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ronald
ronald wrote ...

2020/7/26

Rosace Curve

ronald ronald

2020/7/26

# 
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

#
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

# 
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

#
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

#
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

#
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

# 
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

# 
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

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

2020/7/28

#
it also works thank you
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