From 5fa05d371b9a6dad9ca959a89db02c4cbc09d92c Mon Sep 17 00:00:00 2001
From: H.G. Muller <h.g.muller@hccnet.nl>
Date: Fri, 13 Apr 2012 14:57:15 +0200
Subject: [PATCH 1/1] Also do selective redraw with showTargetSquares on

The XBoard DrawPosition now also keeps track of the previous marker state,
and redraws squares for which thi shas changed. As a result, the routine
MarkTargetSquares does no longer have to force to complete redraw.
(Breaks WinBoard?)
---
 backend.c |    2 +-
 board.c   |    8 ++++++--
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/backend.c b/backend.c
index a2ff648..2bde9f6 100644
--- a/backend.c
+++ b/backend.c
@@ -6932,7 +6932,7 @@ MarkTargetSquares (int clear)
       for(x=0; x<BOARD_WIDTH; x++) for(y=0; y<BOARD_HEIGHT; y++) if(marker[y][x] == 1) marker[y][x] = 0;
     }
   }
-  DrawPosition(TRUE, NULL);
+  DrawPosition(FALSE, NULL);
 }
 
 int
diff --git a/board.c b/board.c
index 676ea0b..a725895 100644
--- a/board.c
+++ b/board.c
@@ -883,6 +883,7 @@ DrawPosition (int repaint, Board board)
     static int lastFlipView = 0;
     static int lastBoardValid[2] = {0, 0};
     static Board lastBoard[2];
+    static char lastMarker[BOARD_RANKS][BOARD_FILES];
     Arg args[16];
     int rrow, rcol;
     int nr = twoBoards*partnerUp;
@@ -928,7 +929,7 @@ DrawPosition (int repaint, Board board)
 	   is flashing on its new square */
 	for (i = 0; i < BOARD_HEIGHT; i++)
 	  for (j = 0; j < BOARD_WIDTH; j++)
-	    if ((board[i][j] != lastBoard[nr][i][j] && board[i][j] == EmptySquare)
+	    if (((board[i][j] != lastBoard[nr][i][j] || !nr && marker[i][j] != lastMarker[i][j]) && board[i][j] == EmptySquare)
 		|| damage[nr][i][j]) {
 		DrawSquare(i, j, board[i][j], 0);
 		damage[nr][i][j] = False;
@@ -937,7 +938,7 @@ DrawPosition (int repaint, Board board)
 	/* Second pass -- Draw piece(s) in new position and flash them */
 	for (i = 0; i < BOARD_HEIGHT; i++)
 	  for (j = 0; j < BOARD_WIDTH; j++)
-	    if (board[i][j] != lastBoard[nr][i][j]) {
+	    if (board[i][j] != lastBoard[nr][i][j] || !nr && marker[i][j] != lastMarker[i][j]) {
 		DrawSquare(i, j, board[i][j], do_flash);
 	    }
     } else {
@@ -955,6 +956,9 @@ DrawPosition (int repaint, Board board)
     lastBoardValid[nr] = 1;
   if(nr == 0) { // [HGM] dual: no highlights on second board yet
     lastFlipView = flipView;
+    for (i = 0; i < BOARD_HEIGHT; i++)
+	for (j = 0; j < BOARD_WIDTH; j++)
+	    lastMarker[i][j] = marker[i][j];
 
     /* Draw highlights */
     if (pm1X >= 0 && pm1Y >= 0) {
-- 
1.7.0.4