import java.awt.*;
//import java.applet.Applet;

class shellPanel extends Panel
{	Raup 		applet;
	int			startAng	= 0;
	int			endAng		= 1440;
	int			stepAng 	= 5;
	double		left		= 0.;
	double		top			= 0.;
	double		width		= 0.;
	double		height		= 0.;
	double		scale		= 0.;

	shellPanel  ( Raup parent )
	{
		applet = parent;
	}

	public boolean mouseDown( Event evt, int x, int y )	// redraw when screen clicked
	{
		repaint();
		return true;
	}

	public void makeRing ( int angle )		// calculates left, top, width, height in shell coords
	{// int		angle			// whorl is at angle (in degrees)...
		double	dTheta;			// whorl is at angle (in radians)...
		double	b1, b2;			// original whorl diameter
		double	a1, a2;			// original offset of edge from axis
		double	T1, T2;			// original translation
		double	dW, dT, dD;		// local versions of shell parameters
		double	alpha;			// angle of presentation

//	set and calc the initial shell conditions
	//	set local parameters
		dW		= applet.dW;
		dD		= applet.dD;
		dT		= applet.dT;
	//	calc initial whorl size, offset
		b1		= 10.0;
		a1		= ( b1 * dD ) / ( 1.0 - dD );
		T1		= 0.0;
	//  calc trigonmetric values
		dTheta	= ((double) angle) * Math.PI / 180.;	// angle to radians
		alpha	= Math.cos ( dTheta );

//	calc new whorl size and position
		b2		= Math.pow ( b1, ( dTheta * Math.log ( dW ) ) / ( 2.0 * Math.PI ) );
		a2		= ( b2 * dD ) / ( 1.0 - dD );
		if ( ( a1 + b1 ) == ( a2 + b2 ) )
		{
			T2	= T1;
		}
		else
		{
			T2	= T1 + ( dT * ( a2 + b2 - a1 - b1 ) );
		}
// calc screen parameters
		top		= T2 - ( b2 / 2.0 );
		left	= Math.min ( alpha * a2, alpha * ( a2 + b2 ) );
		height	= b2;
		width	= Math.abs( alpha * b2 );
	}

	public void paint( Graphics g )
	{
		int		i;
		double	minX, maxX, minY, maxY;
		double	scaleH;
		int		windBorder	= 5;
		double	rangeX, rangeY, midY;
		int		windWidth, windHeight;
		int		windMidW, windMidH;
		int		Yoffset, iMidY;
//	get plot area
		windWidth	= size().width  - 2 * windBorder;
		windHeight	= size().height - 2 * windBorder;
		windMidW	= size().width/2;
		windMidH	= size().height/2;
//	set up drawing area
		g.setColor ( Color.white );
		g.fillRect( 0, 0, size().width, size().height );
		g.setColor ( Color.black );
//	determine drawing scale
		makeRing ( startAng );
		minX = left;
		maxX = left + width;
		minY = top;
		maxY = top + height;
		for ( i = startAng; i <= endAng; i += 90 )
		{
			makeRing ( i );
			minX	= Math.min ( minX, left );
			maxX	= Math.max ( maxX, ( left + width  ) );
			minY	= Math.min ( minY, top  );
			maxY	= Math.max ( maxY, ( top  + height ) );			
		}
// draw 'shell'
	//	center horizontally in pane
		rangeX	= 2. * Math.max ( Math.abs( maxX ), Math.abs ( minX ) );
	// center vertically in pane
		rangeY	= maxY - minY;
		midY	= ( maxY + minY ) / 2.0;
	//	scale image to fit
		scaleH	= ( (double) windWidth  ) / rangeX;
		scale	= ( (double) windHeight ) / rangeY;
		if ( scale > scaleH ) scale = scaleH; // use minimum
		iMidY	= ( int ) ( scale * midY );
	// draw rings
		for ( i = startAng; i <= endAng; i += stepAng )
		{
			makeRing ( i );		// calculates left, top, width, height in shell coords
			g.drawOval (
				  windMidW +			(int) ( left   * scale  ),		// left
				( windMidH - iMidY +	(int) ( top    * scale  ) ),	// top
										(int) ( width  * scale  ),		// width
										(int) ( height * scale  ) );	// height
		}
/*	//	draw circles for visual fill
		for ( i = startAng; i <= endAng; i += stepAng )
		{
			makeRing ( i );		// calculates left, top, width, height in shell coords
			setBackground ( Color.black );
			g.fillOval (
				  windMidW +			(int) ( left   * scale  ),		// left
				( windMidH - iMidY +	(int) ( top    * scale  ) ),	// top
										(int) ( height * scale  ),		// width
										(int) ( height * scale  ) );	// height
			setBackground ( Color.white );
		}
*/
//	update the valued in the informational panel
		applet.setInfoText();
		applet.info.update();
	}
}