CompressScatterSeries.java

/*******************************************************************************
 * Copyright (c) 2008-2009 SWTChart project. All rights reserved. 
 * 
 * This code is distributed under the terms of the Eclipse Public License v1.0
 * which is available at http://www.eclipse.org/legal/epl-v10.html
 *******************************************************************************/
package org.swtchart.internal.compress;

import java.util.ArrayList;

/**
 * A compressor for scatter series data
 */
public class CompressScatterSeries extends Compress
{

    /** the state indicating if line is visible */
    private boolean isLineVisible;

    /** flag indicating whether the grid is occupied */
    private boolean occupied[][];

    /*
     * @see Compress#addNecessaryPlots(ArrayList, ArrayList, ArrayList)
     */
    @Override
    protected void addNecessaryPlots ( ArrayList<Double> xList, ArrayList<Double> yList, ArrayList<Integer> indexList )
    {

        if ( isLineVisible )
        {
            for ( int i = 0; i < xSeries.length; i++ )
            {
                if ( !isInSameGridAsPrevious ( xSeries[i], ySeries[i] ) )
                {
                    addToList ( xList, yList, indexList, xSeries[i], ySeries[i], i );
                }
            }
        }
        else
        {
            int width = (int)config.getWidthInPixel ();
            int height = (int)config.getHeightInPixel ();

            if ( width <= 0 || height <= 0 )
            {
                return;
            }

            // initialize flag
            occupied = new boolean[width][height];

            for ( int i = 0; i < xSeries.length; i++ )
            {
                if ( xSeries[i] >= xLower && xSeries[i] <= xUpper && ySeries[i] >= yLower && ySeries[i] <= yUpper && !isOccupied ( xSeries[i], ySeries[i] ) )
                {
                    addToList ( xList, yList, indexList, xSeries[i], ySeries[i], i );
                }
            }
        }
    }

    /**
     * check if the grid is already occupied
     * 
     * @param x
     *            the X coordinate
     * @param y
     *            the Y coordinate
     * @return true if the grid is already occupied
     */
    private boolean isOccupied ( double x, double y )
    {
        int xGridIndex;
        int yGridIndex;

        // calculate the X grid index
        if ( config.isXLogScale () )
        {
            double lower = Math.log10 ( config.getXLowerValue () );
            double upper = Math.log10 ( config.getXUpperValue () );
            xGridIndex = (int) ( ( Math.log10 ( x ) - lower ) / ( upper - lower ) * config.getWidthInPixel () );
        }
        else
        {
            xGridIndex = (int) ( ( x - config.getXLowerValue () ) / ( config.getXUpperValue () - config
                    .getXLowerValue () ) * config.getWidthInPixel () );
        }

        // calculate the Y grid index
        if ( config.isYLogScale () )
        {
            double lower = Math.log10 ( config.getYLowerValue () );
            double upper = Math.log10 ( config.getYUpperValue () );
            yGridIndex = (int) ( ( Math.log10 ( y ) - lower ) / ( upper - lower ) * config.getHeightInPixel () );
        }
        else
        {
            yGridIndex = (int) ( ( y - config.getYLowerValue () ) / ( config.getYUpperValue () - config
                    .getYLowerValue () ) * config.getHeightInPixel () );
        }

        boolean isOccupied = occupied[xGridIndex][yGridIndex];

        occupied[xGridIndex][yGridIndex] = true;

        return isOccupied;
    }

    /**
     * Sets the state indicating if the line is visible.
     * 
     * @param visible
     *            the state indicating if the line is visible
     */
    public void setLineVisible ( boolean visible )
    {
        isLineVisible = visible;
    }
}