Streamline XBoard board drawing

XBoard was drawing in a very inefficient way. To improve efficiency
alteration of highlights will not immediately be exposed, but be
marked as damage so that a subsequent DrawPosition call will show them.
Squares touched by a to-be-erased arrow will be treated likewise.
The drawing now has three passes: repairing damage (which erases
highlights and arrow), emptying the from-square, and drawing new
pieces and highlights.

diff --git a/board.c b/board.c
index a368356..cb6ae94 100644 (file)
--- a/board.c
+++ b/board.c
@@ -150,42 +150,31 @@ int pm1X = -1, pm1Y = -1, pm2X = -1, pm2Y = -1;
 
 void
 SetHighlights (int fromX, int fromY, int toX, int toY)
-{
-    int arrow = hi2X >= 0 && hi1Y >= 0 && IsDrawArrowEnabled();
-
-    if (hi1X != fromX || hi1Y != fromY) {
-       if (hi1X >= 0 && hi1Y >= 0) {
-           drawHighlight(hi1X, hi1Y, 0);
-       }
-    } // [HGM] first erase both, then draw new!
+{   // [HGM] schedule old for erasure, and leave drawing new to DrawPosition
+    int change = 0;
 
-    if (hi2X != toX || hi2Y != toY) {
-       if (hi2X >= 0 && hi2Y >= 0) {
-           drawHighlight(hi2X, hi2Y, 0);
+    if (hi1X >= 0 && hi1Y >= 0) {
+       if (hi1X != fromX || hi1Y != fromY) {
+           damage[0][hi1Y][hi1X] |= 2;
+           change |= 1;
        }
+       change |= 4;
     }
 
-    if(arrow) // there currently is an arrow displayed
-       ArrowDamage(hi1X, hi1Y, hi2X, hi2Y); // mark which squares it damaged
-
-    if (hi1X != fromX || hi1Y != fromY) {
-       if (fromX >= 0 && fromY >= 0) {
-           drawHighlight(fromX, fromY, 1);
-       }
-    }
-    if (hi2X != toX || hi2Y != toY) {
-       if (toX >= 0 && toY >= 0) {
-           drawHighlight(toX, toY, 1);
+    if (hi2X >= 0 && hi2Y >= 0) {
+       if (hi2X != toX || hi2Y != toY) {
+           damage[0][hi2Y][hi2X] |= 2;
+           change |= 2;
        }
+       change |= 8;
     }
 
+    if(change > 12 && IsDrawArrowEnabled()) ArrowDamage(hi1X, hi1Y, hi2X, hi2Y);
+
     hi1X = fromX;
     hi1Y = fromY;
     hi2X = toX;
     hi2Y = toY;
-
-    if(arrow || toX >= 0 && fromY >= 0 && IsDrawArrowEnabled())
-       DrawPosition(FALSE, NULL); // repair any arrow damage, or draw a new one
 }
 
 void
@@ -200,18 +189,12 @@ SetPremoveHighlights (int fromX, int fromY, int toX, int toY)
 {
     if (pm1X != fromX || pm1Y != fromY) {
        if (pm1X >= 0 && pm1Y >= 0) {
-           drawHighlight(pm1X, pm1Y, 0);
-       }
-       if (fromX >= 0 && fromY >= 0) {
-           drawHighlight(fromX, fromY, 2);
+           damage[0][pm1Y][pm1X] |= 2;
        }
     }
     if (pm2X != toX || pm2Y != toY) {
        if (pm2X >= 0 && pm2Y >= 0) {
-           drawHighlight(pm2X, pm2Y, 0);
-       }
-       if (toX >= 0 && toY >= 0) {
-           drawHighlight(toX, toY, 2);
+           damage[0][pm1Y][pm1X] |= 2;
        }
     }
     pm1X = fromX;
@@ -661,8 +644,8 @@ again:
       if((i-toX)*(i-toX) + (j-toY)*(j-toY) < 6) damage[0][j][i] |=  1 + ((i-toX ^ j-toY) & 1);
   }
 
