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Sierpinski Gasket implementation in Java Swing only shows up sometimes

So I have to create an implementation of a Sierpinski Gasket with Swing.
I can't use recursion or triangles. I have to use the following
algorithm:
Pick 3 points to define a triangle.
Select one of the vertices as current Loop 50,000 times:
Randomly choose a vertex as the target.
Draw a pixel at the mid-point between the target and current.
Make current the mid-point.
In the image below is what I sometimes get upon compilation, but other times it will pop up and disappear or it will not show up at all. If it does show up, and then I resize the window it disappears (I don't care about this, but if it helps.) I can only produce the below image sometimes when I compile (about 1/3rd of the time.) Below the image is my code, separated in two classes.
Image of when it works
import java.awt.*;
import javax.swing.JFrame;
public class SierpinskiGasket {
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setTitle("SierpinskiGasket");
frame.setSize(630,580);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
drawSierpinski Sierpinski = new drawSierpinski();
frame.add(Sierpinski);
frame.setVisible(true);
}
}
import javax.swing.*;
import java.awt.*;
public class drawSierpinski extends JPanel{
Point point1 = new Point(10,550),
point2 = new Point(300,30),
point3 = new Point(600,555),
current = point1, target;
private int count = 0;
public void paintComponent(Graphics g){
super.paintComponent(g);
while(count<= 50000){
int choice = (int)(Math.random()*3);
switch(choice){
case 0: target = point1; break;
case 1: target = point2; break;
case 2: target = point3; break;
default: System.exit(0);
}
current = midpoint(current,target);
g.drawLine(current.x,current.y,current.x,current.y);
count++;
}
}
public Point midpoint(Point a, Point b){
return new Point((Math.round(a.x+b.x)/2),
(Math.round(a.y+b.y)/2));
}
}
I am assuming that it has something to do with how Swing does multithreading, but unfortunately I don't have too much knowledge of how to fix it. Thank you very much for any help!

