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ronald
ronald wrote ...

2020/7/26

Rosace Curve

ronald ronald

2020/7/26

#
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import greenfoot.*;  // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)
 
/**
 * Write a description of class RoseCurve here.
 *
 * @author (your name)
 * @version (a version number or a date)
 */
public class RoseCurve extends Actor
{
    /**
     * Act - do whatever the RoseCurve wants to do. This method is called whenever
     * the 'Act' or 'Run' button gets pressed in the environment.
     */
    double x = 0;
    double y = 0;
    double newX;
    double newY;
    int k = 4;
     
    public RoseCurve()
    {
         
    }
     
    public void act()
    {
        // Add your action code here.
        drawRoseCurve();
         
    }
     
    public void drawRoseCurve()
    {
        GreenfootImage gfim = new GreenfootImage(900,600);
        gfim.setColor(Color.BLUE);
         
        
        for (int theta = 0; theta <= 360; theta++) {
        double k = theta * Math.PI / 180;
        double r = Math.sin(k*theta);
         
        double newX = r*(Math.cos(k));
        double newY = r*(Math.sin(k));
         
        gfim.drawLine((int) x, (int) y, (int) newX, (int) newY);
         
        x = newX;
        y = newY;
    }
         
    setImage(gfim);
     
    }
}
I try to make a simple flower with 6 petals I'm trying to understand math Thank you for your help
danpost danpost

2020/7/26

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I would think the radius used would remain constant. Also, when drawing, you should probably start with the center of the image as the "origin".
ronald ronald

2020/7/27

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public class RosaceCurve extends Actor
{
    /**
     * Act - do whatever the RoseCurve wants to do. This method is called whenever
     * the 'Act' or 'Run' button gets pressed in the environment.
     */
    double x1 = 0;
    double y1 = 0;
    static final int width = 800;
    static final int height = 800;
    int n = 6;
     
    public void act()
    {
        // Add your action code here.
        drawRosaceCurve();
         
    }
     
    public void drawRosaceCurve()
    {
        GreenfootImage gfim = new GreenfootImage(width / 2, height / 2);
        gfim.setColor(Color.BLUE);
         
        for (int theta = 0; theta <= 360; theta++) {
        double k = theta * Math.PI / 180;
        double r = 150*(Math.sin(k*n));
         
        double x2 = r*(Math.cos(k));
        double y2 = r*(Math.sin(k));
         
        gfim.drawLine((int) x1, (int) y1, (int) x2, (int) y2);
         
        x1 = x2;
        y1 = y2;
    }
     
    setImage(gfim);
     
    }
}
i don't really understand what's wrong the design is 1/4, 3 petals instead of 12 petals
danpost danpost

2020/7/28

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danpost wrote...
when drawing, you should probably start with the center of the image as the "origin".
With center of curve at (0, 0) on image, only the lower-right portion is drawn on image.
ronald ronald

2020/7/28

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thank you I put double x1 = 200 and I add x1 to double x2, it is not the same as if I added 200 to double x2 with double x1 = 0, weird, I thought x1 would be replaced by 200 if I added it to double x2 I don't know if you understood me
danpost danpost

2020/7/28

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ronald wrote...
I put double x1 = 200 and I add x1 to double x2, it is not the same as if I added 200 to double x2 with double x1 = 0, weird, I thought x1 would be replaced by 200 if I added it to double x2
Show revised code.
ronald ronald

2020/7/28

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public class RosaceCurve extends Actor
{
    /**
     * Act - do whatever the RoseCurve wants to do. This method is called whenever
     * the 'Act' or 'Run' button gets pressed in the environment.
     */
    double x1 = 0;
    double y1 = 0;
    static final int width = 800;
    static final int height = 800;
    int n = 6;
     
    public void act()
    {
        // Add your action code here.
        drawRosaceCurve();
         
    }
     
    public void drawRosaceCurve()
    {
        GreenfootImage gfim = new GreenfootImage(width / 2, height / 2);
        gfim.setColor(Color.BLUE);
         
        for (int theta = 0; theta <= 360; theta++) {
        double k = theta * Math.PI / 180;
        double r = 150*(Math.sin(k*n));
         
        double x2 = 200+r*(Math.cos(k));
        double y2 = 200+r*(Math.sin(k));
         
        gfim.drawLine((int) x1, (int) y1, (int) x2, (int) y2);
         
        x1 = x2;
        y1 = y2;
    }
     
    setImage(gfim);
     
    }
}
this code works perfectly
ronald ronald

2020/7/28

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public class RosaceCurve extends Actor
{
    /**
     * Act - do whatever the RoseCurve wants to do. This method is called whenever
     * the 'Act' or 'Run' button gets pressed in the environment.
     */
    double x1 = 200;
    double y1 = 200;
    static final int width = 800;
    static final int height = 800;
    int n = 6;
     
    public void act()
    {
        // Add your action code here.
        drawRosaceCurve();
         
    }
     
    public void drawRosaceCurve()
    {
        GreenfootImage gfim = new GreenfootImage(width / 2, height / 2);
        gfim.setColor(Color.BLUE);
         
        for (int theta = 0; theta <= 360; theta++) {
        double k = theta * Math.PI / 180;
        double r = 150*(Math.sin(k*n));
         
        double x2 = x1+r*(Math.cos(k));
        double y2 = y1+r*(Math.sin(k));
         
        gfim.drawLine((int) x1, (int) y1, (int) x2, (int) y2);
         
        x1 = x2;
        y1 = y2;
    }
     
    setImage(gfim);
     
    }
}
this code does not work pk ?
danpost danpost

2020/7/28

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ronald wrote...
<< Code Omitted >> this code works perfectly
Good job. However, I would have just change line 32 in your 2nd initial post to:
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gfim.drawLine(200+(int)x1, 200+(int)y1, 200+(int)x2, 200+(int)y2);
ronald ronald

2020/7/28

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it also works thank you
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