int y, int left, const int64_t start, const int64_t end,
const double pixels_offset, const double samples_per_pixel)
{
const int64_t sample_count = end - start;
int y, int left, const int64_t start, const int64_t end,
const double pixels_offset, const double samples_per_pixel)
{
const int64_t sample_count = end - start;