-----------------------------------

hamid14

Sat Jan 08, 2011 1:16 pm


mandelbrot set in java

-----------------------------------

im trying to draw the mandelbrot set in netbeans using java, but i cant get it work properly. if i use g.drawOval (x,y,1,1); it says you cannot apply doubles to int, which i understand why. but then if i convert the x and y to int, then the whole screen just goes black. I dont understand what i should do at this point.

heres my code:


import java.awt.*;
import BreezyGUI.*;

public class BreezyStuff extends GBFrame {

    public void paint(Graphics g) {
        double imageHeight = 399;
        double imageWidth = 639;
        double minRe = -2;
        double maxRe = 1;
        double minIm = -1.2;
        double maxIm = minIm + (maxRe - minRe) * imageHeight / imageWidth;

        double Re_factor = (maxRe - minRe) / (imageWidth - 1);
        double Im_factor = (maxIm - minIm) / (imageHeight - 1);

        double unsignedMaxIterations = 30;


        for (double y = 0; y < imageHeight; y++) {
            double c_im = maxIm - y * Im_factor;
            for (double x = 0; x < imageWidth; x++) {
                double c_re = minRe + x * Re_factor;
                double Z_re = c_re;
                double Z_im = c_im;
                boolean isInside = true;
                for (double n = 0; n < unsignedMaxIterations; n++) {
                    double Z_re2 = Z_re * Z_re;
                    double Z_im2 = Z_im * Z_im;
                    if (Z_re2 + Z_im2 > 4) {
                        isInside = false;
                    }
                    Z_im = 2 * Z_re * Z_im + c_im;
                    Z_re = Z_re2 - Z_im2 + c_re;
                }
                if (isInside = true) {
                    int e, f;
                    e = (int) x;
                    f = (int) y;
                    g.setColor(Color.BLACK);
                    g.drawOval(e, f, 1, 1);
                }
            }
        }

    }

    public static void main(String[] args) {
        Frame frame = new BreezyStuff();
        frame.setSize(639, 399);
        frame.setVisible(true);

    }
}

im using breezygui because my teacher wanted us to ""implement"" into our code somehow >.> any help is greatly appreciated


-----------------------------------

Tony

Sat Jan 08, 2011 1:26 pm


RE:mandelbrot set in java

-----------------------------------

so presumably to color the entire screen black, "isInside" must always be true. Is this correct for the location you are trying to examine?


-----------------------------------

hamid14

Sat Jan 08, 2011 2:06 pm


Re: mandelbrot set in java

-----------------------------------

when isInside = true then its supposed to draw the black dots on the screen, assuming the background is white. i moved the defining  of the variable isInside to the outside of the for loops but still doesnt work. the screen goes black from top to bottom 4-5 times and then stops.


-----------------------------------

2goto1

Sat Jan 08, 2011 4:58 pm


RE:mandelbrot set in java

-----------------------------------

in your code if (isInside = true), did you intend to compare isInside with the boolean value true, rather than assign it? If so, you should use the == operator, so it becomes if (isInside == true). Otherwise the expression as-is assigns true to isInside, and evaluates as true.


-----------------------------------

Tony

Sat Jan 08, 2011 5:25 pm


RE:mandelbrot set in java

-----------------------------------

hah, I've missed that too D:

Really, the expression should have been
[code]
if (isInside) { ...
[/code]


-----------------------------------

2goto1

Sat Jan 08, 2011 5:40 pm


Re: RE:mandelbrot set in java

-----------------------------------

hah, I've missed that too D:

Really, the expression should have been


Yes that is much cleaner, and an allowed syntax in most common languages. Less is best!


-----------------------------------

hamid14

Sat Jan 08, 2011 6:42 pm


Re: mandelbrot set in java

-----------------------------------

now it doesnt do anything at all i dont know what wrong with it :\


EDIT: i got it working thanks guys


-----------------------------------

hamid14

Sat Jan 08, 2011 7:28 pm


Re: mandelbrot set in java

-----------------------------------

sorry for double posting, but how would i create different colors? couldnt find any tutorials on how to use color functions in java netbeans


-----------------------------------

Tony

Sat Jan 08, 2011 7:39 pm


RE:mandelbrot set in java

-----------------------------------

[code]
Color.BLACK
[/code]
I would assume that Color is some kind of a class and has some methods and/or constants (such as #BLACK) that give you "colours". Read the docs.


-----------------------------------

hamid14

Sat Jan 08, 2011 8:52 pm


Re: mandelbrot set in java

-----------------------------------

no i meant coloring the different spaces, not the black space itself thanks anyways