rotating a (String) object ninety degrees

[Kevin Simonson]

If I extend (JPanel) and in my (paintComponent()) method I call (drawString()) on a (Graphics) object, I can pass in a (String) object as my first parameter and cause that (String) object to be printed horizontally in my (JPanel) window. Is there a way to print that (String) object vertically instead of horizontally? I need to switch each of the characters in the (String) object so that they occur one on top of the other instead of horizontally next to each other, and I also need to rotate each of the characters ninety degrees. Does anybody know how to do that?

[Tim Moores]

By chance, I have an age-old piece of code around that does exactly that. Well, it also writes an image file with the result, but to do that it needs to tweak the Graphics2D to begin with.

import java.awt.*;
import java.awt.geom.Rectangle2D;
import java.awt.image.*;
import java.io.*;
import javax.imageio.ImageIO;

public class VerticalText
{
	private static final String IMAGE_TYPE = "jpg";

	private static final int ORIENTATION_RIGHT = 1;
	private static final int ORIENTATION_UP = 2;
	private static final int ORIENTATION_DOWN = 3;

	public static void main (String[] args) throws Exception
	{
		String fontName = "Arial";

		final String text = args[0];
		final int fontSize = Integer.parseInt(args[1]);
		int buffer = 3;
		Color bgColor = Color.WHITE;
		Color textColor = Color.BLACK;

		int width = 250;
		try {
			width = Integer.parseInt(args[3]);
		} catch (Exception ex) { }

		int height = 250;
		try {
			height = Integer.parseInt(args[4]);
		} catch (Exception ex) { }

		int orientation = ORIENTATION_DOWN;
		try {
			orientation = Integer.parseInt(args[2]);
			if ((orientation < ORIENTATION_RIGHT) || (orientation > ORIENTATION_DOWN))
				orientation = ORIENTATION_DOWN;
		} catch (Exception ex) { }

		//Create an image width x height, before cropping
		BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
		Graphics2D g2d = (Graphics2D) bufferedImage.getGraphics();
		g2d.setBackground(bgColor);
		g2d.clearRect(0, 0, width, height);

		// create font metrics
		final Font font = new Font(fontName, Font.PLAIN, fontSize);
		g2d.setFont(font);
		final FontMetrics fm = g2d.getFontMetrics();

		g2d.setColor(textColor);
		g2d.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);

		Rectangle2D rect = fm.getStringBounds(text, g2d);

		g2d.drawString(text, buffer, (int) rect.getHeight() - fm.getDescent() + buffer);
		BufferedImage croppedImage = bufferedImage.getSubimage(0, 0,
			Math.min(width, (int) rect.getWidth() + 2 * buffer),
			Math.min(height, (int) rect.getHeight() + 2 * buffer));

		BufferedImage finalImage = null;

		if (orientation == ORIENTATION_RIGHT) {
			finalImage = croppedImage;
		} else {
			int croppedH = croppedImage.getHeight();
			int croppedW = croppedImage.getWidth();
			finalImage = new BufferedImage(croppedH, croppedW, BufferedImage.TYPE_INT_RGB);
			for (int y=0; y<croppedH; y++) {
				for (int x=0; x<croppedW; x++) {
					int rgb = croppedImage.getRGB(x, y);
					rgb &= 0xFFFFFF;
					if (orientation == ORIENTATION_DOWN) {
						finalImage.setRGB(croppedH-y-1, x, rgb);
					} else {
						finalImage.setRGB(y, croppedW-x-1, rgb);
					}
				}
			}
		}

		//Free graphic resources
		g2d.dispose();

		//Write the image as a PNG
		OutputStream out = new FileOutputStream("picture.jpg");
		ImageIO.write(finalImage, IMAGE_TYPE, out);
		out.close();
	}
}

[Campbell Ritchie]

The way I would do it requires a second Graphics object. I have had difficulty with Graphics objects when I apply an affine transform to them; it doesn't seem to reverse properly. It is usually shear() that causes problems; translate() and scale() can usually be reversed.

