在Java中,可以使用Java2D庫(kù)和Apache Commons Math庫(kù)來(lái)繪制等值線圖。這里我們將使用Java2D庫(kù)進(jìn)行繪制。以下是一個(gè)簡(jiǎn)單的示例:
首先,確保你已經(jīng)安裝了Java JDK,并正確配置了環(huán)境變量。
創(chuàng)建一個(gè)新的Java類,例如ContourPlot.java
,并導(dǎo)入以下包:
import javax.swing.*;
import java.awt.*;
import java.awt.geom.*;
import java.util.ArrayList;
import java.util.List;
ContourPlot
類中,創(chuàng)建一個(gè)方法drawContour
,用于繪制等值線圖:public void drawContour(Graphics2D g2d, double[][] data, int width, int height) {
// 數(shù)據(jù)點(diǎn)數(shù)量
int numPoints = width * height;
// 創(chuàng)建一個(gè)二維數(shù)組,用于存儲(chǔ)數(shù)據(jù)點(diǎn)的x和y坐標(biāo)
double[][] points = new double[numPoints][2];
// 將數(shù)據(jù)點(diǎn)存儲(chǔ)到二維數(shù)組中
int index = 0;
for (int i = 0; i < height; i++) {
for (int j = 0; j < width; j++) {
points[index][0] = j;
points[index][1] = i;
index++;
}
}
// 對(duì)數(shù)據(jù)進(jìn)行排序,以便繪制等值線
Arrays.sort(points, (a, b) -> Double.compare(data[((int) a[1]) * width + (int) a[0]], data[((int) b[1]) * width + (int) b[0]]));
// 計(jì)算等值線的間隔
double delta = 10;
// 繪制等值線
List<Line2D.Double> lines = new ArrayList<>();
for (double value = data[0][0]; value <= data[height * width - 1][0]; value += delta) {
Line2D.Double line = new Line2D.Double();
boolean isFirstPoint = true;
for (double[] point : points) {
if (isFirstPoint) {
line.setStartPoint(point);
isFirstPoint = false;
} else {
line.setEndPoint(point);
}
if (value == data[((int) point[1]) * width + (int) point[0]][0]) {
lines.add(line);
line = new Line2D.Double();
isFirstPoint = true;
}
}
}
// 設(shè)置畫筆屬性
g2d.setStroke(new BasicStroke(2));
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
// 繪制等值線
for (Line2D.Double line : lines) {
g2d.draw(line);
}
}
ContourPlot
類的main
方法中,創(chuàng)建一個(gè)簡(jiǎn)單的Swing應(yīng)用程序,用于顯示等值線圖:public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
JFrame frame = new JFrame("Contour Plot");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(800, 600);
ContourPlot contourPlot = new ContourPlot();
JPanel panel = new JPanel() {
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
int width = getWidth();
int height = getHeight();
double[][] data = {
{10, 20, 30, 40},
{15, 25, 35, 45},
{20, 30, 40, 50},
{25, 35, 45, 55}
};
contourPlot.drawContour(g2d, data, width, height);
}
};
frame.add(panel);
frame.setVisible(true);
});
}
ContourPlot
類,你將看到一個(gè)簡(jiǎn)單的等值線圖。你可以根據(jù)需要修改數(shù)據(jù)數(shù)組和線條間隔以獲得不同的等值線圖。