Develop Reference

JLabel goes out of alignment (aka funky) when overlaying a rectangle on it

I have a GUI I am making for the popular software ImageMagick in Java SWING.
Now, I am implementing the Crop feature into it and was trying to implement a drawable box to denote the region to be cropped.
The issue is that although I have gotten the rectangle to draw on the JLabel, the JLabel itself starts to move around once I finish painting the graphics on it.
As an example, here is a screenshot of the app before and after the selection is made.
Here is the code for the MouseReleased() event listener
private void input_showerMouseReleased(java.awt.event.MouseEvent evt) {
end_x = evt.getX();
end_y = evt.getY();
paint(input_shower.getGraphics());
input_shower.revalidate();
}
Here is the code for the paint() method
public void paint(Graphics g) {
super.paintComponents(g);
Graphics2D g2 = (Graphics2D) g;
g2.setColor(Color.red);
g2.setStroke(new BasicStroke(5));
Rectangle2D.Double rectangle = new Rectangle2D.Double(start_x, start_y, (end_x - start_x), (end_y - start_y));
g2.draw(rectangle);
}
Are there any ideas as to why this is happening and any possible solutions?

This is dangerous code:
private void input_showerMouseReleased(java.awt.event.MouseEvent evt) {
end_x = evt.getX();
end_y = evt.getY();
paint(input_shower.getGraphics());
input_shower.revalidate();
}
since you're painting directly to a component with a Graphics object that was not given to you by the JVM. Just don't do this, and instead paint passively.
Instead use end_x and end_y in your listened to jcomponent's paintComponent method and draw with that.
e.g.,
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.*;
#SuppressWarnings("serial")
public class PaintComponentCorrect extends JPanel {
public static final String BULL_FIGHT = "https://duke.kenai.com/misc/Bullfight.jpg";
private static final Color RECT_COLOR = new Color(150, 150, 255);
private int startX;
private int startY;
private int endX;
private int endY;
private BufferedImage img;
public PaintComponentCorrect() throws IOException {
URL url = new URL(BULL_FIGHT);
img = ImageIO.read(url);
MyMouseAdapt myMouseAdapt = new MyMouseAdapt();
addMouseListener(myMouseAdapt);
addMouseMotionListener(myMouseAdapt);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (img != null) {
g.drawImage(img, 0, 0, null);
}
g.setColor(RECT_COLOR);
int x = Math.min(startX, endX);
int y = Math.min(startY, endY);
int width = Math.abs(startX - endX);
int height = Math.abs(startY - endY);
g.drawRect(x, y, width, height);
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet() || img == null) {
return super.getPreferredSize();
}
return new Dimension(img.getWidth(), img.getHeight());
}
private class MyMouseAdapt extends MouseAdapter {
private BufferedImage subImg;
#Override
public void mousePressed(MouseEvent e) {
if (e.getButton() != MouseEvent.BUTTON1) {
return;
}
startX = e.getX();
startY = e.getY();
endX = startX;
endY = startY;
repaint();
}
#Override
public void mouseReleased(MouseEvent e) {
if (e.getButton() != MouseEvent.BUTTON1) {
return;
}
endX = e.getX();
endY = e.getY();
repaint();
int x = Math.min(startX, endX);
int y = Math.min(startY, endY);
int w = Math.abs(startX - endX);
int h = Math.abs(startY - endY);
subImg = img.getSubimage(x, y, w, h);
ImageIcon icon = new ImageIcon(subImg);
JOptionPane.showMessageDialog(PaintComponentCorrect.this, icon);
}
#Override
public void mouseDragged(MouseEvent e) {
endX = e.getX();
endY = e.getY();
repaint();
}
}
private static void createAndShowGui() {
PaintComponentCorrect mainPanel = null;
try {
mainPanel = new PaintComponentCorrect();
} catch (IOException e) {
e.printStackTrace();
System.exit(-1);
}
JFrame frame = new JFrame("PaintComponent Correct");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}

public void paint(Graphics g) {
super.paintComponents(g);
Custom painting is done by overriding the paintComponent() method.
You then invoke super.paintComponent(), not "paintComponents" with an "s"
For example check out Custom Painting Approaches. The code isn't designed to do what you want, but it does show how to draw a Rectangle on a component using the above suggestion.

