围绕 x 轴垂直旋转形状 [英] Rotating a shape vertically around the x-axis

问题描述

我有一个带有 x 轴和 y 轴的二维图形，我正在尝试围绕轴旋转形状(一系列点).此旋转将需要包含缩放功能.

I have a 2d graph with an x and y axis and im trying to rotate a shape (series of points) around an axis. This rotation will need to include a scale function.

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.AffineTransform;
import java.awt.geom.Point2D;
import javax.swing.*;
import java.lang.reflect.Array;

public class test extends JPanel implements ActionListener {

    int[] p1x = {200, 200, 240, 240, 220, 220, 200};
    int[] p1y = {200, 260, 260, 240, 240, 200, 200};
    int[] p2x = {600, 600, 620, 620, 640, 640, 660, 660, 600};
    int[] p2y = {400, 420, 420, 460, 460, 420, 420, 400, 400};
    int[] p3x = {400, 400, 460, 460, 440, 440, 420, 420, 400};
    int[] p3y = {400, 460, 460, 400, 400, 440, 440, 400, 400};
    int delay = 1000;
    int dx = 0;
    int dy = 5;
    int steps = 121;
    Polygon t;
    Timer tim = new Timer(delay, this);

    public void actionPerformed(ActionEvent event) {
        for (int i = 0; i < Array.getLength(p2x); i++) {
            //p2x[i] = (int) (p2x[i]*Math.cos(Math.toRadians(1))- p2y[i]*Math.sin(Math.toRadians(1)));
            //p2y[i] = (int) (p2x[i]*Math.sin(Math.toRadians(1))+ p2y[i]*Math.cos(Math.toRadians(1)));;

            Point2D original = new Point2D.Double(p2x[i], p2y[i]);
            AffineTransform at = new AffineTransform();
            //at.setToRotation(.02, 250, 250);
            at.scale(1, -1);
            Point2D rotated = at.transform(original, null);
            p2x[i] = (int) rotated.getX();
            p2y[i] = (int) rotated.getY();
        }
        repaint();

        if (--steps == 0) {
            tim.stop();
        }
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);

        this.setBackground(Color.white);

        g.drawLine(this.getWidth() / 2, 0, this.getWidth() / 2, this.getWidth());
        g.drawLine(0, this.getHeight() / 2, this.getHeight(), this.getHeight() / 2);

        Polygon t = new Polygon(p2x, p2y, 9);
        g.drawPolygon(t);

        Letters u = new Letters(p3x, p3y, 9);
        u.draw(g);

        Letters l = new Letters(p1x, p1y, 7);
        l.draw(g);
    }

    public static void main(String[] args) {

        JFrame frame = new JFrame("Drawing line and a moving polygon");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        test sl = new test();
        frame.getContentPane().add(sl);
        frame.setSize(700, 700);
        frame.setVisible(true);

        sl.tim.start();
    }
}

推荐答案

如果没有明确的问题，使用坐标数组的简单动画如下所示.通常，您可以转换图形上下文(g2d)或多边形Shape 本身(p3)；该示例显示了两者.调整窗口大小以查看每个效果.

Absent a clear question, a simple animation using your coordinate arrays is shown below. In general you can transform the graphics context (g2d) or the polygonal Shape itself (p3); the example shows both. Resize the window to see the effect of each.

注意at 中转换的last-specified-first-applied 顺序.首先将p3上的一个合适的点平移到原点，然后缩放p3，然后将p3平移到面板的中心.应用于 p3 的 +10 模糊因子是没有对称旋转点的人工制品.相对于原点定义多边形可能更容易，如本示例所示.

Note the last-specified-first-applied order of the transformations in at. First, a suitable point on p3 is translated to the origin, then p3 is scaled, and then p3 is translated to the center of the panel. The + 10 fudge factor applied to p3 is an artifact of having no symmetric rotation point. It may be easier to define your polygons relative to the origin, as shown in this example.

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.AffineTransform;
import javax.swing.*;

/** @see http://stackoverflow.com/questions/3405799 */
public class AffineTest extends JPanel implements ActionListener {

    private static final double DELTA_THETA = Math.PI / 45; // 4°
    private static final double DELTA_SCALE = 0.1;
    private int[] p1x = {200, 200, 240, 240, 220, 220, 200};
    private int[] p1y = {200, 260, 260, 240, 240, 200, 200};
    private int[] p2x = {600, 600, 620, 620, 640, 640, 660, 660, 600};
    private int[] p2y = {400, 420, 420, 460, 460, 420, 420, 400, 400};
    private int[] p3x = {400, 400, 460, 460, 440, 440, 420, 420, 400};
    private int[] p3y = {400, 460, 460, 400, 400, 440, 440, 400, 400};
    private Polygon p1 = new Polygon(p1x, p1y, p1x.length);
    private Polygon p2 = new Polygon(p2x, p2y, p2x.length);
    private Polygon p3 = new Polygon(p3x, p3y, p3x.length);
    private AffineTransform at = new AffineTransform();
    private double dt = DELTA_THETA;
    private double theta;
    private double ds = DELTA_SCALE;
    private double scale = 1;
    private Timer timer = new Timer(100, this);

    public AffineTest() {
        this.setPreferredSize(new Dimension(700, 700));
        this.setBackground(Color.white);
        p1.translate(-50, +100);
        p2.translate(-100, -100);
    }

    @Override
    public void actionPerformed(ActionEvent event) {
        theta += dt;
        scale += ds;
        if (scale < .5 || scale > 4) {
            ds = -ds;
        }
        repaint();
    }

    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2d = (Graphics2D) g;
        g2d.setRenderingHint(
            RenderingHints.KEY_ANTIALIASING,
            RenderingHints.VALUE_ANTIALIAS_ON);
        int w = this.getWidth();
        int h = this.getHeight();
        g2d.drawLine(w / 2, 0, w / 2, h);
        g2d.drawLine(0, h / 2, w, h / 2);
        g2d.rotate(theta, w / 2, h / 2);
        g2d.drawPolygon(p1);
        g2d.drawPolygon(p2);
        at.setToIdentity();
        at.translate(w / 2, h / 2);
        at.scale(scale, scale);
        at.translate(-p3x[5] + 10, -p3y[5]);
        g2d.setPaint(Color.blue);
        g2d.fill(at.createTransformedShape(p3));
    }

    public void start() {
        timer.start();
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame("Affine Test");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        AffineTest sl = new AffineTest();
        frame.add(sl);
        frame.pack();
        frame.setVisible(true);
        sl.start();
    }
}

这篇关于围绕 x 轴垂直旋转形状的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！