class Fonction {

    // paramètres du graphiques
    //
    static final double xMin = -7;
    static final double xMax = 7;
    static final double xTic = 1;
    static final double yMin = -1.2;
    static final double yMax = 1.2;
    static final double yTic = 0.2;

    static double f(double x)
    {
        return Math.sin(x * x);
    }

    // conversion coordonnées réelles -> coordonnées fenêtre
    static int rtowX(final DrawingWindow w, double rx)
    {
        return (int)Math.round((w.width - 1) * (rx - xMin) / (xMax - xMin));
    }

    static int rtowY(final DrawingWindow w, double ry)
    {
        return (int)Math.round((w.height - 1) * (yMax - ry) / (yMax - yMin));
    }

    // conversion coordonnées fenêtre -> coordonnées réelles
    static double wtorX(final DrawingWindow w, int wx)
    {
        return (xMax - xMin) * wx / (w.width - 1) + xMin;
    }

    static double wtorY(final DrawingWindow w, int wy)
    {
        return -(yMax - yMin) * wy / (w.height - 1) + yMax;
    }

    // dessine les axes
    static void drawAxes(DrawingWindow w)
    {
        int x0 = rtowX(w, 0);
        int y0 = rtowY(w, 0);
        w.drawLine(0, y0, w.width - 1, y0);
        w.drawLine(x0, 0, x0, w.height - 1);
        for (double x = -xTic; x >= xMin; x -= xTic) {
            int xi = rtowX(w, x);
            w.drawLine(xi, y0 - 2, xi, y0 + 2);
        }
        for (double x = xTic; x <= xMax; x += xTic) {
            int xi = rtowX(w, x);
            w.drawLine(xi, y0 - 2, xi, y0 + 2);
        }
        for (double y = -yTic; y >= yMin; y -= yTic) {
            int yi = rtowY(w, y);
            w.drawLine(x0 - 2, yi, x0 + 2, yi);
        }
        for (double y = yTic; y <= yMax; y += yTic) {
            int yi = rtowY(w, y);
            w.drawLine(x0 - 2, yi, x0 + 2, yi);
        }
    }

    public static void main(String[] args) {
        DrawingWindow w = new DrawingWindow("Fonction", 640, 480);

        drawAxes(w);
        w.setColor("red");
        int xiPrev = 0;
        int yiPrev = rtowY(w, f(wtorX(w, 0)));
        for (int xi = 1; xi < w.width; xi++) {
            int yi = rtowY(w, f(wtorX(w, xi)));
            // deux points consécutifs sont reliés par un trait pour faire
            // plus joli
            w.drawLine(xiPrev, yiPrev, xi, yi);
            xiPrev = xi;
            yiPrev = yi;
        }
    }
}