// ...
@Override
protected void paintComponent(Graphics g)
{
   super.paintComponent(g); // remove any previous painting
   Graphics2D g2 = (Graphics2D)g; // cast should always succeed
   // ...
   {
      Graphics2D g3 =(Graphics2D)g.create();
      g3.rotate(Math.PI / 2.0);  // 90° anti‑clockwise
      g3.drawString("Campbell is brilliant");
      /* Don't know whether you need to call dispose() */
   }
   // ...
}

Graphics#create() method. Graphics2D#rotate() method.

[Carey Brown]

Kevin, can you provide a screen snapshot as to how you expect it to look. From your description I'm guessing (?) you want:
A
B
C

and not just ABC rotated 90 degrees.

[Rob Camick]

Maybe instead of custom painting on your panel you can use Icons.

Check out:

1) Text Icon
2) Rotated Icon

They might allow you to be creative and use any component that can display Icons instead of doing the custom painting.

[Kevin Simonson]

Carey Brown wrote:Kevin, can you provide a screen snapshot as to how you expect it to look. From your description I'm guessing (?) you want:
A
B
C

and not just ABC rotated 90 degrees.

I don't know how to provide a screen snapshot; I was hoping on using the Java interpreter to display it, and I can't figure out how to do that; I don't know any other way to display it. But in response to your guess, I actually do not want
A
B
C
instead I do want ABC rotated 90 degrees.

[Carey Brown]

That's the easier of the two problems. Campbell's suggestion should work for you.

[Kevin Simonson]

Campbell Ritchie wrote:The way I would do it requires a second Graphics object. I have had difficulty with Graphics objects when I apply an affine transform to them; it doesn't seem to reverse properly. It is usually shear() that causes problems; translate() and scale() can usually be reversed.

// ...
@Override
protected void paintComponent(Graphics g)
{
   super.paintComponent(g); // remove any previous painting
   Graphics2D g2 = (Graphics2D)g; // cast should always succeed
   // ...
   {
      Graphics2D g3 =(Graphics2D)g.create();
      g3.rotate(Math.PI / 2.0);  // 90° anti‑clockwise
      g3.drawString("Campbell is brilliant");
      /* Don't know whether you need to call dispose() */
   }
   // ...
}

Graphics#create() method. Graphics2D#rotate() method.

Campbell, using what you said I wrote:

import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Point;
import java.awt.Font;
import java.util.List;
import java.util.ArrayList;
import java.util.Scanner;
import java.io.File;
import java.io.PrintStream;
import java.io.FileNotFoundException;

public class DsgRot extends JPanel
{
  private static final PrintStream SY_O      = System.out;
  private static final         int HF_WIDTH  = 780;
  private static final         int HEIGHT    = 810;
  private static final         int RADIUS    =  10;
  private static final         int NM_EDGES  =  20;
  private static final         int X_OFFSET  =  -6;
  private static final         int Y_OFFSET  =   5; 
  private static final      Double DST_BTW   =  55.0;
  private static final      Double Y_ZERO    = HEIGHT - 3.0 * DST_BTW - RADIUS;
  private static final      Double Z_SEP     = 200.0;
  private static final      Double TO_RDNS   = 2.0 * Math.PI / NM_EDGES;
  private static final      Double SQ_RT_P75 = Math.sqrt( 0.75);

  List< Arc> arcs;

  private static void problem (  String complaint
                              ,  String pLine
                              , Scanner source)
  {
    SY_O.println( complaint + ':');
    SY_O.println( pLine);
    source.close();
    System.exit( 1);
  }

  private static Point plot ( StPoint pnt)
  {
    int xCoo = pnt.getXCoo();
    int yCoo = pnt.getYCoo();
    return
      new Point
        ( HF_WIDTH + (int) (SQ_RT_P75 * DST_BTW * (yCoo - xCoo) + 0.5)
        , (int)
            (Y_ZERO + DST_BTW * (yCoo + xCoo) / 2.0 - Z_SEP * pnt.getZCoo()
                    + 0.5));
  }

