colourutilities.java

FuncPlotter is a combined Java application and applet for displaying two-dimensional plots of explic

/*====================================================================*\

ColourUtilities.java

Colour utility methods class.

------------------------------------------------------------------------

This file is part of FuncPlotter, a combined Java application and applet
for plotting explicit functions in one variable.
Copyright 2005-2007 Andy Morgan-Richards.

FuncPlotter is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation, either version 3 of the License, or (at your
option) any later version.

This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License along
with this program.  If not, see <http://www.gnu.org/licenses/>.

\*====================================================================*/


// PACKAGE


package util;

//----------------------------------------------------------------------


// IMPORTS


import java.awt.Color;

//----------------------------------------------------------------------


// COLOUR UTILITY METHODS CLASS


public class ColourUtilities
{

////////////////////////////////////////////////////////////////////////
//  Constants
////////////////////////////////////////////////////////////////////////

    public static final int     MIN_RGB_COMPONENT_VALUE = 0;
    public static final int     MAX_RGB_COMPONENT_VALUE = 255;

    public static final String  HEX_FORM_PREFIX = "#";

////////////////////////////////////////////////////////////////////////
//  Constructors
////////////////////////////////////////////////////////////////////////

    private ColourUtilities( )
    {
    }

    //------------------------------------------------------------------

////////////////////////////////////////////////////////////////////////
//  Class methods
////////////////////////////////////////////////////////////////////////

    public static String colourToRgbString( Color colour )
    {
        return new String( colour.getRed( ) + ", " + colour.getGreen( ) + ", " + colour.getBlue( ) );
    }

    //------------------------------------------------------------------

    public static String colourToHexString( Color colour )
    {
        Numeric.setHexUpper( );
        return new String( HEX_FORM_PREFIX + Numeric.byteToHexString( colour.getRed( ) ) +
                                                            Numeric.byteToHexString( colour.getGreen( ) ) +
                                                            Numeric.byteToHexString( colour.getBlue( ) ) );
    }

    //------------------------------------------------------------------

    public static Color parseColour( String str )
        throws IllegalArgumentException, IndexOutOfBoundsException
    {
        Color colour = null;
        if ( str.startsWith( HEX_FORM_PREFIX ) )
        {
            str = str.substring( 1 );
            if ( str.length( ) == 3 )
            {
                char[] chars = new char[6];
                for ( int i = 0; i < 3; ++i )
                {
                    char ch = str.charAt( i );
                    chars[2 * i] = ch;
                    chars[2 * i + 1] = ch;
                }
                str = new String( chars );
            }
            else if ( str.length( ) != 6 )
                throw new IllegalArgumentException( );

            int red = Integer.parseInt( str.substring( 0, 2 ), 16 );
            int green = Integer.parseInt( str.substring( 2, 4 ), 16 );
            int blue = Integer.parseInt( str.substring( 4, 6 ), 16 );
            colour = new Color( red, green, blue );
        }
        else
        {
            String[] strs = str.split( " *, *", -1 );
            if ( strs.length != 3 )
                throw new IllegalArgumentException( );

            int red = Integer.parseInt( strs[0] );
            if ( (red < MIN_RGB_COMPONENT_VALUE) || (red > MAX_RGB_COMPONENT_VALUE) )
                throw new IndexOutOfBoundsException( );

            int green = Integer.parseInt( strs[1] );
            if ( (green < MIN_RGB_COMPONENT_VALUE) || (green > MAX_RGB_COMPONENT_VALUE) )
                throw new IndexOutOfBoundsException( );

            int blue = Integer.parseInt( strs[2] );
            if ( (blue < MIN_RGB_COMPONENT_VALUE) || (blue > MAX_RGB_COMPONENT_VALUE) )
                throw new IndexOutOfBoundsException( );

            colour = new Color( red, green, blue );
        }

        return colour;
    }

    //------------------------------------------------------------------

}

//----------------------------------------------------------------------