improved mouse handler

I improved the mouse handler in a way which will preclude disappearence of pieces
on off-board or ambiguous (in-between squares) drag & drop moves. (As was reported
in the "premove bug?" thread. Also the command-line premove problem reported there
is now fixed, by removing the prefixing.

diff --git a/backend.c b/backend.c
index c6eedec..c3178c4 100755 (executable)
--- a/backend.c
+++ b/backend.c
@@ -3232,16 +3232,14 @@ read_from_ics(isr, closure, data, count, error)
                      if (currentMove == 0 &&
                          gameMode == IcsPlayingWhite &&
                          appData.premoveWhite) {
-                       sprintf(str, "%s%s\n", ics_prefix,
-                               appData.premoveWhiteText);
+                       sprintf(str, "%s\n", appData.premoveWhiteText);
                        if (appData.debugMode)
                          fprintf(debugFP, "Sending premove:\n");
                        SendToICS(str);
                      } else if (currentMove == 1 &&
                                 gameMode == IcsPlayingBlack &&
                                 appData.premoveBlack) {
-                       sprintf(str, "%s%s\n", ics_prefix,
-                               appData.premoveBlackText);
+                       sprintf(str, "%s\n", appData.premoveBlackText);
                        if (appData.debugMode)
                          fprintf(debugFP, "Sending premove:\n");
                        SendToICS(str);
@@ -5271,6 +5269,7 @@ UserMoveTest(fromX, fromY, toX, toY, promoChar, captureOwn)
         return ImpossibleMove;
     }
 
+    if(toX < 0 || toY < 0) return ImpossibleMove;
     pdown = boards[currentMove][fromY][fromX];
     pup = boards[currentMove][toY][toX];
 
@@ -5615,16 +5614,11 @@ void LeftClick(ClickType clickType, int xPix, int yPix)
            }
            return;
        }
-       // ignore to-clicks in holdings
+       // ignore clicks on holdings
        if(x < BOARD_LEFT || x >= BOARD_RGHT) return;
     }
 
-    if (clickType == Release && (x == fromX && y == fromY ||
-       x < BOARD_LEFT || x >= BOARD_RGHT)) {
-
-       // treat drags into holding as click on start square
-       x = fromX; y = fromY;
-
+    if (clickType == Release && x == fromX && y == fromY) {
        DragPieceEnd(xPix, yPix);
        if (appData.animateDragging) {
            /* Undo animation damage if any */
@@ -5644,7 +5638,7 @@ void LeftClick(ClickType clickType, int xPix, int yPix)
        return;
     }
 
-    /* we now have a different from- and to-square */
+    /* we now have a different from- and (possibly off-board) to-square */
     /* Completed move */
     toX = x;
     toY = y;
@@ -5667,6 +5661,17 @@ void LeftClick(ClickType clickType, int xPix, int yPix)
        /* Don't animate move and drag both */
        appData.animate = FALSE;
     }
+
+    // moves into holding are invalid for now (later perhaps allow in EditPosition)
+    if(x >= 0 && x < BOARD_LEFT || x >= BOARD_RGHT) {
+       ClearHighlights();
+       fromX = fromY = -1;
+       return;
+    }
+
+    // off-board moves should not be highlighted
+    if(x < 0 || x < 0) ClearHighlights();
+
     if (HasPromotionChoice(fromX, fromY, toX, toY, &promoChoice)) {
        SetHighlights(fromX, fromY, toX, toY);
        if(gameInfo.variant == VariantSuper || gameInfo.variant == VariantGreat) {