package hr.tel.fer.kp.lab3;

import java.awt.*;

public class GraphicThread implements Runnable {

    private static int MAX = 64;
    private double viewX;
    private double viewY;
    private double zoom;

    private Graphics g;
    private Dimension size;
    private int startY, startX, endY, endX;

    public GraphicThread(Graphics g, Dimension size, int startY, int startX, int endY, int endX, double zoom, double viewX, double viewY){
        this.g = g;
        this.startX = startX;
        this.startY = startY;
        this.endX = endX;
        this.endY = endY;
        this.zoom = zoom;
        this.viewX = viewX;
        this.viewY = viewY;
        this.size = size;
    }

    @Override
    public void run() {

        for (int y = startY; y < endY; y++) {
            for (int x = startX; x < endX; x++) {
                double r = zoom / Math.min(size.width, size.height);
                double dx = 2.5 * (x * r + viewX) - 2.0;
                double dy = 1.25 - 2.5 * (y * r + viewY);
                int value = mandel(dx, dy);
                value = value * 255 / MAX;
                synchronized(g){
                    g.setColor(new Color(value, value, value));
                    g.drawLine(x, y, x, y);
                }
            }
        }
    }

    private int mandel(double px, double py) {
        int value = 0;
        double zx = 0.0;
        double zy = 0.0;
        double zx2 = 0.0;
        double zy2 = 0.0;
        while (value < MAX && zx2 + zy2 < 4.0) {
            zy = 2.0 * zx * zy + py;
            zx = zx2 - zy2 + px;
            zx2 = zx * zx;
            zy2 = zy * zy;
            value++;
        }
        return value == MAX ? 0 : MAX - value;
    }
}