addBeforePosition method
Implementation
void addBeforePosition(
double p, Float32List temp, int i, Float32List out, int o) {
final double x1 = temp[i],
y1 = temp[i + 1],
dx = temp[i + 2] - x1,
dy = temp[i + 3] - y1,
r = math.atan2(dy, dx);
out[o] = x1 + p * math.cos(r);
out[o + 1] = y1 + p * math.sin(r);
out[o + 2] = r;
}