forked from 1b-agent/opencadstudio-upstream
Hakan SevenandClaude Opus 5.5
da8e976a60
In the Block Editor, BVSTATE makes a new visibility state, makes one current, renames or deletes one; BVHIDE and BVSHOW hide or show the picked objects in the current state (BVSHOW shows every object of the block while they are picked). The first use makes the block dynamic. The states are stored as the format keeps them: a BLOCKVISIBILITYPARAMETER in the block's ACAD_ENHANCEDBLOCK evaluation graph with its visibility grip and the grip's two location expressions, the round-trip purge preventer, AcDbDynamicBlockTrueName / AcDbDynamicBlockGUID / AcDbBlockRepETag on the definition and element tags on each of its objects. The definition shows its first state; a reference given another state gets its own evaluated *U copy, tagged AcDbBlockRepBTag and linked back through AcDbBlockRepresentation / AcDbRepData, so it shows that state and the other references do not change. Saving the block drops erased objects from the states. Checked: a block authored this way reads back with its states and reference link from DWG and DXF, and the ODA converter accepts the DWG. Closes #1566 Co-Authored-By: Claude Opus 5.5 <[email protected]>