5

我正在尝试用 Java 制作一些形状。我创建了两个具有两种不同颜色的矩形,但我想创建一个星形,但我找不到有用的资源来帮助我这样做。

这是我的代码:

import java.awt.*;
import javax.swing.*;

public class shapes extends JPanel{

    @Override
    public void paintComponent(Graphics GPHCS){
        super.paintComponent(GPHCS);

        GPHCS.setColor(Color.BLUE);
        GPHCS.fillRect(25,25,100,30);

        GPHCS.setColor(Color.GRAY);
        GPHCS.fillRect(25,65,100,30);

        GPHCS.setColor(new Color(190,81,215));
        GPHCS.drawString("This is my text", 25, 120);
    }
}
4

4 回答 4

8

您可以尝试使用多边形和一些基本数学:

    int midX = 500;
    int midY = 340;
    int radius[] = {118,40,90,40};
    int nPoints = 16;
    int[] X = new int[nPoints];
    int[] Y = new int[nPoints];

    for (double current=0.0; current<nPoints; current++)
    {
        int i = (int) current;
        double x = Math.cos(current*((2*Math.PI)/max))*radius[i % 4];
        double y = Math.sin(current*((2*Math.PI)/max))*radius[i % 4];

        X[i] = (int) x+midX;
        Y[i] = (int) y+midY;
    }

    g.setColor(Color.WHITE);
    g.fillPolygon(X, Y, nPoints);
于 2013-05-01T23:05:22.593 回答
4

您还可以使用现有的类,例如http://java-sl.com/shapes.html用于正多边形和星形。

于 2013-05-02T05:38:04.150 回答
3

该类Polygon可以被视为自 Java 1.0 以来一直存在的遗留类,但在新代码中几乎不应该再使用。在单独的数组中指定 x/y 坐标的奇怪方式,更重要的是,它仅支持int[]数组这一事实限制了它的应用领域。虽然它实现了Shape接口,但是这个接口有更现代的实现可以用来表示多边形。在大多数情况下,将多边形描述为 aPath2D更容易且更灵活。可以创建一个Path2D p = new Path2D.Double();然后执行一系列moveTolineTo调用以生成所需的形状。

以下程序显示了如何使用Path2D该类来生成星形。最重要的方法是createStar方法。这是非常通用的。它接收

  • 恒星的中心坐标
  • 恒星的内半径和外半径
  • 恒星应该有的光线数量
  • 第一条射线应该在的角度(即恒星的旋转角度)

如果需要,可以使用一种更简单的方法来围绕这个方法——就像createDefaultStar下面代码中的示例一样。

该程序显示不同的星星,绘制为线条并填充不同的颜色和径向渐变涂料,例如:

星星

作为MCVE的完整程序:

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RadialGradientPaint;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.geom.Path2D;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class DrawStarShape
{
    public static void main(String[] args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            @Override
            public void run()
            {
                createAndShowGUI();
            }
        });
    }

    private static void createAndShowGUI()
    {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(new DrawStarShapePanel());
        f.setSize(600, 600);
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

}

class DrawStarShapePanel extends JPanel
{
    @Override
    protected void paintComponent(Graphics gr)
    {
        super.paintComponent(gr);
        Graphics2D g = (Graphics2D) gr;
        g.setColor(Color.WHITE);
        g.fillRect(0, 0, getWidth(), getHeight());
        g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
            RenderingHints.VALUE_ANTIALIAS_ON);

        g.setColor(Color.BLACK);
        g.draw(createDefaultStar(50, 200, 200));

        g.setPaint(Color.RED);
        g.fill(createStar(400, 400, 40, 60, 10, 0));

        g.setPaint(new RadialGradientPaint(
            new Point(400, 200), 60, new float[] { 0, 1 }, 
            new Color[] { Color.RED, Color.YELLOW }));
        g.fill(createStar(400, 200, 20, 60, 8, 0));

        g.setPaint(new RadialGradientPaint(
            new Point(200, 400), 50, new float[] { 0, 0.3f, 1 }, 
            new Color[] { Color.RED, Color.YELLOW, Color.ORANGE }));
        g.fill(createStar(200, 400, 40, 50, 20, 0));

