BezierAnimationPanel.java

/*
 *
 * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
 *
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 * modification, are permitted provided that the following conditions
 * are met:
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 *     notice, this list of conditions and the following disclaimer.
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 *   - Redistributions in binary form must reproduce the above copyright
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 *     from this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
import javax.swing.border.*;
import javax.swing.colorchooser.*;
import javax.swing.filechooser.*;
import javax.accessibility.*;

import java.awt.*;
import java.awt.font.*;
import java.awt.geom.*;
import java.awt.image.*;
import java.lang.reflect.InvocationTargetException;
import java.awt.event.*;

/**
 * BezierAnimationPanel
 *
 * @author Jim Graham
 * @author Jeff Dinkins (removed dynamic setting changes, made swing friendly)
 */
class BezierAnimationPanel extends JPanel implements Runnable {

    Color backgroundColor =  new Color(0,     0, 153);
    Color outerColor      =  new Color(255, 255, 255);
    Color gradientColorA  =  new Color(255,   0, 101);
    Color gradientColorB  =  new Color(255, 255,   0);

    boolean bgChanged = false;

    GradientPaint gradient = null;

    public final int NUMPTS = 6;

    float[] animpts = new float[NUMPTS * 2];

    float[] deltas = new float[NUMPTS * 2];

    float[] staticpts = {
         50.0f,   0.0f,
        150.0f,   0.0f,
        200.0f,  75.0f,
        150.0f, 150.0f,
         50.0f, 150.0f,
          0.0f,  75.0f,
    };

    float[] movepts = new float[staticpts.length];

    BufferedImage img;

    Rectangle bounds = null;

    Thread anim;

    private final Object lock = new Object();

    /**
     * BezierAnimationPanel Constructor
     */
    public BezierAnimationPanel() {
        addHierarchyListener(
            new HierarchyListener() {
               public void hierarchyChanged(HierarchyEvent e) {
                   if(isShowing()) {
                       start();
                   } else {
                       stop();
                   }
               }
           }
        );
        setBackground(getBackgroundColor());
    }

    public boolean isOpaque() {
        return true;
    }

    public Color getGradientColorA() {
        return gradientColorA;
    }

    public void setGradientColorA(Color c) {
        if(c != null) {
            gradientColorA = c;
        }
    }

    public Color getGradientColorB() {
        return gradientColorB;
    }

    public void setGradientColorB(Color c) {
        if(c != null) {
            gradientColorB = c;
        }
    }

    public Color getOuterColor() {
        return outerColor;
    }

    public void setOuterColor(Color c) {
        if(c != null) {
            outerColor = c;
        }
    }

    public Color getBackgroundColor() {
        return backgroundColor;
    }

    public void setBackgroundColor(Color c) {
        if(c != null) {
            backgroundColor = c;
            setBackground(c);
            bgChanged = true;
        }
    }

    public void start() {
        Dimension size = getSize();
        for (int i = 0; i < animpts.length; i += 2) {
            animpts[i + 0] = (float) (Math.random() * size.width);
            animpts[i + 1] = (float) (Math.random() * size.height);
            deltas[i + 0] = (float) (Math.random() * 4.0 + 2.0);
            deltas[i + 1] = (float) (Math.random() * 4.0 + 2.0);
            if (animpts[i + 0] > size.width / 6.0f) {
                deltas[i + 0] = -deltas[i + 0];
            }
            if (animpts[i + 1] > size.height / 6.0f) {
                deltas[i + 1] = -deltas[i + 1];
            }
        }
        anim = new Thread(this);
        anim.setPriority(Thread.MIN_PRIORITY);
        anim.start();
    }

    public synchronized void stop() {
        anim = null;
        notify();
    }

    public void animate(float[] pts, float[] deltas, int index, int limit) {
        float newpt = pts[index] + deltas[index];
        if (newpt <= 0) {
            newpt = -newpt;
            deltas[index] = (float) (Math.random() * 3.0 + 2.0);
        } else if (newpt >= (float) limit) {
            newpt = 2.0f * limit - newpt;
            deltas[index] = - (float) (Math.random() * 3.0 + 2.0);
        }
        pts[index] = newpt;
    }

    public void run() {
        Thread me = Thread.currentThread();
        while (getSize().width <= 0) {
            try {
                anim.sleep(500);
            } catch (InterruptedException e) {
                return;
            }
        }

