Debug Options

Starting in OpenSlide 3.4.0, the OPENSLIDE_DEBUG environment variable can contain a comma-separated list of debug options that will affect the behavior of the library. Pass OPENSLIDE_DEBUG=help for a list of debug options supported by your copy.

Options

detection
Log the error message returned by each format driver that does not detect support for the specified slide file during openslide_detect_vendor(), openslide_can_open(), or openslide_open(). Useful if openslide_open() returns NULL when you think it shouldn’t.
jpeg-markers
For Hamamatsu VMS and NDPI slides, locate all restart markers and perform an extra verification pass before openslide_open() returns. Slow.
performance
Log conditions causing OpenSlide to exhibit suboptimal performance.
tiles
Draw tile outlines and coordinates in openslide_read_region() output.