Stretching Polygon to other Polygon with Java

Stretching Polygon to other Polygon with Java - java

My problem is that I have a rectangle presented with a small perspective, and I would like to stretch it back to be presented as a rectangle again.
To represent it visually, I currently have within my image something like the red shape, and I have 4 Points (each corner of this shape). As result I would like to have something like the blue shape, and I already have the Rectangle object for it.
I was wondering if there is a method to copy a polygon and draw it as another polygon stretched. I found something for Android (setPolyToPoly), but I couldn't find something like this for java.
Is there some reference or code sample that performs this operation, or maybe some idea how can I solve this problem?

I think I understand what you need: a so-called perspective transformation that can be applied to an image. Java has the built-in AffineTransform, but an affine transform always preserves the "parallelness" of lines, so you cannot use that.
Now if you search the web for "java perspective transformation", you will find lots of options like the JavaFX PerspectiveTransform, the JAI PerspectiveTransform. If you only need to stretch images, you can also use the JHLabs PerspectiveFilter and there are other options as well.

Here is some code that will turn stretch a polygon with four points to a rectangle.
public static Rectangle2D polyToRect(Polygon polygon) {
if (polygon.xpoints.length != 4 || polygon.ypoints.length != 4)
throw new IllegalArgumentException(
"More than four points, this cannot be fitted to a rectangle");
Rectangle2D rect = new Rectangle2D.Double();
for (int i = 0; i < 4; i++) {
Point2D point = new Point2D.Double(polygon.xpoints[i],
polygon.ypoints[i]);
rect.add(point);
}
return rect;
}
public static Polygon rectangleToPolygon(Rectangle2D rect) {
Polygon poly = new Polygon();
poly.addPoint((int) rect.getX(), (int) rect.getY());
poly.addPoint((int) (rect.getX() + rect.getWidth()), (int) rect.getY());
poly.addPoint((int) (rect.getX() + rect.getWidth()),
(int) (rect.getY() + rect.getHeight()));
poly.addPoint((int) rect.getX(), (int) (rect.getY() + rect.getHeight()));
return poly;
}
public static class drawPolyAndRect extends JPanel {
Polygon poly = new Polygon();
public drawPolyAndRect() {
poly.addPoint(0, 0);
poly.addPoint(400, 40);
poly.addPoint(400, 250);
poly.addPoint(0, 400);
}
#Override
#Transient
public Dimension getPreferredSize() {
return new Dimension(1000, 1000);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setColor(Color.green);
g2d.fill(poly);
Composite c = AlphaComposite.getInstance(AlphaComposite.SRC_OVER,
0.5f);
g2d.setColor(Color.blue);
g2d.setComposite(c);
Rectangle2D polyToRect = polyToRect(poly);
g2d.fill(polyToRect);
// displace for drawing
polyToRect.setFrame(polyToRect.getX() + 100,
polyToRect.getY() + 100, polyToRect.getWidth(),
polyToRect.getHeight());
Polygon polyToRectToPoly = rectangleToPolygon(polyToRect);
g2d.fill(polyToRectToPoly);
g2d.dispose();
}
}
public static void main(String[] args) {
JFrame frame = new JFrame("Poly to rect");
frame.getContentPane().add(new drawPolyAndRect());
frame.pack();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
Essentially this uses how adding points to an empty rectangle2d works, it constructs the smallest possible rectangle containing all four points, stretching the polygon. Check the second static method if you want the returned rectangle as a polygon. Picture:

A JavaFX based solution using a PerspectiveTransform as suggested by #lbalazscs answer.
Toggle Perspective switches on and off the perspective effect on the content.
Morph Perspective smoothly animates a transition between the perspective transformed and non-perspective transformed content.
import javafx.animation.*;
import javafx.application.*;
import javafx.beans.value.*;
import javafx.geometry.Pos;
import javafx.scene.*;
import javafx.scene.control.ToggleButton;
import javafx.scene.effect.PerspectiveTransform;
import javafx.scene.image.*;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.scene.text.*;
import javafx.stage.Stage;
import javafx.util.Duration;
public class PerspectiveMovement extends Application {
// perspective transformed group width and height.
private final int W = 280;
private final int H = 96;
// upper right and lower right co-ordinates of perspective transformed group.
private final int URY = 35;
private final int LRY = 65;
#Override public void start(Stage stage) {
final PerspectiveTransform perspectiveTransform = createPerspectiveTransform();
final Group group = new Group();
group.setCache(true);
setContent(group);
final ToggleButton perspectiveToggle = createToggle(
group,
perspectiveTransform
);
VBox layout = new VBox(10);
layout.setAlignment(Pos.CENTER);
layout.getChildren().setAll(
perspectiveToggle,
createMorph(perspectiveToggle, group, perspectiveTransform),
group
);
layout.setStyle("-fx-padding: 10px; -fx-background-color: rgb(17, 20, 25);");
stage.setScene(new Scene(layout));
stage.show();
}
private void setContent(Group group) {
Rectangle rect = new Rectangle(0, 5, W, 80);
rect.setFill(Color.web("0x3b596d"));
Text text = new Text();
text.setX(4.0);
text.setY(60.0);
text.setText("A long time ago");
text.setFill(Color.ALICEBLUE);
text.setFont(Font.font(null, FontWeight.BOLD, 36));
Image image = new Image(
"http://icons.iconarchive.com/icons/danrabbit/elementary/96/Star-icon.png"
);
ImageView imageView = new ImageView(image);
imageView.setX(50);
group.getChildren().addAll(rect, imageView, text);
}
private PerspectiveTransform createPerspectiveTransform() {
PerspectiveTransform perspectiveTransform = new PerspectiveTransform();
perspectiveTransform.setUlx(0.0);
perspectiveTransform.setUly(0.0);
perspectiveTransform.setUrx(W);
perspectiveTransform.setUry(URY);
perspectiveTransform.setLrx(W);
perspectiveTransform.setLry(LRY);
perspectiveTransform.setLlx(0.0);
perspectiveTransform.setLly(H);
return perspectiveTransform;
}
private ToggleButton createToggle(final Group group, final PerspectiveTransform perspectiveTransform) {
final ToggleButton toggle = new ToggleButton("Toggle Perspective");
toggle.selectedProperty().addListener(new ChangeListener<Boolean>() {
#Override public void changed(ObservableValue<? extends Boolean> observable, Boolean wasSelected, Boolean selected) {
if (selected) {
perspectiveTransform.setUry(URY);
perspectiveTransform.setLry(LRY);
group.setEffect(perspectiveTransform);
} else {
group.setEffect(null);
}
}
});
return toggle;
}
private ToggleButton createMorph(final ToggleButton perspectiveToggle, final Group group, final PerspectiveTransform perspectiveTransform) {
final Timeline distorter = new Timeline(
new KeyFrame(
Duration.seconds(0),
new KeyValue(perspectiveTransform.uryProperty(), 0, Interpolator.LINEAR),
new KeyValue(perspectiveTransform.lryProperty(), H, Interpolator.LINEAR)
),
new KeyFrame(
Duration.seconds(3),
new KeyValue(perspectiveTransform.uryProperty(), URY, Interpolator.LINEAR),
new KeyValue(perspectiveTransform.lryProperty(), LRY, Interpolator.LINEAR)
)
);
final ToggleButton morphToggle = new ToggleButton("Morph Perspective");
morphToggle.selectedProperty().addListener(new ChangeListener<Boolean>() {
#Override public void changed(ObservableValue<? extends Boolean> observable, Boolean wasSelected, Boolean selected) {
if (!perspectiveToggle.isSelected()) {
perspectiveToggle.fire();
}
if (selected) {
distorter.setRate(1);
distorter.play();
} else {
distorter.setRate(-1);
distorter.play();
}
}
});
return morphToggle;
}
}

