Develop Reference

Object.drawItself in PaintComponent doesnt work

PaintComponent doest paint figures. Just nothing is happening, clean Jframe appear.
I think something is wrong with list or with the way i called method
List is in class with Paint Component
public class Paint extends JPanel implements ActionListener {
List<Figures> figuresList = new ArrayList<Figures>();
Timer t = new Timer(5, this);
public void paintComponent(Graphics g) {
super.paintComponent(g);
for (Figures figure : figuresList) {
figure.drawItself(g, figure.getLocationX(), figure.getLocationY());
}
t.start();
}
#Override
public void actionPerformed(ActionEvent e) {
{
for (Figures figure : figuresList) {
if (figure.getLocationX() < 0 || figure.getLocationX() > 540) {
figure.setVelocityX(-figure.getVelocityX());
}
if (figure.getLocationY() < 0 || figure.getLocationX() > 220) {
figure.setVelocityY(-figure.getVelocityY());
}
figure.setLocationX(figure.getLocationX()
+ figure.getVelocityX());
figure.setLocationY(figure.getLocationY()
+ figure.getVelocityY());
}
}
repaint();
}
And drawitself:
public class Circle implements Figures {
public int locationX = 12;
public int locationY = 12;
public int velocityX =1;
public int velocityY =1;
public void drawItself(Graphics g, int locationX, int locationY){
this.locationX = locationX;
this.locationY = locationY;
g.drawOval(locationX, locationY, 40, 40);
g.fillOval(locationX, locationY, 40, 40);
}
Main:
public static void main(String[] args) {
Circle c = new Circle();
Quadrat q = new Quadrat();
Paint p = new Paint();
p.figuresList.add(c);
p.figuresList.add(q);
GUI.Configuration();
}
GUI
public class GUI {
public static void Configuration(){
JFrame frame = new JFrame("Figures Animation");
frame.setSize(600,300);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new Paint();
frame.getContentPane().add(BorderLayout.CENTER, panel);
}

You create and add a Paint instance here:
public class GUI {
public static void Configuration(){
JFrame frame = new JFrame("Figures Animation");
frame.setSize(600,300);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new Paint(); // *** new Paint is here, but nothing is added
frame.getContentPane().add(BorderLayout.CENTER, panel);
}
But nothing of use has been added to it. All the important stuff is added to a completely different Paint JPanel, one that is never displayed:
public static void main(String[] args) {
Circle c = new Circle();
Quadrat q = new Quadrat();
Paint p = new Paint(); // **** ANOTHER new Paint is here, and it gets goodies
p.figuresList.add(c);
p.figuresList.add(q);
// but is never added to a JFrame and is never displayed.
GUI.Configuration();
}
Don't do this. Create one Paint JPanel, one only, add the important components to it, and then only add that one to the JFrame. Most important, don't just type in code, think and plan your program before committing it to code, and you won't see errors like this.
Also, and again, do not start a Timer from within paintComponent and don't create Circle there. You can draw your Circle instance in paintComponent, but create it and start your Timer within the Paint constructor.