This loop:
while(count<= 50000) {
// ....
}
may take a while to complete, and meanwhile it will be completely blocking the Swing event thread at its most key point -- while drawing. What's more, any trivial re-draw will trigger the loop to re-run, again freezing your GUI completely.
The solution: do your drawing outside of paintComponent. Instead create a BufferedImage the size of your JPanel, get the image's Graphics object, draw your random dots for your triangle in the BufferedImage, and then display that image within your JPanel's paintComponent method. You could draw the image at program start up, and then start up the GUI after its complete, or you can start the GUI and draw to the BufferedImage in a background thread, and display it when done, either would be fine (if this is the only thing your GUI should be doing).
For example:
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import javax.swing.*;
public class SierpTest {
public static final int BI_WIDTH = 630;
public static final int BI_HEIGHT = 580;
public static void main(String[] args) {
// do this stuff off the swing event thread
final BufferedImage sierpImg = new BufferedImage(BI_WIDTH, BI_HEIGHT, BufferedImage.TYPE_INT_ARGB);
Graphics g = sierpImg.getGraphics();
// draw triangle with g here
g.dispose(); // always dispose of any Graphics you create yourself
// do this on the Swing event thread
SwingUtilities.invokeLater(() -> {
SierpPanel sierpPanel = new SierpPanel(sierpImg); // pass in image
JFrame frame = new JFrame("Siep Frame");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(sierpPanel);
frame.pack(); // size it to the size of the JPanel
frame.setLocationRelativeTo(null); // center it
frame.setVisible(true);
});
}
}
class SierpPanel extends JPanel {
private BufferedImage img = null;
public SierpPanel(BufferedImage img) {
this.img = img;
}
// so that JPanel sizes itself with the image
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet() || img == null) {
return super.getPreferredSize();
}
return new Dimension(img.getWidth(), img.getHeight());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (img != null) {
g.drawImage(img, 0, 0, this);
}
}
}
For example:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.image.BufferedImage;
import javax.swing.*;
public class SierpTest {
public static final int BI_WIDTH = 630;
public static final int BI_HEIGHT = 580;
private static final int MAX_COUNT = 100000;
public static void main(String[] args) {
// do this stuff off the swing event thread
Point point1 = new Point(10, 550);
Point point2 = new Point(300, 30);
Point point3 = new Point(600, 555);
Point current = point1;
Point target = current;
int count = 0;
final BufferedImage sierpImg = new BufferedImage(BI_WIDTH, BI_HEIGHT, BufferedImage.TYPE_INT_ARGB);
Graphics g = sierpImg.getGraphics();
g.setColor(Color.WHITE);
g.fillRect(0, 0, BI_WIDTH, BI_HEIGHT);
g.setColor(Color.BLACK);
while (count <= MAX_COUNT) {
int choice = (int) (Math.random() * 3);
switch (choice) {
case 0:
target = point1;
break;
case 1:
target = point2;
break;
case 2:
target = point3;
break;
default:
System.exit(0);
}
current = midpoint(current, target);
g.drawLine(current.x, current.y, current.x, current.y);
count++;
}
// draw triangle with g here
g.dispose(); // always dispose of any Graphics you create yourself
// do this on the Swing event thread
SwingUtilities.invokeLater(() -> {
SierpPanel sierpPanel = new SierpPanel(sierpImg); // pass in image
JFrame frame = new JFrame("Siep Frame");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(sierpPanel);
frame.pack(); // size it to the size of the JPanel
frame.setLocationRelativeTo(null); // center it
frame.setVisible(true);
});
}
public static Point midpoint(Point a, Point b) {
return new Point((Math.round(a.x + b.x) / 2), (Math.round(a.y + b.y) / 2));
}
}
class SierpPanel extends JPanel {
private BufferedImage img = null;
public SierpPanel(BufferedImage img) {
this.img = img;
}
// so that JPanel sizes itself with the image
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet() || img == null) {
return super.getPreferredSize();
}
return new Dimension(img.getWidth(), img.getHeight());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (img != null) {
g.drawImage(img, 0, 0, this);
}
}
}
Note that if you want to get fancy and draw the triangle as it's being created, and with a delay, then consider using either a Swing Timer or a SwingWorker.

java rotating bufferedimages fast

I develop a game and rotating images currently takes most of the time in the calculation process of a frame. For optimization I'm searching for the fastest way to rotate a buffered-image. I already tried two methods shown down there.
slowest method:
public static BufferedImage rotate(BufferedImage imgOld, int deg){ //Parameter for this method are the picture to rotate and the rotation in degrees
AffineTransform at = AffineTransform.getRotateInstance(Math.toRadians(deg), (int)(imgOld.getWidth()/2), (int)(imgOld.getHeight()/2)); //initialize and configure transformation
BufferedImage imgNew = new BufferedImage(imgOld.getWidth(), imgOld.getHeight(), imgOld.getType()); //create new bufferedimage with the properties of the image to rotate
Graphics2D g = (Graphics2D) imgNew.getGraphics(); //create Graphics
g.setTransform(at); //apply transformation
g.drawImage(imgOld, 0, 0, null); //draw rotated image
g.dispose();
imgOld.flush();
return imgNew;
}
little bit faster method :
public static BufferedImage rotate(BufferedImage imgOld, int deg){ //parameter same as method above
BufferedImage imgNew = new BufferedImage(imgOld.getWidth(), imgOld.getHeight(), imgOld.getType()); //create new buffered image
Graphics2D g = (Graphics2D) imgNew.getGraphics(); //create new graphics
g.rotate(QaDMath.toRadians(deg), imgOld.getWidth()/2, imgOld.getHeight()/2); //configure rotation
g.drawImage(imgOld, 0, 0, null); //draw rotated image
return imgNew; //return rotated image
}
}
I found many topics related to rotating an image but not a single one discussing the fastest, most solution.
I hope i didn't miss any topic and this isn't a duplicate.
Hopefully there is someone more skilled than me out there knowing a solution

