Develop Reference

java code not exporting buffered image when no errors are present

My Java code below places a image on a label.The button when triggered should export the image. There are no runtime error but nothing is being exported. I assume the issue is during the conversion from image icon to buffered image which occurs in b3.addActionListener(new ActionListener() {. I am not seeing anything exported at all not even a blank image.
import java.awt.BorderLayout;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
public class ren {
Frame f;
JLabel b2 = new JLabel("");
ren() throws IOException {
f = new JFrame();
b2.setIcon(new ImageIcon("/Users/johnzalubski/Desktop/dropIn/Complete-Audi-Buying-Guide-gear-patrol-lead-full.jpg"));
JButton b3 = new JButton("Exported");
File file = new File("aa.png");
f.add(b2, BorderLayout.CENTER);
f.add(b3, BorderLayout.SOUTH);
f.setSize(400, 500);
f.setVisible(true);
b3.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
Icon ico = b2.getIcon();
// Create a buffered image
BufferedImage bimg = new BufferedImage(ico.getIconWidth(), ico.getIconHeight(),
BufferedImage.TYPE_INT_RGB);
// Create the graphics context
Graphics g = bimg.createGraphics();
// Now paint the icon
ico.paintIcon(null, g, 0, 0);
g.dispose();
BufferedImage scaledButtonImage =
new BufferedImage(400, 1000, bimg.getType());
Graphics g1 = scaledButtonImage.createGraphics();
g1.drawImage(scaledButtonImage, 0, 0, 400, 1000, null);
//
g1.dispose();
b2.setIcon(new ImageIcon(bimg));
try {
ImageIO.write(bimg, "png", file);
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
});
}
public static void main(String[] args) throws IOException {
new ren();
}
}

JPanel created on click not appearing

The below code is not my actual code but a concise, runnable remake of what I am trying to achieve. I want the JPanel CP, an instance of clickPanel, to appear when the user clicks on the image in JPanel hasAnImage. I can see in the Netbeans console that the is executing because of the Sys.out.print, but nothing appears on the screen. I have tried setting visible to false then true again and revalidate() in the mousePressed event; the image moves to the left, but nothing appears on the screen. The goal is for CP to appear. What am I missing? Hope my question is clear.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.BorderFactory;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class Testo extends JFrame{
public Testo(){
BufferedImage image = null;
try {
image = ImageIO.read(new File("C:\\Users\\someimage.jpg"));
} catch (IOException ex) {
ex.printStackTrace();
}
;
final JLabel label = new JLabel(new ImageIcon(image));
JPanel hasAnImage = new JPanel();
hasAnImage.addMouseListener(new MouseAdapter(){
#Override //I override only one method for presentation
public void mousePressed(MouseEvent e) {
clickPanel CP = new clickPanel();
hasAnImage.add(CP);
revalidate();
//setVisible(false);
//setVisible(true);
}
});
hasAnImage.add(label);
add(hasAnImage);
setVisible(true);
}
public static void main(String[] args) {
Testo frame = new Testo();
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
frame.getContentPane().setBackground(Color.WHITE);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public class clickPanel extends JPanel{
public clickPanel() {
setPreferredSize(new Dimension(100,60));
setMaximumSize(new Dimension(100,60));
setBackground(new Color(1.0f,1.0f,1.0f,0.1f));
setBorder(BorderFactory.createMatteBorder(2,2,2,2,Color.GREEN));
System.out.println("This is being executed...");
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setFont(new Font("Arial", Font.PLAIN, 12));
g.setColor(Color.GREEN);
g.drawString("CLICK", 2, 2);
}
}
}

Beyond revalidate();ing the pane, you also need to repaint(); it. Thus your mousePressed method should become:
public void mousePressed(MouseEvent e) {
clickPanel CP = new clickPanel();
hasAnImage.add(CP);
revalidate();
repaint();
}
For further reading: http://docs.oracle.com/javase/7/docs/api/java/awt/Component.html#repaint()

How do I draw an image in the shape of a parallelogram?

So, I know that images can be cropped, shrunk, and expanded, but can you adapt an image into the shape of a parallelogram? I'm using Java Swing to draw images. I was thinking maybe some class or some method of BufferedImage might do the trick, but I couldn't find anything. I have also searched Google for a while, but I cannot find an answer. Does anyone know of a way I could do this, or a webpage that explains it? Thanks in advance.

