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在Java堆栈溢出的东西中绘制一个简单的折线图为绘制折线图提供了一个好主意。但我不知道如何在图中标记X和Y-axis。谁能告诉我如何标记 x 和 y 坐标。

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.Stroke;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.*;

@SuppressWarnings("serial")
public class DrawGraph extends JPanel {
   private static final int MAX_SCORE = 20;
   private static final int PREF_W = 800;
   private static final int PREF_H = 650;
   private static final int BORDER_GAP = 30;
   private static final Color GRAPH_COLOR = Color.green;
   private static final Color GRAPH_POINT_COLOR = new Color(150, 50, 50, 180);
   private static final Stroke GRAPH_STROKE = new BasicStroke(3f);
   private static final int GRAPH_POINT_WIDTH = 12;
   private static final int Y_HATCH_CNT = 10;
   private List<Integer> scores;

   public DrawGraph(List<Integer> scores) {
      this.scores = scores;
   }

   @Override
   protected void paintComponent(Graphics g) {
      super.paintComponent(g);
      Graphics2D g2 = (Graphics2D)g;
      g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

      double xScale = ((double) getWidth() - 2 * BORDER_GAP) / (scores.size() - 1);
      double yScale = ((double) getHeight() - 2 * BORDER_GAP) / (MAX_SCORE - 1);

      List<Point> graphPoints = new ArrayList<Point>();
      for (int i = 0; i < scores.size(); i++) {
         int x1 = (int) (i * xScale + BORDER_GAP);
         int y1 = (int) ((MAX_SCORE - scores.get(i)) * yScale + BORDER_GAP);
         graphPoints.add(new Point(x1, y1));
      }

      // create x and y axes 
      g2.drawLine(BORDER_GAP, getHeight() - BORDER_GAP, BORDER_GAP, BORDER_GAP);
      g2.drawLine(BORDER_GAP, getHeight() - BORDER_GAP, getWidth() - BORDER_GAP, getHeight() - BORDER_GAP);

      // create hatch marks for y axis. 
      for (int i = 0; i < Y_HATCH_CNT; i++) {
         int x0 = BORDER_GAP;
         int x1 = GRAPH_POINT_WIDTH + BORDER_GAP;
         int y0 = getHeight() - (((i + 1) * (getHeight() - BORDER_GAP * 2)) / Y_HATCH_CNT + BORDER_GAP);
         int y1 = y0;
         g2.drawLine(x0, y0, x1, y1);
      }

      // and for x axis
      for (int i = 0; i < scores.size() - 1; i++) {
         int x0 = (i + 1) * (getWidth() - BORDER_GAP * 2) / (scores.size() - 1) + BORDER_GAP;
         int x1 = x0;
         int y0 = getHeight() - BORDER_GAP;
         int y1 = y0 - GRAPH_POINT_WIDTH;
         g2.drawLine(x0, y0, x1, y1);
      }

      Stroke oldStroke = g2.getStroke();
      g2.setColor(GRAPH_COLOR);
      g2.setStroke(GRAPH_STROKE);
      for (int i = 0; i < graphPoints.size() - 1; i++) {
         int x1 = graphPoints.get(i).x;
         int y1 = graphPoints.get(i).y;
         int x2 = graphPoints.get(i + 1).x;
         int y2 = graphPoints.get(i + 1).y;
         g2.drawLine(x1, y1, x2, y2);         
      }

      g2.setStroke(oldStroke);      
      g2.setColor(GRAPH_POINT_COLOR);
      for (int i = 0; i < graphPoints.size(); i++) {
         int x = graphPoints.get(i).x - GRAPH_POINT_WIDTH / 2;
         int y = graphPoints.get(i).y - GRAPH_POINT_WIDTH / 2;;
         int ovalW = GRAPH_POINT_WIDTH;
         int ovalH = GRAPH_POINT_WIDTH;
         g2.fillOval(x, y, ovalW, ovalH);
      }
   }

   @Override
   public Dimension getPreferredSize() {
      return new Dimension(PREF_W, PREF_H);
   }

   private static void createAndShowGui() {
      List<Integer> scores = new ArrayList<Integer>();
      Random random = new Random();
      int maxDataPoints = 16;
      int maxScore = 20;
      for (int i = 0; i < maxDataPoints ; i++) {
         scores.add(random.nextInt(maxScore));
      }
      DrawGraph mainPanel = new DrawGraph(scores);

      JFrame frame = new JFrame("DrawGraph");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.getContentPane().add(mainPanel);
      frame.pack();
      frame.setLocationByPlatform(true);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }
}
4

1 回答 1

1

很多都归结为您要呈现文本的“位置”。

我的意思是，你想修改现有线条的位置，还是你想用BORDER_GAP

您可以从查看使用文本 API开始

你可以从一些简单的事情开始，例如...

FontMetrics fm = g2.getFontMetrics();
// create hatch marks for y axis. 
for (int i = 0; i < Y_HATCH_CNT; i++) {
    int x0 = BORDER_GAP;
    int x1 = GRAPH_POINT_WIDTH + BORDER_GAP;
    int y0 = getHeight() - (((i + 1) * (getHeight() - BORDER_GAP * 2)) / Y_HATCH_CNT + BORDER_GAP);
    int y1 = y0;
    g2.drawLine(x0, y0, x1, y1);
    String value = Integer.toString(i);
    g2.drawString(value, x0 - fm.stringWidth(value), y0 + (fm.getAscent() / 2));
}

// and for x axis
for (int i = 0; i < scores.size() - 1; i++) {
    int x0 = (i + 1) * (getWidth() - BORDER_GAP * 2) / (scores.size() - 1) + BORDER_GAP;
    int x1 = x0;
    int y0 = getHeight() - BORDER_GAP;
    int y1 = y0 - GRAPH_POINT_WIDTH;
    g2.drawLine(x0, y0, x1, y1);
    String value = Integer.toString(i);
    g2.drawString(value, x0 - (fm.stringWidth(value) / 2), y0 + fm.getAscent());
}

例如，它将在每个舱口旁边渲染一个数字（对应于循环的索引）......

更新了旋转示例

现在如果你想旋转，比如 x 系列，所以标签垂直运行，你可以做类似的事情......

FontMetrics fm = g2.getFontMetrics();
// create hatch marks for y axis. 
for (int i = 0; i < Y_HATCH_CNT; i++) {
    int x0 = BORDER_GAP;
    int x1 = GRAPH_POINT_WIDTH + BORDER_GAP;
    int y0 = getHeight() - (((i + 1) * (getHeight() - BORDER_GAP * 2)) / Y_HATCH_CNT + BORDER_GAP);
    int y1 = y0;
    g2.drawLine(x0, y0, x1, y1);
    AffineTransform oldTransform = g2.getTransform();
    AffineTransform newTransform = new AffineTransform();
    newTransform.translate(-fm.getHeight() / 2, 0);
    newTransform.rotate(Math.toRadians(-90), x0, y0);
    g2.setTransform(newTransform);
    String value = Integer.toString(i);
    g2.drawString(value, x0 - (fm.stringWidth(value) / 2), y0 + (fm.getAscent() / 2));
    g2.setTransform(oldTransform);
}
于 2013-03-04T06:17:19.277 回答