Develop Reference

Make running (marquee ) of JLabel in Netbeans [duplicate]

How can I implement Marquee effect in Java Swing

Here's an example using javax.swing.Timer.
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Timer;
/** #see http://stackoverflow.com/questions/3617326 */
public class MarqueeTest {
private void display() {
JFrame f = new JFrame("MarqueeTest");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
String s = "Tomorrow, and tomorrow, and tomorrow, "
+ "creeps in this petty pace from day to day, "
+ "to the last syllable of recorded time; ... "
+ "It is a tale told by an idiot, full of "
+ "sound and fury signifying nothing.";
MarqueePanel mp = new MarqueePanel(s, 32);
f.add(mp);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
mp.start();
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new MarqueeTest().display();
}
});
}
}
/** Side-scroll n characters of s. */
class MarqueePanel extends JPanel implements ActionListener {
private static final int RATE = 12;
private final Timer timer = new Timer(1000 / RATE, this);
private final JLabel label = new JLabel();
private final String s;
private final int n;
private int index;
public MarqueePanel(String s, int n) {
if (s == null || n < 1) {
throw new IllegalArgumentException("Null string or n < 1");
}
StringBuilder sb = new StringBuilder(n);
for (int i = 0; i < n; i++) {
sb.append(' ');
}
this.s = sb + s + sb;
this.n = n;
label.setFont(new Font("Serif", Font.ITALIC, 36));
label.setText(sb.toString());
this.add(label);
}
public void start() {
timer.start();
}
public void stop() {
timer.stop();
}
#Override
public void actionPerformed(ActionEvent e) {
index++;
if (index > s.length() - n) {
index = 0;
}
label.setText(s.substring(index, index + n));
}
}

I know this is a late answer, but I just saw another question about a marquee that was closed because it was considered a duplicate of this answer.
So I thought I'd add my suggestion which takes a approach different from the other answers suggested here.
The MarqueePanel scrolls components on a panel not just text. So this allows you to take full advantage of any Swing component. A simple marquee can be used by adding a JLabel with text. A fancier marquee might use a JLabel with HTML so you can use different fonts and color for the text. You can even add a second component with an image.

Basic answer is you draw your text / graphic into a bitmap and then implement a component that paints the bitmap offset by some amount. Usually marquees / tickers scroll left so the offset increases which means the bitmap is painted at -offset. Your component runs a timer that fires periodically, incrementing the offset and invalidating itself so it repaints.
Things like wrapping are a little more complex to deal with but fairly straightforward. If the offset exceeds the bitmap width you reset it back to 0. If the offset + component width > bitmap width you paint the remainder of the component starting from the beginning of the bitmap.
The key to a decent ticker is to make the scrolling as smooth and as flicker free as possible. Therefore it may be necessary to consider double buffering the result, first painting the scrolling bit into a bitmap and then rendering that in one go rather than painting straight into the screen.

Here is some code that I threw together to get you started. I normally would take the ActionListener code and put that in some sort of MarqueeController class to keep this logic separate from the panel, but that's a different question about organizing the MVC architecture, and in a simple enough class like this it may not be so important.
There are also various animation libraries that would help you do this, but I don't normally like to include libraries into projects only to solve one problem like this.
public class MarqueePanel extends JPanel {
private JLabel textLabel;
private int panelLocation;
private ActionListener taskPerformer;
private boolean isRunning = false;
public static final int FRAMES_PER_SECOND = 24;
public static final int MOVEMENT_PER_FRAME = 5;
/**
* Class constructor creates a marquee panel.
*/
public MarqueePanel() {
this.setLayout(null);
this.textLabel = new JLabel("Scrolling Text Here");
this.panelLocation = 0;
this.taskPerformer = new ActionListener() {
public void actionPerformed(ActionEvent evt) {
MarqueePanel.this.tickAnimation();
}
}
}
/**
* Starts the animation.
*/
public void start() {
this.isRunning = true;
this.tickAnimation();
}
/**
* Stops the animation.
*/
public void stop() {
this.isRunning = false;
}
/**
* Moves the label one frame to the left. If it's out of display range, move it back
* to the right, out of display range.
*/
private void tickAnimation() {
this.panelLocation -= MarqueePanel.MOVEMENT_PER_FRAME;
if (this.panelLocation < this.textLabel.getWidth())
this.panelLocaton = this.getWidth();
this.textLabel.setLocation(this.panelLocation, 0);
this.repaint();
if (this.isRunning) {
Timer t = new Timer(1000 / MarqueePanel.FRAMES_PER_SECOND, this.taskPerformer);
t.setRepeats(false);
t.start();
}
}
}

