ASS_FEATURE_WHOLE_TEXT_LAYOUT constant

int const ASS_FEATURE_WHOLE_TEXT_LAYOUT

When this feature is disabled, text is split into VSFilter-compatible segments and text in each segment is processed in isolation. Notably, this includes running the Unicode Bidirectional Algorithm and shaping the text within each run separately. The individual runs are then laid out left-to-right, even if they contain right-to-left text.

When this feature is enabled, each event's text is processed as a whole (as far as possible). In particular, the Unicode Bidirectional Algorithm is run on the whole text, and text is shaped across override tags.

This is incompatible with VSFilter and disabled by default.

libass extensions to ASS such as Encoding -1 can cause individual events to be always processed as if this feature is enabled.

Implementation

static const int ASS_FEATURE_WHOLE_TEXT_LAYOUT = 2;