xaxis.java

这是一个十分有用的java图形工具包

package net.turbochen.graph;

import java.awt.Graphics;
import java.awt.Color;
/**
 * 绘制横坐标轴,刻度及其网络线.
 * @author Turbo Chen
 */
public class XAxis extends Axis
{

    
    public XAxis(XScale scale,int tickCount)
    {
        this.scale = scale;
        this.tickCount = tickCount;
        gridColor = Color.LIGHT_GRAY;
        axisColor = Color.BLACK;
        tickLength = 5;
        drawGrid = false;
    }
    
    public XAxis(XAxis peerAxis, XScale scale,int tickCount)
    {
        this(scale,tickCount);
        this.peerAxis = peerAxis;
    }
    /**
     * 绘制x轴线,刻度线及格线.
     * @see net.turbochen.graph.ChartWidget#draw(java.awt.Graphics)
     */
    public void draw(Graphics g)
    {

        if ( ! (scale instanceof XScale) ) return;
        int ticks = getTickCount();       
        int tickDist = (int) 
            ((double)(scale.getScreenMax() - scale.getScreenMin())/(double)(ticks+1));
        int tickX = scale.getScreenMin();
        int tickY = peerAxis.getScale().getScreenMin(); 
        int gridLength = peerAxis.getScale().getScreenMax();
        int axisLength = scale.getScreenMax()-scale.getScreenMin();
        g.setColor(axisColor);
        g.drawLine(tickX, tickY, tickX+axisLength,tickY);
        double vtickDist = (scale.getMax() - scale.getMin())/(ticks+1);
        for ( int t=0,i = (int) scale.getMin() ; i < scale.getMax(); i++,t++ )
        {
            tickX = (int) (scale.getScreenMin()+tickDist*(t+1));
            if ( isDrawGrid() )
            {
                g.setColor(gridColor);
                g.drawLine(tickX, tickY , tickX, gridLength );
            }
            g.setColor(axisColor);
            g.drawLine(tickX, tickY , tickX, tickY+tickLength);
            String tickLabel = String.valueOf(vtickDist*(i+1));
            int tickLabelWidth = 
                            g.getFontMetrics().stringWidth(tickLabel);
            int tickLabelHeight = g.getFontMetrics().getHeight();
            g.drawString(tickLabel, 
                            tickX-(tickLabelWidth/2),
                            tickY+tickLabelHeight);
        }

    }

    /* (non-Javadoc)
     * @see net.turbochen.graph.Axis#calculateTickLabelSize(java.awt.Graphics)
     */
    protected int calculateTickLabelSize(Graphics g)
    {
        int SPACE_WIDTH = 20;
        int tickH = 
            g.getFontMetrics().getHeight();
        return tickLength+tickH+SPACE_WIDTH;
    }

}