Adding multiple graphic objects to one JFrame

Here is my code it is a guy and a background but only one thing shows up at a time or sometimes nothing at all.
I have a brain class, a frame class, a redPlayer class, and a background class.
The way it works is the brain makes a player and a brain and adds it to the frame.
I think it has something to do with layouts but I tried everything but nothing works.
Please Help!!!
Thanks in advance.
here is the brain:
public class Brain
{
private Frame frame;
private static RedPlayer redPlayer;
private Background background;
private SensorKeys sensor;
public Brain()
{
frame = new Frame();
redPlayer = new RedPlayer();
background = new Background();
sensor = new SensorKeys();
frame.addComponent(redPlayer);
frame.addComponent(background);
frame.addKeySensor(sensor);
redPlayer.revalidate();
}
public static void setRedPlayerVelX(double vx)
{
redPlayer.setVelX(vx);
}
public static void setRedPlayerVelY(double vy)
{
redPlayer.setVelY(vy);
}
public static void makeRedPlayerBullet()
{
}
}
`
here is the frame class
public class Frame
{
private JFrame jf;
public Frame()
{
drawFrame();
}
public void drawFrame()
{
jf = new JFrame();
jf.setSize(800, 600);
jf.setLocation(10, 10);
jf.setVisible(true);
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jf.setBackground(Color.WHITE);
jf.setLayout(null);
}
public void addComponent(JComponent jc)
{
jc.setBounds(jc.getX(), jc.getY(), 100, 100);
jf.add(jc);
}
public void addPanel(JPanel jp)
{
jf.add(jp);
}
public void addKeySensor(KeyListener kl)
{
jf.addKeyListener(kl);
}
}
here is the player class:
public class RedPlayer extends JComponent implements ActionListener
{
private int x,y;
private double velX = 0, velY = 0;
private Timer timer = new Timer(2,this);
private Image redplayer;
public RedPlayer()
{
x = 100;
y = 100;
ImageIcon II = new ImageIcon("redPlayerRight.png");
redplayer = II.getImage();
revalidate();
timer.start();
}
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D graphics = (Graphics2D) g;
graphics.drawImage(redplayer, x,y, null);
}
public void actionPerformed(ActionEvent arg0)
{
x += velX;
y += velY;
repaint();
revalidate();
}
public void setVelX(double vx)
{
velX = vx;
}
public void setVelY(double vy)
{
velY = vy;
}
}
And Lastly here is the background class:
public class Background extends JComponent
{
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D graphics = (Graphics2D) g;
graphics.setColor(Color.green);
graphics.fillRect(0, 400, 500, 200);
}
}

I think it has something to do with layouts
Yes, you should read the Swing tutorial on Using Layout Managers to better understand how they work and for examples.
The default layout manager for a JFrame is a BorderLayout. You can't just add 3 components to the same area of the BorderLayout.
I don't know what you are trying to accomplish but start simple. Since you have a background the basic code should be something like:
redPlayer = new RedPlayer();
background = new Background();
background.add( redPlayer );
frame.addComponent(background);
So the red player should display on top of the background. And the background is added to the frame.
Of course you must use a proper layout manager for the background. And you must make sure you override the getPreferredSize() method when you do custom painting so the layout manager knows what the size of every component should be.
Get those two components working first, then move on to the 3rd component.

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.

Paint a JPanel to a BufferedImage or Print it without rendering it to screen first

