X-Git-Url: http://winboard.nl/cgi-bin?p=xboard.git;a=blobdiff_plain;f=engine-intf.html;h=bc4815f5fbb466b8b7a7f1b7e98e0ef8294ebd17;hp=058f14755665abffa4c473dd43720876e274f409;hb=HEAD;hpb=0d88a109c226fc27d24f0e28cd3f4c7da1b59367
diff --git a/engine-intf.html b/engine-intf.html
index 058f147..bc4815f 100644
--- a/engine-intf.html
+++ b/engine-intf.html
@@ -1139,6 +1139,9 @@ The "lift" command is sent by the GUI when the user 'picks up' (or selects) a pi
so that the engine can reply with a "highlight" command to mark the squares where that piece can move to.
The "put" command similarly indicates where the user releases that piece;
as the GUI clears the highlights on that event by itself, usually no engine response would be required.
+For promotion moves you can get a double "put" command, the first one sent when the piece lands on the square,
+without being decided yet what it promotes to, so the engine can send a "choice" command to
+specify the promotion choice the GUI should offer when promotion wasn't already implied by the "lift" location.
The "hover" command is sent whenever the mouse pointer enters a square that is currently marked in red,
(reserved for captures)
so that the engine can (optionally) reply with a "highlight" command to mark victims of non-standard capture
@@ -1865,6 +1868,16 @@ the corresponding lower-case character can be used for the color.
For indicating a legal destination square without visibly marking it, T (transparent) can be used.
+choice PIECESTRING
+
+This command can be sent to the GUI in response to a 'lift' or 'put' command that implies a promotion move,
+to alter the choice offered to the user for the promotion piece from what the GUI would naturally assume,
+to the piece IDs mentioned in the PIECESTRING.
+The IDs in that string should be given as capitals irrespective of color.
+The first piece mentioned will be the default choice.
+
+
+
click SQUARE
The GUI will treat this command as if the user had clicked the mentioned SQUARE.