FontWeight property

FontWeight reports the weight class of the font referenced by the page object at the given index, mirroring the CSS / OpenType convention: 100 (Thin) up to 900 (Black), with 400 = Regular and 700 = Bold. It is derived from the embedded font descriptor or, for non-embedded fonts, from PDFium's substitution table.

The index is the 0-based page object index, valid from 0 to ObjectCount - 1. Only text objects carry a meaningful weight; querying a non-text object returns 0. For weights tied to individual extracted characters (rather than to a page object's font dictionary) use CharacterFontWeight.

A page must be active (PageNumber already set). The weight is decoded from the font handle obtained via FontHandle; if the font itself does not declare a weight, PDFium returns 0 and the property does likewise.

• Standard mapping: 100 Thin, 200 ExtraLight, 300 Light, 400 Regular, 500 Medium, 600 SemiBold, 700 Bold, 800 ExtraBold, 900 Black.
• Returns 0 when the page object is not text, when the font handle is invalid, or when no weight is encoded.
• The visual boldness ultimately seen on screen also depends on synthesized bolding flags inside the font dictionary — weight alone is not always the full story.
• Many embedded subset fonts encode a single weight even though the source family ships several — do not assume the document includes 100/200/etc. just because a 700 was reported.
• For the weight associated with a specific extracted character (text-page index), call CharacterFontWeight instead.