I am attempting to write a program that renders the Mandelbrot set, and then a Julia Set for a complex number in another panel, when the user clicks on a point on the Mandelbrot set panel.
However, my Julia's set rendering code for some reason does not work. It appears to only colour the top-left most pixel, and I cannot figure out why this might me. I don't know if the maths is wrong in the rendering method, or if the colouring is the issue. Any pointers or a solution would be fantastic - been scratching my head over this for awhile.
If anyone would find this easier to solve by having all of the code, please let me know - thanks.
Here is the code for just the Julia's Set Panel, everything else has been omitted.
class juliaPanel extends JPanel {
ComplexNumber fixedNumber = new ComplexNumber(0,0);
double newReal, newImaginary, oldReal, oldImaginary;
public void setFixedNumber(ComplexNumber fixedNumberIn) {
fixedNumber = fixedNumberIn;
}
public void paintComponent(Graphics g){
super.paintComponent(g);
newReal = 0;
newImaginary = 0;
int i;
for(int y = 0; y < height; y++) {
for(int x = 0; x < width; x++) {
for (i=0; i< iterationsToDo; i++) {
oldReal = newReal;
oldImaginary = newImaginary;
newReal = oldReal * oldReal - oldImaginary * oldImaginary + fixedNumber.getReal();
newImaginary = 2 * oldReal * oldImaginary + fixedNumber.getImaginary();
if((newReal * newReal + newImaginary * newImaginary) > 4) break;
}
if(i == 255){
g.setColor(Color.BLACK);
}else{
g.setColor(Color.getHSBColor(i/100.0F,1F,1F));
}
g.fillRect(x, y, 1, 1);
}
}
}
Before starting the inner loop over i, i.e., after x and y have changed to the next pixel, you need to set the initial complex number according to this pixel, something like
newReal = minReal + x*deltaReal;
newImag = maxImag - y*deltaImag;
where the min and max are -2.0 and 2.0 and the delta are 4.0/width and 4.0/height or the minimum of both to get 1:1 aspect ratio.