Getting the (starting) X and Y coordinates of a Path2D shape drawn on Jpanel

So, I have a program where I can add shapes to JPanel using Path2D objects and then I can click and drag them around. What I want to do is be able to find the final X and Y coordinates of the shape AFTER it has been drug. The coordinates need to be the top-left coordinates. Any ideas?
// add a circle to center of the screen
public void addCircle(int width, int height) {
Path2D circ = new Path2D.Double();
circ.append(new Ellipse2D.Double(getWidth() / 2 - width / 2,
getHeight() / 2 - height / 2, width, height), true);
shapes.add(circ);
repaint();
}
..................
//paint all shapes
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
this.setOpaque(true);
this.setBackground(Color.WHITE);
Graphics2D g2 = (Graphics2D) g;
g2.setStroke(new BasicStroke(2));
for (Path2D shape : shapes) {
g2.draw(shape);
}
}
..................
// if the mouse click is in the circle, set pressed=true
#Override
public void mousePressed(MouseEvent e) {
if (e.getButton() != MouseEvent.BUTTON1) {
return;
}
for (int i = 0; i < shapes.size(); i++) {
if (shapes.get(i) != null
&& shapes.get(i).contains(e.getPoint())) {
currentIndex = i;
pressed = true;
this.point = e.getPoint();
}
}
}
//if pressed=true, move circle with mouse
#Override
public void mouseDragged(MouseEvent e) {
if (pressed && !lineSelected) {
int deltaX = e.getX() - point.x;
int deltaY = e.getY() - point.y;
shapes.get(currentIndex).transform(
AffineTransform.getTranslateInstance(deltaX, deltaY));
point = e.getPoint();
//I need to find the new coordinates here!!!!!!!!!!!
repaint();
}
}
Full Code
class Canvas extends JPanel {
private static final long serialVersionUID = 1L;
private List<Path2D> shapes = new ArrayList<Path2D>();
private int currentIndex;
private Point lineStartingPoint = new Point();
private Point lineEndingPoint = new Point();
private boolean drawing;
private boolean lineSelected;
private Path2D.Double linePath;
private Shapes myShapes = new Shapes();
private List<Path2D> circles = new ArrayList<Path2D>();
public Canvas() {
MyMouseAdapter myMouseAdapter = new MyMouseAdapter();
addMouseListener(myMouseAdapter);
addMouseMotionListener(myMouseAdapter);
}
public void setList(ArrayList<UMLCircle> shapes) {
}
public List<UMLCircle> getList() {
return null;
}
public void addSquare(int width, int height) {
Path2D rect2 = new Path2D.Double();
rect2.append(new Rectangle(getWidth() / 2 - width / 2, getHeight() / 2
- height / 2, width, height), true);
shapes.add(rect2);
repaint();
}
public void addLine() {
lineSelected = true;
repaint();
}
public void addCircle(int width, int height) {
myShapes.addCircle(getWidth() / 2 - width / 2, getHeight() / 2 - height
/ 2, width, height);
Path2D circ = new Path2D.Double();
circ.append(new Ellipse2D.Double(getWidth() / 2 - width / 2,
getHeight() / 2 - height / 2, width, height), true);
circles.add(circ);
shapes.add(circ);
repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
this.setOpaque(true);
this.setBackground(Color.WHITE);
Graphics2D g2 = (Graphics2D) g;
if (lineSelected) {
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2.setStroke(new BasicStroke(2));
g2.drawLine(lineStartingPoint.x, lineStartingPoint.y,
lineEndingPoint.x, lineEndingPoint.y);
}
g2.setStroke(new BasicStroke(2));
for (Path2D shape : shapes) {
g2.draw(shape);
}
}
class MyMouseAdapter extends MouseAdapter {
private boolean pressed = false;
private Point point;
#Override
public void mousePressed(MouseEvent e) {
if (e.getButton() != MouseEvent.BUTTON1) {
return;
}
for (int i = 0; i < shapes.size(); i++) {
if (shapes.get(i) != null
&& shapes.get(i).contains(e.getPoint())) {
currentIndex = i;
pressed = true;
this.point = e.getPoint();
}
if (circles.get(i) != null
&& circles.get(i).contains(e.getPoint())) {
currentIndex = i;
pressed = true;
this.point = e.getPoint();
}
}
if (lineSelected) {
drawing = true;
lineStartingPoint = e.getPoint();
lineEndingPoint = lineStartingPoint;
}
}
#Override
public void mouseDragged(MouseEvent e) {
if (pressed && !lineSelected) {
int deltaX = e.getX() - point.x;
int deltaY = e.getY() - point.y;
shapes.get(currentIndex).transform(
AffineTransform.getTranslateInstance(deltaX, deltaY));
point = e.getPoint();
myShapes.updateCircleLocation(currentIndex, point.x, point.y);
System.out.println(point.x + " " + point.y);
repaint();
}
if (drawing) {
lineEndingPoint = e.getPoint();
repaint();
}
}
#Override
public void mouseReleased(MouseEvent e) {
if (drawing && lineSelected) {
drawing = false;
lineSelected = false;
lineEndingPoint = e.getPoint();
linePath = new Path2D.Double();
linePath.moveTo(lineStartingPoint.getX(),
lineStartingPoint.getY());
linePath.lineTo(lineEndingPoint.getX(), lineEndingPoint.getY());
shapes.add(linePath);
repaint();
}
pressed = false;
}
}
}
EDIT
Calculation for offset:
int deltaX = e.getX() - point.x;
int deltaY = e.getY() - point.y;
shapes.get(currentIndex).transform(
AffineTransform.getTranslateInstance(deltaX, deltaY));
point = e.getPoint();
int newXPos = e.getX() - deltaX; // final X pos
int newXPos = e.getX() - deltaX; // final Y pos

