Use the full range of ACS line drawing characters to draw pane borders,

including intersections.

screen-redraw.c

@@ -22,14 +22,61 @@
 
 #include "tmux.h"
 
+int	screen_redraw_cell_border(struct client *, u_int, u_int);
 int	screen_redraw_check_cell(struct client *, u_int, u_int);
 
 #define CELL_INSIDE 0
-#define CELL_LEFT 1
-#define CELL_RIGHT 2
-#define CELL_TOP 3
-#define CELL_BOTTOM 4
-#define CELL_OUTSIDE 5
+#define CELL_LEFTRIGHT 1
+#define CELL_TOPBOTTOM 2
+#define CELL_TOPLEFT 3
+#define CELL_TOPRIGHT 4
+#define CELL_BOTTOMLEFT 5
+#define CELL_BOTTOMRIGHT 6
+#define CELL_TOPJOIN 7
+#define CELL_BOTTOMJOIN 8
+#define CELL_LEFTJOIN 9
+#define CELL_RIGHTJOIN 10
+#define CELL_JOIN 11
+#define CELL_OUTSIDE 12
+
+/* Check if a cell is on the pane border. */
+int
+screen_redraw_cell_border(struct client *c, u_int px, u_int py)
+{
+	struct window		*w = c->session->curw->window;
+	struct window_pane	*wp;
+
+	/* Check all the panes. */
+	TAILQ_FOREACH(wp, &w->panes, entry) {
+		if (!window_pane_visible(wp))
+			continue;
+
+		/* Inside pane. */
+		if (px >= wp->xoff && px < wp->xoff + wp->sx &&
+		    py >= wp->yoff && py < wp->yoff + wp->sy)
+			return (0);
+
+		/* Left/right borders. */
+		if ((wp->yoff == 0 || py >= wp->yoff - 1) &&
+		    py <= wp->yoff + wp->sy) {
+			if (wp->xoff != 0 && px == wp->xoff - 1)
+				return (1);
+			if (px == wp->xoff + wp->sx)
+				return (1);
+		}
+
+		/* Top/bottom borders. */
+		if ((wp->xoff == 0 || px >= wp->xoff - 1) && 
+		    px <= wp->xoff + wp->sx) {
+			if (wp->yoff != 0 && py == wp->yoff - 1)
+				return (1);
+			if (py == wp->yoff + wp->sy)
+				return (1);
+		}
+	}
+
+	return (0);
+}
 
 /* Check if cell inside a pane. */
 int
@@ -37,6 +84,7 @@ screen_redraw_check_cell(struct client *c, u_int px, u_int py)
 {
 	struct window		*w = c->session->curw->window;
 	struct window_pane	*wp;
+	int			 borders;
 
 	if (px > w->sx || py > w->sy)
 		return (CELL_OUTSIDE);
@@ -45,25 +93,59 @@ screen_redraw_check_cell(struct client *c, u_int px, u_int py)
 		if (!window_pane_visible(wp))
 			continue;
 
-		/* Inside pane. */
-		if (px >= wp->xoff && px < wp->xoff + wp->sx &&
-		    py >= wp->yoff && py < wp->yoff + wp->sy)
+		/* If outside the pane and its border, skip it. */
+		if ((wp->xoff != 0 && px < wp->xoff - 1) ||
+		    px > wp->xoff + wp->sx ||
+		    (wp->yoff != 0 && py < wp->yoff - 1) ||
+		    py > wp->yoff + wp->sy)
+			continue;
+
+		/* If definitely inside, return so. */
+		if (!screen_redraw_cell_border(c, px, py))
 			return (CELL_INSIDE);
 
-		/* Left/right borders. */
-		if (py >= wp->yoff && py < wp->yoff + wp->sy) {
-			if (wp->xoff != 0 && px == wp->xoff - 1)
-				return (CELL_LEFT);
-			if (px == wp->xoff + wp->sx)
-				return (CELL_RIGHT);
-		}
+		/* 
+		 * Construct a bitmask of whether the cells to the left (bit
+		 * 4), right, top, and bottom (bit 1) of this cell are borders.
+		 */
+		borders = 0;
+		if (px == 0 || screen_redraw_cell_border(c, px - 1, py))
+			borders |= 8;
+		if (px <= w->sx && screen_redraw_cell_border(c, px + 1, py))
+			borders |= 4;
+		if (py == 0 || screen_redraw_cell_border(c, px, py - 1))
+			borders |= 2;
+		if (py <= w->sy && screen_redraw_cell_border(c, px, py + 1))
+			borders |= 1;
 
-		/* Top/bottom borders. */
-		if (px >= wp->xoff && px < wp->xoff + wp->sx) {
-			if (wp->yoff != 0 && py == wp->yoff - 1)
-				return (CELL_TOP);
-			if (py == wp->yoff + wp->sy)
-				return (CELL_BOTTOM);
+		/* 
+		 * Figure out what kind of border this cell is. Only one bit
+		 * set doesn't make sense (can't have a border cell with no
+		 * others connected).
+		 */
+		switch (borders) {
+		case 15:	/* 1111, left right top bottom */
+			return (CELL_JOIN);
+		case 14:	/* 1110, left right top */
+			return (CELL_BOTTOMJOIN);
+		case 13:	/* 1101, left right bottom */
+			return (CELL_TOPJOIN);
+		case 12:	/* 1100, left right */
+			return (CELL_TOPBOTTOM);
+		case 11:	/* 1011, left top bottom */
+			return (CELL_RIGHTJOIN);
+		case 10:	/* 1010, left top */
+			return (CELL_BOTTOMRIGHT);
+		case 9:		/* 1001, left bottom */
+			return (CELL_TOPRIGHT);
+		case 7:		/* 0111, right top bottom */
+			return (CELL_LEFTJOIN);
+		case 6:		/* 0110, right top */
+			return (CELL_BOTTOMLEFT);
+		case 5:		/* 0101, right bottom */
+			return (CELL_TOPLEFT);
+		case 3:		/* 0011, top bottom */
+			return (CELL_LEFTRIGHT);
 		}
 	}
 
@@ -96,10 +178,10 @@ screen_redraw_screen(struct client *c, int status_only)
 	/* Draw background and borders. */
 	tty_reset(tty);
 	if (tty_term_has(tty->term, TTYC_ACSC)) {
-		border = " xxqq~";
+		border = " xqlkmjwvtun~";
 		tty_putcode(tty, TTYC_SMACS);
 	} else 
-		border = " ||--.";
+		border = " |-....--||+.";
 	for (j = 0; j < tty->sy - status; j++) {
 		if (status_only && j != tty->sy - 1)
 			continue;