//----------------------------------------------------------------------
//
// 		Slider
//
//----------------------------------------------------------------------

import java.awt.*;

public class Slider extends Canvas
{
	float		_value = 0.0f;
	float		_minValue, _maxValue;
	int			_oldXPos = 0;
	boolean		_clicked = false;
	Graphics	_offscreen;				// double buffering
	Image		_offscreenImage;
	int			_leftX, _rightX;		// positions of the end of the line
	Image		_bullet;
	Rectangle	_bulletRect;

 	//----------------------------------------------------------------------
	//	Construct a slider - a bullet on a line.  Returns value from 0-1.
	//----------------------------------------------------------------------
	public Slider( float inValue, float inMinValue, float inMaxValue)
	{
	//	_bullet = Toolkit.getDefaultToolkit().getImage("images/b2.gif");
		_bulletRect = new Rectangle( 0, 0, 8, 16 );
		_minValue = inMinValue;
		_maxValue = inMaxValue;
		
		setValue( inValue, false );
		
	}
	public Slider( float inValue )
	{	
		this( inValue, 0.0f, 1.0f );
	}
	
	public Dimension preferredSize() 
	{
		return new Dimension( 200, 16 );
	}
	
 	//----------------------------------------------------------------------
	// Accessors
 	//----------------------------------------------------------------------
	public float getValue() 
	{
		return _value;
	}
	
	public void setValue( 	float inValue, 
							boolean inIsMoreComing ) 	// flag if more events are coming soon
	{												// i.e. we're in mid-drag
		_value = inValue;
		if (_value > _maxValue)	
			_value = _maxValue;
		if (_value < _minValue)		
			_value = _minValue;

		positionBullet();
		deliverEvent( new Event( this, Event.ACTION_EVENT, new Boolean(inIsMoreComing) ));
	}

	void positionBullet()
	{
		float normalVal = _value / (_maxValue - _minValue);		// adjust to [0.0 - 1.0]
		
		_bulletRect.x = _leftX + (int) (normalVal * (_rightX - _leftX));
			
		invalidate();
		repaint();
	}
	
 	//----------------------------------------------------------------------
	//	paint - only draw things that might have changed
	//----------------------------------------------------------------------
	public void paint( Graphics inGfx )
	{
		if (_offscreenImage == null)
			resetViewport();

		setBackground( getParent().getBackground() );

//		_offscreen = _offscreenImage.getGraphics();

		_offscreen.setColor( Color.black );
		_offscreen.clearRect( _leftX + _oldXPos, 0, _bulletRect.width, _bulletRect.height );

//		_offscreen.drawLine( _oldXPos, 8, _oldXPos + _bulletRect.width, 8);		// patch line
		_offscreen.drawLine( _leftX, 8, _rightX + _bulletRect.width, 8);		// full line

		// draw bullet
		_offscreen.setColor( Color.blue );
		_offscreen.fillRoundRect(	_bulletRect.x, _bulletRect.y, 
									_bulletRect.width, _bulletRect.height,
									8, 8);
//		_offscreen.drawImage( _bullet, _leftX + _bulletRect.x, 0, this);

		_oldXPos = _bulletRect.x;	
		
		inGfx.drawImage( _offscreenImage, 0, 0, null );
//		_offscreen.dispose();
	}
	
 	//----------------------------------------------------------------------
	//	mouseDown - grab bullet
	//----------------------------------------------------------------------
	public boolean mouseDown( Event inEvent, int x, int y)
	{
		if (_bulletRect.inside( x, y ))
			_clicked = true;
			
		return true;
	}

	public boolean mouseDrag( Event inEvent, int x, int y )
	{
		if (_clicked) {
			setValue( (_maxValue - _minValue) * (float) (x - _leftX) / (_rightX - _leftX), true );
			positionBullet();
		}
		return true;
	}
	
	public boolean mouseUp( Event inEvent, int x, int y )
	{
		if (_clicked) {
			setValue( (_maxValue - _minValue) * (float) (x - _leftX) / (_rightX - _leftX), false );
			positionBullet();
		}
		_clicked = false;
		return true;
	}
	
	public void resize( Dimension inDim )
	{
		super.resize( inDim );
		resetViewport( );
	}
	
	void resetViewport()
	{	
		_offscreenImage = createImage( size().width, size().height );
		_offscreen = _offscreenImage.getGraphics();
		_leftX = 0;
		_rightX = size().width - _bulletRect.width;
		positionBullet();
	}
	
}	// end of Slider