Add a JLabel to your frame or panel.
ScrollText s= new ScrollText("ello Everyone.");
jLabel3.add(s);
public class ScrollText extends JComponent {
private BufferedImage image;
private Dimension imageSize;
private volatile int currOffset;
private Thread internalThread;
private volatile boolean noStopRequested;
public ScrollText(String text) {
currOffset = 0;
buildImage(text);
setMinimumSize(imageSize);
setPreferredSize(imageSize);
setMaximumSize(imageSize);
setSize(imageSize);
noStopRequested = true;
Runnable r = new Runnable() {
public void run() {
try {
runWork();
} catch (Exception x) {
x.printStackTrace();
}
}
};
internalThread = new Thread(r, "ScrollText");
internalThread.start();
}
private void buildImage(String text) {
RenderingHints renderHints = new RenderingHints(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
renderHints.put(RenderingHints.KEY_RENDERING,
RenderingHints.VALUE_RENDER_QUALITY);
BufferedImage scratchImage = new BufferedImage(1, 1,
BufferedImage.TYPE_INT_RGB);
Graphics2D scratchG2 = scratchImage.createGraphics();
scratchG2.setRenderingHints(renderHints);
Font font = new Font("Serif", Font.BOLD | Font.ITALIC, 24);
FontRenderContext frc = scratchG2.getFontRenderContext();
TextLayout tl = new TextLayout(text, font, frc);
Rectangle2D textBounds = tl.getBounds();
int textWidth = (int) Math.ceil(textBounds.getWidth());
int textHeight = (int) Math.ceil(textBounds.getHeight());
int horizontalPad = 600;
int verticalPad = 10;
imageSize = new Dimension(textWidth + horizontalPad, textHeight
+ verticalPad);
image = new BufferedImage(imageSize.width, imageSize.height,
BufferedImage.TYPE_INT_RGB);
Graphics2D g2 = image.createGraphics();
g2.setRenderingHints(renderHints);
int baselineOffset = (verticalPad / 2) - ((int) textBounds.getY());
g2.setColor(Color.BLACK);
g2.fillRect(0, 0, imageSize.width, imageSize.height);
g2.setColor(Color.GREEN);
tl.draw(g2, 0, baselineOffset);
// Free-up resources right away, but keep "image" for
// animation.
scratchG2.dispose();
scratchImage.flush();
g2.dispose();
}
public void paint(Graphics g) {
// Make sure to clip the edges, regardless of curr size
g.setClip(0, 0, imageSize.width, imageSize.height);
int localOffset = currOffset; // in case it changes
g.drawImage(image, -localOffset, 0, this);
g.drawImage(image, imageSize.width - localOffset, 0, this);
// draw outline
g.setColor(Color.black);
g.drawRect(0, 0, imageSize.width - 1, imageSize.height - 1);
}
private void runWork() {
while (noStopRequested) {
try {
Thread.sleep(10); // 10 frames per second
// adjust the scroll position
currOffset = (currOffset + 1) % imageSize.width;
// signal the event thread to call paint()
repaint();
} catch (InterruptedException x) {
Thread.currentThread().interrupt();
}
}
}
public void stopRequest() {
noStopRequested = false;
internalThread.interrupt();
}
public boolean isAlive() {
return internalThread.isAlive();
}
}