I don't know if this could help you but let me give you what i made with what i understand:
import javax.swing.*;
import java.awt.*;
public class PolyToRectangle extends JPanel {
public static final int SPEED = 50; //less = more fast.
private int ax = 0, bx = 800, cx = 800, dx = 0,
ay = 0, by = 40, cy = 250, dy = 400;
private Polygon poly;
public PolyToRectangle() {
setPreferredSize(new Dimension(1200, 720));
poly = new Polygon(new int[]{ax, bx, cx, dx}, new int[]{ay, by, cy, dy}, 4);
}
#Override
public void paintComponent(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
g2d.draw(poly);
g2d.fill(poly);
}
public void polyToRectangle() throws InterruptedException {
int flag = 0;
for (int i = 0; i < 150; i++) {
flag++;
poly.addPoint(ax, ay);
poly.addPoint(bx, (by = flag % 3 == 0 ? --by : by));
poly.addPoint(cx, cy++);
poly.addPoint(dx, dy);
Thread.sleep(SPEED);
repaint();
}
}
protected void clear(Graphics g) {
super.paintComponent(g);
}
public static void main(String[] args) throws InterruptedException {
Frame frame = new JFrame();
PolyToRectangle se = new PolyToRectangle();
frame.add(se);
frame.pack();
frame.setVisible(true);
se.polyToRectangle();
}
}
Ok as you can see this code is more a "PolyToSquare" more than PolyToRectangle, but the main was to show the "effect" of repainting with a Thread.sleep in a for, maybe that's the "visual stretch" you are talking about, note that the numbers of iterations on the for depends on numbers of pixels from point 1 and 2 to "stretch" from polygon to rectangle, this is a "hand made" effect, maybe what #lbalazscs is suggesting is the best solution, hope to be helpful, regards.
EDIT: edited the code to be more clean and to follow in a more specific way your goal
(now is more a PolyToRectangle, fixed the bx and cx values).

Related

Clearing the screen for new graphics in Java (awt)

