FULL PRODUCT VERSION :
java version "1.4.2_05"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_05-b04)
Java HotSpot(TM) Client VM (build 1.4.2_05-b04, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

A DESCRIPTION OF THE PROBLEM :
With antialiasing turned on, rotated fonts at 0,90,180,270 degrees are drawn much darker than all other angles, including angles close to 90 degree multiples, like 0.01, 90.01 etc.

I suspect some code treats 90-degree rotation multiples as "special"


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
With antialiasing turned on, derive a font from an existing font using
an AffineTransform.getRotateInstance() using an angle that is
very close to a multiple of 90 degrees (90.01 for example) and the resulting text is drawn far lighter that if the angle was a multiple of 90 degrees.


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Expected rotated derived fonts to be drawn as dark as each other regardless of rotation angle.
ACTUAL -
Rotated derived fonts were drawn much darker if the rotation angle was a multiple of 90 degrees.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.awt.*;
import java.awt.geom.AffineTransform;
import javax.swing.*;

public class AATest extends JComponent
{
  static final double RADIANS_PER_DEGREE = 0.01745329251994;
private Font font;
  public AATest()
{
font = new Font("Serif",Font.PLAIN,10);
  }

  protected void paintComponent(Graphics g)
{
Graphics2D g2 = (Graphics2D)g;
Dimension dim = getSize();
paintComponent(g2,dim.width,dim.height);
}

protected void paintComponent(Graphics2D g,int width,int height)
{
g.setColor(Color.white);
g.fillRect(0,0,width,height);
g.setColor(Color.black);
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);
//g.drawLine(0,0,width,height);
g.setFont(font);
int y=20;
g.drawString("Horizontal",10,y);y+=20;

Font rotatedfont=getRotatedFont(0.01);
g.setFont(rotatedfont);
g.drawString("Rotated 0.01 degrees",10,y);y+=20;

rotatedfont=getRotatedFont(0.0);
g.setFont(rotatedfont);
g.drawString("Rotated 0.0 degrees",10,y);y+=20;

rotatedfont=getRotatedFont(-90.0);
g.setFont(rotatedfont);
g.drawString("Rotated 90 degrees",10,y);

rotatedfont=getRotatedFont(-90.01);
g.setFont(rotatedfont);
g.drawString("Rotated 90.01 degrees",30,y);
}

Font getRotatedFont(double angleDegrees)
{
double angle=angleDegrees*RADIANS_PER_DEGREE;
  AffineTransform xf=AffineTransform.getRotateInstance(-angle);
  return font.deriveFont(xf);
}

public static void main(String[] args) throws Exception
{
JFrame f = new JFrame("Antialias test");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().setLayout(new BorderLayout());
f.getContentPane().add(new AATest(),BorderLayout.CENTER);
f.setBounds(50,50,100,210);
f.setVisible(true);
}
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Turn off antialiasing (too bad since things look so nice with it turned on)
###@###.### 10/21/04 10:08 GMT