gitk: Add some more comments to the optimize_rows procedure

Signed-off-by: Paul Mackerras <paulus@samba.org>

diff --git a/gitk b/gitk
index de5bae7a0e6e2603d0eaf15d9b3212934ea5fd56..a67137443b2c3cf9083c4ae5c07298032388f01c 100755 (executable)
--- a/gitk
+++ b/gitk
@@ -2739,7 +2739,13 @@ proc optimize_rows {row col endrow} {
                    set isarrow 1
                }
            }
+           # Looking at lines from this row to the previous row,
+           # make them go straight up if they end in an arrow on
+           # the previous row; otherwise make them go straight up
+           # or at 45 degrees.
            if {$z < -1 || ($z < 0 && $isarrow)} {
+               # Line currently goes left too much;
+               # insert pads in the previous row, then optimize it
                set npad [expr {-1 - $z + $isarrow}]
                set offs [incrange $offs $col $npad]
                insert_pad $y0 $x0 $npad
@@ -2750,6 +2756,8 @@ proc optimize_rows {row col endrow} {
                set x0 [expr {$col + $z}]
                set z0 [lindex $rowoffsets $y0 $x0]
            } elseif {$z > 1 || ($z > 0 && $isarrow)} {
+               # Line currently goes right too much;
+               # insert pads in this line and adjust the next's rowoffsets
                set npad [expr {$z - 1 + $isarrow}]
                set y1 [expr {$row + 1}]
                set offs2 [lindex $rowoffsets $y1]
@@ -2780,6 +2788,7 @@ proc optimize_rows {row col endrow} {
                    set z0 [expr {$xc - $x0}]
                }
            }
+           # avoid lines jigging left then immediately right
            if {$z0 ne {} && $z < 0 && $z0 > 0} {
                insert_pad $y0 $x0 1
                set offs [incrange $offs $col 1]
@@ -2788,6 +2797,7 @@ proc optimize_rows {row col endrow} {
        }
        if {!$haspad} {
            set o {}
+           # Find the first column that doesn't have a line going right
            for {set col [llength $idlist]} {[incr col -1] >= 0} {} {
                set o [lindex $offs $col]
                if {$o eq {}} {
@@ -2806,6 +2816,8 @@ proc optimize_rows {row col endrow} {
                }
                if {$o eq {} || $o <= 0} break
            }
+           # Insert a pad at that column as long as it has a line and
+           # isn't the last column, and adjust the next row' offsets
            if {$o ne {} && [incr col] < [llength $idlist]} {
                set y1 [expr {$row + 1}]
                set offs2 [lindex $rowoffsets $y1]