How to fix the holes in this console rotation animation - c

Question

I have a square rotating in the console, but I get some holes. How can I fill it correctly?
#include <stdio.h>
#include <Windows.h>
#include <math.h>
void moveTo (int x, int y)
{
COORD coord = { x, y };
SetConsoleCursorPosition(GetStdHandle(STD_OUTPUT_HANDLE), coord);
}
double round (double number)
{
return number < 0.0 ? ceil(number - 0.5) : floor(number + 0.5);
}
double deg2rad (double a)
{
double pi = 3.14159265358979323846;
return a * pi / 180.0;
}
int main ()
{
int w = 8;
int h = 8;
int cx = 20;
int cy = 10;
double a = 0;
while (1)
{
system("cls");
for (int y = 0; y < h; y++)
{
for (int x = 0; x < w; x++)
{
double xx = x - 4;
double yy = y - 4;
double fx = xx * cos(a) - yy * sin(a);
double fy = xx * sin(a) + yy * cos(a);
int ix = cx + round(fx);
int iy = cy + round(fy);
moveTo(ix, iy);
printf("X");
}
}
a += deg2rad(15.0);
Sleep(100);
}
return 0;
}

Answer 1

Not an actual answer
Aparently your code will always print the same number of X in the screen, even though this might not be always the case.
I think you shouldn't be recalculating the positions of each predefinedX but instead calculate the geometry of the lines around the square and fill the space between with Xs, as many as necessary until it hit the opposite border or something.
An alternative solution could be doubling the "density" of your square:
int w = 8*2;
int h = 8*2;
int cx = 20*2;
int cy = 10*2;
...
moveTo(ix/2, iy/2);
This should double print some dots, but should also fill gaps.