userpointpanel.java~1~

来自「一个一元曲线多项式数值演示例子」· JAVA~1~ 代码 · 共 195 行

package numbercruncher.pointutils;

import java.awt.*;
import java.awt.event.*;

import numbercruncher.graphutils.GraphPanel;
import numbercruncher.graphutils.PlotProperties;

/**
 * The base panel for all demo panels that allow
 * the user to set data points with the mouse.
 */
public abstract class UserPointPanel extends GraphPanel
{
    private static final float INIT_X_MIN = -0.5f;
    private static final float INIT_X_MAX = 11.5f;
    private static final float INIT_Y_MIN = -0.75f;
    private static final float INIT_Y_MAX =  9.5f;

    /** control panel */    protected Panel  controlPanel  = new Panel();
    /** n label */          protected Label  nLabel        = new Label();
    /** n text */           protected Label  nText         = new Label();
    /** action button 1 */  protected Button actionButton1 = new Button();
    /** action button 2 */  protected Button actionButton2 = new Button();

    /** count of data points */     protected int n;

    /** array of data point coordinates */  private Point   data[];
    /** maximum number of data points */    private int     maxPoints;
    /** true if OK to set data points */    private boolean dotOK  = true;

    /** initial plot properties */
    protected static PlotProperties plotProps =
            new PlotProperties(INIT_X_MIN, INIT_X_MAX, INIT_Y_MIN, INIT_Y_MAX);

    /**
     * Constructor.
     * @param maxPoints the maximum number of data points
     * @param nLabelText the text of the n label
     * @param actionButton1Label the label for action button 1
     * @param actionButton2Label the label for action button 2
     */
    protected UserPointPanel(int maxPoints, String nLabelText,
                           String actionButton1Label,
                           String actionButton2Label)
    {
        super(" ", plotProps);
        this.maxPoints = maxPoints;

        Font labelFont = getLabelFont();
        Font textFont  = getTextFont();

        // Controls.
        nLabel.setFont(labelFont);
        nLabel.setAlignment(Label.RIGHT);
        nLabel.setText(nLabelText);
        nText.setFont(textFont);
        nText.setAlignment(Label.LEFT);
        nText.setText(" ");
        actionButton1.setLabel(actionButton1Label);
        actionButton2.setLabel(actionButton2Label);

        // Action button 1 handler.
        actionButton1.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent ev)
            {
                doButton1Action();
            }
        });

        // Action button 2 handler.
        actionButton2.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent ev)
            {
                doButton2Action();
            }
        });

        // Data points.
        data = new Point[maxPoints];
    }

    /**
     * Perform the dot action.  (Do nothing here.)
     * @param r the dot's row
     * @param c the dot's column
     */
    protected void doDotAction(int r, int c) {}

    /**
     * Perform the button 1 action 1.  (Do nothing here.)
     */
    protected void doButton1Action() {}

    /**
     * Perform the button 2 action 2.  (Do nothing here.)
     */
    protected void doButton2Action() {}

    /**
     * Mouse pressed on the plot:  Add an interpolation point.
     * @param ev the mouse event
     */
    public void mousePressedOnPlot(MouseEvent ev)
    {
        if (!dotOK()) return;
        if (n == maxPoints) return;

        int c = ev.getX();
        int r = ev.getY();

        // Record the new data point.
        data[n] = new Point(c, r);

        ++n;
        drawDots();
        nText.setText(Integer.toString(n));
        doDotAction(r, c);
    }

    /**
     * Return true if it is OK to add another data point.
     * @return true or false
     */
    public boolean dotOK() { return dotOK; }

    /**
     * Draw the data points.
     */
    protected void drawDots()
    {
        if (n > 0) plotDots(data, n, 8, Color.red);
    }

    /**
     * Reset.
     */
    protected void reset()
    {
        n     = 0;
        dotOK = true;

        // Initialize n in the control panel.
        nText.setText(Integer.toString(n));
    }

    //------------------//
    // Method overrides //
    //------------------//

    /**
     * Notification that the plot bounds changed.
     * Redraw the panel.
     */
    public void plotBoundsChanged()
    {
        reset();
        draw();
    }

    /**
     * Notification that the panel was resized.  (Callback from DemoFrame.)
     */
    public void panelResized()
    {
        reset();
        draw();
    }

    /**
     * Notification that a user input error occurred.
     * Disable the action1 button and enable the action2 button.
     */
    protected void userErrorOccurred()
    {
        dotOK = false;
        actionButton1.setEnabled(false);
        actionButton2.setEnabled(true);
    }

    /**
     * Redraw the dots.
     */
    public void draw()
    {
        super.draw();
        drawDots();

        // Set the focus to an action button to avoid spurious
        // repaints caused by the text losing focus later.
        actionButton2.requestFocus();
    }
}