3

我正在做一个项目，我想显示一个看起来像条形图的单线直方图，除了条形图中的每条线代表一个像素及其灰度值。

我有一个充满灰度值的数组，我只需要将它们放入此直方图中并让它显示代表值的线条..有点像这样

IMAGE             [minimize][maximize][close]



    picture                histogram

                          I
   (Loaded Picture)       I       I
                          I  I    I
                          I  I  I I  

[open][save]

下面是加载数组的代码......我只需要获取一些将使用这些灰度值并将它们表示为像上面一样的条形的代码。

 public void showImage(File fileName) {
        Scanner scan;
        try {
            scan = new Scanner(fileName);
            typefile = scan.next();
            iname = scan.next();       
            width = scan.nextInt();
            height = scan.nextInt();
            maxshade = scan.nextInt();
            array = new int[width][height];


            for(int r = 0; r < array.length; r++){
                for(int c = 0; c < array[r].length; c++){
                    array[r][c] = scan.nextInt();                       




            imageArray = array;         
            repaint();                  


        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }

 }

我知道我必须做类似...

     int hist[] = new int[256];
     for (int r = 0; r < array.length; r++)
            for (int c = 0; c < array[r].length; c++)
                hist[array[r][c]]++;

但我不知道从那里去哪里或如何绘制我的图表。

4

1 回答 1

8

就像是

在此处输入图像描述

也许？？

就个人而言，我仍然会使用JFreeChart 之类的东西，但这是一个有趣的小练习......

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.Rectangle2D;
import java.util.Map;
import java.util.TreeMap;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;

public class TestHisogram {
//http://stackoverflow.com/a/12520104/714968

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                new TestHisogram();
            }
        });
    }

    public TestHisogram() {
        // For this example, I just randomised some data, you would
        // Need to load it yourself...
        int width = 256;
        int height = 256;
        int[][] data = new int[width][height];
        for (int c = 0; c < height; c++) {
            for (int r = 0; r < width; r++) {
                data[c][r] = (int) (256 * Math.random());
            }
        }
        Map<Integer, Integer> mapHistory = new TreeMap<Integer, Integer>();
        for (int c = 0; c < data.length; c++) {
            for (int r = 0; r < data[c].length; r++) {
                int value = data[c][r];
                int amount = 0;
                if (mapHistory.containsKey(value)) {
                    amount = mapHistory.get(value);
                    amount++;
                } else {
                    amount = 1;
                }
                mapHistory.put(value, amount);
            }
        }
        JFrame frame = new JFrame("Test");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLayout(new BorderLayout());
        frame.add(new JScrollPane(new Graph(mapHistory)));
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    protected class Graph extends JPanel {

        protected static final int MIN_BAR_WIDTH = 4;
        private Map<Integer, Integer> mapHistory;

        public Graph(Map<Integer, Integer> mapHistory) {
            this.mapHistory = mapHistory;
            int width = (mapHistory.size() * MIN_BAR_WIDTH) + 11;
            Dimension minSize = new Dimension(width, 128);
            Dimension prefSize = new Dimension(width, 256);
            setMinimumSize(minSize);
            setPreferredSize(prefSize);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            if (mapHistory != null) {
                int xOffset = 5;
                int yOffset = 5;
                int width = getWidth() - 1 - (xOffset * 2);
                int height = getHeight() - 1 - (yOffset * 2);
                Graphics2D g2d = (Graphics2D) g.create();
                g2d.setColor(Color.DARK_GRAY);
                g2d.drawRect(xOffset, yOffset, width, height);
                int barWidth = Math.max(MIN_BAR_WIDTH,
                        (int) Math.floor((float) width
                        / (float) mapHistory.size()));
                System.out.println("width = " + width + "; size = "
                        + mapHistory.size() + "; barWidth = " + barWidth);
                int maxValue = 0;
                for (Integer key : mapHistory.keySet()) {
                    int value = mapHistory.get(key);
                    maxValue = Math.max(maxValue, value);
                }
                int xPos = xOffset;
                for (Integer key : mapHistory.keySet()) {
                    int value = mapHistory.get(key);
                    int barHeight = Math.round(((float) value
                            / (float) maxValue) * height);
                    g2d.setColor(new Color(key, key, key));
                    int yPos = height + yOffset - barHeight;
//Rectangle bar = new Rectangle(xPos, yPos, barWidth, barHeight);
                    Rectangle2D bar = new Rectangle2D.Float(
                            xPos, yPos, barWidth, barHeight);
                    g2d.fill(bar);
                    g2d.setColor(Color.DARK_GRAY);
                    g2d.draw(bar);
                    xPos += barWidth;
                }
                g2d.dispose();
            }
        }
    }
}
于 2012-09-20T20:06:27.363 回答