This is supposed to be an improvement of #camickr MarqueePanel. Please see above.
To map mouse events to the specific components added to MarqueePanel
Override add(Component comp) of MarqueePanel in order to direct all mouse events of the components
An issue here is what do do with the MouseEvents fired from the individual components.
My approach is to remove the mouse listeners form the components added and let the MarqueePanel redirect the event to the correct component.
In my case these components are supposed to be links.
#Override
public Component add(Component comp) {
comp = super.add(comp);
if(comp instanceof MouseListener)
comp.removeMouseListener((MouseListener)comp);
comp.addMouseListener(this);
return comp;
}
Then map the component x to a MarqueePanel x and finally the correct component
#Override
public void mouseClicked(MouseEvent e)
{
Component source = (Component)e.getSource();
int x = source.getX() + e.getX();
int y = source.getY();
MarqueePanel2 marqueePanel = (MarqueePanel2) ((JComponent)e.getSource()).getParent();
double x2 = marqueePanel.getWidth();
double x1 = Math.abs(marqueePanel.scrollOffset);
if(x >= x1 && x <= x2)
{
System.out.println("Bang " + x1);
Component componentAt = getComponentAt(x+marqueePanel.scrollOffset, y);
if(comp instanceof MouseListener)
((MouseListener) componentAt).mouseClicked(e);
System.out.println(componentAt.getName());
}
else
{
return;
}
//System.out.println(x);
}

rectangle and circle collision detection in java swing [duplicate]

I am wanting to make a game that has each level loaded from an image.
I want to draw up the whole level in Photoshop, and then set it as the background and allow the player to walk over it.
I want another invisible image to go over top which will be black in all places that I want to collide with.
The reason I don't want to use tiles, which are much easier with rectangle collision and such, is because there will be complex corners and not everything will be rectangle.
Is this a good idea, and is it possible to do easily?
Would this be a big CPU hog or is there a better way to do this?
Level image
Obstacles shown in red

..there will be complex corners and not everything will be rectangle.
This could be achieved by drawing and dealing with Shape and Area instances. E.G.
Yellow is a little animated 'player'.
The bounds of the image represent walls that contain the path of the player (it bounces off them).
Obstacles are painted green when not in collision, red otherwise.
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
class ShapeCollision {
private BufferedImage img;
private Area[] obstacles = new Area[4];
private Area walls;
int x;
int y;
int xDelta = 3;
int yDelta = 2;
/** A method to determine if two instances of Area intersect */
public boolean doAreasCollide(Area area1, Area area2) {
boolean collide = false;
Area collide1 = new Area(area1);
collide1.subtract(area2);
if (!collide1.equals(area1)) {
collide = true;
}
Area collide2 = new Area(area2);
collide2.subtract(area1);
if (!collide2.equals(area2)) {
collide = true;
}
return collide;
}
ShapeCollision() {
int w = 400;
int h = 200;
img = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
final JLabel imageLabel = new JLabel(new ImageIcon(img));
x = w/2;
y = h/2;
//circle
obstacles[0] = new Area(new Ellipse2D.Double(40, 40, 30, 30));
int[] xTriangle = {330,360,345};
int[] yTriangle = {60,60,40};
//triangle
obstacles[1] = new Area(new Polygon(xTriangle, yTriangle, 3));
int[] xDiamond = {60,80,60,40};
int[] yDiamond = {120,140,160,140};
//diamond
obstacles[2] = new Area(new Polygon(xDiamond, yDiamond, 4));
int[] xOther = {360,340,360,340};
int[] yOther = {130,110,170,150};
// other
obstacles[3] = new Area(new Polygon(xOther, yOther, 4));
walls = new Area(new Rectangle(0,0,w,h));
ActionListener animate = new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
animate();
imageLabel.repaint();
}
};
Timer timer = new Timer(50, animate);
timer.start();
JOptionPane.showMessageDialog(null, imageLabel);
timer.stop();
}
public void animate() {
Graphics2D g = img.createGraphics();
g.setRenderingHint(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g.setColor(Color.BLUE);
g.fillRect(0, 0, img.getWidth(), img.getHeight());
x+=xDelta;
y+=yDelta;
int s = 15;
Area player = new Area(new Ellipse2D.Double(x, y, s, s));
// Acid test of edge collision;
if (doAreasCollide(player,walls)) {
if ( x+s>img.getWidth() || x<0 ) {
xDelta *= -1;
}
if(y+s>img.getHeight() || y<0 ) {
yDelta *= -1;
}
}
g.setColor(Color.ORANGE);
for (Area obstacle : obstacles) {
if (doAreasCollide(obstacle, player)) {
g.setColor(Color.RED);
} else {
g.setColor(Color.GREEN);
}
g.fill(obstacle);
}
g.setColor(Color.YELLOW);
g.fill(player);
g.dispose();
}
public static void main(String[] args) {
Runnable r = new Runnable() {
#Override
public void run() {
new ShapeCollision();
}
};
// Swing GUIs should be created and updated on the EDT
// http://docs.oracle.com/javase/tutorial/uiswing/concurrency/initial.html
SwingUtilities.invokeLater(r);
}
}
Edit
make it detect all the red color and set that as the collision bounds
At start-up, use the source seen in the Smoothing a jagged path question to get an outline of the red pixels (see the getOutline(Color target, BufferedImage bi) method). Store that Area as the single obstacle on start-up.