I would guess that part of the problem is that you are continually creating new BufferedImages to do the rotation. This results in you doing the painting twice, once when you paint onto the BufferedImage and the second time when you paint the BufferedImage on the frame.
You could try to just paint the existing BufferedImage rotated. For example you could use the Rotated Icon and then just paint the icon using
rotated.paintIcon(...);
Whenever you need to rotate the image you just use:
rotated.setDegrees(...);
Simple example:
import java.awt.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.event.*;
public class Rotation3 extends JPanel
{
private Icon icon;
private RotatedIcon rotated;
private int degrees;
public Rotation3(Image image)
{
icon = new ImageIcon( image );
rotated = new RotatedIcon(icon, 0);
rotated.setCircularIcon( true );
setDegrees( 0 );
setPreferredSize( new Dimension(600, 600) );
}
#Override
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
double radians = Math.toRadians( degrees );
// translate x/y so Icon rotated around a specific point (300, 300)
int x = 300 - (rotated.getIconWidth() / 2);
int y = 300 - (rotated.getIconHeight() / 2);
rotated.paintIcon(this, g, x, y);
g.setColor(Color.RED);
g.fillOval(295, 295, 10, 10);
}
public void setDegrees(int degrees)
{
this.degrees = degrees;
rotated.setDegrees(degrees);
repaint();
}
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
try
{
String path = "dukewavered.gif";
ClassLoader cl = Rotation3.class.getClassLoader();
BufferedImage bi = ImageIO.read(cl.getResourceAsStream(path));
final Rotation3 r = new Rotation3(bi);
final JSlider slider = new JSlider(JSlider.HORIZONTAL, 0, 360, 0);
slider.addChangeListener(new ChangeListener()
{
public void stateChanged(ChangeEvent e)
{
int value = slider.getValue();
r.setDegrees( value );
}
});
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(new JScrollPane(r));
f.add(slider, BorderLayout.SOUTH);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
catch(IOException e)
{
System.out.println(e);
}
}
});
}
}
Just drag the slider to see the rotation.

Graphical/File output for Grayscale BufferedImage

I am doing this for a project at school, in which much more functionality will be added later, but I am having trouble getting the basic setup done.
I tried doing this in C++ initially, but decided to switch to Java after reading some documentation on BufferedImage, but I am running into an issue with output. Essentially this is what I am designing the flow of the program to be:
1) Extract original image's (BMP image that is supplied in grayscale) grayscale values. 2) Create a currentImage variable to preserve the original image and perform the modifications to the image I intend to perform in the later stages of the project. 3) Create a reusable output method that will take the currentImage BufferedImage, and output it to a panel (and maybe a file as well.
Here is what I have so far, which currently results in nothing being outputted to the screen, and when I tried doing System logs, it is not setting the pixel values in my draw mechanism:
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.awt.image.Raster;
import java.io.File;
import java.io.IOException;
#SuppressWarnings("serial")
public class ImageDriver extends JFrame {
DrawPanel paintPanel;
static int width = 1024, height = 768;
BufferedImage originalImage, currentImage;
File theImageFile;
int[][] imageData;
public ImageDriver() {
super("Image Processing");
setSize(width, height);
setDefaultCloseOperation(EXIT_ON_CLOSE);
paintPanel = new DrawPanel(width, height);
add(paintPanel);
}
public void updateImageDisplay() {
System.out.println("In updateImageDisplay!");
paintPanel.setImage(currentImage);
}
public void readImage() {
try {
theImageFile = new File("images/img1.bmp");
originalImage = ImageIO.read(theImageFile);
currentImage = originalImage;
}
catch (IOException e) {
e.printStackTrace();
}
//get a raster to extract grayscale values
Raster image_raster = currentImage.getData();
//get pixel by pixel
int[] pixel = new int[1];
int[] buffer = new int[1];
imageData = new int[image_raster.getWidth()][image_raster.getHeight()];
for(int i = 0 ; i < image_raster.getWidth() ; i++)
for(int j = 0 ; j < image_raster.getHeight() ; j++) {
pixel = image_raster.getPixel(i, j, buffer);
imageData[i][j] = pixel[0];
//System.out.println("Pixel at: " + i + " x " + j + ": " + imageData[i][j]);
}
}
public void increaseContrast() {
}
public static void main(String[] args) {
ImageDriver driver = new ImageDriver();
driver.setVisible(true);
driver.readImage();
driver.updateImageDisplay();
driver.increaseContrast();
driver.updateImageDisplay();
}
class DrawPanel extends JPanel {
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_BYTE_GRAY);
public DrawPanel(int width, int height) {
setPreferredSize(new Dimension(width, height));
}
public void setImage(BufferedImage image) {
System.out.println("In setImage!");
this.image = image;
repaint();
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
System.out.println("in paintPanel component!");
g = image.getGraphics();
g.drawImage(image, 0, 0, null);
}
}
}
I have a hunch that it is because I am declaring image in my DrawPanel to be an empty image at first, and setImage is not properly copying over all of its contents upon assignment. I tried fiddling around with using this:
this.image.setData(image.getData());
but to no avail.
I missing something here? Or is a complete re-write if the mechanism in order?
Thank you for reading.