I have this code which is basically a home menu with two clickable rectangles.
Start Game
Info
Start Game works fine.
Info is what is not really working. When pressed, the info screen will appear, but the home menu buttons will still be there though not visible (can be clicked).. it seems that when the info menu is appearing, the home menu buttons are not getting cleared.
Also, any point on the info menu is clickable and will show the home menu again. (not what intended, only the back buttons should do that).
How can I fix those problems ?
package test;
import javax.swing.*;
import java.awt.*;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.font.FontRenderContext;
import java.awt.font.TextLayout;
import java.awt.geom.Rectangle2D;
import java.awt.image.ImageObserver;
import java.awt.image.ImageProducer;
public class HomeMenu extends JComponent implements MouseListener, MouseMotionListener {
private static final String GAME_TITLE = "BRICK DESTROY";
private static final String START_TEXT = "START";
private static final String INFO_TEXT = "INFO";
private static final String howtoPlay = """
1- Click Start\n
2- Choose the mode\n
3- Each mode has 3 levels\n
4- To play/pause press space, use 'A' and 'D' to move\n
5- To open pause menu press 'ESC'\n
6- To open DebugPanel press 'ALT-SHIFT-F1'""";
private static final String backText = "BACK";
private static final Color BORDER_COLOR = new Color(200,8,21); //Venetian Red
private static final Color DASH_BORDER_COLOR = new Color(255, 216, 0);//school bus yellow
private static final Color TEXT_COLOR = new Color(255, 255, 255);//white
private static final Color CLICKED_BUTTON_COLOR = Color.ORANGE.darker();;
private static final Color CLICKED_TEXT = Color.ORANGE.darker();
private static final int BORDER_SIZE = 5;
private static final float[] DASHES = {12,6};
private Rectangle menuFace;
private Rectangle infoFace;
private Rectangle startButton;
private Rectangle infoButton;
private Rectangle backButton;
private BasicStroke borderStoke;
private BasicStroke borderStoke_noDashes;
private Image img = Toolkit.getDefaultToolkit().createImage("1.jpeg");
private Font gameTitleFont;
private Font infoFont;
private Font buttonFont;
private Font howtoPlayFont;
private GameFrame owner;
private boolean startClicked;
private boolean infoClicked = false;
private boolean backClicked = false;
public HomeMenu(GameFrame owner,Dimension area){
this.setFocusable(true);
this.requestFocusInWindow();
this.addMouseListener(this);
this.addMouseMotionListener(this);
this.owner = owner;
menuFace = new Rectangle(new Point(0,0),area);
infoFace = new Rectangle(new Point(0,0),area);
this.setPreferredSize(area);
Dimension btnDim = new Dimension(area.width / 3, area.height / 12);
startButton = new Rectangle(btnDim);
infoButton = new Rectangle(btnDim);
backButton = new Rectangle(btnDim);
borderStoke = new BasicStroke(BORDER_SIZE,BasicStroke.CAP_ROUND,BasicStroke.JOIN_ROUND,0,DASHES,0);
borderStoke_noDashes = new BasicStroke(BORDER_SIZE,BasicStroke.CAP_ROUND,BasicStroke.JOIN_ROUND);
gameTitleFont = new Font("Calibri",Font.BOLD,28);
infoFont = new Font("Calibri",Font.BOLD,24);
buttonFont = new Font("Calibri",Font.BOLD,startButton.height-2);
howtoPlayFont = new Font("Calibri",Font.PLAIN,14);
}
public void paint(Graphics g){
drawMenu((Graphics2D)g);
}
public void drawMenu(Graphics2D g2d){
if(infoClicked) {
drawInfoMenu(g2d);
return;
}else{
drawContainer(g2d);
Color prevColor = g2d.getColor();
Font prevFont = g2d.getFont();
double x = menuFace.getX();
double y = menuFace.getY();
g2d.translate(x,y);
//methods calls
drawText(g2d);
drawButton(g2d);
//end of methods calls
g2d.translate(-x,-y);
g2d.setFont(prevFont);
g2d.setColor(prevColor);
}
Toolkit.getDefaultToolkit().sync();
}
private void drawContainer(Graphics2D g2d){
Color prev = g2d.getColor();
//g2d.setColor(BG_COLOR);
g2d.drawImage(img,0,0,menuFace.width,menuFace.height,this);
//g2d.fill(menuFace);
Stroke tmp = g2d.getStroke();
g2d.setStroke(borderStoke_noDashes);
g2d.setColor(DASH_BORDER_COLOR);
g2d.draw(menuFace);
g2d.setStroke(borderStoke);
g2d.setColor(BORDER_COLOR);
g2d.draw(menuFace);
g2d.setStroke(tmp);
g2d.setColor(prev);
}
private void drawText(Graphics2D g2d){
g2d.setColor(TEXT_COLOR);
FontRenderContext frc = g2d.getFontRenderContext();
Rectangle2D gameTitleRect = gameTitleFont.getStringBounds(GAME_TITLE,frc);
int sX,sY;
sY = (int)(menuFace.getHeight() / 4);
sX = (int)(menuFace.getWidth() - gameTitleRect.getWidth()) / 2;
sY += (int) gameTitleRect.getHeight() * 1.1;//add 10% of String height between the two strings
