rotate text

[Raschin Ghanad]

can anyone help me, I am trying to rotate the text for the scale of my x-axis, but when I use the Graphics2D rotate-method, everything disappears...

I did it the following way:

g2.rotate(45.0d)
drawString("200",10,10);
g2.rotate(-45.0d)

Why don't I see anything?
Maybe I have to use other coordinates?
I tried many variants, but non worked...

Maybe theres another way to rotate a text?

[Rachel Swailes]

I think that in your second line that you need
g2.drawString("200",10,10);

Cheers,
Rachel

[Raschin Ghanad]

sorry, I forgot to write it correctly...
I did it with g2.drawString(...)

the real code was:

  
 for(int i=x0+range;i<x1;i=i+range) {   // Beschriftung
      g2.drawLine(i,y1-2,i,y1+2);    
      if(isMarking()) {
            scl_str = Integer.toString(scal);            
            g2.rotate(35.0d);            
            g2.drawString(scl_str,i-6,y1+15);            
            g2.rotate(-35.0d);
            scal = scal + range;
      }
    }

I tried to write it in an easy, understanding way...

[Craig Wood]

Rotating the graphics context happens at the origin, ie, at (0,0) of your JPanel so the rendered text is somewhere off the screen in the direction of 45 radians which is Math.toDegrees(45) % 360 = 58.31 degrees clockwise. 45 degrees is Math.PI/4 or Math.toRadians(45).

The java tutorial has some resources that you might enjoy:

The Performing Custom Painting lesson in the Creating a GUI with JFC/Swing trail covers the basics and contains links to more in–depth material.

The specialized trail 2D Graphics takes you a little farther. The Transforming Shapes, Text, and Images page in the Displaying Graphics with Graphics2D lesson has a discussion of rotating the graphics context.

Here's a demo:

import java.awt.*;
import java.awt.event.*;
import java.awt.font.*;
import java.awt.geom.*;
import javax.swing.*;
import javax.swing.event.*;
 
public class RotatingText
{
    public static void main(String[] args)
    {
        RotatingTextPanel textPanel = new RotatingTextPanel();
        RotationWrangler wrangler = textPanel.wrangler;
        JFrame f = new JFrame("click on white");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(wrangler.getTextPanel(), "North");
        f.getContentPane().add(textPanel);
        f.getContentPane().add(wrangler.getInputPanel(), "South");
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
}
 
class RotatingTextPanel extends JPanel
{
    double theta;
    boolean showBounds;
    String text;
    int x, y;
    Font font;
    RotationWrangler wrangler;
 
    public RotatingTextPanel()
    {
        theta = 0;
        showBounds = false;
        text = "";
        x = y = 0;
        font = new Font("lucida sans regular", Font.PLAIN, 18);
        wrangler = new RotationWrangler(this);
        addMouseListener(wrangler);
        setBackground(Color.white);
    }
 
    protected void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        g2.setFont(font);
        g2.rotate(theta, x, y);
        g2.drawString(text, x, y);
        System.out.println("text = " + text + "\tx = " + x + "\ty = " + y);
        if(showBounds)
        {
            FontRenderContext frc = g2.getFontRenderContext();
            float textWidth = (float)font.getStringBounds(text, frc).getWidth();
            LineMetrics lm = font.getLineMetrics(text, frc);
            float ascent = lm.getAscent();
            float descent = lm.getDescent();
            float height = ascent + descent;
            Rectangle2D r = new Rectangle2D.Double(x, y - ascent, textWidth, height);
            g2.setPaint(Color.red);
            g2.draw(r);
        }
    }
 
    public void setLocation(Point p)
    {
        x = p.x;
        y = p.y;
        text = wrangler.getText();
        repaint();
    }
 
    public void setShowBounds(boolean isVisible)
    {
        showBounds = isVisible;
    }
 
    public void setAngle(int degrees)
    {
        theta = Math.toRadians(degrees);
    }
}
 
class RotationWrangler extends MouseAdapter
{
    RotatingTextPanel textPanel;
    JTextField textField;
 
    public RotationWrangler(RotatingTextPanel rtp)
    {
        textPanel = rtp;
    }
 
    public void mousePressed(MouseEvent e)
    {
        textPanel.setLocation(e.getPoint());
    }
 
    public String getText()
    {
        return textField.getText();
    }
 
    public JPanel getTextPanel()
    {
        textField = new JTextField("hello world", 6);
        JPanel panel = new JPanel();
        panel.add(new JLabel("enter string"));
        panel.add(textField);
        return panel;
    }
 
    public JPanel getInputPanel()
    {
        final JCheckBox boundsBox = new JCheckBox("show bounds");
        boundsBox.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                textPanel.setShowBounds(boundsBox.isSelected());
            }
        });
        final SpinnerNumberModel model = new SpinnerNumberModel(0, -180, 180, 10);
        JSpinner spinner = new JSpinner(model);
        spinner.addChangeListener(new ChangeListener()
        {
            public void stateChanged(ChangeEvent e)
            {
                int angle = model.getNumber().intValue();
                textPanel.setAngle(angle);
            }
        });
        JPanel panel = new JPanel(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.insets = new Insets(2,2,2,2);
        gbc.weightx = 1.0;
        panel.add(boundsBox, gbc);
        gbc.anchor = gbc.EAST;
        panel.add(new JLabel("angle"), gbc);
        gbc.anchor = gbc.WEST;
        panel.add(spinner, gbc);
        return panel;
    }
}

[ August 04, 2004: Message edited by: Craig Wood ]

[David Weitzman]

You can also use Graphics2D.setComposite(AlphaComposite.getRotateInstance(theta)) to rotate text or anything else you want to draw.