/*
 * Slider
 * 
 * Version 1.1 - Java 1.1 compatible
 *
 * Dec 6 2001
 * 
 * Copyright 2001 David Joiner and the Shodor Education Foundation
 */
import java.awt.*;
import java.awt.event.*;

/**
 * The Slider class extends the traditional functionality
 * of scrollbars by provding routines that store and associate
 * a real value with the slider position. Sliders are designed
 * specifically to be used for numerical input.
 */
public class Slider extends Scrollbar implements AdjustmentListener {

    public final static int STYLE_LINEAR=0;
    public final static int STYLE_LOG=1;
    public final static int STYLE_INTEGER=2;
    
    protected double realMin;
    protected double realMax;
    protected double realValue;
    protected int sliderStyle;
    
    /*
     * Constructors
     */
        
    public Slider() {
        this(Slider.STYLE_LINEAR,50.0,0.0,100.0);
    }
    
    public Slider(double realValue, double realMin, double realMax) {
        this(Slider.STYLE_LINEAR,realValue,realMin,realMax);
    }

    public Slider(int sliderStyle, double realValue,
            double realMin, double realMax)  {
        super(Scrollbar.HORIZONTAL,50,10,0,110);
        this.sliderStyle = sliderStyle;
        setRealMax(realMax);
        setRealMin(realMin);
        setRealValue(realValue);
        addAdjustmentListener(this);
    }    
    
    /*
     * Set and Get methods
     */
    
    public int realToDisplay(double real) {
        if (sliderStyle == STYLE_LINEAR) {
            // linear scale
            double fraction = (real - realMin)/(realMax - realMin);
            return (int)(fraction*(double)(getMaximum()-
                getVisibleAmount()-getMinimum()))+
                getMinimum();
        } else if (sliderStyle==STYLE_INTEGER) {
            double fraction = ((double)((int)real) -
                realMin)/(realMax - realMin);
            return (int)(fraction*(double)(getMaximum()-
                getVisibleAmount()-getMinimum()))+
                getMinimum();
        } else {
            // logarithmic scale
            int n = getMaximum()-getVisibleAmount()-getMinimum();
            double factor = Math.pow((realMax/realMin),1.0/(double)(n));
            return (int)(Math.log(real/realMin)/Math.log(factor))+getMinimum();
        }
    }
    
    public double displayToReal(int display) {
        if (sliderStyle == STYLE_LINEAR) {
            // linear scale
            double fraction = (double)(display - getMinimum())/
                (double)(getMaximum()-getVisibleAmount()-getMinimum());
            return fraction*(realMax-realMin)+realMin;
        } else if (sliderStyle == STYLE_INTEGER) {
            double fraction = (double)(display - getMinimum())/
                (double)(getMaximum()-getVisibleAmount()-getMinimum());
            return (double)((int)fraction*(realMax-realMin)+realMin);
        } else {
            // logarithmic scale
            int n = getMaximum()-getVisibleAmount()-getMinimum();
            double factor = Math.pow((realMax/realMin),1.0/(double)(n));
            return realMin*Math.pow(factor,(double)(display-getMinimum()));
        }
    }

    public void setRealMin(double realMin) {
        this.realMin = realMin;
    }
    
    public void setRealMax(double realMax) {
        this.realMax = realMax;
    }
    
    public void setRealValue(double realValue) {
        this.realValue = realValue;
        if (sliderStyle == STYLE_INTEGER) {
            this.realValue = (double)((int)this.realValue);
        }
        setValue(realToDisplay(this.realValue));
    }
    
    public double getRealMin() {
        return realMin;
    }
    
    public double getRealMax() {
        return realMax;
    }
    
    public double getRealValue() {
        return realValue;
    }
    
    /*
     * Event handling
     */
    
    public void adjustmentValueChanged(AdjustmentEvent e) {
        realValue = displayToReal(getValue());
    }

}