Let magenta marker activate sweep promotion

This allows an engine to indicate non-standard promotion possibilities.

diff --git a/backend.c b/backend.c
index 24ae75d..1a30148 100644 (file)
--- a/backend.c
+++ b/backend.c
@@ -7025,6 +7025,7 @@ MarkByFEN(char *fen)
        while(*fen) {
            int s = 0;
            marker[r][f] = 0;
+           if(*fen == 'M') legal[r][f] = 2; else // request promotion choice
            if(*fen >= 'A' && *fen <= 'Z') legal[r][f] = 1; else
            if(*fen >= 'a' && *fen <= 'z') *fen += 'A' - 'a';
            if(*fen == '/' && f > BOARD_LEFT) f = BOARD_LEFT, r--; else
@@ -7124,8 +7125,8 @@ HoverEvent (int hiX, int hiY, int x, int y)
          // [HGM] lift: entered new to-square; redraw arrow, and inform engine
          for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
            marker[r][f] = baseMarker[r][f], legal[r][f] = baseLegal[r][f];
-         if(marker[y][x] == 2 && legal[y][x] == 1) {
-           char buf[MSG_SIZ];
+         if((marker[y][x] == 2 || marker[y][x] == 6) && legal[y][x]) {
+           char buf[MSG_SIZ];
            snprintf(buf, MSG_SIZ, "hover %c%d\n", x + AAA, y + ONE - '0');
            SendToProgram(buf, &first);
          }
@@ -7378,7 +7379,7 @@ LeftClick (ClickType clickType, int xPix, int yPix)
            if(x >= BOARD_LEFT && x < BOARD_RGHT) clearFlag = 1; // and defer click-click move of empty-square to up-click
            return;
        }
-       if(HasPromotionChoice(fromX, fromY, toX, toY, &promoChoice, FALSE)) {
+       if(legal[y][x] == 2 || HasPromotionChoice(fromX, fromY, toX, toY, &promoChoice, FALSE)) {
          if(appData.sweepSelect) {
            ChessSquare piece = boards[currentMove][fromY][fromX];
            promoSweep = defaultPromoChoice;