Before you can do anything, you need to know the offset of the mouse click from the corner of the shape, this will allow you to drag the object so it doesn't suddenly "jump" to your current mouse position...
#Override
public void mousePressed(MouseEvent e) {
//...
for (Shape shape : myShapes) {
//...
this.point = e.getPoint();
int deltaX = point.x - shape.getBounds().x;
int deltaY = point.y - shape.getBounds().y;
offset = new Point(deltaX, deltaY);
//...
}
}
}
Then, you would calculate the delta of change, between the current mouse position and the offset. Because you're applying a translate, you also need to subtract the shape's current location, as the translation is based on the shape's current location and we only want to apply the amount of change
#Override
public void mouseDragged(MouseEvent e) {
if (pressed) {
int index = myShapes.indexOf(clickedShape);
myShapes.remove(index);
int deltaX = e.getPoint().x - offset.x;
int deltaY = e.getPoint().y - offset.y;
clickedShape = new Path2D.Double(clickedShape,
AffineTransform.getTranslateInstance(
deltaX - clickedShape.getBounds().x,
deltaY - clickedShape.getBounds().y));
myShapes.add(index, clickedShape);
point = e.getPoint();
repaint();
}
}
Now, having said all that, don't do this...
protected void paintComponent(Graphics g) {
//...
this.setOpaque(true);
this.setBackground(Color.WHITE);
Changing the state of the component from within the paint method can setup a infinite loop of repaint requests, which can chock your system. Also, the changes you make won't be applied to the current graphics context, as these properties are generally applied by the paint method...
And a working copy....
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.AffineTransform;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Path2D;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
class Canvas extends JPanel {
private static final long serialVersionUID = 1L;
private boolean drawing;
private List<Shape> myShapes = new ArrayList<Shape>();
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new Canvas());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public Canvas() {
MyMouseAdapter myMouseAdapter = new MyMouseAdapter();
addMouseListener(myMouseAdapter);
addMouseMotionListener(myMouseAdapter);
addSquare(100, 100);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 400);
}
public void setList(ArrayList<Shape> shapes) {
}
public List<Shape> getList() {
return null;
}
public void addSquare(int width, int height) {
Path2D rect2 = new Path2D.Double();
rect2.append(new Rectangle(getWidth() / 2 - width / 2, getHeight() / 2
- height / 2, width, height), true);
myShapes.add(rect2);
repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setStroke(new BasicStroke(2));
for (Shape shape : myShapes) {
g2.draw(shape);
}
}
class MyMouseAdapter extends MouseAdapter {
private boolean pressed = false;
private Point point;
private Point offset;
private Shape clickedShape;
#Override
public void mousePressed(MouseEvent e) {
if (e.getButton() != MouseEvent.BUTTON1) {
return;
}
for (Shape shape : myShapes) {
if (shape != null
&& shape.contains(e.getPoint())) {
System.out.println("Clicked");
pressed = true;
clickedShape = shape;
this.point = e.getPoint();
int deltaX = point.x - shape.getBounds().x;
int deltaY = point.y - shape.getBounds().y;
offset = new Point(deltaX, deltaY);
System.out.println(point + "x" + offset);
repaint();
break;
}
}
}
#Override
public void mouseDragged(MouseEvent e) {
if (pressed) {
int index = myShapes.indexOf(clickedShape);
myShapes.remove(index);
int deltaX = e.getPoint().x - offset.x;
int deltaY = e.getPoint().y - offset.y;
clickedShape = new Path2D.Double(clickedShape,
AffineTransform.getTranslateInstance(
deltaX - clickedShape.getBounds().x,
deltaY - clickedShape.getBounds().y));
myShapes.add(index, clickedShape);
point = e.getPoint();
repaint();
}
}
#Override
public void mouseReleased(MouseEvent e) {
offset = null;
pressed = false;
}
}
}