The first thing that jumps out at me is this (in your paintComponent method)...
g = image.getGraphics();
g.drawImage(image, 0, 0, null);
Basically, you are painting the image back to itself, instead you should do something like like...
g.drawImage(image, 0, 0, this);
Using the Graphics context you were passed

Proper way to use JLabels to update an image

I am creating a GUI, and am fairly new to swing and awt. I am trying to create a gui that, upon launch, sets the background to an image, then uses a method to create a slideshow of sorts. I have attempted it, and I am not attached to the code so I am able to take both revisions and/or whole new concepts.
EDIT(9/15/13): I am having trouble with the slideshow, I cant seem to get it to work.
Here is my current code.
public class MainFrame extends JFrame{
JLabel backgroundL = null;
private JLabel bakckgroundL;
BufferedImage backimg;
Boolean busy;
double width;
double height;
public MainFrame() throws IOException {
initMainframe();
}
public void initMainframe() throws IOException {
//misc setup code, loads a default jpg as background
setTitle("Pemin's Aura");
busy = true;
String backgroundDir = "resources/frame/background.jpg";
backimg = ImageIO.read(new File(backgroundDir));
backgroundL = new JLabel(new ImageIcon(backimg));
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
refreshframe();
setVisible(true);
busy = false;
}
public void adjSize() { // the attempted start of a fullscreen mode
GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice().setFullScreenWindow(this);
width = this.getWidth();
height = this.getHeight();
setVisible(true);
}
public void setmastheadText() {//unfinished code
busy = true;
busy = false;
}
public void setbackground() {
add(backgroundL);
}
public void refreshframe() { //should refresh image?
setSize(2049, 2049);
setSize(2048, 2048);
}
public void loadingscreen() throws IOException, InterruptedException {
//this is the code in question that is faulty.
if (busy == false) {
busy = true;
String backgroundDir1 = "resources/frame/background.jpg";
String backgroundDir2 = "resources/frame/scr1.jpg";
String backgroundDir3 = "resources/frame/scr2.jpg";
BufferedImage backimg1 = ImageIO.read(new File(backgroundDir1));
BufferedImage backimg2 = ImageIO.read(new File(backgroundDir2));
BufferedImage backimg3 = ImageIO.read(new File(backgroundDir3));
backgroundL = new JLabel(new ImageIcon(backimg1));
Thread.sleep(2000);
setbackground();
setVisible(true);
backgroundL = new JLabel(new ImageIcon(backimg2));
setbackground();
setVisible(true);
Thread.sleep(2000);
bakckgroundL = new JLabel(new ImageIcon(backimg3));
setbackground();
setVisible(true);
if(backimg != null) {
backgroundL = new JLabel(new ImageIcon(backimg));;
}
}
busy = false;
}//end of loading screen