g2d.setFont(gameTitleFont);
g2d.drawString(GAME_TITLE,sX,sY);
}
private void drawButton(Graphics2D g2d){
FontRenderContext frc = g2d.getFontRenderContext();
Rectangle2D txtRect = buttonFont.getStringBounds(START_TEXT,frc);
Rectangle2D mTxtRect = buttonFont.getStringBounds(INFO_TEXT,frc);
g2d.setFont(buttonFont);
int x = (menuFace.width - startButton.width) / 2;
int y =(int) ((menuFace.height - startButton.height) * 0.5);
startButton.setLocation(x,y);
x = (int)(startButton.getWidth() - txtRect.getWidth()) / 2;
y = (int)(startButton.getHeight() - txtRect.getHeight()) / 2;
x += startButton.x;
y += startButton.y + (startButton.height * 0.9);
if(startClicked){
Color tmp = g2d.getColor();
g2d.setColor(CLICKED_BUTTON_COLOR);
g2d.draw(startButton);
g2d.setColor(CLICKED_TEXT);
g2d.drawString(START_TEXT,x,y);
g2d.setColor(tmp);
}
else{
g2d.draw(startButton);
g2d.drawString(START_TEXT,x,y);
}
x = startButton.x;
y = startButton.y;
y *= 1.3;
infoButton.setLocation(x,y);
x = (int)(infoButton.getWidth() - mTxtRect.getWidth()) / 2;
y = (int)(infoButton.getHeight() - mTxtRect.getHeight()) / 2;
x += infoButton.getX();
y += infoButton.getY() + (startButton.height * 0.9);
if(infoClicked){
Color tmp = g2d.getColor();
g2d.setColor(CLICKED_BUTTON_COLOR);
g2d.draw(infoButton);
g2d.setColor(CLICKED_TEXT);
g2d.drawString(INFO_TEXT,x,y);
g2d.setColor(tmp);
}
else{
g2d.draw(infoButton);
g2d.drawString(INFO_TEXT,x,y);
}
}
private void drawInfoMenu(Graphics2D g2d){
FontRenderContext frc = g2d.getFontRenderContext();
Rectangle2D infoRec = infoFont.getStringBounds(INFO_TEXT,frc);
Color prev = g2d.getColor();
Stroke tmp = g2d.getStroke();
g2d.setStroke(borderStoke_noDashes);
g2d.setColor(DASH_BORDER_COLOR);
g2d.draw(infoFace);
g2d.setStroke(borderStoke);
g2d.setColor(BORDER_COLOR);
g2d.draw(infoFace);
g2d.fillRect(0,0,infoFace.width,infoFace.height);
g2d.setStroke(tmp);
g2d.setColor(prev);
g2d.setColor(TEXT_COLOR);
int sX,sY;
sY = (int)(infoFace.getHeight() / 15);
sX = (int)(infoFace.getWidth() - infoRec.getWidth()) / 2;
sY += (int) infoRec.getHeight() * 1.1;//add 10% of String height between the two strings
g2d.setFont(infoFont);
g2d.drawString(INFO_TEXT,sX,sY);
TextLayout layout = new TextLayout(howtoPlay, howtoPlayFont, frc);
String[] outputs = howtoPlay.split("\n");
for(int i=0; i<outputs.length; i++) {
g2d.setFont(howtoPlayFont);
g2d.drawString(outputs[i], 40, (int) (80 + i * layout.getBounds().getHeight() + 0.5));
}
backButton.setLocation(getWidth()/3,getHeight()-50);
int x = (int)(backButton.getWidth() - infoRec.getWidth()) / 2;
int y = (int)(backButton.getHeight() - infoRec.getHeight()) / 2;
x += backButton.x+11;
y += backButton.y + (layout.getBounds().getHeight() * 1.35);
backButton.setLocation(getWidth()/3,getHeight()-50);
if(backClicked){
Color tmp1 = g2d.getColor();
g2d.setColor(CLICKED_BUTTON_COLOR);
g2d.draw(backButton);
g2d.setColor(CLICKED_TEXT);
g2d.drawString(backText,x,y);
g2d.setColor(tmp1);
infoClicked = false;
repaint();
}
else{
g2d.draw(backButton);
g2d.drawString(backText,x,y);
}
}
#Override
public void mouseClicked(MouseEvent mouseEvent) {
Point p = mouseEvent.getPoint();
if(startButton.contains(p)){
owner.enableGameBoard();
}
else if(infoButton.contains(p)){
infoClicked = true;
}
else if(backButton.contains(p)){
infoClicked = false;
}
repaint();
}
#Override
public void mousePressed(MouseEvent mouseEvent) {
Point p = mouseEvent.getPoint();
if(startButton.contains(p)){
startClicked = true;
repaint(startButton.x,startButton.y,startButton.width+1,startButton.height+1);
}
else if(infoButton.contains(p)){
infoClicked = true;
}
else if(backButton.contains(p)){
infoClicked = false;
}
repaint();
}
#Override
public void mouseReleased(MouseEvent mouseEvent) {
if(startClicked){
startClicked = false;
repaint(startButton.x,startButton.y,startButton.width+1,startButton.height+1);
}
else if(infoClicked){
infoClicked = false;
}
else if(backClicked){
infoClicked = true;
}
repaint();
}
#Override
public void mouseEntered(MouseEvent mouseEvent) {
}
#Override
public void mouseExited(MouseEvent mouseEvent) {
}
#Override
public void mouseDragged(MouseEvent mouseEvent) {
}
#Override
public void mouseMoved(MouseEvent mouseEvent) {
Point p = mouseEvent.getPoint();
if(startButton.contains(p) || infoButton.contains(p) || backButton.contains(p)) {
this.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
}
else {
this.setCursor(Cursor.getDefaultCursor());
}
}
}
Here are the images of both windows
main menu
info menu, pressing anywhere = back to home menu, pressing roughly in the middle = start game or back to main menu too