Collision detection with complex shapes

I am wanting to make a game that has each level loaded from an image.
I want to draw up the whole level in Photoshop, and then set it as the background and allow the player to walk over it.
I want another invisible image to go over top which will be black in all places that I want to collide with.
The reason I don't want to use tiles, which are much easier with rectangle collision and such, is because there will be complex corners and not everything will be rectangle.
Is this a good idea, and is it possible to do easily?
Would this be a big CPU hog or is there a better way to do this?
Level image
Obstacles shown in red

..there will be complex corners and not everything will be rectangle.
This could be achieved by drawing and dealing with Shape and Area instances. E.G.
Yellow is a little animated 'player'.
The bounds of the image represent walls that contain the path of the player (it bounces off them).
Obstacles are painted green when not in collision, red otherwise.
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
class ShapeCollision {
private BufferedImage img;
private Area[] obstacles = new Area[4];
private Area walls;
int x;
int y;
int xDelta = 3;
int yDelta = 2;
/** A method to determine if two instances of Area intersect */
public boolean doAreasCollide(Area area1, Area area2) {
boolean collide = false;
Area collide1 = new Area(area1);
collide1.subtract(area2);
if (!collide1.equals(area1)) {
collide = true;
}
Area collide2 = new Area(area2);
collide2.subtract(area1);
if (!collide2.equals(area2)) {
collide = true;
}
return collide;
}
ShapeCollision() {
int w = 400;
int h = 200;
img = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
final JLabel imageLabel = new JLabel(new ImageIcon(img));
x = w/2;
y = h/2;
//circle
obstacles[0] = new Area(new Ellipse2D.Double(40, 40, 30, 30));
int[] xTriangle = {330,360,345};
int[] yTriangle = {60,60,40};
//triangle
obstacles[1] = new Area(new Polygon(xTriangle, yTriangle, 3));
int[] xDiamond = {60,80,60,40};
int[] yDiamond = {120,140,160,140};
//diamond
obstacles[2] = new Area(new Polygon(xDiamond, yDiamond, 4));
int[] xOther = {360,340,360,340};
int[] yOther = {130,110,170,150};
// other
obstacles[3] = new Area(new Polygon(xOther, yOther, 4));
walls = new Area(new Rectangle(0,0,w,h));
ActionListener animate = new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
animate();
imageLabel.repaint();
}
};
Timer timer = new Timer(50, animate);
timer.start();
JOptionPane.showMessageDialog(null, imageLabel);
timer.stop();
}
public void animate() {
Graphics2D g = img.createGraphics();
g.setRenderingHint(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g.setColor(Color.BLUE);
g.fillRect(0, 0, img.getWidth(), img.getHeight());
x+=xDelta;
y+=yDelta;
int s = 15;
Area player = new Area(new Ellipse2D.Double(x, y, s, s));
// Acid test of edge collision;
if (doAreasCollide(player,walls)) {
if ( x+s>img.getWidth() || x<0 ) {
xDelta *= -1;
}
if(y+s>img.getHeight() || y<0 ) {
yDelta *= -1;
}
}
g.setColor(Color.ORANGE);
for (Area obstacle : obstacles) {
if (doAreasCollide(obstacle, player)) {
g.setColor(Color.RED);
} else {
g.setColor(Color.GREEN);
}
g.fill(obstacle);
}
g.setColor(Color.YELLOW);
g.fill(player);
g.dispose();
}
public static void main(String[] args) {
Runnable r = new Runnable() {
#Override
public void run() {
new ShapeCollision();
}
};
// Swing GUIs should be created and updated on the EDT
// http://docs.oracle.com/javase/tutorial/uiswing/concurrency/initial.html
SwingUtilities.invokeLater(r);
}
}
Edit
make it detect all the red color and set that as the collision bounds
At start-up, use the source seen in the Smoothing a jagged path question to get an outline of the red pixels (see the getOutline(Color target, BufferedImage bi) method). Store that Area as the single obstacle on start-up.

