From 6aa1160fe03fe2286ce00b2bc64f87e10d4041ba Mon Sep 17 00:00:00 2001
From: Keith OHara <k-ohara5a5a@oco.net>
Date: Sat, 28 Jul 2012 14:14:34 +0200
Subject: [PATCH] Issue 2691: page-layout: consider relative indents in
 loose-line spacing

---
 .../page-spacing-nonstaff-lines-skylines.ly   | 19 +++++++++++++++++
 lily/axis-group-interface.cc                  | 12 -----------
 lily/include/page-layout-problem.hh           |  8 ++++---
 lily/page-layout-problem.cc                   | 21 +++++++++++++------
 4 files changed, 39 insertions(+), 21 deletions(-)
 create mode 100644 input/regression/page-spacing-nonstaff-lines-skylines.ly

diff --git a/input/regression/page-spacing-nonstaff-lines-skylines.ly b/input/regression/page-spacing-nonstaff-lines-skylines.ly
new file mode 100644
index 0000000000..43dac9520e
--- /dev/null
+++ b/input/regression/page-spacing-nonstaff-lines-skylines.ly
@@ -0,0 +1,19 @@
+\version "2.15.42"
+
+\header {
+  texidoc = "Relative indentation between systems is taken into
+  account in allowing space for loose lines between systems."
+}
+
+\paper {
+  ragged-right = ##t
+  indent = 10
+  short-indent = 00
+}
+
+\book {
+  \score { <<
+    \chords {s1\break c2 c2 }
+    \new Staff {\clef bass c,1 | c''2 c2 }
+  >> }
+}
diff --git a/lily/axis-group-interface.cc b/lily/axis-group-interface.cc
index 1b937985ee..febff36afb 100644
--- a/lily/axis-group-interface.cc
+++ b/lily/axis-group-interface.cc
@@ -828,18 +828,6 @@ Axis_group_interface::calc_maybe_pure_staff_staff_spacing (Grob *me, bool pure,
   return me->get_maybe_pure_property ("default-staff-staff-spacing", pure, start, end);
 }
 
-Real
-Axis_group_interface::minimum_distance (Grob *g1, Grob *g2, Axis a)
-{
-  SCM sym = ly_symbol2scm ((a == Y_AXIS) ? "vertical-skylines" : "horizontal-skylines");
-
-  Skyline_pair *s1 = Skyline_pair::unsmob (g1->get_property (sym));
-  Skyline_pair *s2 = Skyline_pair::unsmob (g2->get_property (sym));
-  if (s1 && s2)
-    return (*s1)[DOWN].distance ((*s2)[UP]);
-  return 0;
-}
-
 ADD_INTERFACE (Axis_group_interface,
                "An object that groups other layout objects.",
 
diff --git a/lily/include/page-layout-problem.hh b/lily/include/page-layout-problem.hh
index ccc2538905..b7d63a2e13 100644
--- a/lily/include/page-layout-problem.hh
+++ b/lily/include/page-layout-problem.hh
@@ -64,14 +64,16 @@ protected:
     Prob *prob;
     vector<Grob *> staves;
     vector<Real> min_offsets;
-    // Store the appropriate '*-*-spacing 'padding,
-    //  for spacing any adjacent loose line
+    // Store the appropriate '*-*-spacing 'padding, and skyline-distance,
+    //  considering indentation, from the previous system.
+    Real min_distance;
     Real padding;
 
-    Element (vector<Grob *> const &a, vector<Real> const &o, Real p)
+    Element (vector<Grob *> const &a, vector<Real> const &o, Real m, Real p)
     {
       staves = a;
       min_offsets = o;
+      min_distance = m;
       padding = p;
       prob = 0;
     }
diff --git a/lily/page-layout-problem.cc b/lily/page-layout-problem.cc
index dd9b6da71c..68f870b2dc 100644
--- a/lily/page-layout-problem.cc
+++ b/lily/page-layout-problem.cc
@@ -583,8 +583,19 @@ Page_layout_problem::append_system (System *sys, Spring const &spring, Real inde
   spring_copy.ensure_min_distance (minimum_distance);
   springs_.push_back (spring_copy);
 
+  if (elts.size () && !is_spaceable (elts[0]))
+    {
+      // store the minimum distance, considering relative indents,
+      // for a loose line
+      Skyline first_skyline (UP);
+      Skyline_pair *sky = Skyline_pair::unsmob (elts[0]->get_property ("vertical-skylines"));
+      if (sky)
+        first_skyline.merge ((*sky)[UP]);
+      first_skyline.shift (indent);
+      minimum_distance = first_skyline.distance (bottom_skyline_) - bottom_loose_baseline_ ;
+    }
   bottom_skyline_ = down_skyline;
-  elements_.push_back (Element (elts, minimum_offsets, padding));
+  elements_.push_back (Element (elts, minimum_offsets, minimum_distance, padding));
 
   // Add the springs for the VerticalAxisGroups in this system.
 
@@ -840,7 +851,7 @@ Page_layout_problem::find_system_offsets ()
                   found_spaceable_staff = true;
                   spring_idx++;
                 }
-              else
+              else // ! is_spaceable
                 {
                   if (loose_lines.empty ())
                     loose_lines.push_back (last_spaceable_line);
@@ -859,16 +870,14 @@ Page_layout_problem::find_system_offsets ()
                         {
                           // distance to the final line in the preceding system,
                           // including 'system-system-spacing 'padding
-                          min_dist = (Axis_group_interface::minimum_distance (loose_lines.back (),
-                                                                              staff, Y_AXIS)
-                                      + elements_[i].padding);
+                          min_dist = elements_[i].min_distance + elements_[i].padding;
                           // A null line to break any staff-affinity for the previous system
                           loose_line_min_distances.push_back (0.0);
                           loose_lines.push_back (0);
                         }
                       else if (!last_title_extent.is_empty ())
                         // distance to the preceding title,
-                        //  including 'markup-system-spacing 'padding
+                        //  including 'markup-system-wg 'padding
                         min_dist = (staff->extent (staff, Y_AXIS)[UP] - last_title_extent[DOWN]
                                     + elements_[i].padding);
                       else // distance to the top margin
-- 
2.39.5