/* -------------------------------------------------------------
ColorChart.java: This applet draws a 2D chart of a 6 x 6 x 6 color map.

Classes: ColorChart

Steve Witham <sw@tiac.net>

------------------------ history ---------------------------

1999.08.03: Started.  I think it drew one swatch using
			Graphics.drawPolygon().
			That's when I started writing DGeom2D.
1999.09.04: Drawing one swatch using DGeom2D!  55 Java lines.
1999.09.04.2: Works just like the original!  97 Java lines.
              -----------------------------------------------
              Made newSwatch() use template.through( 
            	  DTransform2D.newScaleRotateXY() ).
              93 Java lines.
1999.09.11: Create view in init(), call adjust() in paint().
			Call view.dispose() in destroy(). 109 Java lines.  

------------------------------------------------------------- */

import java.applet.Applet;
import java.util.*;
import java.awt.*;
import java.lang.Math;

public class ColorChart extends Applet {

	DView2D view;	
	double d;  // Sort of the "radius" of the swatches.

	
	public void init( )  {
		d = .08;
		view = new DView2D( this,
			DRectangle.newXXYY( -d, 1 + d, 1 + d, -d ), false );
			// Notice the y's are swapped compared to the TrueBASIC
			// "set window," because Java's y goes down not up:
			// Basic: set window left, right, bottom, top
			// Java: DRectangle.newXXYY( left, right, top, bottom )
		}


	DPolygon newSwatch( double size, double angle, double x, double y ) {	
		final DPolygon template = new DPolygon( new DPoint2D [] {
				new DPoint2D( .81, .27 ), new DPoint2D( .81, -.27 ),
				new DPoint2D( -.81, -.09 ), new DPoint2D( -.81, .09 )
			} );
		
		return( template.through( 
			DTransform2D.newScaleRotateXY( size, angle, x, y )
			) );
		}

   
	public void paint( Graphics givenG ) {
		view.adjust( );  // The window's size may have changed.

		view.setRGB( .6, .6, .6 );
		DRectangle.newXXYY( 0, 1, 0, 1 ).fillInView( view );

		for( int w = 0;  w <= 15;  w++ )  {
			double angle = Math.PI * ( w / 15.0 + .25 );
			for( int r = (int) Math.max( 0, w - 10 );
					r <= (int) Math.min( w, 5 );  r++ )  {
				int cyan = w - r;
				for( int g = (int) Math.max( 0, cyan - 5 );
						g <= (int) Math.min( cyan, 5 );  g++ )  {
					int b = cyan - g;

					double x = ( g * .8 + b * .2 ) / 5;
					double y = ( r * .7 + b * .3 ) / 5;			
					DPolygon swatch = newSwatch( d, angle, x, y );
						
					view.setRGB( r / 5.0, g / 5.0, b / 5.0 );
					swatch.fillInView( view );
					
					/* Now decide what color border to draw: */
					if( r == g  &&  g == b )  {  // On grey scale:
						if( g > 2 )  {
							view.setRGB( .4, .4, .4 );
							} 
						else {
							view.setRGB( .6, .6, .6 );
							}
						}
					else if (	( r == 0  ||  r == 5 ) &&
								( g == 0  ||  g == 5 ) &&
								( b == 0  ||  b == 5 )    ) {
						// One of { red, yellow, green, cyan, blue, magenta }:				
						view.setColor( Color.black );
						}
					else {
						// Draw the border in the fill color.
						}
					swatch.drawInView( view );
					}
				}
			}
		}
		
		
	public void destroy( )  {
		view.dispose( );
		}
		   
	}
	
/* The original TrueBASIC program (simplified but still correct):

let d = .08
set window -d, 1+d,  -d, 1+d

option angle degrees

call setMacPallette  ! same colors as the Netscape pallette

! Grey background (60% white)
call setrgb( 3, 3, 3 )
plot area: 0, 0;  0, 1;  1, 1;  1, 0

for w = 0 to 15
    let a = 180 * 1/15 * w + 45
    let dx = d * .8 * cos(a)
    let dy = d * .8 * sin(a)
    let ex = dx / 3
    let ey = dy / 3
    let fx = ex / 3
    let fy = ey / 3
    for r = max( 0, w - 10 ) to min( w, 5 )
        let cy = w - r
        for g = max( 0, cy - 5 ) to min( cy, 5 )
            let b = cy - g
            call setrgb( r, g, b )
            let x = g/5 * .8  +  b/5 * .2
            let y = r/5 * .7  +  b/5 * .3
            plot area: x+dx-ey,y+dy+ex;x+dx+ey,y+dy-ex;x-dx+fy,y-dy-fx;x-dx-fy,y-dy+fx
            if r=0 or r=5 then let redge = 1  else  let redge = 0
            if g=0 or g=5 then let gedge = 1  else  let gedge = 0
            if b=0 or b=5 then let bedge = 1  else  let bedge = 0
            if r = g  and  g = b  then
                if g > 2  then  call setrgb( 2, 2, 2 )  else  call setrgb( 3, 3, 3 )
                ! call setrgb( r + 2*sgn(2.5-r), g + 2*sgn(2.5-g), b + 2*sgn(2.5-b) )
                let doborder = 1
               else  if redge + gedge + bedge = 3  then
                call setrgb( 0, 0, 0 )
                let doborder = 1
               else
                let doborder = 0
               end if
            if doborder = 1  then
                plot x+dx-ey,y+dy+ex; x+dx+ey,y+dy-ex; x-dx+fy,y-dy-fx;
                plot x-dx-fy,y-dy+fx; x+dx-ey,y+dy+ex
               end if
          next g
      next r
  next w

end

sub setrgb( r, g, b )
    if r=0 and g=0 and b=0 then
        set color 255
      else 
        set color 36 * (5-r) + 6 * (5-g) + (5-b)
      end if
  end sub

sub setMacPallette
   for r = 0 to 5
      for g = 0 to 5
         for b = 0 to 5
            if r=0 and g=0 and b=0 then
               set color mix(255) r/5, g/5, b/5
              else 
               set color mix(36*(5-r)+6*(5-g)+(5-b)) r/5, g/5, b/5
              end if
           next b
        next g
     next r
  end sub

*/