From 24eec7ef0db2c98df79453e377a72cefe12b7569 Mon Sep 17 00:00:00 2001
From: H.G.Muller <hgm@hgm-xboard.(none)>
Date: Fri, 26 Feb 2016 23:35:39 +0100
Subject: [PATCH] Use mouse wheel for selecting piece in Edit Position mode (XB)

Rather than calling ForwardEvent() and BackwardEvent() directly from the
mouse-wheel handler, we now call a backend routine Wheel(), which gets
the pointer coordinates passed to it (which we must remember during
mouse move events). This then calls the Forward/Backward event, except
in EditPosition mode, where it changes the piece in the square below the
pointer.
---
 backend.c  |   17 +++++++++++++++++
 dialogs.c  |    7 ++++---
 frontend.h |    1 +
 3 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/backend.c b/backend.c
index b49ba15..36131f6 100644
--- a/backend.c
+++ b/backend.c
@@ -7981,6 +7981,23 @@ RightClick (ClickType action, int x, int y, int *fromX, int *fromY)
 }
 
 void
+Wheel (int dir, int x, int y)
+{
+    if(gameMode == EditPosition) {
+	int xSqr = EventToSquare(x, BOARD_WIDTH);
+	int ySqr = EventToSquare(y, BOARD_HEIGHT);
+	if(ySqr < 0 || xSqr < BOARD_LEFT || xSqr >= BOARD_RGHT) return;
+	if(flipView) xSqr = BOARD_WIDTH - 1 - xSqr; else ySqr = BOARD_HEIGHT - 1 - ySqr;
+	do {
+	    boards[currentMove][ySqr][xSqr] += dir;
+	    if((int) boards[currentMove][ySqr][xSqr] < WhitePawn) boards[currentMove][ySqr][xSqr] = BlackKing;
+	    if((int) boards[currentMove][ySqr][xSqr] > BlackKing) boards[currentMove][ySqr][xSqr] = WhitePawn;
+	} while(PieceToChar(boards[currentMove][ySqr][xSqr]) == '.');
+	DrawPosition(FALSE, boards[currentMove]);
+    } else if(dir > 0) ForwardEvent(); else BackwardEvent();
+}
+
+void
 SendProgramStatsToFrontend (ChessProgramState * cps, ChessProgramStats * cpstats)
 {
 //    char * hint = lastHint;
diff --git a/dialogs.c b/dialogs.c
index 3f445bb..35b3aef 100644
--- a/dialogs.c
+++ b/dialogs.c
@@ -2579,7 +2579,7 @@ MenuCallback (int n)
 static Option *
 Exp (int n, int x, int y)
 {
-    static int but1, but3, oldW, oldH;
+    static int but1, but3, oldW, oldH, oldX, oldY;
     int menuNr = -3, sizing, f, r;
     TimeMark now;
     extern Boolean right;
@@ -2590,6 +2590,7 @@ Exp (int n, int x, int y)
     }
 
     if(n == 0) { // motion
+	oldX = x; oldY = y;
 	if(SeekGraphClick(Press, x, y, 1)) return NULL;
 	if((but1 || dragging == 2) && !PromoScroll(x, y)) DragPieceMove(x, y);
 	if(but3) MovePV(x, y, lineGap + BOARD_HEIGHT * (squareSize + lineGap));
@@ -2612,8 +2613,8 @@ Exp (int n, int x, int y)
 	case  3: menuNr = RightClick(Press,   x, y, &pmFromX, &pmFromY), but3 = 1; break;
 	case -2: shiftKey = !shiftKey;
 	case -3: menuNr = RightClick(Release, x, y, &pmFromX, &pmFromY), but3 = 0; break;
-	case  4: BackwardEvent(); break;
-	case  5: ForwardEvent(); break;
+	case  4: Wheel(-1, oldX, oldY); break;
+	case  5: Wheel(1, oldX, oldY); break;
 	case 10:
 	    sizing = (oldW != x || oldH != y);
 	    oldW = x; oldH = y;
diff --git a/frontend.h b/frontend.h
index f536dba..2a39fca 100644
--- a/frontend.h
+++ b/frontend.h
@@ -136,6 +136,7 @@ void DragPieceEnd P((int x, int y));
 void DragPieceMove P((int x, int y));
 void LeftClick P((ClickType c, int x, int y));
 int  RightClick P((ClickType c, int x, int y, int *col, int *row));
+void Wheel P((int dir, int x, int y));
 
 int StartChildProcess P((char *cmdLine, char *dir, ProcRef *pr));
 void DestroyChildProcess P((ProcRef pr, int/*boolean*/ signal));
-- 
1.7.0.4