    }

    private static Shape createDefaultStar(double radius, double centerX,
        double centerY)
    {
        return createStar(centerX, centerY, radius, radius * 2.63, 5,
            Math.toRadians(-18));
    }

    private static Shape createStar(double centerX, double centerY,
        double innerRadius, double outerRadius, int numRays,
        double startAngleRad)
    {
        Path2D path = new Path2D.Double();
        double deltaAngleRad = Math.PI / numRays;
        for (int i = 0; i < numRays * 2; i++)
        {
            double angleRad = startAngleRad + i * deltaAngleRad;
            double ca = Math.cos(angleRad);
            double sa = Math.sin(angleRad);
            double relX = ca;
            double relY = sa;
            if ((i & 1) == 0)
            {
                relX *= outerRadius;
                relY *= outerRadius;
            }
            else
            {
                relX *= innerRadius;
                relY *= innerRadius;
            }
            if (i == 0)
            {
                path.moveTo(centerX + relX, centerY + relY);
            }
            else
            {
                path.lineTo(centerX + relX, centerY + relY);
            }
        }
        path.closePath();
        return path;
    }
}
于 2016-10-01T15:49:33.257 回答
0

我有两种方法。

1)

public static Bitmap drawStar(int W, int H, int color, boolean andRing)
{
    Path path = new Path();
    Bitmap output = Bitmap.createBitmap(W, H, Config.ARGB_8888);
    Canvas canvas = new Canvas(output);
    final Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
    paint.setColor(color);

    float midW ,min ,fat ,half ,radius;

    if(andRing)
    {
        midW = W / 2;
        min = Math.min(W, H);
        half = min / 2;
        midW = midW - half;

        fat = min / 17;
        radius = half - fat;

        paint.setStrokeWidth(fat);
        paint.setStyle(Paint.Style.STROKE);
        canvas.drawCircle(midW + half, half, radius, paint);

        path.reset();
        paint.setStyle(Paint.Style.FILL);
        path.moveTo( half * 0.5f, half * 0.84f);
        path.lineTo( half * 1.5f, half * 0.84f);
        path.lineTo( half * 0.68f, half * 1.45f);
        path.lineTo( half * 1.0f, half * 0.5f);
        path.lineTo( half * 1.32f, half * 1.45f);
        path.lineTo( half * 0.5f, half * 0.84f);
    }
    else
    {
        min = Math.min(W, H);
        half = min/2;

        path.reset();
        paint.setStyle(Paint.Style.FILL);

        path.moveTo( half * 0.1f  , half * 0.65f);
        path.lineTo( half * 1.9f  , half * 0.65f);
        path.lineTo( half * 0.40f , half * 1.65f);
        path.lineTo( half       , 0           );
        path.lineTo( half * 1.60f, half * 1.65f);
        path.lineTo( half * 0.1f, half * 0.65f);
    }

    canvas.drawPath(path, paint);

    return output;
}

2)

  public static Bitmap drawStar(int W,int H,int spikes,int innerRadius,int outerRadius, int backColor,boolean border, int borderColor)
{
    if(W < 10)
        W = 10;

    if(H < 10)
        H = 10;

    if(spikes < 5)
        spikes = 5;

    int smallL = W;

    if(H < W)
        smallL = H;

    if(outerRadius > smallL/2)
        outerRadius = smallL/2;

    if(innerRadius < 5)
        innerRadius = 5;

    if(border)
    {
        outerRadius -=2;
        innerRadius -=2;
    }

    Path path = new Path();
    Bitmap output = Bitmap.createBitmap(W, H, Config.ARGB_8888);
    Canvas canvas = new Canvas(output);
    final Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
    paint.setColor(backColor);
    int cx = W/2;
    int cy = H/2;

    double rot = Math.PI / 2 * 3;
    float x,y;
    double step = Math.PI / spikes;

    path.moveTo(cx, cy - outerRadius);

    for (int i = 0; i < spikes; i++)
    {
        x = (float) (cx + Math.cos(rot) * outerRadius);
        y = (float) (cy + Math.sin(rot) * outerRadius);
        path.lineTo(x, y);
        rot += step;

        x = (float) (cx + Math.cos(rot) * innerRadius);
        y = (float) (cy + Math.sin(rot) * innerRadius);
        path.lineTo(x, y);
        rot += step;
    }

    path.lineTo(cx, cy - outerRadius);
    path.close();

    canvas.drawPath(path, paint);

    if(border)
    {
        paint.setStyle(Style.STROKE);
        paint.setStrokeWidth(2);
        paint.setColor(borderColor);
        canvas.drawPath(path, paint);
    }
    return output;
}
于 2017-07-30T10:19:33.737 回答