See ImageViewer for a working example of displaying images using a Swing based Timer.
See also How to use Swing Timers.
And while I'm here, another (prettier) example of animating an image. It uses this Mercator map of land masses. The image can be tiled horizontally, and therefore be scrolled left/right as needed.
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.Point2D;
import java.awt.image.BufferedImage;
import javax.swing.*;
import java.net.URL;
import javax.imageio.ImageIO;
public class WorldView {
public static void main(String[] args) throws Exception {
URL url = new URL("http://i.stack.imgur.com/P59NF.png");
final BufferedImage bi = ImageIO.read(url);
Runnable r = new Runnable() {
#Override
public void run() {
int width = 640;
int height = 316;
Graphics2D g = bi.createGraphics();
float[] floats = new float[]{0f, .4f, .55f, 1f};
Color[] colors = new Color[]{
new Color(20, 20, 20, 0),
new Color(0, 10, 20, 41),
new Color(0, 10, 20, 207),
new Color(0, 10, 20, 230),};
final LinearGradientPaint gp2 = new LinearGradientPaint(
new Point2D.Double(320f, 0f),
new Point2D.Double(0f, 0f),
floats,
colors,
MultipleGradientPaint.CycleMethod.REFLECT);
final BufferedImage canvas = new BufferedImage(
bi.getWidth(), bi.getHeight() + 60,
BufferedImage.TYPE_INT_RGB);
final JLabel animationLabel = new JLabel(new ImageIcon(canvas));
ActionListener animator = new ActionListener() {
int x = 0;
int y = 30;
#Override
public void actionPerformed(ActionEvent e) {
Graphics2D g = canvas.createGraphics();
g.setColor(new Color(55, 75, 125));
g.fillRect(0, 0, canvas.getWidth(), canvas.getHeight());
int offset = (x % bi.getWidth());
g.drawImage(bi, offset, y, null);
g.drawImage(bi, offset - bi.getWidth(), y, null);
g.setPaint(gp2);
g.fillRect(0, 0, canvas.getWidth(), canvas.getHeight());
g.dispose();
animationLabel.repaint();
x++;
}
};
Timer timer = new Timer(40, animator);
timer.start();
JOptionPane.showMessageDialog(null, animationLabel);
timer.stop();
}
};
// Swing GUIs should be created and updated on the EDT
// http://docs.oracle.com/javase/tutorial/uiswing/concurrency
SwingUtilities.invokeLater(r);
}
}
Here is a version of that image with the equator added (it is 44 pixels 'south' of the center of the image).

You're calling Thread.sleep(...) and likely on the EDT or Swing event thread (full name is the Event Dispatch Thread). This thread is responsible for all Swing painting/drawing and user interactions, and so sleeping it will only serve to freeze your entire GUI. Instead you should use a Swing Timer to allow you to swap a JLabel's ImageIcon.
So, briefly:
Don't call Thread.sleep(...) on the Swing event thread (Event Dispatch Thread or EDT).
Do use a Swing Timer to do your repeating delayed actions.
Don't make and add many JLabels. Just make and add one.
Do Swap the ImageIcon that the JLabel displays by calling setIcon(...) on the label.
Better (cleaner) to write if (busy == false) { as if (!busy) {
e.g.,
ImageIcon[] icons = {...}; // filled up with your ImageIcons
if (!busy) {
int timerDelay = 2000;
new Timer(timerDelay, new ActionListener() {
private int i = 0;
public void actionPerfomed(ActionEvent e) {
myLabel.setIcon(icons(i));
i++;
if (i == icons.length) {
((Timer)e.getSource).stop();
}
};
}).start();
}

How to make drawn images transparent in Java

I got the animation to work in my Snake Clone Game. But the problem based on the picture is that the images do not have transparency(notice the white background of the circle pictures. Programming-wise, is there a fix to be able to include transparency to these drawn images?
Here's a picture containing my code and the output of the program.
P.S. On a side note, I decided to paste the direct link instead of the IMG code because I cannot seem to get it to display on StackOverFlow. I put an exclamation point in the front of the IMG code but it did not work so here's the direct link.