JScrollPane doesn't update JScrollBar on JSplitPane

I want to create simple app able to edit images. Main view of app contains JSplitPane with two JScrollPane. Each JScrollPane contains JPanel. The right JPanel has several buttons etc. and the left JPanel is my drawing area.
Here is my problem...
When I first created JPanelDrawingArea I could set preferred size. If the size is bigger than size of JScrollPane the JScrollBars show up (in default it is equal). But when I load image to JPanelDrawingArea scroll bars don't update. Despite the fact I set new preferred size of JPanelDrawingArea (bigger than size of JScrollPane) scroll bars don't update unless I manually change the JSplitPanes divider position.
Here is my JSplitPane custom class:
public class DrawingPaneView extends JSplitPane{
private DrawingWorkMode drawingWorkMode;
private ImageWorkerView imageWorker;
JScrollPane workScrollPane;
JScrollPane pictureScrollPane;
private DrawingPaneController controller;
private Dimension minimumSize = new Dimension(100, 200);
private JPanel imagePanel;
public DrawingPaneView() {
setPreferredSize(new Dimension(ConfigClass.APP_WIDTH,ConfigClass.DRAWING_PANE_HEIGHT));
controller = new DrawingPaneController(this);
//Panel
drawingWorkMode = new DrawingWorkMode();
workScrollPane = new JScrollPane(drawingWorkMode);
//Image
imageWorker = new ImageWorkerView();
pictureScrollPane = new JScrollPane(imageWorker);
workScrollPane.setMinimumSize(minimumSize);
pictureScrollPane.setMinimumSize(minimumSize);
//addJPanels
this.setOrientation(JSplitPane.HORIZONTAL_SPLIT);
this.setRightComponent(workScrollPane);
this.setLeftComponent(pictureScrollPane);
//addLeftPanelWithJButtonOnly
imagePanel = new ImagePanelView();
pictureScrollPane.setRowHeaderView(imagePanel);
this.setDividerLocation(ConfigClass.DRAWING_PANE_WIDTH);
this.setOneTouchExpandable(true);
}
//Change mode
public void changeMode(String mode){
drawingWorkMode.changeMode(mode);
}
}
And there is my custom JPanel which perform drawing:
public class ImageWorkerView extends JPanel {
private BufferedImage img;
private ImageWorkerController controller;
private int defaultBounds = 50;
private double scale=1.0;
int imgW;
int imgH;
public ImageWorkerView() {
//setLayout(new BorderLayout(0, 0));
controller = new ImageWorkerController(this);
}
public void setScale(double scale) {
this.scale = scale;
}
public void setImage(File image) {
try {
img = ImageIO.read(image);
if (img.getType() != BufferedImage.TYPE_INT_RGB) {
BufferedImage img2 =
new BufferedImage(img.getWidth(null), img.getHeight(null), BufferedImage.TYPE_INT_RGB);
Graphics big = img2.getGraphics();
big.drawImage(img, 0, 0, null);
img = img2;
}
} catch (IOException e) {
System.out.println("Image could not be read");
}
}
private void adjustPreferredSize(Boolean defaultSize){
if(defaultSize){
//Calculate the proper size of drawing area
imgW = ConfigClass.DRAWING_PANE_WIDTH - ImagePanelView.PREFERRED_WIDTH-10;
imgH = ConfigClass.DRAWING_PANE_HEIGHT-50;
setPreferredSize(new Dimension(imgW,imgH));
controller.setWindowHeight(imgH);
}
else{
imgW = (int)(img.getWidth() * scale + (defaultBounds*2));
imgH = (int)(img.getHeight() * scale + (defaultBounds*2));
setPreferredSize(new Dimension(imgW,imgH));
controller.setWindowHeight(imgH);
}
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
if(img!=null){
if(scale!=1.0){
AffineTransform at = AffineTransform.getScaleInstance(scale, scale);
AffineTransformOp aop =
new AffineTransformOp(at, AffineTransformOp.TYPE_BICUBIC);
g2.drawImage(img, aop, defaultBounds, defaultBounds);
}
else
g2.drawImage(img, defaultBounds, defaultBounds, null);
adjustPreferredSize(false);
}
else{
adjustPreferredSize(true);
}
}
}
And how i load image:
public class ImageWorkerController {
ImageWorkerView view;
ImageModel model;
public ImageWorkerController(ImageWorkerView workerView) {
this.view = workerView;
this.model = ApplicationContext.getObject(ImageModel.class);
//Load image
ApplicationContext.getObject(Context.class).addPropertyChangeListener(new PropertyChangeListener() {
public void propertyChange(PropertyChangeEvent evt) {
if(Context.IMAGE_LOADED.equals(evt.getPropertyName())){
view.setImage((File) evt.getNewValue());
view.repaint();
}
}
});
public void setWindowHeight(int h){
model.setDrawingWindowHeight(h);
}
}
As you can see there is adjustPreferredSize() method, when it is first called, and it sets preferredSize bigger than JScrollPane, JScrollBars appear. But when it is called again it does nothing.
What is interesting, when I manually change divider's location JScrollBars show up, on screen below you have an example:
http://s17.postimage.org/e1nkja3zx/liliebead.jpg
So there is some kind of event, which makes JScrollPane to update? I've tried several ways: updateUI(), repaint(), revalidate(). None of them worked.
Any ideas what I am doing wrong?