Call JDialog from JDialog

I'm trying to build an application, in which allows calling JDialog from JDialog. I've tried it, but at the time of the call dialog B of A, B dialog appears and then immediately disappears. Is there a solution to these problems?
My code :
I have a class A which extends javax.swing.JDialog. Then there is a label that has the action to call dialog from class PadAndZoom as below:
private void lblSuratRekomendasiMouseClicked(java.awt.event.MouseEvent evt) {
try {
PadAndZoom app = new PadAndZoom();
BufferedImage img = ImageIO.read(PadAndZoom.class.getResource("/tampilan/background5.jpg"));
app.tes(img);
} catch (IOException ex) {
Logger.getLogger(RincianBukuBesar.class.getName()).log(Level.SEVERE, null, ex);
}
}
then I have one more class to be invoked by the method lblSuratRekomendasiMouseClicked (java.awt.event.MouseEvent evt) of class A
package dispertasih;
import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.awt.geom.*;
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.*;
import javax.swing.event.*;
public class PadAndZoom implements ChangeListener {
BufferedImage image;
PanPanelX label;
public void stateChanged(ChangeEvent e) {
int value = ((JSlider) e.getSource()).getValue();
double scale = value / 200.0;
BufferedImage scaled = getScaledImage(scale);
label.setImage(scaled);
}
public BufferedImage getScaledImage(double scale) {
int w = (int)(scale*image.getWidth());
int h = (int)(scale*image.getHeight());
BufferedImage bi = new BufferedImage(w, h, image.getType());
Graphics2D g2 = bi.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
RenderingHints.VALUE_INTERPOLATION_BICUBIC);
AffineTransform at = AffineTransform.getScaleInstance(scale, scale);
g2.drawRenderedImage(image, at);
g2.dispose();
return bi;
}
public PanPanelX getContent() {
// createAnImage();
label = new PanPanelX(image);
//label.setHorizontalAlignment(JLabel.CENTER);
return label;
}
public void createAnImage(BufferedImage imgbuf) {
int w = 500;
int h = 500;
int type = BufferedImage.TYPE_INT_RGB; // many options
image = imgbuf;
}
public JSlider getControl() {
JSlider slider = new JSlider(JSlider.HORIZONTAL, 50, 200, 50);
slider.setMajorTickSpacing(50);
slider.setMinorTickSpacing(10);
slider.setPaintTicks(true);
slider.setPaintLabels(true);
slider.addChangeListener(this);
return slider;
}
public void tes(BufferedImage img) {
PadAndZoom app = new PadAndZoom();
JDialog f = new JDialog();
JButton b = new JButton();
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException e) { }
app.createAnImage(img);
f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
f.getContentPane().add(new JScrollPane(app.getContent()));
//f.getContentPane().add(new JButton("tessss"));
f.getContentPane().add(app.getControl(), "Last");
f.setSize(400, 400);
f.setLocation(200,200);
f.setVisible(true);
}
}
class PanPanelX extends JPanel {
public int x, y;
public int width = 800, height = 800;
BufferedImage img;
public final static RenderingHints textRenderHints = new RenderingHints(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
public final static RenderingHints imageRenderHints = new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
public final static RenderingHints renderHints = new RenderingHints(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
static int startX, startY;
public void setImage(BufferedImage img) {
this.img = img;
revalidate();
repaint();
}
public PanPanelX(BufferedImage img) {
x = 20;
y = 20;
this.img = img;
addMouseListener(new MouseAdapter() {
#Override
public void mousePressed(MouseEvent me) {
super.mousePressed(me);
startX = me.getX();
startY = me.getY();
}
});
addMouseMotionListener(new MouseMotionAdapter() {
#Override
public void mouseDragged(MouseEvent me) {
super.mouseDragged(me);
if (me.getX() < startX) {//moving image to right
x -= 2;
} else if (me.getX() > startX) {//moving image to left
x += 2;
}
if (me.getY() < startY) {//moving image up
y -= 2;
} else if (me.getY() > startY) {//moving image to down
y += 2;
}
repaint();
}
});
}
#Override
protected void paintComponent(Graphics grphcs) {
super.paintComponent(grphcs);
Graphics2D g2d = (Graphics2D) grphcs;
//turn on some nice effects
applyRenderHints(g2d);
g2d.drawImage(img, x, y, null);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(width, height);
}
public static void applyRenderHints(Graphics2D g2d) {
g2d.setRenderingHints(textRenderHints);
g2d.setRenderingHints(imageRenderHints);
g2d.setRenderingHints(renderHints);
}
}
thanks u ..

