Adding to your collection
Looking at the catalogue
Note: this page describes an as-yet unfinished feature.
An album is a user-defined arrangement of collection objects (or stamp types). Each album consists of a number of pages, each of which is a 2-dimensional layout of objects, graphics, and text. An album may be "real", in which case it is a reflection of physical reality - any object can only appear once, it takes up space in proportion to its actual size, etc - or "virtual", which can be arranged in any way at all.
The layout description is conceptually similar to HTML; pages have titles, subtitles, and sections, text flows around images, etc.
For objects, user designates its place, then in real albums it gets a fixed size. A display-type album requires a specified amount of space around each object, a stockbook-type should allow overlapping.
Given a list of stamps/objects, the user can ask to have an album auto-generated, perhaps filling in some general requirements. Generator then estimates how many on a page, preferring to break at years/issues. Within an issue, compute most-even centered layout (is there an algorithm?), add textual elements for captions.
Albums have the usual visibility options. Album visibility applies to all pages of an album.
Albums may be open or closed. An open album may be changed, a closed album may not (like write-protection for a disk or file).
Each page in the album gets a number that is assigned to it automatically. This is different from the page label, which is a property of the page and goes with it if the page is moved to a different album.
A page may have an image. While the image could be anything, it's most useful if the image is a scan or photograph of the real-life album page.