        Graphics2D g2d = null;
        Graphics2D BufferG2D = null;
        Graphics2D ScreenG2D = null;
        BasicStroke solid = new BasicStroke(9.0f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_ROUND, 9.0f);
        GeneralPath gp = new GeneralPath(GeneralPath.WIND_NON_ZERO);
        int rule = AlphaComposite.SRC_OVER;
        AlphaComposite opaque = AlphaComposite.SrcOver;
        AlphaComposite blend = AlphaComposite.getInstance(rule, 0.9f);
        AlphaComposite set = AlphaComposite.Src;
        int frame = 0;
        int frametmp = 0;
        Dimension oldSize = getSize();
        Shape clippath = null;
        while (anim == me) {
            Dimension size = getSize();
            if (size.width != oldSize.width || size.height != oldSize.height) {
                img = null;
                clippath = null;
                if (BufferG2D != null) {
                    BufferG2D.dispose();
                    BufferG2D = null;
                }
                if (ScreenG2D != null) {
                    ScreenG2D.dispose();
                    ScreenG2D = null;
                }
            }
            oldSize = size;

            if (img == null) {
                img = (BufferedImage) createImage(size.width, size.height);
            }

        if (BufferG2D == null) {
                BufferG2D = img.createGraphics();
                BufferG2D.setRenderingHint(RenderingHints.KEY_RENDERING,
                                           RenderingHints.VALUE_RENDER_DEFAULT);
                BufferG2D.setClip(clippath);
            }
            g2d = BufferG2D;

            float[] ctrlpts;
            for (int i = 0; i < animpts.length; i += 2) {
                animate(animpts, deltas, i + 0, size.width);
                animate(animpts, deltas, i + 1, size.height);
            }
            ctrlpts = animpts;
            int len = ctrlpts.length;
            gp.reset();
            int dir = 0;
            float prevx = ctrlpts[len - 2];
            float prevy = ctrlpts[len - 1];
            float curx = ctrlpts[0];
            float cury = ctrlpts[1];
            float midx = (curx + prevx) / 2.0f;
            float midy = (cury + prevy) / 2.0f;
            gp.moveTo(midx, midy);
            for (int i = 2; i <= ctrlpts.length; i += 2) {
                float x1 = (midx + curx) / 2.0f;
                float y1 = (midy + cury) / 2.0f;
                prevx = curx;
                prevy = cury;
                if (i < ctrlpts.length) {
                    curx = ctrlpts[i + 0];
                    cury = ctrlpts[i + 1];
                } else {
                    curx = ctrlpts[0];
                    cury = ctrlpts[1];
                }
                midx = (curx + prevx) / 2.0f;
                midy = (cury + prevy) / 2.0f;
                float x2 = (prevx + midx) / 2.0f;
                float y2 = (prevy + midy) / 2.0f;
                gp.curveTo(x1, y1, x2, y2, midx, midy);
            }
            gp.closePath();

            synchronized(lock) {
        g2d.setComposite(set);
            g2d.setBackground(backgroundColor);
            g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                                 RenderingHints.VALUE_ANTIALIAS_OFF);

            if(bgChanged || bounds == null) {
                bounds = new Rectangle(0, 0, getWidth(), getHeight());
                bgChanged = false;
            }

        // g2d.clearRect(bounds.x-5, bounds.y-5, bounds.x + bounds.width + 5, bounds.y + bounds.height + 5);
            g2d.clearRect(0, 0, getWidth(), getHeight());

            g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                                 RenderingHints.VALUE_ANTIALIAS_ON);
            g2d.setColor(outerColor);
            g2d.setComposite(opaque);
            g2d.setStroke(solid);
            g2d.draw(gp);
            g2d.setPaint(gradient);

            if(!bgChanged) {
                bounds = gp.getBounds();
            } else {
                bounds = new Rectangle(0, 0, getWidth(), getHeight());
                bgChanged = false;
            }
            gradient = new GradientPaint(bounds.x, bounds.y, gradientColorA,
                                         bounds.x + bounds.width, bounds.y + bounds.height,
                                         gradientColorB, true);
            g2d.setComposite(blend);
            g2d.fill(gp);
        }
            if (g2d == BufferG2D) {
                try {
                    SwingUtilities.invokeAndWait(new Runnable() {

                        @Override
                        public void run() {
                            repaint();
                        }
                    });
                } catch (InvocationTargetException | InterruptedException e) {
                    e.printStackTrace();
                }
            }
            ++frame;
        }
        if (g2d != null) {
            g2d.dispose();
        }
    }

    public void paint(Graphics g) {
        synchronized (lock) {
           Graphics2D g2d = (Graphics2D) g;
           if (img != null) {
               g2d.setComposite(AlphaComposite.Src);
               g2d.drawImage(img, null, 0, 0);
           }
        }
    }
}