First read, Performing Custom Painting and Painting in AWT and Swing to get a better understanding how painting in Swing works and how you're suppose to work with it.
But I already have ...
public void paint(Graphics g){
drawMenu((Graphics2D)g);
}
would suggest otherwise. Seriously, go read those links so you understand all the issues that the above decision is going to create for you.
You're operating in a OO language, you need to take advantage of that and decouple your code and focus on the "single responsibility" principle.
I'm kind of tired of talking about it, so you can do some reading:
https://softwareengineering.stackexchange.com/questions/244476/what-is-decoupling-and-what-development-areas-can-it-apply-to
Cohesion and Decoupling, what do they represent?
Single Responsibility Principle
Single Responsibility Principle in Java with Examples
SOLID Design Principles Explained: The Single Responsibility Principle
These are basic concepts you really need to understand as they will make your live SOOO much easier and can be applied to just about any language.
As an example, from your code...
public HomeMenu(GameFrame owner,Dimension area){
//...
this.setPreferredSize(area);
There is no good reason (other than laziness (IMHO)) that any caller should be telling a component what size it should be, that's not their responsibility. It's the responsibility of the component to tell the parent container how big it would like to be and for the parent component to figure out how it's going to achieve that (or ignore it as the case may be).
The "basic" problem you're having is a simple one. Your "God" class is simply trying to do too much (ie it's taken on too much responsibility). Now we "could" add a dozen or more flags into the code to compensate for this, which is just going to increase the coupling and complexity, making it harder to understand and maintain, or we can take a step back, break it down into individual areas of responsibility and build the solution around those, for example...
import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.Stroke;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.font.FontRenderContext;
import java.awt.font.TextLayout;
import java.awt.geom.Rectangle2D;
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.JLabel;
import javax.swing.JPanel;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
frame.add(new HomePane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class HomePane extends JPanel {
public HomePane() {
setLayout(new BorderLayout());
navigateToMenu();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 400);
}
protected void navigateToMenu() {
removeAll();
HomeMenuPane pane = new HomeMenuPane(new HomeMenuPane.NavigationListener() {
#Override
public void navigateToInfo(HomeMenuPane source) {
HomePane.this.navigateToInfo();
}
#Override
public void navigateToStartGame(HomeMenuPane source) {
startGame();
}
});
add(pane);
revalidate();
repaint();
}
protected void navigateToInfo() {
removeAll();
HowToPlayPane pane = new HowToPlayPane(new HowToPlayPane.NavigationListener() {
#Override
public void navigateBack(HowToPlayPane source) {
navigateToMenu();
}
});
add(pane);
revalidate();
repaint();
}
protected void startGame() {
removeAll();
add(new JLabel("This is pretty awesome, isn't it!", JLabel.CENTER));
revalidate();
repaint();
}
}
public abstract class AbstractBaseMenuPane extends JPanel {
protected static final Color BORDER_COLOR = new Color(200, 8, 21); //Venetian Red
protected static final Color DASH_BORDER_COLOR = new Color(255, 216, 0);//school bus yellow
protected static final Color TEXT_COLOR = new Color(255, 255, 255);//white
protected static final Color CLICKED_BUTTON_COLOR = Color.ORANGE.darker();
protected static final Color CLICKED_TEXT = Color.ORANGE.darker();
protected static final int BORDER_SIZE = 5;
protected static final float[] DASHES = {12, 6};
private Rectangle border;
private BasicStroke borderStoke;
private BasicStroke borderStoke_noDashes;
private BufferedImage backgroundImage;
public AbstractBaseMenuPane() {
borderStoke = new BasicStroke(BORDER_SIZE, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND, 0, DASHES, 0);
borderStoke_noDashes = new BasicStroke(BORDER_SIZE, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND);
border = new Rectangle(new Point(0, 0), getPreferredSize());
// You are now responsible for filling the background
setOpaque(false);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 400);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
BufferedImage backgroundImage = getBackgroundImage();
if (backgroundImage != null) {
g2d.drawImage(backgroundImage, 0, 0, getWidth(), getHeight(), this);
}
Color prev = g2d.getColor();
Stroke tmp = g2d.getStroke();
g2d.setStroke(borderStoke_noDashes);
g2d.setColor(DASH_BORDER_COLOR);
g2d.draw(border);
g2d.setStroke(borderStoke);
g2d.setColor(BORDER_COLOR);
g2d.draw(border);
g2d.dispose();
}
public void setBackgroundImage(BufferedImage backgroundImage) {
this.backgroundImage = backgroundImage;
repaint();
}
public BufferedImage getBackgroundImage() {
return backgroundImage;
}
}
public class HomeMenuPane extends AbstractBaseMenuPane {
public static interface NavigationListener {
public void navigateToInfo(HomeMenuPane source);
public void navigateToStartGame(HomeMenuPane source);
}
private static final String GAME_TITLE = "BRICK DESTROY";
private static final String START_TEXT = "START";
private static final String INFO_TEXT = "INFO";
private Rectangle startButton;
private Rectangle infoButton;
private Font gameTitleFont;
private Font buttonFont;
// Don't do this, this just sucks (for so many reasons)
// Use ImageIO.read instead and save yourself a load of frustration
//private Image img = Toolkit.getDefaultToolkit().createImage("1.jpeg");
private Point lastClickPoint;
private NavigationListener navigationListener;
public HomeMenuPane(NavigationListener navigationListener) {
this.navigationListener = navigationListener;
try {
setBackgroundImage(ImageIO.read(getClass().getResource("/images/BrickWall.jpg")));
} catch (IOException ex) {
Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
}
this.addMouseListener(new MouseAdapter() {
#Override
public void mousePressed(MouseEvent mouseEvent) {
Point p = mouseEvent.getPoint();
lastClickPoint = p;
if (startButton.contains(p)) {
peformStartGameAction();
} else if (infoButton.contains(p)) {
performInfoAction();
}
repaint();
}
#Override
public void mouseReleased(MouseEvent mouseEvent) {
lastClickPoint = null;
repaint();
}
});
this.addMouseMotionListener(new MouseAdapter() {
#Override
public void mouseMoved(MouseEvent mouseEvent) {
Point p = mouseEvent.getPoint();
if (startButton.contains(p) || infoButton.contains(p)) {
setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
} else {
setCursor(Cursor.getDefaultCursor());
}
}
});
