import java.awt.*;

//==============================================================================
// HueDial Class
//
// AGG - Alexander Gee
//
// 041497 - code converted to Java
//==============================================================================
public class HueDial extends Canvas
{
	private Dimension offsize;         // off screen buffer size
	private Graphics  offgraphics;     // off screen buffer
	private Image     offimage;        // off screen buffer image
	private boolean   redrawall;       // redraw state
	private int       width;           // Component width
	private int       height;          // Component height
	private Color     hue_list[];      // list   of colors
	private int       hue_count;       // number of colors
	private double    oldpos;          // previous marker position (radians)
	private int       diam_outer;      // dial outer  diameter
	private int       diam_inner;      // dial inner  diameter
	private int       diam_marker;     // dial marker diameter
	private int       center_x;        // dial center x-position
	private int       center_y;        // dial center y-position

	public  double    newpos;           // current  marker position (radians)


	// HueDial Class Constructor 1:
	//--------------------------------------------------------------------------
	public HueDial() 
	{
		width       = 200;
		height      = 200;
		resize( width, height );

		diam_outer  = 100;
		diam_inner  = 40;
		diam_marker = 120;
		center_x    = width/2;
		center_y    = height/2;
		newpos      = 0.0;
		oldpos      = 0.0;
		redrawall   = true;

		hue_count   = 256;
		hue_list    = new Color[hue_count];
		for( int i = 0; i < hue_count; i++ )
		{
			hue_list[i] = new Color( 
				Color.HSBtoRGB( 
					(float)i/(float)hue_count, (float)1, (float)1 ) );
		}
	}

	// HueDial Class Constructor 2:
	//--------------------------------------------------------------------------
	public HueDial( int width, int height ) 
	{
		this.width  = width;
		this.height = height;
		resize( this.width, this.height );

		if( width < height ) {
			diam_outer = width - 60;
		} else {
			diam_outer = height - 60;
		}
		diam_inner  = 40;
		diam_marker = diam_outer + 20;
		center_x    = this.width/2;
		center_y    = this.height/2;
		newpos      = 0.0;
		oldpos      = 0.0;
		redrawall   = true;

		hue_count   = 256;
		hue_list    = new Color[hue_count];
		for( int i = 0; i < hue_count; i++ )
		{
			hue_list[hue_count-1-i] = new Color( 
				Color.HSBtoRGB( 
					(float)i/(float)hue_count, (float)1, (float)1 ) );
		}
	}

	public void update( Graphics g )
	{
		paint( g );
	}

	public void paint( Graphics g ) 
	{
		if( offgraphics == null ) {
			offsize     = size();
			offimage    = createImage( offsize.width, offsize.height );
			offgraphics = offimage.getGraphics();
		}

		if( redrawall ) {
			offgraphics.setColor( getBackground() );
			offgraphics.fillRect( 0, 0, width, height );
			offgraphics.setColor( Color.white );
			offgraphics.drawRect( 5, 5, width-10, height-10 );
			for( int i = 0; i < 360; i++ )
			{
				offgraphics.setColor( hue_list[(int)(i*255.0/360.0)] );
				offgraphics.fillArc(
					center_x - (int)(diam_outer/2.0),
					center_y - (int)(diam_outer/2.0),
					diam_outer, diam_outer, 360-i, 3 );
			}
			offgraphics.setColor( getBackground() );
			offgraphics.fillArc(
				center_x - (int)(diam_inner/2.0),
				center_y - (int)(diam_inner/2.0),
				diam_inner, diam_inner, 0, 360 );
		}

		g.drawImage( offimage, 0, 0, this );

		g.setColor( Color.black );
		//g.drawString( "( " + (int)(newpos*180.0/Math.PI) + " )", 10, 20 );
		int mx = center_x + (int)(Math.cos( newpos )*diam_marker/2.0);
		int my = center_y - (int)(Math.sin( newpos )*diam_marker/2.0);
		g.fillArc( mx-2, my-2, 6, 6, 0, 360 );
	}

	// MOUSE SUPPORT:
	//      The mouseDown() method is called if the mouse button is pressed
	// while the mouse cursor is over the applet's portion of the screen.
	//--------------------------------------------------------------------------
	public boolean mouseDown( Event evt, int x, int y )
	{
		calculatePositionAngle( x, y );
		redrawall = false;
		repaint();
		return false;
	}

	// MOUSE SUPPORT:
	//      The mouseUp() method is called if the mouse button is released
	// while the mouse cursor is over the applet's portion of the screen.
	//--------------------------------------------------------------------------
	public boolean mouseUp( Event evt, int x, int y )
	{
		calculatePositionAngle( x, y );
		redrawall = false;
		repaint();
		return false;
	}

	// MOUSE SUPPORT:
	//      The mouseDrag() method is called if the mouse cursor moves over the
	// applet's portion of the screen while the mouse button is being held.
	//--------------------------------------------------------------------------
	public boolean mouseDrag( Event evt, int x, int y )
	{
		calculatePositionAngle( x, y );
		redrawall = false;
		repaint();
		return false;
	}

	//--------------------------------------------------------------------------
	private void calculatePositionAngle( int x, int y )
	{
		double xx = x - center_x;
		double yy = center_y - y;
		oldpos    = newpos;
		if( -0.001 < xx  &&  xx < 0.001 ) {
			if( yy < 0 ) {
				newpos = 0.5*Math.PI;
			} else {
				newpos = 1.5*Math.PI;
			}
		} else {
			newpos = Math.atan( yy/xx );
			if( yy > 0 ) {
				if( xx > 0 ) {
					// no action
				} else {
					newpos = Math.PI + newpos;
				}
			} else {
				if( xx < 0 ) {
					newpos = Math.PI + newpos;
				} else {
					newpos = 2.0*Math.PI + newpos;
				}
			}
		}
	}


	// public access functions
	//-------------------------------------------------------------------------
	public float getValue()
	{
		return (float)(newpos*180.0/Math.PI); // convert RAD to DEG
	}

	public void setValue( float pos )
	{
		newpos = (double)pos*Math.PI/180.0; // convert DEG to RAD
		repaint();
	}
}