In short, you need to revalidate() your ImageWorkerView (right where you call repaint()). This will ask the component and its parent for "re-layout" and that in turn will trigger necessary adjustments for the scroll bars.

Thanks for your answer! Your suggestion made me think. What actually I did wrong is call revalidate() immediatelly after repaint() so in fact revalidate() executes before paintComponent method in ImageWorkerView (I found this out during debugging). The proper way to do this is:
ApplicationContext.getObject(Context.class).addPropertyChangeListener(new PropertyChangeListener() {
public void propertyChange(PropertyChangeEvent evt) {
if(Context.IMAGE_LOADED.equals(evt.getPropertyName())){
view.setImage((File) evt.getNewValue());
//view.repaint();
view.paintImmediately(new Rectangle(1, 1));
view.revalidate();
}
}
});
So now paintComponent sets preferred size and then revalidate() adjust scroll bars.

Smoothing a jagged path

I was participating in the thread Image/Graphic into a Shape the other day and made a hackish attempt to get the outline of an image by adding a Rectangle iteratively to an Area. That was very slow.
This example instead builds a GeneralPath and creates the Area from the GP. Much faster.
The image on the upper left is the 'source image'. The two on the right are various stages of processing the outline. Both of them have jagged edges around the circle and along the slanted sides of the triangle.
I'd like to gain a shape that has that jaggedness removed or reduced.
In ASCII art.
Case 1:
1234
1 **
2 **
3 ***
4 ***
5 ****
6 ****
Corners are at:
(2,3) inner corner
(3,3)
(3,5) inner corner
(4,5)
Case 2:
1234
1 ****
2 ****
3 **
4 **
5 ****
6 ****
Corners are at:
(4,2)
(2,2) inner corner
(2,5) inner corner
(4,5)
Assuming our path had the shapes shown, and the points as listed, I'd like to drop the 'inner corner' points of the first set, while retaining the 'pair' of inner corners (a bite out of the image) for the 2nd.
Can anybody suggest some clever inbuilt method to do the heavy lifting of this job?
Failing that, what would be a good approach to identifying the location & nature (pair/single) of the inner corners? (I'm guessing I could get a PathIterator and build a new GeneralPath dropping the singular inner corners - if only I could figure how to identify them!).
Here's the code to play with:
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import java.awt.geom.*;
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.event.*;
/* Gain the outline of an image for further processing. */
class ImageOutline {
private BufferedImage image;
private TwoToneImageFilter twoToneFilter;
private BufferedImage imageTwoTone;
private JLabel labelTwoTone;
private BufferedImage imageOutline;
private Area areaOutline = null;
private JLabel labelOutline;
private JLabel targetColor;
private JSlider tolerance;
private JProgressBar progress;
private SwingWorker sw;
public ImageOutline(BufferedImage image) {
this.image = image;
imageTwoTone = new BufferedImage(
image.getWidth(),
image.getHeight(),
BufferedImage.TYPE_INT_RGB);
}
public void drawOutline() {
if (areaOutline!=null) {
Graphics2D g = imageOutline.createGraphics();
g.setColor(Color.WHITE);
g.fillRect(0,0,imageOutline.getWidth(),imageOutline.getHeight());
g.setColor(Color.RED);
g.setClip(areaOutline);
g.fillRect(0,0,imageOutline.getWidth(),imageOutline.getHeight());
g.setColor(Color.BLACK);
g.setClip(null);
g.draw(areaOutline);
g.dispose();
}
}
public Area getOutline(Color target, BufferedImage bi) {
// construct the GeneralPath
GeneralPath gp = new GeneralPath();
boolean cont = false;
int targetRGB = target.getRGB();
for (int xx=0; xx<bi.getWidth(); xx++) {
for (int yy=0; yy<bi.getHeight(); yy++) {
if (bi.getRGB(xx,yy)==targetRGB) {
if (cont) {
gp.lineTo(xx,yy);
gp.lineTo(xx,yy+1);
gp.lineTo(xx+1,yy+1);
gp.lineTo(xx+1,yy);
gp.lineTo(xx,yy);
} else {
gp.moveTo(xx,yy);
}
cont = true;
} else {
cont = false;
}
}
cont = false;
}
gp.closePath();
// construct the Area from the GP & return it
return new Area(gp);
}
public JPanel getGui() {
JPanel images = new JPanel(new GridLayout(2,2,2,2));
JPanel gui = new JPanel(new BorderLayout(3,3));
JPanel originalImage = new JPanel(new BorderLayout(2,2));
final JLabel originalLabel = new JLabel(new ImageIcon(image));
targetColor = new JLabel("Target Color");
targetColor.setForeground(Color.RED);
targetColor.setBackground(Color.WHITE);
targetColor.setBorder(new LineBorder(Color.BLACK));