Dimension area = getPreferredSize();
Dimension btnDim = new Dimension(area.width / 3, area.height / 12);
startButton = new Rectangle(btnDim);
infoButton = new Rectangle(btnDim);
gameTitleFont = new Font("Calibri", Font.BOLD, 28);
buttonFont = new Font("Calibri", Font.BOLD, startButton.height - 2);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
Color prevColor = g2d.getColor();
Font prevFont = g2d.getFont();
//methods calls
drawText(g2d);
drawButton(g2d);
//end of methods calls
g2d.setFont(prevFont);
g2d.setColor(prevColor);
g2d.dispose();
}
private void drawText(Graphics2D g2d) {
g2d.setColor(TEXT_COLOR);
FontRenderContext frc = g2d.getFontRenderContext();
Rectangle2D gameTitleRect = gameTitleFont.getStringBounds(GAME_TITLE, frc);
int sX, sY;
sY = (int) (getHeight() / 4);
sX = (int) (getWidth() - gameTitleRect.getWidth()) / 2;
sY += (int) gameTitleRect.getHeight() * 1.1;//add 10% of String height between the two strings
g2d.setFont(gameTitleFont);
g2d.drawString(GAME_TITLE, sX, sY);
}
private void drawButton(Graphics2D g2d) {
FontRenderContext frc = g2d.getFontRenderContext();
Rectangle2D txtRect = buttonFont.getStringBounds(START_TEXT, frc);
Rectangle2D mTxtRect = buttonFont.getStringBounds(INFO_TEXT, frc);
g2d.setFont(buttonFont);
int x = (getWidth() - startButton.width) / 2;
int y = (int) ((getHeight() - startButton.height) * 0.5);
startButton.setLocation(x, y);
x = (int) (startButton.getWidth() - txtRect.getWidth()) / 2;
y = (int) (startButton.getHeight() - txtRect.getHeight()) / 2;
x += startButton.x;
y += startButton.y + (startButton.height * 0.9);
if (lastClickPoint != null && startButton.contains(lastClickPoint)) {
Color tmp = g2d.getColor();
g2d.setColor(CLICKED_BUTTON_COLOR);
g2d.draw(startButton);
g2d.setColor(CLICKED_TEXT);
g2d.drawString(START_TEXT, x, y);
g2d.setColor(tmp);
} else {
g2d.draw(startButton);
g2d.drawString(START_TEXT, x, y);
}
x = startButton.x;
y = startButton.y;
y *= 1.3;
infoButton.setLocation(x, y);
x = (int) (infoButton.getWidth() - mTxtRect.getWidth()) / 2;
y = (int) (infoButton.getHeight() - mTxtRect.getHeight()) / 2;
x += infoButton.getX();
y += infoButton.getY() + (startButton.height * 0.9);
if (lastClickPoint != null && infoButton.contains(lastClickPoint)) {
Color tmp = g2d.getColor();
g2d.setColor(CLICKED_BUTTON_COLOR);
g2d.draw(infoButton);
g2d.setColor(CLICKED_TEXT);
g2d.drawString(INFO_TEXT, x, y);
g2d.setColor(tmp);
} else {
g2d.draw(infoButton);
g2d.drawString(INFO_TEXT, x, y);
}
}
protected void peformStartGameAction() {
navigationListener.navigateToStartGame(this);
}
protected void performInfoAction() {
navigationListener.navigateToInfo(this);
}
}
public class HowToPlayPane extends AbstractBaseMenuPane {
public static interface NavigationListener {
public void navigateBack(HowToPlayPane source);
}
private static final String HOW_TO_PLAY_TEXT = """
1- Click Start\n
2- Choose the mode\n
3- Each mode has 3 levels\n
4- To play/pause press space, use 'A' and 'D' to move\n
5- To open pause menu press 'ESC'\n
6- To open DebugPanel press 'ALT-SHIFT-F1'""";
private static final String BACK_TEXT = "BACK";
private static final String INFO_TEXT = "INFO";
private Rectangle backButton;
private boolean backClicked = false;
private Font infoFont;
private Font howtoPlayFont;
private NavigationListener navigationListener;
public HowToPlayPane(NavigationListener navigationListener) {
this.navigationListener = navigationListener;
this.addMouseListener(new MouseAdapter() {
#Override
public void mousePressed(MouseEvent mouseEvent) {
Point p = mouseEvent.getPoint();
if (backButton.contains(p)) {
backClicked = true;
repaint();
performBackAction();
}
}
#Override
public void mouseReleased(MouseEvent e) {
backClicked = false;
}
});
this.addMouseMotionListener(new MouseAdapter() {
#Override
public void mouseMoved(MouseEvent mouseEvent) {
Point p = mouseEvent.getPoint();
if (backButton.contains(p)) {
setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
} else {
setCursor(Cursor.getDefaultCursor());
}
}
});
Dimension btnDim = new Dimension(getPreferredSize().width / 3, getPreferredSize().height / 12);
backButton = new Rectangle(btnDim);
infoFont = new Font("Calibri", Font.BOLD, 24);
howtoPlayFont = new Font("Calibri", Font.PLAIN, 14);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 400);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setColor(BORDER_COLOR);
g2d.fillRect(0, 0, getWidth(), getHeight());
FontRenderContext frc = g2d.getFontRenderContext();
Rectangle2D infoRec = infoFont.getStringBounds(INFO_TEXT, frc);
//
// Color prev = g2d.getColor();
//
// Stroke tmp = g2d.getStroke();
//
// g2d.setStroke(borderStoke_noDashes);
// g2d.setColor(DASH_BORDER_COLOR);
// g2d.draw(infoFace);
//
// g2d.setStroke(borderStoke);
// g2d.setColor(BORDER_COLOR);
// g2d.draw(infoFace);
//
// g2d.fillRect(0, 0, infoFace.width, infoFace.height);
//
// g2d.setStroke(tmp);
//
// g2d.setColor(prev);
//
g2d.setColor(TEXT_COLOR);
int sX, sY;
sY = (int) (getHeight() / 15);
sX = (int) (getWidth() - infoRec.getWidth()) / 2;
sY += (int) infoRec.getHeight() * 1.1;//add 10% of String height between the two strings
g2d.setFont(infoFont);
g2d.drawString(INFO_TEXT, sX, sY);
TextLayout layout = new TextLayout(HOW_TO_PLAY_TEXT, howtoPlayFont, frc);
String[] outputs = HOW_TO_PLAY_TEXT.split("\n");
for (int i = 0; i < outputs.length; i++) {
g2d.setFont(howtoPlayFont);
g2d.drawString(outputs[i], 40, (int) (80 + i * layout.getBounds().getHeight() + 0.5));
}
backButton.setLocation(getWidth() / 3, getHeight() - 50);
int x = (int) (backButton.getWidth() - infoRec.getWidth()) / 2;
int y = (int) (backButton.getHeight() - infoRec.getHeight()) / 2;
x += backButton.x + 11;
y += backButton.y + (layout.getBounds().getHeight() * 1.35);
backButton.setLocation(getWidth() / 3, getHeight() - 50);
if (backClicked) {
Color tmp1 = g2d.getColor();
g2d.setColor(CLICKED_BUTTON_COLOR);
g2d.draw(backButton);
g2d.setColor(CLICKED_TEXT);
g2d.drawString(BACK_TEXT, x, y);
g2d.setColor(tmp1);
repaint();
} else {
g2d.draw(backButton);
g2d.drawString(BACK_TEXT, x, y);
}
g2d.dispose();
}
protected void performBackAction() {
navigationListener.navigateBack(this);
}
}
}
Now, this example makes use of components to present different views (it even has a nice abstract implementation to allow for code re-use 😱), but it occurs to me, that, if you "really" wanted to, you could have a series of "painter" classes, which could be used to delegate the painting of the current state to, and mouse clicks/movements could be delegated to, meaning you could have a single component, which would simple delegate the painting (via the paintComponent method) to which ever painter is active.
And, wouldn't you know it, they have a design principle for that to, the Delegation Pattern
The above example also makes use of the observer pattern, so you might want to have a look into that as well