Picture this... A program GUI JFrame that is split in 2, EAST and WEST. The first JPanel is just a print preview screen. The EAST side of the JFrame is where the user can create a 1 2 or 3 size image. The user clicks the "Add" button and the defined image on the right goes to the panel on the left. So if the user clicks "Add" 3 times with different size images, then the panel uses FlowLayout to organize the added panel images added on the left.
When you run this code, you can see a sorta idea of what I want. Really what would be nice is to create all this off-screen and call it MainPanel. Then have printPreview extend MainPanel and scale it down for screen view. And have the Printable method paint the MainPanel into the print method which would be a correct size.
So my question...
-Can you copy or paint a JPanel before it is rendered on the screen?
-Is there a better way to do what I want, I FlowLayout solves what I want amazingly, so a JPanel seems to be the answer unless there is something I do not know of.
Ok now that that is pictured. I have built some code that is about as SSCCE as I can get.
Guys I have tried asking this question at New To Java forums and they just do not respond, I am not double posting on purpose, I completely rewrote this from scratch.
import javax.swing.*;
import java.awt.*;
import java.awt.image.*;
import java.awt.print.*;
import java.awt.event.*;
public class PrintGrid extends JFrame {
Paper paper = new Paper();
PrintGrid() {
super("Check out this grid panel");
setSize(672, 750);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
add(paper);
setVisible(true);
} // end PrintGrid constructor
// **************************
// ****** PAPER CLASS *******
// **************************
private class Paper extends JPanel {
final int PAPER_X = 672, PAPER_Y = 975, UNIT = 12, DPI = 72;
X1 x1a = new X1(), x1b = new X1(), x1c = new X1();
X2 x2a = new X2(), x2b = new X2(), x2c = new X2();
X3 x3a = new X3(), x3b = new X3(), x3c = new X3();
Paper() {
setPreferredSize(new Dimension(PAPER_X, PAPER_Y));
setBackground(Color.GRAY);
setLayout(new FlowLayout(FlowLayout.LEADING));
//Users will manually add different sizes to this sheet.
add(x1a);
add(x2a);
add(x3a);
add(x1b);
add(x1c);
add(x2b);
add(x3b);
}
// ******* Parent Class for GridUnits *******
abstract class GridUnit extends JPanel {
MouseListen ml = new MouseListen();
float alpha = 1.0f;
GridUnit() {
this.addMouseListener(ml);
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
this.setBackground(Color.BLACK);
Graphics2D g2 = (Graphics2D) g;
g2.setComposite(makeComposite(alpha));
g.setColor(Color.WHITE);
g.drawRect(0, 0, this.getWidth()-1, this.getHeight()-1);
g.setColor(Color.darkGray);
g.fillRect(15, 15, this.getWidth()-30, this.getHeight()-30);
} // end paintComponent.
private AlphaComposite makeComposite(float alpha) {
int type = AlphaComposite.SRC_OVER;
return(AlphaComposite.getInstance(type, alpha));
}
void click() {
setVisible(false);
}
void entered() {
alpha = 0.8f;
repaint();
}
void exited() {
alpha = 1.0f;
repaint();
}
class MouseListen extends MouseAdapter {
public void mouseEntered(MouseEvent event) {
entered();
}
public void mouseExited(MouseEvent event) {
exited();
}
public void mousePressed(MouseEvent event) {
click();
}
}
} // end GridUnit class
class X1 extends GridUnit {
X1() {
setPreferredSize(new Dimension(UNIT*13, UNIT*18));
}
} // end X1 Class
class X2 extends GridUnit {
X2() {
setPreferredSize(new Dimension(UNIT*26, UNIT*18));
}
} // end X1 Class
class X3 extends GridUnit {
X3() {
setPreferredSize(new Dimension(UNIT*39, UNIT*18));
}
} // end X1 Class
} // end Paper class.
public static void main(String[] args) {
new PrintGrid();
} // end main method.
} // end PrintGrid class.

It's quite trivial to paint any Java component to an offscreen image, from which you can do as you please, including copying a portion or scaled image to a final target.
Subclass JComponent and override void paintComponent(Graphics g). Paint to a BufferedImage, then copy the image to the target component. Off the top of my head, something like:
void paintComponent(Graphics g) {
BufferedImage img=new BufferedImage(getWidth(),getHeight(),BufferedImage.TYPE_INT_ARGB);
Graphics2D gph=(Graphics2D)img.getGraphics();
// paint to gph here
gph.dispose();
g.drawImage(img); // paints the contents of img to the component's graphics context.
}

Painted content invisible while resizing in Java

Please note I haven't tested this on a Windows-machine only on a Mac-machine. I'm not so sure whether this also occurs on a Windows-machine...
When I resize my Java-application the content is invisible. I already found a way to fix it after resizing it, but not while the user is resizing the window.
I'm not using Swing or something because it makes my binary so slow (in my opinion).
The structure is like this:
Frame My main-window
Container Content view of main-window
Container-based subviews that including the paint(Graphics g)-method
I've added all listeners to My main-window and now I'm able to redraw the Content-view after resizing the window.
public void componentResized(ComponentEvent e) {
this.contentView.paint(this.contentView.getGraphics());
}
I am beware of the fact using the paint(getGraphics())-method isn't a really good way to do this, but since the repaint()-method doesn't do anything at all, it's the only working possibility.
While resizing, all painted content becomes invisible. However, when I add a Button-instance to my Content-view and resize my Main-window, the button doesn't get invisible.
I am able to trace the 'live'-resize event:
public void componentMoved(ComponentEvent e) {
System.out.println("Live-resize");
}
When I start resizing this method is not being called.
While resizing it generates "Live-resize" in my log every single pixel I resize the window.
When I stop resizing this method is not being called, the componentResized-method does.
When I add my repaint-method (or the official repaint-method) to the 'live'-resize event like this, I still get the output, however, it's not repainting or something
public void componentMoved(ComponentEvent e) {
System.out.println("Live-resize");
this.contentView.paint(this.contentView.getGraphics());
}
Or
public void componentMoved(ComponentEvent e) {
System.out.println("Live-resize");
this.contentView.repaint();
}
When I minimize my application to the dock and maximize the application again, the same thing happens, I guess that the same code is needed to fix this.
I'm not using Graphics2D or something, just Graphics.
Could you please explain me how I can repaint the views?
Thanks in advance,
Tim

