The source project of this merge request has been removed.
When Adaptive Sampling is on, m_PreviewSampling is changed dynamically...
When Adaptive Sampling is on, m_PreviewSampling is changed dynamically depending on available memory. This MR fixes an issue whereas m_PreviewSampling keeps increasing exponentially until it resets to zero which then causes KStars to crash. This also fixes scaling issue when dealing with large images with overlay since m_PreviewSampling can be larger than 1.