java changing panel field of view

I am trying to create a simple Java 2D physics game, and the current problem that I am running into is that I cannot think of a way to center the camera on the spaceship as it moves around.
I have the model of the ship as a component in the panel Universe which is in the frame main. Currently the panel displays the pixels from (0, 0) to (1000, 1000).
What I want to happen, is if the ship moves 10 pixels to the right, then the panel will display pixels from (10, 0) to (1010, 1000), following the ship, but remaining rigid in the frame.
Or maybe there is a better way to achieve a similar effect.
This is the relevant part I believe:
public class Main extends JFrame {
public static void main(String[] args) {
M = new Main(1000, 1000);
}
public Main(int width, int height) {
boardWidth = width;
boardHeight = height;
FRAMERATE = 60;
setSize(boardWidth, boardHeight);
setTitle("space");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
createUniverse();
createShip();
runThreads();
}
private void createUniverse() {
U = new Universe();
U.setLayout(new BorderLayout());
add(U, BorderLayout.CENTER);
}
private void createShip() {
U.createShip();
}
private void runThreads() {
ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(5);
long lengthOfFrame = (long) (1000 / FRAMERATE);
executor.scheduleAtFixedRate(new Input(U.getShip(), FRAMERATE), 0L, lengthOfFrame, TimeUnit.MILLISECONDS);
executor.scheduleAtFixedRate(new UpdatePhysics(U.getObjects(), FRAMERATE), 0L, lengthOfFrame, TimeUnit.MILLISECONDS);
executor.scheduleAtFixedRate(new RepaintFrame(this), 0L, lengthOfFrame, TimeUnit.MILLISECONDS);
this.addKeyListener(new UserInput());
}
}
That is the JFrame that holds this panel:
public class Universe extends JPanel {
public Universe() {
setSize(Main.boardWidth, Main.boardHeight);
setBackground(Color.BLACK);
setVisible(true);
}
public void createShip() {
ship = new Ship(new double[]{getWidth() / 2, getHeight() / 2});
shipM = new ShipModel(ship);
_objects = new MassiveObject[1];
_objects[0] = ship;
add(shipM, BorderLayout.CENTER);
}
}
The ShipModel is just a Java component that is represented by a few polygons.
The frame is painted by the thread in Main which basically just calls Main.repaint() repeatedly.
I think thats all the relevant bits. My bad for the link, never posted before.

My suggestion would be to go a different route, or at least a slightly different route.
You definitely do not want to retrieve pixels from the picture and draw the new pixels every frame (you will draw the pixels every frame, but getting pixels every tick will slow you down)
You could load the background image altogether (which you are likely already doing from your abstract description) and then move that background image's position according to button presses. The ship would always be rendered in the middle. (The edges of the background image is where this gets tricky -- a whole other challenge to tackle)
There is also the option of splitting the background image into tiles and moving those accordingly.
I've done both of the above, and since I wanted the background image to be extremely large, it only moved smoothly after I split it up into tiles programmatically, storing it in memory and rending each tile according to the position.
Like I said, the edges are where it gets tricky if you want your spaceship to move to the edge. If you just show infinite black behind the background image and you don't mind showing that, then you can just keep the same physics and have only half of the screen showing the background image.
So summary, just move the background image within the frame/panel accordingly.
Your question was not super clear and linking to your code is not great practice on Stack Overflow (it's better to include the relevant code snippets in your post using backticks like this:
This is code, I used backticks to surround it
That makes it scroll if it's long.

Consider placing your background image within a JScrollPane, remove the scrollbars by setting the appropriate scrolling policy:
scrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_NEVER);
You can move the image held within the JScrollPane by calling
backgroundLabel.scrollRectToVisible(rect);
and change the location of this rect based on button presses.
For example:
import java.awt.Dimension;
import java.awt.Graphics2D;
import java.awt.GridBagLayout;
import java.awt.Rectangle;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.*;
#SuppressWarnings("serial")
public class SideScroll extends JLayeredPane {
public static final String BG_IMG_PATH = "https://upload.wikimedia.org/wikipedia/commons"
+ "/a/ad/Tomada_da_cidade_de_S%C3%A3o_Salvador_s%C3%A9culo_XVIII_%28panor%C3%A2mico%29.jpg";
public static final String CAMEL_PATH = "https://upload.wikimedia.org/wikipedia/commons/thumb/3/33/PEO-bactrian_camel.svg/200px-PEO-bactrian_camel.svg.png";
private static final int PREF_W = 800;
private static final int PREF_H = 650;
protected static final int SCALE = 10;
private JLabel backgroundLabel = new JLabel();
JScrollPane scrollPane = new JScrollPane(backgroundLabel);
private JLabel camelLabel = new JLabel();
public SideScroll(Icon bgIcon, Icon camelIcon) {
camelLabel.setIcon(camelIcon);
camelLabel.setSize(camelLabel.getPreferredSize());
JPanel camelPanel = new JPanel(new GridBagLayout());
camelPanel.setOpaque(false);
camelPanel.add(camelLabel);
camelPanel.setSize(getPreferredSize());
backgroundLabel.setIcon(bgIcon);
scrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_NEVER);
scrollPane.setSize(getPreferredSize());
add(scrollPane, JLayeredPane.DEFAULT_LAYER);
add(camelPanel, JLayeredPane.PALETTE_LAYER);
setFocusable(true);
addKeyListener(new KeyAdapter() {
#Override
public void keyPressed(KeyEvent e) {
int keyCode = e.getKeyCode();
switch (keyCode) {
case KeyEvent.VK_LEFT:
moveImg(-1, 0);
break;
case KeyEvent.VK_RIGHT:
moveImg(1, 0);
break;
case KeyEvent.VK_UP:
moveImg(0, -1);
break;
case KeyEvent.VK_DOWN:
moveImg(0, 1);
break;
default:
break;
}
}
private void moveImg(int right, int down) {
Rectangle rect = backgroundLabel.getVisibleRect();
int x = rect.x + SCALE * right;
int y = rect.y + SCALE * down;
int width = rect.width;
int height = rect.height;
rect = new Rectangle(x, y, width, height);
backgroundLabel.scrollRectToVisible(rect);
}
});
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
private static void createAndShowGui() {
Icon bgIcon = null;
BufferedImage camel = null;
Icon camelIcon = null;
BufferedImage bgImg;
try {
URL bgImageUrl = new URL(BG_IMG_PATH);
URL camelUrl = new URL(CAMEL_PATH);
bgImg = ImageIO.read(bgImageUrl);
camel = ImageIO.read(camelUrl);
// make background one quarter the size because it's too big
int imgW = bgImg.getWidth() / 4;
int imgH = bgImg.getHeight() / 4;
BufferedImage bgImage2 = new BufferedImage(imgW, imgH, BufferedImage.TYPE_INT_ARGB);
Graphics2D g2 = bgImage2.createGraphics();
g2.drawImage(bgImg, 0, 0, imgW, imgH, null);
g2.dispose();
bgIcon = new ImageIcon(bgImage2);
// flip camel image so facing right
imgW = camel.getWidth();
imgH = camel.getHeight();
BufferedImage camelImg = new BufferedImage(imgW, imgH, BufferedImage.TYPE_INT_ARGB);
g2 = camelImg.createGraphics();
AffineTransform xform = AffineTransform.getTranslateInstance(imgW, 0);
xform.scale(-1, 1);
g2.drawImage(camel, xform, null);
g2.dispose();
camelIcon = new ImageIcon(camelImg);
} catch (IOException e) {
e.printStackTrace();
System.exit(-1);
}
JFrame frame = new JFrame("SideScroll");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new SideScroll(bgIcon, camelIcon));
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}

