116 lines
3.2 KiB
Java
116 lines
3.2 KiB
Java
import java.awt.Color;
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import java.awt.Dimension;
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import java.awt.Graphics;
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import javax.swing.JFrame;
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import javax.swing.JPanel;
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import javax.swing.SwingUtilities;
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import javax.swing.WindowConstants;
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public class Bresenham {
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public static void main(String[] args) {
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SwingUtilities.invokeLater(Bresenham::run);
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}
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private static void run() {
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JFrame f = new JFrame();
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f.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
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f.setTitle("Bresenham");
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f.getContentPane().add(new BresenhamPanel());
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f.pack();
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f.setLocationRelativeTo(null);
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f.setVisible(true);
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}
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}
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class BresenhamPanel extends JPanel {
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private final int pixelSize = 10;
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BresenhamPanel() {
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setPreferredSize(new Dimension(600, 500));
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setBackground(Color.WHITE);
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}
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@Override
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public void paintComponent(Graphics g) {
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super.paintComponent(g);
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int w = (getWidth() - 1) / pixelSize;
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int h = (getHeight() - 1) / pixelSize;
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int maxX = (w - 1) / 2;
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int maxY = (h - 1) / 2;
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int x1 = -maxX, x2 = maxX * -2 / 3, x3 = maxX * 2 / 3, x4 = maxX;
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int y1 = -maxY, y2 = maxY * -2 / 3, y3 = maxY * 2 / 3, y4 = maxY;
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drawLine(g, 0, 0, x3, y1); // NNE
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drawLine(g, 0, 0, x4, y2); // ENE
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drawLine(g, 0, 0, x4, y3); // ESE
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drawLine(g, 0, 0, x3, y4); // SSE
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drawLine(g, 0, 0, x2, y4); // SSW
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drawLine(g, 0, 0, x1, y3); // WSW
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drawLine(g, 0, 0, x1, y2); // WNW
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drawLine(g, 0, 0, x2, y1); // NNW
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}
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private void plot(Graphics g, int x, int y) {
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int w = (getWidth() - 1) / pixelSize;
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int h = (getHeight() - 1) / pixelSize;
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int maxX = (w - 1) / 2;
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int maxY = (h - 1) / 2;
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int borderX = getWidth() - ((2 * maxX + 1) * pixelSize + 1);
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int borderY = getHeight() - ((2 * maxY + 1) * pixelSize + 1);
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int left = (x + maxX) * pixelSize + borderX / 2;
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int top = (y + maxY) * pixelSize + borderY / 2;
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g.setColor(Color.black);
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g.drawOval(left, top, pixelSize, pixelSize);
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}
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private void drawLine(Graphics g, int x1, int y1, int x2, int y2) {
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// delta of exact value and rounded value of the dependent variable
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int d = 0;
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int dx = Math.abs(x2 - x1);
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int dy = Math.abs(y2 - y1);
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int dx2 = 2 * dx; // slope scaling factors to
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int dy2 = 2 * dy; // avoid floating point
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int ix = x1 < x2 ? 1 : -1; // increment direction
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int iy = y1 < y2 ? 1 : -1;
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int x = x1;
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int y = y1;
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if (dx >= dy) {
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while (true) {
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plot(g, x, y);
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if (x == x2)
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break;
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x += ix;
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d += dy2;
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if (d > dx) {
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y += iy;
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d -= dx2;
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}
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}
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} else {
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while (true) {
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plot(g, x, y);
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if (y == y2)
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break;
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y += iy;
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d += dx2;
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if (d > dy) {
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x += ix;
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d -= dy2;
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}
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}
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}
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}
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}
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