how to drag object

i want to drag a box and i want my mouse cursor to be where i clicked in a rectangle while im draging rectangle. i tried this code and i got bunch of errors when i tried to drag.
import objectdraw.*;
import java.awt.*;
public class TouchWindow extends WindowController
{
private FilledRect a;
private boolean b;
private Location c;
private int x;
private int y;
public void begin()
{
b=false;
a=new FilledRect(0,0,50,50,canvas);
}
public void onMouseClick(Location pt)
{
if(a.contains(pt))
{
b=true;
pt=c;
}
}
public void onMouseDrag(Location pt2)
{
if(b==true)
{
x=(int)c.getX()-(int)pt2.getX();
y=(int)c.getY()-(int)pt2.getY();
a.move(x,y);
}
}
}

Hmm here is an example I had lying around, although not an applet it can be very simply ported.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class ShapeMover {
public ShapeMover() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setTitle("Shape Mover");
initComponents(frame);
frame.pack();
frame.setVisible(true);
}
public static void main(String s[]) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new ShapeMover();
}
});
}
private void initComponents(JFrame frame) {
frame.getContentPane().add(new DragPanel());
}
}
class DragPanel extends JPanel {
Rectangle rect = new Rectangle(0, 0, 100, 50);
int preX, preY;
boolean isFirstTime = true;
Rectangle area;
boolean pressOut = false;
private Dimension dim = new Dimension(400, 300);
public DragPanel() {
setBackground(Color.white);
addMouseMotionListener(new MyMouseAdapter());
addMouseListener(new MyMouseAdapter());
}
#Override
public Dimension getPreferredSize() {
return dim;
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
if (isFirstTime) {
area = new Rectangle(dim);
rect.setLocation(50, 50);
isFirstTime = false;
}
g2d.setColor(Color.black);
g2d.fill(rect);
}
boolean checkRect() {
if (area == null) {
return false;
}
if (area.contains(rect.x, rect.y, rect.getWidth(), rect.getHeight())) {
return true;
}
int new_x = rect.x;
int new_y = rect.y;
if ((rect.x + rect.getWidth()) > area.getWidth()) {
new_x = (int) area.getWidth() - (int) (rect.getWidth() - 1);
}
if (rect.x < 0) {
new_x = -1;
}
if ((rect.y + rect.getHeight()) > area.getHeight()) {
new_y = (int) area.getHeight() - (int) (rect.getHeight() - 1);
}
if (rect.y < 0) {
new_y = -1;
}
rect.setLocation(new_x, new_y);
return false;
}
private class MyMouseAdapter extends MouseAdapter {
#Override
public void mousePressed(MouseEvent e) {
preX = rect.x - e.getX();
preY = rect.y - e.getY();
if (rect.contains(e.getX(), e.getY())) {
updateLocation(e);
} else {
pressOut = true;
}
}
#Override
public void mouseDragged(MouseEvent e) {
if (!pressOut) {
updateLocation(e);
} else {
}
}
#Override
public void mouseReleased(MouseEvent e) {
if (rect.contains(e.getX(), e.getY())) {
updateLocation(e);
} else {
pressOut = false;
}
}
public void updateLocation(MouseEvent e) {
rect.setLocation(preX + e.getX(), preY + e.getY());
checkRect();
repaint();
}
}
}