-  /* Be sure end square is redrawn */
-  damage[0][toY][toX] |= True;
+  /* Be sure end square is redrawn, with piece in it */
+  damage[0][toY][toX] |= 4;
 
   if(toX == x2 && toY == kill2Y) { fromX = toX; fromY = toY; toX = killX; toY = killY; x2 = -1; goto again; } // second leg
   if(toX != x || toY != y) { fromX = toX; fromY = toY; toX = x; toY = y; goto again; } // second leg
@@ -913,6 +896,22 @@ check_castle_draw (Board newb, Board oldb, int *rrow, int *rcol)
 }
 
 void
+SquareExpose(int i, int j, int d)
+{
+    int x, y;
+    if (flipView) {
+       x = lineGap + ((BOARD_WIDTH-1)-j) *
+         (squareSize + lineGap);
+       y = lineGap + i * (squareSize + lineGap);
+    } else {
+       x = lineGap + j * (squareSize + lineGap);
+       y = lineGap + ((BOARD_HEIGHT-1)-i) *
+         (squareSize + lineGap);
+    }
+    GraphExpose(currBoard, x-d, y-d, squareSize+2*d, squareSize+2*d);
+}
+
+void
 DrawPosition (int repaint, Board board)
 {
     int i, j, do_flash, exposeAll = False;
@@ -920,7 +919,7 @@ DrawPosition (int repaint, Board board)
     static int lastBoardValid[2] = {0, 0};
     static Board lastBoard[2];
     static char lastMarker[BOARD_RANKS][BOARD_FILES], messedUp;
-    int rrow, rcol;
+    int rrow = -1, rcol = -1;
     int nr = twoBoards*partnerUp;
 
     repaint |= messedUp;
@@ -944,9 +943,6 @@ DrawPosition (int repaint, Board board)
 
     if (!repaint && lastBoardValid[nr] && (nr == 1 || lastFlipView == flipView)) {
 
-//     if ( lineGap && IsDrawArrowEnabled())
-//         DrawGrid();
-
        /* If too much changes (begin observing new game, etc.), don't
           do flashing */
        do_flash = too_many_diffs(board, lastBoard[nr]) ? 0 : 1;
@@ -954,33 +950,40 @@ DrawPosition (int repaint, Board board)
        /* Special check for castling so we don't flash both the king
           and the rook (just flash the king). */
        if (do_flash) {
-           if (check_castle_draw(board, lastBoard[nr], &rrow, &rcol)) {
-               /* Mark rook for drawing with NO flashing. */
-               damage[nr][rrow][rcol] |= 1;
-           }
+           /* Mark rook for drawing with NO flashing. */
+           check_castle_draw(board, lastBoard[nr], &rrow, &rcol);
        }
 
-       /* First pass -- Draw (newly) empty squares and repair damage.
+       /* First pass -- Erase arrow and grid highlights, but keep square content unchanged. Except for new markers. */
+       for (i = 0; i < BOARD_HEIGHT; i++)
+         for (j = 0; j < BOARD_WIDTH; j++)
+           if (damage[nr][i][j] ||  !nr && marker[i][j] != lastMarker[i][j]) {
+               DrawSquare(i, j, board[i][j], 0);
+               if(lineGap && damage[nr][i][j] & 2) {
+                   drawHighlight(j, i, 0);
+                   SquareExpose(i, j, 1);
+               } else SquareExpose(i, j, 0);
+               damage[nr][i][j] = 0;
+           }
+
+       /* Second pass -- Draw (newly) empty squares
           This prevents you from having a piece show up twice while it
           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] || !nr && marker[i][j] != lastMarker[i][j]) && board[i][j] == EmptySquare)
-               || damage[nr][i][j]) {
+           if (board[i][j] != lastBoard[nr][i][j] && board[i][j] == EmptySquare) {
                DrawSquare(i, j, board[i][j], 0);
-               if(damage[nr][i][j] & 2) {
-                   drawHighlight(j, i, 0);   // repair arrow damage
-                   if(lineGap) damage[nr][i][j] = False; // this flushed the square as well
-               } else damage[nr][i][j] = 1;  // mark for expose
+               SquareExpose(i, j, 0);
            }
 