You could use AffineTransform.getShearInstance.
This example uses a AffineTransformOp to "filter" the original image
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.RenderingHints;
import java.awt.geom.AffineTransform;
import java.awt.image.AffineTransformOp;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class SkewImage {
public static void main(String[] args) {
new SkewImage();
}
public SkewImage() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
setLayout(new GridLayout(1, 2));
try {
BufferedImage original = ImageIO.read(new File("C:\\hold\\thumbnails\\Megatokyo_707___Torn_by_crusaderky.jpg"));
BufferedImage skew = new BufferedImage(original.getWidth(), original.getHeight(), BufferedImage.TYPE_INT_ARGB);
// Adjust the image width if we use a negative skew...
double skewX = 0.3d;
double x = (skewX < 0) ? -skewX * original.getHeight() : 0;
AffineTransform at = AffineTransform.getTranslateInstance(x, 0);
at.shear(skewX, 0);
AffineTransformOp op = new AffineTransformOp(at,
new RenderingHints(RenderingHints.KEY_INTERPOLATION,
RenderingHints.VALUE_INTERPOLATION_BICUBIC));
skew = op.filter(original, null);
add(new JLabel(new ImageIcon(original)));
add(new JLabel(new ImageIcon(skew)));
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
}

Just an example using a Java image processing framework.
Output:
public class SkewExample extends JFrame{
MarvinImagePlugin skew = MarvinPluginLoader.loadImagePlugin("org.marvinproject.image.transform.skew");
public SkewExample(){
super("Skew Example");
// Layout
setLayout(new GridLayout(6,1));
// Load Image
MarvinImage image = MarvinImageIO.loadImage("./res/chamaleon.jpg");
skew.setAttribute("skew", "Horizontal");
// Process the image multiple times with different angle.
for(int i=1; i<=6; i++){
add(new JLabel(new ImageIcon(skew(image, i*7).getBufferedImage())));
}
setSize(340,880);
setVisible(true);
}
private MarvinImage skew(MarvinImage imageIn, int angle){
skew.setAttribute("SkewAngle", angle);
MarvinImage ret = new MarvinImage(imageIn.getWidth(),imageIn.getHeight());
ret.fillRect(0, 0,imageIn.getWidth(),imageIn.getHeight(), new Color(238,238,238));
ret.update();
skew.process(imageIn, ret);
ret.update();
return ret;
}
public static void main(String[] args) {
new SkewExample().setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}

'Highgui cannot be resolved', JavaCV, Eclipse

I'm trying to set up face detection with JavaCV. I've got working code with cvLoadImage but when I try to load an image via Highgui.imread there's an error: 'Highgui cannot be resolved' and 'Highgui' has red wavy underlining. For some reason Eclipse cannot deal properly with imported com.googlecode.javacv.cpp.opencv_highgui or ...?
Problem here:
CvMat myImg = Highgui.imread(myFileName);
Full code:
import java.awt.EventQueue;
import java.awt.Insets;
import javax.swing.ImageIcon;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import java.awt.BorderLayout;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import com.googlecode.javacv.cpp.opencv_core.CvMemStorage;
import com.googlecode.javacv.cpp.opencv_core.CvRect;
import com.googlecode.javacv.cpp.opencv_core.CvScalar;
import com.googlecode.javacv.cpp.opencv_core.CvSeq;
import com.googlecode.javacv.cpp.opencv_core.IplImage;
import com.googlecode.javacv.cpp.opencv_objdetect.CvHaarClassifierCascade;
import static com.googlecode.javacv.cpp.opencv_core.*;
import static com.googlecode.javacv.cpp.opencv_highgui.*;
import static com.googlecode.javacv.cpp.opencv_objdetect.*;
import java.awt.Button;
import java.io.File;
import javax.swing.SwingConstants;
import javax.swing.JLabel;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import com.googlecode.javacv.cpp.opencv_core.CvMat;
import com.googlecode.javacv.cpp.opencv_highgui;
//import opencv_highgui;
public class Form1 {
static private final String newline = "\n";
JButton openButton, saveButton;
JTextArea log;
JFileChooser fc;
String myFileName = "";
//Load haar classifier XML file
public static final String XML_FILE =
"resources/!--master--haarcascade_frontalface_alt_tree.xml";
private JFrame frame;
//Detect for face using classifier XML file
public static void detect(IplImage src){
//Define classifier
CvHaarClassifierCascade cascade = new CvHaarClassifierCascade(cvLoad(XML_FILE));
CvMemStorage storage = CvMemStorage.create();
//Detect objects
CvSeq sign = cvHaarDetectObjects(
src,
cascade,
storage,
1.1,
3,
0);
cvClearMemStorage(storage);
int total_Faces = sign.total();
//Draw rectangles around detected objects
for(int i = 0; i < total_Faces; i++){
CvRect r = new CvRect(cvGetSeqElem(sign, i));
cvRectangle (
src,
cvPoint(r.x(), r.y()),
cvPoint(r.width() + r.x(), r.height() + r.y()),
CvScalar.RED,
2,
CV_AA,
0);
}
//Display result
cvShowImage("Result", src);
cvWaitKey(0);
}
/**
* Create the application.
*/
public Form1() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
JLabel Label1 = new JLabel(" ");
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 301, 222);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JButton btnDetect = new JButton("Detect");
btnDetect.setVerticalAlignment(SwingConstants.TOP);
btnDetect.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
//IplImage img = cvLoadImage("resources/lena.jpg");
IplImage img = cvLoadImage(myFileName);
CvMat myImg = Highgui.imread(myFileName);
detect(img);
}
});
frame.getContentPane().add(btnDetect, BorderLayout.SOUTH);
Label1.setHorizontalAlignment(SwingConstants.CENTER);
frame.getContentPane().add(Label1, BorderLayout.CENTER);
JButton btnNewButton = new JButton("Open");
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
JFileChooser fileopen = new JFileChooser();
int ret = fileopen.showDialog(null, "Открыть файл");
if (ret == JFileChooser.APPROVE_OPTION) {
File file = fileopen.getSelectedFile();
myFileName = file.getAbsolutePath();
Label1.setText(myFileName);
}
}
});
frame.getContentPane().add(btnNewButton, BorderLayout.NORTH);
}
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Form1 window = new Form1();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
//Load image
//IplImage img = cvLoadImage("resources/lena.jpg");
//detect(img);
}
}
External JARs: http://pasteboard.co/jwqNHC9.png
Full project in ZIP
I've also followed all steps from here: http://opencvlover.blogspot.in/2012/04/javacv-setup-with-eclipse-on-windows-7.html
Any help will be appreciated.