How to Zoom specific area of Image on Canvas in Swing

I want to Zoom specific area on image. which is selected by the user. image display on canvas using Swing. i already done full image zoom on canvas but can't implement specific area zoom.
please help

Canvas is awt not swing. Try JPanel instead. Example.
But if you already done full image zoom, try to make the same on a sub-image.
BufferedImage.getSubimage(x, y, w, h);
EDIT
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
public class Example {
private Point startPoint = new Point(0, 0);
private Point rectLocale = new Point();
private Dimension rectSize = new Dimension();
private int zoom = 80;
private BufferedImage capture = null;
private BufferedImage raw;
public Example() throws Exception {
raw = new Robot().createScreenCapture(new Rectangle(
Toolkit.getDefaultToolkit().getScreenSize()));
MouseBehavior behavior = new MouseBehavior();
JPanel b = new JPanel() {
private static final long serialVersionUID = 1L;
#Override
public Dimension getMinimumSize() {
return new Dimension(500, 500);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(500, 500);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = ((Graphics2D) g);
g2d.drawImage(raw, 0, 0, null);
if (capture != null) {
int width2 = (int) (rectSize.width + rectSize.width * (zoom / 500d));
int height2 = (int) (rectSize.height + rectSize.height * (zoom / 500d));
int x2 = rectLocale.x - ((width2 - rectSize.width) / 2);
int y2 = rectLocale.y - ((height2 - rectSize.height) / 2);
Image scaledInstance = capture.getScaledInstance(
width2, height2, Image.SCALE_AREA_AVERAGING);
g2d.drawImage(scaledInstance, x2, y2, null);
g2d.drawRect(x2, y2, width2, height2);
} else {
g2d.draw(new Rectangle(rectLocale, rectSize));
}
}
};
b.addMouseMotionListener(behavior);
b.addMouseListener(behavior);
b.addMouseWheelListener(behavior);
JFrame f = new JFrame();
f.setLocation(10, 10);
f.setDefaultCloseOperation(3);
f.add(b);
f.pack();
f.setVisible(true);
}
private class MouseBehavior extends MouseAdapter {
#Override
public void mousePressed(MouseEvent e) {
startPoint = e.getPoint();
rectLocale = new Point();
rectSize = new Dimension();
capture = null;
if (e.getSource() instanceof JComponent) {
((JComponent) e.getSource()).repaint();
}
}
#Override
public void mouseDragged(MouseEvent e) {
Point currentPoint = e.getPoint();
rectSize.width = Math.abs(currentPoint.x - startPoint.x);
rectSize.height = Math.abs(currentPoint.y - startPoint.y);
if (e.isShiftDown()) {
rectSize.width = rectSize.height = Math.min(
rectSize.width, rectSize.height);
int dx = startPoint.x - rectSize.width;
int dy = startPoint.y - rectSize.height;
rectLocale.x = startPoint.x < currentPoint.x ? startPoint.x
: Math.max(dx, dy);
rectLocale.y = startPoint.y < currentPoint.y ? startPoint.y
: Math.min(dx, dy);
} else {
rectLocale.x = Math.min(currentPoint.x, startPoint.x);
rectLocale.y = Math.min(currentPoint.y, startPoint.y);
}
if (e.getSource() instanceof JComponent) {
((JComponent) e.getSource()).repaint();
}
}
#Override
public void mouseReleased(MouseEvent e) {
if (rectSize.width <= 0 || rectSize.height <= 0) {
capture = null;
} else {
capture = raw.getSubimage(Math.max(0, rectLocale.x),
Math.max(0, rectLocale.y), rectSize.width, rectSize.height);
}
if (e.getSource() instanceof JComponent) {
((JComponent) e.getSource()).repaint();
}
}
#Override
public void mouseWheelMoved(MouseWheelEvent e) {
zoom = Math.min(2000, Math.max(0, zoom + e.getUnitsToScroll() * 10));
if (e.getSource() instanceof JComponent) {
((JComponent) e.getSource()).repaint();
}
}
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
Example example = new Example();
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
}