/*	Date: %H% %T%  File is: %Y%/%M%  Release: %I%
 *	Last Modified: %G% %U% by: abb@nuccard.eushc.org
 *	Copyright (c) Andrew B. Barclay %H%. All rights reserved.
 */

/*
 * A quickie applet to try grayscale window/level using ImageFilter's.
 * Original URL http://www.emory.edu/CRL/abb/WindowLevel/
 *
 * @see GrayFilter
 * @see RGBImageFilter
 * @see Rotator
 *
 * @version	%I% %D%
 * @author 	Andrew Barclay
 *
 * Required Params (same as Rotator):
 *    src    -- Name of source image file
 *    width  -- Width of display window
 *    height -- Height of display window
 * Optional Params (same as Rotator):
 *    frames      -- Number of source image frames (default: 1)
 *    framewidth  -- Width of source image frames (default: width)
 *    frameheight -- Height of source image frames (default: height)
 *    rate        -- Rate in frames per second (default: 6)
 *    columns     -- Number of frames across the image (default: frames)
 *    rows        -- Number of frames down the image (default: 1)
 *    autoReverse -- self explanatory? (default: false)
 */


// I like to know what I'm importing for sanity checks.
import java.applet.Applet ;
import java.awt.image.ImageObserver ;
import java.awt.image.FilteredImageSource ;
import java.awt.Color ;
import java.awt.Event ;
import java.awt.FontMetrics ;
import java.awt.Graphics ;
import java.awt.Image ;
import java.awt.Polygon ;
import java.awt.Rectangle ;

// Classes that I've added:
import Rotator ;
import GrayFilter ;

public class WindowLevel extends Rotator {
    final static int handlesize = 10 ;
    double upper, lower ;
    Polygon upperP, lowerP ;
    int dragging = 0 ;
    Image srcim, filteredim ;
    GrayFilter filter ;
    boolean forcepaint = false ;

    public String getAppletInfo() {
	return "Grayscale Window/Level by Andrew Barclay" ;
    }

    /* ============================================================
     * Initializing stuff:
     */
    public void init() {
	super.init() ;

	srcim = spinImage ;
	setUpper( 0.975 ) ;
	setLower( 0.05 ) ;
    }

    /* ============================================================
     * Image painting stuff.
     */
    public void paint( Graphics gr ) {
	// filter the srcim to make filteredim.
	windowImage() ;
	spinImage = filteredim ;

	// Invoke Rotator.paint()
	super.paint( gr ) ;

	// paint our manipulation handles.
	paintHandle( gr, upperP ) ;
	paintHandle( gr, lowerP ) ;
    }

    void windowImage() {
	if( filter == null || filter.upper != upper ||
		filter.lower != lower || forcepaint ) {
	    filter = new GrayFilter( upper, lower ) ;
	    filteredim = createImage( 
		new FilteredImageSource( srcim.getSource(), filter )
	    ) ;
	    forcepaint = false ;
	}
    }

    /* ============================================================
     * Grayscale manipulation stuff.
     */
    synchronized void setUpper( double value ) {
	upper = value ;
	upperP = newPolygon( value ) ;
    }

    synchronized void setLower( double value ) {
	lower = value ;
	lowerP = newPolygon( value ) ;
    }

    Polygon newPolygon( double value ) {
	int xpoints[] = new int[3] ;
	int ypoints[] = new int[3] ;
	int yloc = (int)( 0.5 + value*(windowHeight-1) ) ;

	xpoints[0] = xpoints[2] = 0 ;
	xpoints[1] = handlesize ;
	ypoints[0] = yloc + handlesize/2 ;
	ypoints[1] = yloc ;
	ypoints[2] = yloc - handlesize/2 ;

	return new Polygon( xpoints, ypoints, 3 ) ;
    }

    void paintHandle( Graphics gr, Polygon polygon ) {
	Rectangle bbox = polygon.getBoundingBox() ;
	int yc = bbox.y + bbox.width/2 ;
	int yt = yc + (gr.getFontMetrics()).getHeight()/4 ;

	gr.setColor( Color.red ) ;
	gr.fillPolygon( polygon ) ;

	gr.setColor( Color.red ) ;
	gr.drawString( Integer.toString( yc ), handlesize, yt ) ;
    }

    public boolean mouseUp( Event evt, int x, int y ) {
	dragging = 0 ;
	System.out.println( "mouseUp: forcing repaint" ) ;
	forcepaint = true ;
	repaint( 0 ) ;
	return true ;
    }

    public boolean mouseDown( Event evt, int x, int y ) {
	if( upperP != null && upperP.inside( x, y ) ) {
	    dragging = 1 ;
	    return true ;
	} else if( lowerP != null && lowerP.inside( x, y ) ) {
	    dragging = 2 ;
	    return true ;
	} else {
	    dragging = 0 ;
	    return false ;
	}
    }

    public boolean mouseDrag( Event evt, int x, int y ) {
	if( dragging != 0 ) {
	    double dy = (double)y/windowHeight ;
	    dy = (dy < 0.0) ? 0.0 : ((dy > 1.0) ? 1.0 : dy) ;
	    if( dragging == 1 ) {
		if( dy > lower ) {
		    setUpper( dy ) ;
		}
	    } else {
		if( dy < upper ) {
		    setLower( dy ) ;
		}
	    }
	    repaint( 100 ) ;
	    return true ;
	} else {
	    return false ;
	}
    }
}