targetColor.setOpaque(true);
JPanel controls = new JPanel(new BorderLayout());
controls.add(targetColor, BorderLayout.WEST);
originalLabel.addMouseListener( new MouseAdapter() {
#Override
public void mouseEntered(MouseEvent me) {
originalLabel.setCursor(
Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR));
}
#Override
public void mouseExited(MouseEvent me) {
originalLabel.setCursor(Cursor.getDefaultCursor());
}
#Override
public void mouseClicked(MouseEvent me) {
int x = me.getX();
int y = me.getY();
Color c = new Color( image.getRGB(x,y) );
targetColor.setBackground( c );
updateImages();
}
});
originalImage.add(originalLabel);
tolerance = new JSlider(
JSlider.HORIZONTAL,
0,
255,
104
);
tolerance.addChangeListener( new ChangeListener() {
public void stateChanged(ChangeEvent ce) {
updateImages();
}
});
controls.add(tolerance, BorderLayout.CENTER);
gui.add(controls,BorderLayout.NORTH);
images.add(originalImage);
labelTwoTone = new JLabel(new ImageIcon(imageTwoTone));
images.add(labelTwoTone);
images.add(new JLabel("Smoothed Outline"));
imageOutline = new BufferedImage(
image.getWidth(),
image.getHeight(),
BufferedImage.TYPE_INT_RGB
);
labelOutline = new JLabel(new ImageIcon(imageOutline));
images.add(labelOutline);
updateImages();
progress = new JProgressBar();
gui.add(images, BorderLayout.CENTER);
gui.add(progress, BorderLayout.SOUTH);
return gui;
}
private void updateImages() {
if (sw!=null) {
sw.cancel(true);
}
sw = new SwingWorker() {
#Override
public String doInBackground() {
progress.setIndeterminate(true);
adjustTwoToneImage();
labelTwoTone.repaint();
areaOutline = getOutline(Color.BLACK, imageTwoTone);
drawOutline();
return "";
}
#Override
protected void done() {
labelOutline.repaint();
progress.setIndeterminate(false);
}
};
sw.execute();
}
public void adjustTwoToneImage() {
twoToneFilter = new TwoToneImageFilter(
targetColor.getBackground(),
tolerance.getValue());
Graphics2D g = imageTwoTone.createGraphics();
g.drawImage(image, twoToneFilter, 0, 0);
g.dispose();
}
public static void main(String[] args) throws Exception {
int size = 150;
final BufferedImage outline =
new BufferedImage(size,size,BufferedImage.TYPE_INT_RGB);
Graphics2D g = outline.createGraphics();
g.setColor(Color.WHITE);
g.fillRect(0,0,size,size);
g.setRenderingHint(
RenderingHints.KEY_DITHERING,
RenderingHints.VALUE_DITHER_ENABLE);
g.setRenderingHint(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
Polygon p = new Polygon();
p.addPoint(size/2, size/10);
p.addPoint(size-10, size-10);
p.addPoint(10, size-10);
Area a = new Area(p);
Rectangle r = new Rectangle(size/4, 8*size/10, size/2, 2*size/10);
a.subtract(new Area(r));
int radius = size/10;
Ellipse2D.Double c = new Ellipse2D.Double(
(size/2)-radius,
(size/2)-radius,
2*radius,
2*radius
);
a.subtract(new Area(c));
g.setColor(Color.BLACK);
g.fill(a);
ImageOutline io = new ImageOutline(outline);
JFrame f = new JFrame("Image Outline");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(io.getGui());
f.pack();
f.setResizable(false);
f.setLocationByPlatform(true);
f.setVisible(true);
}
}
class TwoToneImageFilter implements BufferedImageOp {
Color target;
int tolerance;
TwoToneImageFilter(Color target, int tolerance) {
this.target = target;
this.tolerance = tolerance;
}
private boolean isIncluded(Color pixel) {
int rT = target.getRed();
int gT = target.getGreen();
int bT = target.getBlue();
int rP = pixel.getRed();
int gP = pixel.getGreen();
int bP = pixel.getBlue();
return(
(rP-tolerance<=rT) && (rT<=rP+tolerance) &&
(gP-tolerance<=gT) && (gT<=gP+tolerance) &&
(bP-tolerance<=bT) && (bT<=bP+tolerance) );
}
public BufferedImage createCompatibleDestImage(
BufferedImage src,
ColorModel destCM) {
BufferedImage bi = new BufferedImage(
src.getWidth(),
src.getHeight(),
BufferedImage.TYPE_INT_RGB);
return bi;
}
public BufferedImage filter(
BufferedImage src,
BufferedImage dest) {
if (dest==null) {
dest = createCompatibleDestImage(src, null);
}
for (int x=0; x<src.getWidth(); x++) {
for (int y=0; y<src.getHeight(); y++) {
Color pixel = new Color(src.getRGB(x,y));
Color write = Color.BLACK;
if (isIncluded(pixel)) {
write = Color.WHITE;
}
dest.setRGB(x,y,write.getRGB());
}
}
return dest;
}
public Rectangle2D getBounds2D(BufferedImage src) {
return new Rectangle2D.Double(0, 0, src.getWidth(), src.getHeight());
}
public Point2D getPoint2D(
Point2D srcPt,
Point2D dstPt) {
// no co-ord translation
return srcPt;
}
public RenderingHints getRenderingHints() {
return null;
}
}

