From ee06cbe1ce0c115b0d7b3510ba0a9b06853770a0 Mon Sep 17 00:00:00 2001
From: Han-Wen Nienhuys <hanwen@xs4all.nl>
Date: Sun, 12 Sep 2004 08:55:24 +0000
Subject: [PATCH] * input/regression/system-overstrike.ly: new file.

* scm/page-layout.scm (ly:optimal-page-breaks): add
betweensystempadding also to fixed distance for the spring.

This fixes: morgenlied.ly and input/regression/beam-concave.ly
---
 ChangeLog                             |  5 +++++
 input/regression/system-overstrike.ly | 18 ++++++++++++++++++
 scm/page-layout.scm                   | 17 +++++++++--------
 3 files changed, 32 insertions(+), 8 deletions(-)
 create mode 100644 input/regression/system-overstrike.ly

diff --git a/ChangeLog b/ChangeLog
index c4056bc0f8..896358812d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
 2004-09-12  Han-Wen Nienhuys   <hanwen@xs4all.nl>
 
+	* input/regression/system-overstrike.ly: new file.
+
+	* scm/page-layout.scm (ly:optimal-page-breaks): add
+	betweensystempadding also to fixed distance for the spring.
+ 
 	* scm/define-grobs.scm (all-grob-descriptions): fix order of
 	key-cancellation.
 
diff --git a/input/regression/system-overstrike.ly b/input/regression/system-overstrike.ly
new file mode 100644
index 0000000000..0537736ad9
--- /dev/null
+++ b/input/regression/system-overstrike.ly
@@ -0,0 +1,18 @@
+\version "2.3.16"
+\header { texidoc = "By setting betweensystempadding to a negative
+value, it is possible to eliminate the anti-collision constraints.
+Then  setting @code{betweensystemspace} to a low (nonzero) value,
+print  systems in overstrike. "
+}
+
+\bookpaper {
+    raggedbottom =##t
+    betweensystempadding = - 4\cm
+    betweensystemspace = 3\mm
+}
+
+{
+    c1 \break
+    c'''1
+}
+
diff --git a/scm/page-layout.scm b/scm/page-layout.scm
index 296444317b..3912db064b 100644
--- a/scm/page-layout.scm
+++ b/scm/page-layout.scm
@@ -273,13 +273,15 @@ is what have collected so far, and has ascending page numbers."
 		   (-  (car (vector-ref real-extents (1- no-systems))))
 		   ))
 
+	 (fixed-dist (ly:output-def-lookup bookpaper 'betweensystempadding))
 	 (calc-spring
 	  (lambda (idx)
 	    (let*
 		((this-system-ext (vector-ref staff-extents idx))
 		 (next-system-ext (vector-ref staff-extents (1+ idx)))
-		 (fixed (- (cdr next-system-ext)
-			   (car this-system-ext)))
+		 (fixed (max 0  (- (+ (cdr next-system-ext)
+				      fixed-dist)
+				   (car this-system-ext))))
 		 (ideal (+ inter-system-space fixed))
 		 (hooke (/ 1 (- ideal fixed)))
 		 )
@@ -287,16 +289,15 @@ is what have collected so far, and has ascending page numbers."
 	    ))
 
 	 (springs (map calc-spring (iota (1- no-systems))))
-	 (fixed-dist (ly:output-def-lookup bookpaper 'betweensystempadding))
 	 (calc-rod
 	  (lambda (idx)
 	    (let*
 		((this-system-ext (vector-ref real-extents idx))
 		 (next-system-ext (vector-ref real-extents (1+ idx)))
-		 (distance (- (+ (cdr next-system-ext)
+		 (distance (max  (- (+ (cdr next-system-ext)
 				 fixed-dist)
-			      (car this-system-ext)
-			      ))
+				    (car this-system-ext)
+				    ) 0)) 
 		 (entry (list idx (1+ idx) distance)))
 	      entry)))
 	 (rods (map calc-rod (iota (1- no-systems))))
@@ -314,13 +315,13 @@ is what have collected so far, and has ascending page numbers."
 	       (cdr  result)))
 	 )
 
-     (if #f ;; debug.
+     (if #t ;; debug.
 	 (begin
 	   (display (list "\n# systems: " no-systems
 			  "\nreal-ext" real-extents "\nstaff-ext" staff-extents
 			  "\ninterscore" inter-system-space
 			  "\nspace-letf" space-left
-			  "\npage empty" page-very-empty
+			  "\npage empty" page-very-empty?
 			  "\nspring,rod" springs rods
 			  "\ntopskip " topskip
 			  " space " space
-- 
2.39.5