Mat m = Highgui.imread(myFileName); is from the builtin opencv java wrappers , not from javacv ( which is a independant, 3rd party wrapper ).
unfortunately, both concurrent apis are pretty incompatible, as javacv is wrapping the outdated c-api, and the opencv ones are wrapping the more modern c++ api.

Autoscroll a JScrollpane when dragging an object

I have created a appointment calendar which essentially is a JPanel which contains other movable and resizable JPanels all surrounded by a JScrollpane, this all works well and I am able to scroll around the JPanel using the scrollbars correctly. I close to finishing my application but would like to achieve one more thing.
What I would like to do is when a user is moving the appointment (JPanel), when you reach the edge of scrollpane it automatically will scroll at a desired speed. I am confused which existing method or class can do this (if there is one) or if anyone knows of a jar library available out there that will suit my needs?
Is that being lazy? Yeah probably, I guess I should code it myself, if you do agree could someone suggest where I would start? I'm still learning Java and I might need a gentle nudge to keep my code clean and tidy.
If I can provide anymore detail to help with an answer, let me know.

Ok, it's actually not much complicated. You need to call setAutoscroll(true); on your "scrollable" component and add a MouseMotionListener which invokes scrollRectToVisible.
Here is a small example code:
import java.awt.BorderLayout;
import java.awt.Rectangle;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.awt.event.MouseMotionListener;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
public class TestImageResize {
protected void initUI() throws MalformedURLException, IOException {
final JFrame frame = new JFrame(TestImageResize.class.getSimpleName());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
BufferedImage bi = ImageIO.read(new URL(
"http://www.desktopwallpaperhd.net/wallpapers/19/5/islands-paradise-maldive-nature-background-image-landscape-194469.jpg"));
JPanel panel = new JPanel(new BorderLayout());
JLabel label = new JLabel(new ImageIcon(bi));
panel.add(label);
MouseMotionListener doScrollRectToVisible = new MouseMotionAdapter() {
#Override
public void mouseDragged(MouseEvent e) {
Rectangle r = new Rectangle(e.getX(), e.getY(), 1, 1);
((JPanel) e.getSource()).scrollRectToVisible(r);
}
};
panel.addMouseMotionListener(doScrollRectToVisible);
panel.setAutoscrolls(true);
frame.add(new JScrollPane(panel));
frame.pack();
frame.setSize(frame.getWidth() / 2, frame.getHeight() / 2);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
try {
new TestImageResize().initUI();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
});
}
}