-       /* Second pass -- Draw piece(s) in new position and flash them */
+       /* Third 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] || !nr && marker[i][j] != lastMarker[i][j]) {
-               DrawSquare(i, j, board[i][j], do_flash);
+           if (board[i][j] != lastBoard[nr][i][j]) {
+               DrawSquare(i, j, board[i][j], do_flash && (i != rrow || j != rcol));
                damage[nr][i][j] = 1; // mark for expose
            }
+
     } else {
        if (lineGap > 0)
          DrawGrid();
@@ -1005,19 +1008,19 @@ DrawPosition (int repaint, Board board)
     /* Draw highlights */
     if (pm1X >= 0 && pm1Y >= 0) {
       drawHighlight(pm1X, pm1Y, 2);
-      if(lineGap) damage[nr][pm1Y][pm1X] = False;
+      if(lineGap) damage[nr][pm1Y][pm1X] |= 2;
     }
     if (pm2X >= 0 && pm2Y >= 0) {
       drawHighlight(pm2X, pm2Y, 2);
-      if(lineGap) damage[nr][pm2Y][pm2X] = False;
+      if(lineGap) damage[nr][pm2Y][pm2X] |= 2;
     }
     if (hi1X >= 0 && hi1Y >= 0) {
       drawHighlight(hi1X, hi1Y, 1);
-      if(lineGap) damage[nr][hi1Y][hi1X] = False;
+      if(lineGap) damage[nr][hi1Y][hi1X] |= 2;
     }
     if (hi2X >= 0 && hi2Y >= 0) {
       drawHighlight(hi2X, hi2Y, 1);
-      if(lineGap) damage[nr][hi2Y][hi2X] = False;
+      if(lineGap) damage[nr][hi2Y][hi2X] |= 2;
     }
     DrawArrowHighlight(hi1X, hi1Y, hi2X, hi2Y);
   }
@@ -1032,21 +1035,11 @@ DrawPosition (int repaint, Board board)
        for (i = 0; i < BOARD_HEIGHT; i++)
            for (j = 0; j < BOARD_WIDTH; j++)
                if(damage[nr][i][j]) {
-                   int x, y;
-                   if (flipView) {
-                       x = lineGap + ((BOARD_WIDTH-1)-j) *
-                         (squareSize + lineGap);
-                       y = lineGap + i * (squareSize + lineGap);
-                   } else {
-                       x = lineGap + j * (squareSize + lineGap);
-                       y = lineGap + ((BOARD_HEIGHT-1)-i) *
-                         (squareSize + lineGap);
-                   }
                    if(damage[nr][i][j] & 2) // damage by old or new arrow
-                       GraphExpose(currBoard, x - lineGap, y - lineGap, squareSize + 2*lineGap, squareSize  + 2*lineGap);
+                       SquareExpose(i, j, lineGap);
                    else
-                       GraphExpose(currBoard, x, y, squareSize, squareSize);
-                   damage[nr][i][j] &= 2; // remember damage by newly drawn error in '2' bit, to schedule it for erasure next draw
+                       SquareExpose(i, j, 0);
+                   damage[nr][i][j] = 0;
                }
     }
 

diff --git a/draw.c b/draw.c
index 8d3dbf4..89f4851 100644 (file)
--- a/draw.c
+++ b/draw.c
@@ -636,7 +636,7 @@ DrawBorder (int x, int y, int type, int odd)
     SetPen(cr, lineGap, col, 0);
     cairo_stroke(cr);
     cairo_destroy(cr);
-    GraphExpose(currBoard, x - lineGap/2, y - lineGap/2, squareSize+2*lineGap+odd, squareSize+2*lineGap+odd);
+//    GraphExpose(currBoard, x - lineGap/2, y - lineGap/2, squareSize+2*lineGap+odd, squareSize+2*lineGap+odd);
 }
 
 static int