As the other answer mentioned, the easiest way would probably be to simply use PNG images which have a transparent background (you can create these with an image editor like GIMP). Alternatively, if you are limited to PNG images with a solid background, here's an example of how to change a given color (e.g. white) in the PNG to transparent:
import java.awt.*;
import java.awt.image.*;
import javax.swing.*;
public class SimpleFrame extends JFrame {
JPanel mainPanel = new JPanel() {
ImageIcon originalIcon = new ImageIcon("~/Pictures/apple.png");
ImageFilter filter = new RGBImageFilter() {
int transparentColor = Color.white.getRGB() | 0xFF000000;
public final int filterRGB(int x, int y, int rgb) {
if ((rgb | 0xFF000000) == transparentColor) {
return 0x00FFFFFF & rgb;
} else {
return rgb;
}
}
};
ImageProducer filteredImgProd = new FilteredImageSource(originalIcon.getImage().getSource(), filter);
Image transparentImg = Toolkit.getDefaultToolkit().createImage(filteredImgProd);
public void paintComponent(Graphics g) {
g.setColor(getBackground());
g.fillRect(0, 0, getSize().width, getSize().height);
// draw the original icon
g.drawImage(originalIcon.getImage(), 100, 10, this);
// draw the transparent icon
g.drawImage(transparentImg, 140, 10, this);
}
};
public SimpleFrame() {
super("Transparency Example");
JPanel content = (JPanel)getContentPane();
mainPanel.setBackground(Color.black);
content.add("Center", mainPanel);
}
public static void main(String[] argv) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
SimpleFrame c = new SimpleFrame();
c.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
c.setSize(280,100);
c.setVisible(true);
}
});
}
}

Don't use paint to draw your images. Use some other program that uses alpha like Paint.net or Photoshop... If your going to use circles forever then you can use g.drawOval(x, y, w, h).

Simple use type to ARGB like this
BufferedImage image = new BufferedImage(
width, height,
BufferedImage.TYPE_INT_ARGB);
I hope it should work.

public BufferedImage makeTransparentImage(BufferedImage br) {
for (int i = 0; i < br.getHeight(); i++) {
for (int j = 0; j < br.getWidth(); j++) {
Color c = new Color(br.getRGB(j, i));
int r = c.getRed();
int b = c.getBlue();
int g = c.getGreen();
if ((r == 255 && b == 255 && g == 255)) {
System.out.println("r g b " + r + g + b);
br.setRGB(j, i, 0xFF000000);
}
}
}
return br;
}

If you draw a simple picture,
The easiest and fastest way I know...
Draw a picture in Macrosoft PowerPoint and click "Save as Picture" to get a transparent background. Next...
public class Node {
Image nodeImage[] = new Image[3];
public Node() {
try {
String address = "C:\\Users\\Desktop\\practice\\Simulation\\img\\";
nodeImage[0] = ImageIO.read(new File(address + "Node_noVehicle.png"));
nodeImage[1] = ImageIO.read(new File(address + "Node_setVehicle.png"));
nodeImage[2] = ImageIO.read(new File(address + "Node_inVehicle.png"));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2dtemp = (Graphics2D) g.create();
g2dtemp.drawImage(Node.nodeImage[0],(int)x,(int)y,width,height,this);
}
}
Draw a picture in Macrosoft PowerPoint and click "Save as Picture" to get a transparent background.