  private DsgRot ( Scanner source)
  {
    arcs            = new ArrayList<>();
    boolean pstStrt = false;
    boolean rchdGl  = false;
    Arc current     = null;
    String pLine;
    int plLength;
    int cooIx;
    for (; ; )
    { pLine    = source.nextLine();
      plLength = pLine.length();
      if (2 < plLength)
      { if (pLine.charAt( 0) == 'H')
        { break;
        }
        if (! pLine.substring( 0, 3).equals( "   "))
        { if (pstStrt)
          { if (current.nmCoos() < 2)
            { problem( "Arc before line only had one point", pLine, source);
            }
            current.setGoal( rchdGl);
            arcs.add( current);
          }
          else
          { pstStrt = true;
          }
          rchdGl  = false;
          current = new Arc();
        }
        cooIx = pLine.indexOf( '(') + 1;
        if (0 <= cooIx)
        { current
            .addTriple
               ( pLine.charAt( cooIx) - '0', pLine.charAt( cooIx + 3) - '0'
                                           , pLine.charAt( cooIx + 6) - '0');
        }
        else
        { problem( "Input line didn't have an open paren", pLine, source);
        }
        if (pLine.endsWith( "*#*"))
        { rchdGl = true;
        }
      }
      else
      { problem
          ( "Input line's length " + plLength + " is too low", pLine, source);
      }
    }
    source.close();
    setPreferredSize( new Dimension( HF_WIDTH << 1, HEIGHT));
    setBackground( Color.WHITE);
  }

  public void paintComponent ( Graphics page)
  {
    super.paintComponent( page);
    Graphics2D flipped = (Graphics2D) page.create();
    flipped.rotate( Math.PI / 2.0);
    int angle;
    int state;
    Point center;
    double inRdns;
    int zCoo;
    int yCoo;
    int xCoo;
    int[] yCoos = new int[ 20];
    int[] xCoos = new int[ 20];
    for (zCoo = 0; zCoo < 4; zCoo++)
    { for (yCoo = 0; yCoo < 4; yCoo++)
      { for (xCoo = 0; xCoo < 4; xCoo++)
        { center = plot( new StPoint( xCoo, yCoo, zCoo));
          for (angle = 0; angle < NM_EDGES; angle++)
          { inRdns        = angle * TO_RDNS;
            xCoos[ angle] = center.x + (int) (RADIUS * Math.cos( inRdns) + 0.5);
            yCoos[ angle] = center.y + (int) (RADIUS * Math.sin( inRdns) + 0.5);
          }
          flipped.setColor( Color.RED);
          flipped.drawPolygon( xCoos, yCoos, 20);
          state = ((zCoo << 2) + yCoo << 2) + xCoo;
          flipped.setColor( Color.BLACK);
          flipped
            .drawString
               ( (9 < state ? "" : "0") + state, center.x + X_OFFSET
                                               , center.y + Y_OFFSET);
        }
      }
    }
    int ix;
    int arcLength;
    StPoint current;
    StPoint next;
    for (Arc arc : arcs)
    { next = arc.getCoos( 0);
      arcLength = arc.nmCoos();
      for (ix = 1; ix < arcLength; ix++)
      { current = next;
        next    = arc.getCoos( ix);
      }
    }
  }

  public static void main ( String[] arguments)
  {
    if (arguments.length == 1)
    { String srName = arguments[ 0];
      try
      { DsgRot dsg  = new DsgRot( new Scanner( new File( srName)));
        JFrame sgFr = new JFrame( "DsgRot " + srName);
        sgFr.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE);
        sgFr.getContentPane().add( dsg);
        sgFr.pack();
        sgFr.setVisible( true);
      }
      catch (FileNotFoundException nfExc)
      { SY_O.println( "Unable to open file \"" + srName + "\" for input!");
      }
    }
    else
    { SY_O.println( "Usage is");
      SY_O.println( "  java DsgRot <source>");
    }
  }
}

Then when I ran it with

java DsgRot Cube_15_10.0

I got a large (JFrame) window with "DsgRot Cube_15_10.0" in the upper left corner, but nothing actually appeared in the window; it's all completely white. Any idea what I'm doing wrong?

