Changed screen coordinates

mandelbrot.c

@@ -16,8 +16,8 @@ int main()
 {
          /* screen ( integer) coordinate */
        int iX,iY;
-       const int iXmax = 4000;
-       const int iYmax = 4000;
+       const int iXmax = 8000;
+       const int iYmax = 8000;
        /* world ( double) coordinate = parameter plane*/
        double Cx,Cy;
        const double CxMin=-2.5;