For reference, here is the same program using Swing. Because JPanel is double buffered, it doesn't flicker as the mouse is released after resizing.
import java.awt.*;
import java.awt.event.*;
import java.util.Random;
import javax.swing.*;
public class SwingPaint {
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.add(new CirclePanel());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
private static class CirclePanel extends JPanel {
private static final Random r = new Random();
public CirclePanel() {
this.setPreferredSize(new Dimension(320, 240));
this.setForeground(new Color(r.nextInt()));
this.addMouseListener(new MouseAdapter() {
#Override
public void mousePressed(MouseEvent e) {
CirclePanel.this.update();
}
});
}
public void update() {
this.setForeground(new Color(r.nextInt()));
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Dimension size = this.getSize();
int d = Math.min(size.width, size.height) - 10;
int x = (size.width - d) / 2;
int y = (size.height - d) / 2;
g.fillOval(x, y, d, d);
g.setColor(Color.blue);
g.drawOval(x, y, d, d);
}
}
}

I'm more familiar with Swing, but the article Painting in AWT and Swing distinguishes between system- and application-triggered painting. The example below shows how the system invokes paint() as the window is resized, while the application invokes repaint(), which calls update(), in response to a mouse event. The behavior is cross-platform.
import java.awt.*;
import java.awt.event.*;
import java.util.Random;
public class AWTPaint {
public static void main(String[] args) {
Frame frame = new Frame();
frame.add(new CirclePanel());
frame.addWindowListener(new WindowAdapter() {
#Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
frame.pack();
frame.setVisible(true);
}
private static class CirclePanel extends Panel {
private static final Random r = new Random();
public CirclePanel() {
this.setPreferredSize(new Dimension(320, 240));
this.setForeground(new Color(r.nextInt()));
this.addMouseListener(new MouseAdapter() {
#Override
public void mousePressed(MouseEvent e) {
CirclePanel.this.repaint();
}
});
}
#Override
public void update(Graphics g) {
this.setForeground(new Color(r.nextInt()));
}
#Override
public void paint(Graphics g) {
Dimension size = this.getSize();
int d = Math.min(size.width, size.height) - 10;
int x = (size.width - d) / 2;
int y = (size.height - d) / 2;
g.fillOval(x, y, d, d);
g.setColor(Color.blue);
g.drawOval(x, y, d, d);
}
}
}

Okay, I finally fixed it.
Instead of redrawing it every time in the paint(Graphics g)-method, you need to buffer the output and only redraw that image (I kinda hoped Java would be already doing that, just like Obj-C).
public BufferedImage buffer;
public void redraw() {
buffer = new BufferedImage(
200, // height
300, // width
BufferedImage.TYPE_4BYTE_ABGR); // ABGR = RGBA, 4-byte (r, g, b, a) per pixel
Graphics g = buffer.getGraphics();
// do your drawing here
if (this.getGraphics()) {
// 'this' is already shown, so it needs a redraw
this.paint(this.getGraphics()); // little hack
}
}
public void update(Graphics g) {
this.paint(g);
}
public void paint(Graphics g) {
g.drawImage(buffer, 0, 0, this);
}
Now, when you minimize the window and maximize it again, the paintings remain. Only, the window's flickering now for .1-second or so, but I don't really care about that.