[Kevin Simonson]

Campbell Ritchie wrote:The way I would do it requires a second Graphics object. I have had difficulty with Graphics objects when I apply an affine transform to them; it doesn't seem to reverse properly. It is usually shear() that causes problems; translate() and scale() can usually be reversed.

// ...
@Override
protected void paintComponent(Graphics g)
{
   super.paintComponent(g); // remove any previous painting
   Graphics2D g2 = (Graphics2D)g; // cast should always succeed
   // ...
   {
      Graphics2D g3 =(Graphics2D)g.create();
      g3.rotate(Math.PI / 2.0);  // 90° anti‑clockwise
      g3.drawString("Campbell is brilliant");
      /* Don't know whether you need to call dispose() */
   }
   // ...
}

Graphics#create() method. Graphics2D#rotate() method.

Actually, let me make it easier. I tried:

import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;

public class Ritchie extends JPanel
{
  private Ritchie ()
  {
    setPreferredSize( new Dimension( 500, 500));
    setBackground( Color.GRAY);
  }

  public void paintComponent ( Graphics page)
  {
    super.paintComponent( page);
    Graphics2D flipped = (Graphics2D) page.create();
    flipped.rotate( Math.PI / 2.0);
    flipped.setColor( Color.GREEN);
    flipped.drawString( "Campbell is brilliant", 250, 250);
  }

  public static void main ( String[] arguments)
  {
    Ritchie ri = new Ritchie();
    JFrame rFr = new JFrame( "Ritchie");
    rFr.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE);
    rFr.getContentPane().add( ri);
    rFr.pack();
    rFr.setVisible( true);
  }
}

And then I executed "java Ritchie", and got a window with a white strip on top with an icon and "Ritchie" on the left, and then underneath it I got an apparently 500 pixel by 500 pixel square that was completely gray; there's no trace of a green "Campbell is brilliant" anywhere near the center of the square where it should have appeared. Once again, what am I doing wrong?

[Rob Camick]

flipped.drawString( "Campbell is brilliant", 250, 250);

When you do the rotate the string gets drawn down 250 and to the left 250, so effectively it is painted off the panel.

Instead try:

    flipped.drawString( "Campbell is brilliant", 0, 0);
    //flipped.drawString( "Campbell is brilliant", 250, 0);

to see the difference.

If you want the starting point to be (250, 250) then try:

    flipped.translate(250, 250);
    flipped.drawString( "Campbell is brilliant", 0, 0);

Another example to get you started:

import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;

public class Rotate    extends JComponent
{
    public void paintComponent(Graphics g)
    {
       	super.paintComponent(g);

        Graphics2D g2 = (Graphics2D)g.create();

        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON );
        g2.setFont( new Font( "Helvetica", Font.BOLD, 12 ) );

        for( double angle = 0; angle < 90; angle+=30 )
        {
            String text = "Rotate angle is " + (int)angle;
            AffineTransform af = new AffineTransform();
            af.translate(10, 10);
            af.rotate( Math.toRadians( angle ) );
            g2.setTransform( af );

            g2.setColor( Color.black );
            g2.drawString(text, 50, 0);
            g2.setColor( Color.red );
            g2.drawLine(0, 0, 200, 0 );
        }

		g2.dispose();
    }

    public static void main(String s[])
    {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
        f.getContentPane().add(new Rotate());
        f.setSize( 600, 600 );
        f.setVisible(true);
    }
}

[Kevin Simonson]

Rob Camick wrote:

flipped.drawString( "Campbell is brilliant", 250, 250);

When you do the rotate the string gets drawn down 250 and to the left 250, so effectively it is painted off the panel.

Thanks! I got my code working the way I like it. I really appreciate the help.

[Campbell Ritchie]

I forgot that rotation is around the (0, 0) point, so you would want to translate it by (width / 2, height / 2) (or similar) to move the origin to the centre of the display.