Indic Matra Category - Top And Bottom

Top And Bottom is a value that classifies vowel signs in Indic scripts based on whether they attach to the top or bottom of a consonant stem, specifically covering marks that appear above or below the base character. It describes the visual positioning of these dependent vowel diacritics, where the matra is rendered either as an overhang above the syllable block or as a subscript below it, distinct from other positions like left or right. This categorization helps text shaping engines correctly place the mark relative to the consonant, ensuring that the vowel’s position is preserved during rendering and reordering processes. While the value does not specify the exact shape or size of the diacritic, it identifies the dominant vertical orientation, which is crucial for accurate glyph attachment and line breaking in complex script composition.