i cant draw more than one light.
How can i modify my code to make more lights?
Thank you..
I propose you this :
package solamda;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RadialGradientPaint;
import java.awt.geom.Point2D;
import javax.swing.JFrame;
import javax.swing.JLabel;
public class Main {
private static final Color transparency = new Color(0, 0, 0, 0);
private static final int WIDTH = 500;
private static final int HEIGHT = 500;
public static void main(String[] args) {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setMinimumSize(new Dimension(WIDTH, HEIGHT));
f.setLayout(new BorderLayout());
f.add(new JLabel() {
#Override
public void paint(Graphics g) {
super.paint(g);
render(g);
}
});
f.pack();
f.setVisible(true);
}
public static void render(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
Point[] lights = { new Point(WIDTH / 2, HEIGHT / 2), new Point(0,0),
new Point(WIDTH / 2+10, HEIGHT / 2), new Point(WIDTH / 2-10, HEIGHT / 2) };
for (Point center : lights) {
paintlight(g2d, center);
}
g2d.dispose();
}
private static void paintlight(Graphics2D g2d, Point center) {
float[] dist = { 0.2f, 1.0f };
Color[] color = { Color.white, transparency };
RadialGradientPaint p = new RadialGradientPaint(center, 10, dist, color);
g2d.setPaint(p);
g2d.fillRect(center.x - 20, center.y - 20, 40, 40);
}
}
You don need to fill whole rect just the part where the light is . So from your code i just extract a method where center is a parameter (call paintlight) then in your method render, i can draw as many ligh as i want ; i simply paint a white hallo arround this point and i keep the transparency in the pattern when i paint it
I Have 3 Questing Regarding My Code
1==> How to remove Selected Shape in my code; when i right click every shape is deleted,
2==> I TOTALLY don't know how to highlight the overlapped are
3==> right now when i click on my JPanel, shape drawn from the point where mouse clicked, where as it should be the in the center of the mouse pointer
Thanks In advance
actually i'm new to Java. this is my code,
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.awt.Shape;
import javax.swing.JPanel;
import javax.swing.JButton;
import Delete.Selection;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.Area;
import java.util.ArrayList;
public class MyPanel extends JPanel {
ArrayList<MyRect> list = new ArrayList<MyRect>();
public MyPanel() {
addMouseListener(new MouseAdapter() {
#Override
public void mousePressed(MouseEvent e) {
if(e.getButton() == MouseEvent.BUTTON1) {
MyRect r = new MyRect(e.getX(), e.getY());
list.add(r);
repaint();
}
else {
list.clear();
repaint();
}
}
}
);
setPreferredSize(new Dimension(600, 400));
setBackground(Color.CYAN);
}
public void paintComponent(Graphics g){
super.paintComponent(g);
for (int i = 0; i < list.size(); i++) {
MyRect r = list.get(i);
g.fillRect(r.x, r.y, r.w, r.h);
}
}
class MyRect {
int x, y, w=100, h=100;
Color c = Color.BLACK;
public MyRect(int x, int y, int w, int h, Color color) {
this.x = x;
this.y = y;
this.w = w;
this.h = h;
this.c = color;
}
public MyRect(int x, int y) {
this.x = x;
this.y = y;
}
}}
how to highlight the overlapped area
You can use the intersection(...) method of the Rectangle class to get a Rectangle to paint:
import java.awt.*;
import javax.swing.*;
import java.awt.geom.*;
public class IntersectingRectangles extends JPanel
{
#Override
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
Dimension d = getSize();
int width = d.width * 3 / 4;
int height = d.height * 3 / 4;
Rectangle r1 = new Rectangle(0, 0, width, height);
g2d.setColor( Color.BLUE );
g2d.fill( r1 );
Rectangle r2 = new Rectangle(d.width - width, d.height - height, width, height);
g2d.setColor( Color.YELLOW );
g2d.fill( r2 );
// Specific solution when using Rectangles only
Rectangle r3 = r1.intersection(r2);
g2d.setColor(Color.GREEN);
g2d.fill(r3);
/*
// For a more generic solution using any Shape
Area area = new Area(r1);
area.intersect( new Area(r2) );
g2d.setColor(Color.GREEN);
g2d.fill(area);
*/
g2d.dispose();
}
#Override
public Dimension getPreferredSize()
{
return new Dimension(300, 300);
}
private static void createAndShowGUI()
{
JFrame frame = new JFrame("Intersecting Rectangles");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new IntersectingRectangles());
frame.setLocationByPlatform( true );
frame.pack();
frame.setVisible( true );
}
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
createAndShowGUI();
}
});
}
}
How to remove Selected Shape in my code; when i right click every shape is deleted,
You need to iterate through the ArrayList containing the Rectangles. Then you can use the Rectangle.contains( yourMousePoint ) method to determine which Rectangle you clicked on. You will need to save the reference to the Rectangle. Then when the loop finishes executing you can remove the Rectangle from the ArrayList.
shape drawn from the point where mouse clicked, where as it should be the in the center of the mouse pointer
Then you need to change the x/y location of the Rectangle. It should be:
int x = mousePoint.x - (width / 2);
int y = mousePoint.y - (height / 2);
where width/height represent the size of the Rectangle you want to draw.
Basically I'm constructing a world map. I know how to have a square click area. But I'd like to make it so I can put the countries together and be able to click on the country. Now it's pretty obvious that I can't use square click areas for that because I'd have overlapping click areas. Could I do it by looking at the transparency of each pixel? Even so I don't know how to do that?