This is a big subject. You might find Depixelizing Pixel Art1 by Johannes Kopf & Dani Lischinski useful: it's readable, recent, includes a summary of previous work, and explains their approach in detail.
See also slides covering similar background and video(!).
Here are some screenshots from the document of 'nearest neighbor' vs. 'their technique'.

The most general version of this problem is one of the initial stages in most computer vision pipelines. It's called Image Segementation. It splits an image into regions of pixels considered to be visually identical. These regions are separated by "contours" (see for example this article), which amount to paths through the image running along pixel boundaries.
There is a simple recursive algorithm for representing contours as a polyline defined such that no point in it deviates more than some fixed amount (say max_dev) you get to pick. Normally it's 1/2 to 2 pixels.
function getPolyline(points [p0, p1, p2... pn] in a contour, max_dev) {
if n <= 1 (there are only one or two pixels), return the whole contour
Let pi, 0 <= i <= n, be the point farthest from the line segment p0<->pn
if distance(pi, p0<->pn) < max_dev
return [ p0 -> pn ]
else
return concat(getPolyline [ p0, ..., pi ], getPolyline [ pi, ..., pn] )
The thought behind this is that you seem to have cartoon-like images that are already segmented. So if you code a simple search that assembles the edge pixels into chains, you can use the algorithm above to convert them into line segment chains that will will be smooth. They can even be drawn with anti-aliasing.

If you already know the segment or edge try blurring with Gaussian or average or one of your own kernel and move to the edge you want to smooth.
This is a quick solution and may not suit best in complex images but for self drawn, its good.