The slide module provides a simple high-level interface to handle a WSI; it contains the Slide class, which wraps functions, methods and properties of a virtual slide in a single object. The Slide class encapsulates OpenSlide, and relies on the openslide-python library for the low-level operations on digital slides. A WSI is usually stored in pyramidal format, where each level corresponds to a specific magnification factor. Therefore, two relevant properties of a WSI are: (i) its dimensions at native magnification; (ii) the number of levels and the dimensions at a specified level.


OpenSlide identifies each magnification level of the WSI with a positive integer number, starting from 0.

A Slide is initialized by providing the path where the WSI is stored and the path where processed images (such as the WSI thumbnail or the extracted tiles) will be saved. Further, the slide module implements the SlideSet class, which handles a collection of Slide objects stored in the same directory, possibly filtered by the valid_extensions parameter.

The slides_stats property of a SlideSet computes statistics for the WSI collection, namely the number of available slides; the slide with the maximum/minimum width; the slide with the maximum/minimum height; the slide with the maximum/minimum size; the average width/height/size of the slides.