/* 
 * File $CLASSHOME/example-progs/scrollBar/ScrollTest.java
 * Copyright BF Caviness
 * 04 November 1997 Version 1.0
 * 25 Nov 1998 changes by E Kaltofen
 */


/**
 * This example demonstrates the use of the JDK component Scrollbar
 * and further methods for TextField components.  It uses three scroll
 * bars in addition to three TextFields to specify the red, green,
 * and blue components of a  color to be displayed.  The text fields
 * and the scroll bars interact with each other.  For example, when the
 * red scoll bar is changed, it changes the value of the red text field
 * as well as the color.  When the red text field is changed, the 
 * corresponding change is made in the setting of the red scroll bar.
 * The green and blue textfield/scrollbar pairs work in an analogous 
 * fashion.
 */

import java.awt.*;

public class ScrollTest extends Frame{
// EK: has two Panels (tfp, sbp) and a Canvas (palette)
//     tfp (textfieldpanel) has three TextFields
//     sbp (scrollbarpanel) has three Scrollbars (which are painted in
//                          an Panel holding the Label and the Scrollbar)
//                          and layed out vertically

    private TextField redTF;	// Text field variables
    private TextField greenTF;
    private TextField blueTF;

    private Scrollbar redSB;	// Scroll bar variables
    private Scrollbar greenSB;
    private Scrollbar blueSB;

    private ColorCanvas palette;// Canvas for color palette; EK:local class def'd below
    
    public ScrollTest( String title ){
        super( title );				// Set frame title

        Panel tfp = new Panel();		// A panel to hold the TextFields
        redTF = addTextField( tfp,"Red" );	// EK: ScrollTest.addTextfield
        greenTF = addTextField( tfp,"Green" );
        blueTF = addTextField( tfp,"Blue" );

        Panel sbp = new Panel();		// A panel to hold the Scrollbars
        sbp.setLayout( new BorderLayout() );	// EK: Container.setLayout
        redSB = addScrollbar( sbp,"Red","North" ); // EK: ScrollTest.addScrollbar
        greenSB = addScrollbar( sbp,"Green","Center" );
        blueSB = addScrollbar( sbp,"Blue","South" );

        setLayout( new BorderLayout() );	// Layout frame
        setSize( 600,300 );                     // EK: Component.setSize
        add( tfp,"North" );			// Add text fields
                                                // EK: Container.add(Component,Object)
        palette = new ColorCanvas();           
        add( palette,"Center" );
        add( sbp,"South" );			// Add scroll bars
    }// end ScrollTest(String)


    /**
     * Two auxilary functions used by the constructor
     */
    public TextField addTextField( Panel p, String label ){
        p.add( new Label( label ) );
        TextField t = new TextField( "255" );
        p.add( t ); // EK: Container.add(...)
        return t;
    }

    public Scrollbar addScrollbar( Panel p, String label, String here ){
        Scrollbar b = new Scrollbar( Scrollbar.HORIZONTAL,0,0,0,255 );
                              // EK: orientation,visible,min,max
        b.setValue( 255 );		// Set initial value; EK: Scrollbar.setValue
        Panel pair = new Panel();	// Panel to hold each label and
        pair.add( new Label( label ) );	// scroll bar pair
        pair.add( b );
        p.add( pair, here );
        return b;
    }



    /**
     * Handles events on the TextFields.  Overrides Component.action().
     * This method is deprecated in JDK 1.1.  Here we are using the Java
     * 1.0 event handling paradigm.
     */
    public boolean action( Event e, Object inputStr ){
        if ( e.target instanceof TextField ){
        System.out.println( "ScrollTest.action() w e = " + e +
                            ", inputStr = " + inputStr );
            int r = Integer.parseInt( redTF.getText() );
            redSB.setValue( r );	// Set red scroll bar
            int g = Integer.parseInt( greenTF.getText() );
            greenSB.setValue( g );	// Set green scroll bar
            int b = Integer.parseInt( blueTF.getText() );
            blueSB.setValue( b );	// Set blue scroll bar
            palette.setColor( r,g,b );  // EK: repaints
            return true;
        }
        return false;
    }

    /**
     * Handles events on the Scrollbars.  Overrides Component.handleEvent().
     * We are using the deprecated Java 1.0 event handling paradigm.
     */
    public boolean handleEvent( Event e ){
        // EK: catch Toolkit "close"
        if ( e.target == this ) // catch Toolkit actions on Frame
           { System.out.println( "ScrollTest.handleEvent() w e = " + e );
             if ( e.id == Event.WINDOW_DESTROY )
                { this.dispose(); System.exit(0); }
           }

        int r,g,b;
        switch( e.id ){
            case Event.SCROLL_LINE_UP:
            case Event.SCROLL_LINE_DOWN:
            case Event.SCROLL_ABSOLUTE:
                 // EK: don't track every event
                 System.out.println( "ScrollTest.handleEvent() w e = " + e );
                                   r = redSB.getValue();
                                   redTF.setText( "" + r ); // Set red textf
                                   // EK: TextField.setText
                                   g = greenSB.getValue();
                                   greenTF.setText( "" + g );
                                   b = blueSB.getValue();
                                   blueTF.setText( "" + b );
                                   palette.setColor( r,g,b );
        }
        return super.handleEvent( e );
    } // end handleEvent


    public static void main( String arg[] ){
        Frame f = new ScrollTest( "Color Mixer" );
        f.show();
    }
}// end class ScrollTest

class ColorCanvas extends Canvas{

    private Color backGround;
    private int red;
    private int green;
    private int blue;

    public ColorCanvas(){
        setColor( 255,255,255 );
    }

    public void setColor( int r, int g, int b ){
        
        backGround = new Color( r,g,b );
        setBackground( backGround );	// Note that paint() does not need
        // EK: Component.setBackground  // to be redefined as we are only
        repaint();			// changing the bkground color and
    }                                   // repaint() redoes the background.
}// end class ColorCanvas