Java2D (WeatherWizard)

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package com.han.java2d;import javax.imageio.ImageIO;import javax.swing.*;import javax.swing.event.ChangeEvent;import javax.swing.event.ChangeListener;import java.awt.*;import java.awt.font.FontRenderContext;import java.awt.geom.Rectangle2D;import java.awt.image.BufferedImage;import java.net.URL;/** * The WeatherWizard demo uses the JSlider component as well as various graphics capabilities to generate and display * a specified weather type.<p> * Class note: Created by Gaowen on 14-1-11. */public class WeatherWizard extends JPanel implements ChangeListener {    private final WeatherPainter painter;    private WeatherWizard() {        setLayout(new BorderLayout());        Box box = Box.createHorizontalBox();        box.add(Box.createGlue());        box.add(new JLabel("Temperature:"));        JSlider jSlider = new JSlider(20, 100, 65);        jSlider.setMinorTickSpacing(5);        jSlider.setMajorTickSpacing(20);        jSlider.setPaintTicks(true);        jSlider.setPaintLabels(true);        jSlider.addChangeListener(this);        box.add(jSlider);        box.add(Box.createGlue());        add(box, BorderLayout.NORTH);        painter = new WeatherPainter(loadImage("sun"), loadImage("cloud"), loadImage("rain"), loadImage("snow"));        add(painter, BorderLayout.CENTER);    }    private BufferedImage loadImage(String name) {        String imgFileName = "images/weather-" + name + ".png";        URL url = WeatherWizard.class.getResource(imgFileName);        BufferedImage img = null;        try {            img = ImageIO.read(url);        } catch (Exception e) {            e.printStackTrace();        }        return img;    }    private class WeatherPainter extends Component {        private final BufferedImage snow;        private final BufferedImage rain;        private final BufferedImage cloud;        private final BufferedImage sun;        private int temperature;        private Color textColor;        private String feels;        private String condStr;        private Composite alpha0;        private Composite alpha1;        private BufferedImage img0;        private BufferedImage img1;        private WeatherPainter(BufferedImage snow, BufferedImage rain, BufferedImage cloud, BufferedImage sun) {            this.snow = snow;            this.rain = rain;            this.cloud = cloud;            this.sun = sun;            temperature = 65;            textColor = Color.yellow;        }        public void setTemperature(int temperature) {            this.temperature = temperature;            repaint();        }        @Override        public Dimension getPreferredSize() {            return new Dimension(450, 125);        }        @Override        public void paint(Graphics g) {            Graphics2D g2 = (Graphics2D) g.create();            Dimension size = getSize();            Composite origComposite;            setupWeatherReport();            origComposite = g2.getComposite();            if (alpha0 != null) g2.setComposite(alpha0);            g2.drawImage(img0, 0, 0, size.width, size.height, 0, 0, img0.getWidth(null), img0.getHeight(null), null);            if (img1 != null) {                if (alpha1 != null) g2.setComposite(alpha1);                g2.drawImage(img1, 0, 0, size.width, size.height, 0, 0, img1.getWidth(null), img1.getHeight(null),                        null);            }            g2.setComposite(origComposite);            Font font = new Font("Serif", Font.PLAIN, 36);            g2.setFont(font);            String tempString = feels + " " + temperature + "F";            FontRenderContext frc = g2.getFontRenderContext();            Rectangle2D boundsTemp = font.getStringBounds(tempString, frc);            Rectangle2D boundsCond = font.getStringBounds(condStr, frc);            int wText = Math.max((int) boundsTemp.getWidth(), (int) boundsCond.getWidth());            int hText = (int) boundsTemp.getHeight() + (int) boundsCond.getHeight();            int rX = (size.width - wText) / 2;            int rY = (size.height - hText) / 2;            g2.setColor(Color.LIGHT_GRAY);            g2.fillRect(rX, rY, wText, hText);            g2.setColor(textColor);            int xTextTemp = rX - (int) boundsTemp.getX();            int yTextTemp = rY - (int) boundsTemp.getY();            g2.drawString(tempString, xTextTemp, yTextTemp);            int xTextCond = rX - (int) boundsCond.getX();            int yTextCond = rY - (int) boundsCond.getY() + (int) boundsTemp.getHeight();            g2.drawString(condStr, xTextCond, yTextCond);        }        private void setupWeatherReport() {            if (temperature <= 32) {                setupImages(snow);                setupText("Snow", null);            } else if (temperature <= 40) {                setupImages(32, 40, snow, rain);                setupText("Snow", "Rain");            } else if (temperature <= 50) {                setupImages(rain);                setupText("Rain", null);            } else if (temperature <= 58) {                setupImages(50, 58, rain, cloud);                setupText("Rain", "Cloud");            } else if (temperature <= 65) {                setupImages(cloud);                setupText("Cloud", null);            } else if (temperature <= 75) {                setupImages(65, 75, cloud, sun);                setupText("Cloud", "Sun");            } else {                setupImages(sun);                setupText("Sun", null);            }        }        private void setupText(String s1, String s2) {            if (temperature <= 32) {                textColor = Color.blue;                feels = "Freezing";            } else if (temperature <= 50) {                textColor = Color.green;                feels = "Cold";            } else if (temperature <= 65) {                textColor = Color.yellow;                feels = "Cool";            } else if (temperature <= 75) {                textColor = Color.orange;                feels = "Warm";            } else {                textColor = Color.red;                feels = "Hot";            }            condStr = s1;            if (s2 != null) {                condStr += "/" + s2;            }        }        private void setupImages(BufferedImage i0) {            alpha0 = null;            alpha1 = null;            img0 = i0;            img1 = null;        }        private void setupImages(int min, int max, BufferedImage i0, BufferedImage i1) {            float alpha = (max - temperature) / (float) (max - min);            alpha0 = AlphaComposite.getInstance(AlphaComposite.SRC_OVER, alpha);            alpha1 = AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 1 - alpha);            img0 = i0;            img1 = i1;        }    }    @Override    public void stateChanged(ChangeEvent e) {        JSlider jSlider = (JSlider) e.getSource();        painter.setTemperature(jSlider.getValue());    }    public static void main(String[] args) {        SwingUtilities.invokeLater(new Runnable() {            @Override            public void run() {                createAndShowGUI();            }        });    }    private static void createAndShowGUI() {        JFrame jFrame = new JFrame("Weather Wizard");        JPanel contentPane = new WeatherWizard();        jFrame.setContentPane(contentPane);        jFrame.pack();        jFrame.setLocationRelativeTo(null);        jFrame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);        jFrame.setVisible(true);    }}
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