Use Shape.contains(Point2D) - something like this:
This example uses overlapping ellipses to show how the contains(..) method will accurately identify which ovals the mouse click falls inside. But the kind of map you are referring to will probably be made of a number of GeneralPath objects (one for each country) that do not overlap.
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.BasicStroke;
import java.awt.RenderingHints;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
import java.io.File;
import java.util.*;
import javax.imageio.ImageIO;
public class ShapeContainment {
List<Ellipse2D> shapes = new ArrayList<Ellipse2D>();
int w = 400;
int h = 100;
BufferedImage img = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
Point2D mouse = new Point2D.Double(0, 0);
JLabel l;
ShapeContainment() {
Random r = new Random();
for (int ii = 0; ii < 10; ii++) {
int x = r.nextInt(w / 2);
int y = r.nextInt(h / 2);
int wE = r.nextInt(w - x);
int hE = r.nextInt(h - y);
Ellipse2D ellipse = new Ellipse2D.Double(x, y, wE, hE);
shapes.add(ellipse);
}
l = new JLabel(new ImageIcon(img));
MouseAdapter listener = new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent me) {
mouse = me.getPoint();
drawImage();
}
};
l.addMouseListener(listener);
drawImage();
JOptionPane.showMessageDialog(null, l);
}
public void drawImage() {
Graphics2D g = img.createGraphics();
g.setColor(Color.WHITE);
g.fillRect(0, 0, w, h);
RenderingHints hints = new RenderingHints(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g.setRenderingHints(hints);
Color bg = new Color(0, 128, 0, 60);
Color inside = new Color(0, 0, 255, 120);
Color outside = new Color(255, 0, 0, 120);
g.setStroke(new BasicStroke(4));
for (Ellipse2D shape : shapes) {
g.setColor(bg);
g.fill(shape);
if (shape.contains(mouse)) {
g.setColor(inside);
} else {
g.setColor(outside);
}
g.draw(shape);
}
g.setColor(Color.RED);
int x = (int) mouse.getX();
int y = (int) mouse.getY();
g.setStroke(new BasicStroke(2));
int s = 3;
g.drawLine(x-s, y, x+s, y);
g.drawLine(x, y-s, x, y+s);
l.setIcon(new ImageIcon(img));
g.dispose();
try {
ImageIO.write(
img,
"png",
new File(System.currentTimeMillis() + ".png"));
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
Runnable run = new Runnable() {
#Override
public void run() {
new ShapeContainment();
}
};
// Swing GUIs should be created and updated on the EDT
// http://docs.oracle.com/javase/tutorial/uiswing/concurrency/initial.html
SwingUtilities.invokeLater(run);
}
}
I am writing a test app. To set Alpha for image I use paintComponent method. Watch next snippet...
public class TestImage extends JLabel{
public void paintComponent( Graphics g ) {
super.paintComponent( g );
Graphics2D g2d=(Graphics2D)g;
g2d.drawImage(this.bImage, rop, 0, 0);
}
public void setRescaleOp(RescaleOp rop){this.rop=rop;}
}
As you can see,
g2d.drawImage(this.bImage, rop, 0, 0);
does not allow to set width and height as if I use g.drawImage(bImage, 0, 0,width,height, null);
So the question is... How to set width and height for bImage in this case?
Any useful comment is appreciated
Andrew
First filter(), as shown here, and then scale using drawImage() or AffineTransformOp, as shown here.
Addendum: Alternatively, you can scale the image first (using either approach above) and then use your RescaleOp in drawImage().
As an aside, RescaleOp scales the image's color bands; it does not change the image's dimensions. To avoid confusion, dimensional scaling is sometimes called resampling.
Addendum: Here's an example of using drawImage() to resample and RescaleOp to adjust the alpha of an image.
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.awt.image.RescaleOp;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
/**
* #see https://stackoverflow.com/questions/5838842
* #see https://stackoverflow.com/questions/5864490
*/
public class AlphaTest {
private static void display() {
JFrame f = new JFrame("AlphaTest");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
ImageIcon icon = new ImageIcon("image.jpg");
final AlphaPanel ip = new AlphaPanel(icon, 0.75);
final JSlider slider = new JSlider();
slider.addChangeListener(new ChangeListener() {
#Override
public void stateChanged(ChangeEvent e) {
int v = slider.getValue();
ip.setAlpha((float) v / slider.getMaximum());
ip.repaint();
}
});
f.add(ip, BorderLayout.CENTER);
f.add(slider, BorderLayout.SOUTH);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
display();
}
});
}
}
class AlphaPanel extends JPanel {
private BufferedImage bi;
private float[] scales = {1f, 1f, 1f, 0.5f};
private float[] offsets = new float[4];
private RescaleOp rop;
public AlphaPanel(ImageIcon icon, double scale) {
int width = (int) (scale * icon.getIconWidth());
int height = (int) (scale * icon.getIconHeight());
this.setPreferredSize(new Dimension(width, height));
this.bi = new BufferedImage(
width, height, BufferedImage.TYPE_INT_ARGB);
this.bi.createGraphics().drawImage(
icon.getImage(), 0, 0, width, height, null);
rop = new RescaleOp(scales, offsets, null);
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
g2d.drawImage(bi, rop, 0, 0);
}
public void setAlpha(float alpha) {
this.scales[3] = alpha;
this.rop = new RescaleOp(scales, offsets, null);
}
}