Method saveRastered

! Saves the plot to a rastered image file \a fileName in the image format \a format. The plot is sized to \a width and \a height in pixels and scaled with \a scale. (width 100 and scale 2.0 lead to a full resolution file with width 200.) If the \a format supports compression, \a quality may be between 0 and 100 to control it. Returns true on success. If this function fails, most likel