MacTech 1 to 12/MacTech-vol-1-12.toast/Source/MacTech® Magazine/Volume 13 - 1997 (partial)/13.03 Mar 97/Getting Started, ShapeWorld/ShapeWorld.java

Java Source | 1997-01-21 | 4.9 KB | 259 lines | [TEXT/CWIE]

import java.awt.*;
import java.util.*;

abstract class Shape
{
    boolean        highlighted;
    ShapeCanvas    shapeCanvas;
    int            shapeX, shapeY, shapeWidth, shapeHeight;
    Rectangle    boundsRect;

    Shape( ShapeCanvas canv, int x, int y, int width, int height )
    {
        shapeCanvas = canv;
        highlighted = false;

        shapeX = x;
        shapeY = y;
        shapeWidth = width;
        shapeHeight = height;

        boundsRect = new Rectangle( x, y, width, height );
    }

    abstract public void draw( Graphics g );

    public void erase( Graphics g ) //Added for Step2
    {
        g.clearRect( shapeX, shapeY, shapeWidth, shapeHeight );
    }

    public void setHighlight( boolean newHighlight )
    {
        highlighted = newHighlight;
    }

    public boolean isHighlighted()
    {
        return highlighted;
    }

    public boolean isPointInShape( int x, int y )
    {
        return boundsRect.inside( x, y );
    }

    public void    moveThisMuch( int x, int y ) //Added for Step2
    {
        boundsRect.move( shapeX + x, shapeY + y );
        shapeX = boundsRect.x;
        shapeY = boundsRect.y;
        shapeWidth = boundsRect.width;
        shapeHeight = boundsRect.height;
    }
}

class RectShape extends Shape
{
    RectShape( ShapeCanvas canv, int x, int y, int width, int height )
    {
        super( canv, x, y, width, height );
    }

    public void draw( Graphics g )
    {
        if ( isHighlighted() )
        {
            g.setColor( Color.black );
            g.fillRect( shapeX, shapeY, shapeWidth, shapeHeight );
            g.setColor( Color.red );
            g.fillRect( shapeX+2, shapeY+2, shapeWidth-4, shapeHeight-4 );
        }
        else
        {
            g.setColor( Color.red );
            g.fillRect( shapeX, shapeY, shapeWidth, shapeHeight );
        }
    }
}

//Step 1: Add new Shape subclass
class OvalShape extends Shape
{
    OvalShape( ShapeCanvas canv, int x, int y, int width, int height )
    {
        super( canv, x, y, width, height );
    }

    public void draw( Graphics g )
    {
        if ( isHighlighted() )
        {
            g.setColor( Color.black );
            g.fillOval( shapeX, shapeY, shapeWidth, shapeHeight );
            g.setColor( Color.red );
            g.fillOval( shapeX+2, shapeY+2, shapeWidth-4, shapeHeight-4 );
        }
        else
        {
            g.setColor( Color.red );
            g.fillOval( shapeX, shapeY, shapeWidth, shapeHeight );
        }
    }
}
//END Step 1

class ShapeCanvas extends Canvas
{
    Vector        shapes;
    Shape        curShape;
    Point        mousePosition; //Part of Step 2, used for drag tracking

    ShapeCanvas( int width, int height )
    {
        shapes = new Vector();
        curShape = null;

        setBackground( Color.yellow );

        resize( width, height );
    }

    public void addShape( Shape newShape )
    {
        shapes.addElement( newShape );
    }

    public void paint( Graphics g )
    {
        for ( Enumeration e = shapes.elements(); e.hasMoreElements(); )
        {
            Shape s = (Shape)e.nextElement();
            s.draw( g );
        }
    }

    public Shape findInShapeList( int x, int y )
    {
        for ( Enumeration e = shapes.elements(); e.hasMoreElements(); )
        {
            Shape s = (Shape)e.nextElement();

            if ( s.isPointInShape( x, y ) )
            {
                s.draw( getGraphics() );

                return s;
            }
        }

        return null;
    }

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

    public boolean mouseDown( Event e, int x, int y )
    {
        curShape = findInShapeList( x, y );

        if ( curShape != null ) //For Step2
        {
            curShape.setHighlight( true );
            mousePosition = new Point( x, y );

            return true;
        }

        return false;
    }

//Step 2: Add Shape dragging
    public boolean mouseDrag( Event e, int x, int y )
    {
        Graphics    g;

        if ( curShape != null )
        {
            g = getGraphics();

            curShape.erase( g );

            curShape.moveThisMuch( x - mousePosition.x,
                y - mousePosition.y );

            mousePosition.x = x;
            mousePosition.y = y;

            curShape.draw( g );

            return true;
        }

        return false;
    }

    public boolean mouseUp( Event e, int x, int y )
    {
        if ( curShape != null )
        {
            curShape.setHighlight( false );
            repaint();

            return true;
        }

        return false;
    }
//End Step 2
}

public class ShapeWorld extends java.applet.Applet
{
    ShapeCanvas    sCanvas;
    final int    shapeWidth = 20;
    final int    shapeHeight = 20;

    public void init()
    {
        int            x, y;

        sCanvas = new ShapeCanvas( 440, 290 );
        add( sCanvas );

        Random ran = new Random();
        Rectangle b = sCanvas.bounds();

        for ( int i=1; i<=10; i++ )
        {
            x = b.x + (int)((float)(b.width) * ran.nextFloat() );
            if ( x > b.x + b.width - shapeWidth )
                x -= shapeWidth;

            y = b.y + (int)((float)(b.height) * ran.nextFloat() );
            if ( y > b.y + b.height - shapeHeight )
                y -= shapeHeight;

            RectShape r = new RectShape( sCanvas, x, y, shapeWidth, shapeHeight );
            sCanvas.addShape( r );
        }

//Step3: Create some of the new shape
        for ( int i=1; i<=10; i++ )
        {
            x = b.x + (int)((float)(b.width) * ran.nextFloat() );
            if ( x > b.x + b.width - shapeWidth )
                x -= shapeWidth;

            y = b.y + (int)((float)(b.height) * ran.nextFloat() );
            if ( y > b.y + b.height - shapeHeight )
                y -= shapeHeight;

            OvalShape r = new OvalShape( sCanvas, x, y, shapeWidth, shapeHeight );
            sCanvas.addShape( r );
        }
//End Step3
    }
}