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.

How to implement oval GradientPaint?

We know that there are a class named RadialGradientPaint in Java and we can use it to have a gradient painting for circle.
But I want to have an oval (ellipse) GradientPaint. How to implement oval GradientPaint?

Use an AffineTransform when drawing the RadialGradientPaint. This would require a scale instance of the transform. It might end up looking something like this:
import java.awt.*;
import java.awt.MultipleGradientPaint.CycleMethod;
import java.awt.geom.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
public class OvalGradientPaint {
public static void main(String[] args) {
Runnable r = new Runnable() {
#Override
public void run() {
// the GUI as seen by the user (without frame)
JPanel gui = new JPanel(new BorderLayout());
gui.setBorder(new EmptyBorder(2, 3, 2, 3));
gui.add(new OvalGradientPaintSurface());
gui.setBackground(Color.WHITE);
JFrame f = new JFrame("Oval Gradient Paint");
f.add(gui);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// See http://stackoverflow.com/a/7143398/418556 for demo.
f.setLocationByPlatform(true);
// ensures the frame is the minimum size it needs to be
// in order display the components within it
f.pack();
// should be done last, to avoid flickering, moving,
// resizing artifacts.
f.setVisible(true);
}
};
// Swing GUIs should be created and updated on the EDT
// http://docs.oracle.com/javase/tutorial/uiswing/concurrency/initial.html
SwingUtilities.invokeLater(r);
}
}
class OvalGradientPaintSurface extends JPanel {
public int yScale = 150;
public int increment = 1;
RadialGradientPaint paint;
AffineTransform moveToOrigin;
OvalGradientPaintSurface() {
Point2D center = new Point2D.Float(100, 100);
float radius = 90;
float[] dist = {0.05f, .95f};
Color[] colors = {Color.RED, Color.MAGENTA.darker()};
paint = new RadialGradientPaint(center, radius, dist, colors,CycleMethod.REFLECT);
moveToOrigin = AffineTransform.
getTranslateInstance(-100d, -100d);
ActionListener listener = new ActionListener() {
#Override
public void actionPerformed(ActionEvent ae) {
if (increment < 0) {
increment = (yScale < 50 ? -increment : increment);
} else {
increment = (yScale > 150 ? -increment : increment);
}
yScale += increment;
repaint();
}
};
Timer t = new Timer(15, listener);
t.start();
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
AffineTransform moveToCenter = AffineTransform.
getTranslateInstance(getWidth()/2d, getHeight()/2d);
g2.setPaint(paint);
double y = yScale/100d;
double x = 1/y;
AffineTransform at = AffineTransform.getScaleInstance(x, y);
// We need to move it to the origin, scale, and move back.
// Counterintutitively perhaps, we concatentate 'in reverse'.
moveToCenter.concatenate(at);
moveToCenter.concatenate(moveToOrigin);
g2.setTransform(moveToCenter);
// fudge factor of 3 here, to ensure the scaling of the transform
// does not leave edges unpainted.
g2.fillRect(-getWidth(), -getHeight(), getWidth()*3, getHeight()*3);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(500, 200);
}
}
Original image: The original static (boring) 'screen shot' of the app.

RadialGradientPaint provides two ways to paint itself as an ellipse instead of a circle:
Upon construction, you can specify a transform for the gradient. For example, if you provide the following transform: AffineTransform.getScaleInstance(0.5, 1), your gradient will be an upright oval (the x dimension will be half that of the y dimension).
Or, you can use the constructor that requires a Rectangle2D be provided. An appropriate transform will be created to make the gradient ellipse bounds match that of the provided rectangle. I found the class documentation helpful: RadialGradientPaint API. In particular, see the documentation for this constructor.

We Keep Coding

Java is a programming language and computing platform first released by Sun Microsystems in 1995.