X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=lily%2Fstencil.cc;h=7be0b5f8af63b1562984da11a5fea9602552aa6c;hb=3fd5eabae695f90c0cea826bcea33d54a242b01b;hp=833d5be0fd55cb12b732b0725d17738196d5b75f;hpb=a8ac663bf03c250ea84bc499437ffc8d529fc047;p=lilypond.git

diff --git a/lily/stencil.cc b/lily/stencil.cc
index 833d5be0fd..7be0b5f8af 100644
--- a/lily/stencil.cc
+++ b/lily/stencil.cc
@@ -1,7 +1,7 @@
 /*
   This file is part of LilyPond, the GNU music typesetter.
 
-  Copyright (C) 1997--2012 Han-Wen Nienhuys <hanwen@xs4all.nl>
+  Copyright (C) 1997--2014 Han-Wen Nienhuys <hanwen@xs4all.nl>
 
   LilyPond is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -25,7 +25,6 @@
 #include "string-convert.hh"
 #include "warn.hh"
 
-#include "ly-smobs.icc"
 
 Stencil::Stencil ()
 {
@@ -39,24 +38,13 @@ Stencil::Stencil (Box b, SCM func)
   dim_ = b;
 }
 
-int
-Stencil::print_smob (SCM, SCM port, scm_print_state *)
-{
-  scm_puts ("#<Stencil ", port);
-  scm_puts (" >", port);
-  return 1;
-}
-
 SCM
-Stencil::mark_smob (SCM smob)
+Stencil::mark_smob ()
 {
-  Stencil *s = (Stencil *) SCM_CELL_WORD_1 (smob);
-  return s->expr_;
+  return expr_;
 }
 
-IMPLEMENT_SIMPLE_SMOBS (Stencil);
-IMPLEMENT_TYPE_P (Stencil, "ly:stencil?");
-IMPLEMENT_DEFAULT_EQUAL_P (Stencil);
+const char Stencil::type_p_name_[] = "ly:stencil?";
 
 Interval
 Stencil::extent (Axis a) const
@@ -71,6 +59,12 @@ Stencil::is_empty () const
           || dim_.is_empty ());
 }
 
+bool
+Stencil::is_empty (Axis a) const
+{
+  return dim_.is_empty (a);
+}
+
 SCM
 Stencil::expr () const
 {
@@ -176,8 +170,7 @@ Stencil::translate (Offset o)
     expr_ = scm_list_n (ly_symbol2scm ("translate-stencil"),
                         ly_offset2scm (o),
                         expr_, SCM_UNDEFINED);
-  if (!is_empty ())
-    dim_.translate (o);
+  dim_.translate (o);
 }
 
 void
@@ -245,7 +238,7 @@ Stencil::set_empty (bool e)
 void
 Stencil::align_to (Axis a, Real x)
 {
-  if (is_empty ())
+  if (is_empty (a))
     return;
 
   Interval i (extent (a));
@@ -253,28 +246,155 @@ Stencil::align_to (Axis a, Real x)
 }
 
 /*  See scheme Function.  */
+
+// Any stencil that is empty in the orthogonal axis is spacing.
+// Spacing is not subjected to the max (0) rule and can thus be
+// negative.
+
 void
 Stencil::add_at_edge (Axis a, Direction d, Stencil const &s, Real padding)
 {
-  Interval my_extent = dim_[a];
-  Interval i (s.extent (a));
-  Real his_extent;
-  if (i.is_empty ())
+  // Material that is empty in the axis of reference has only limited
+  // usefulness for combining.  We still retain as much information as
+  // available since there may be uses like setting page links or
+  // background color or watermarks, and off-axis extents.
+
+  if (is_empty (a))
     {
-      programming_error ("Stencil::add_at_edge: adding empty stencil.");
-      his_extent = 0.0;
+      add_stencil (s);
+      return;
     }
-  else
-    his_extent = i[-d];
 
-  Real offset = (my_extent.is_empty () ? 0.0 : my_extent[d] - his_extent)
-                + d * padding;
+  Interval first_extent = extent (a);
+
+  if (s.is_empty (a))
+    {
+      Stencil toadd (s);
+      // translation does not affect axis-empty extent box.
+      toadd.translate_axis (first_extent[d], a);
+      add_stencil (toadd);
+      return;
+    }
+
+  Interval next_extent = s.extent (a);
+
+  bool first_is_spacing = is_empty (other_axis (a));
+  bool next_is_spacing = s.is_empty (other_axis (a));
+
+  Real offset = first_extent[d] - next_extent[-d];
+
+  if (!(first_is_spacing || next_is_spacing))
+    {
+      offset += d * padding;
+    }
 
   Stencil toadd (s);
   toadd.translate_axis (offset, a);
   add_stencil (toadd);
 }
 
+// Stencil::stack is mainly used for assembling lines or columns
+// of stencils.  For the most common case of adding at the right, the
+// reference point of the added stencil is usually placed at the right
+// edge of the current one, unless the added stencil has a negative
+// left extent in which case its left edge is placed at the right edge
+// of the current one.
+//
+// Spacing is special in that it is applied without padding.  Spacing
+// at the right edge shifts the right edge accordingly.
+//
+// For spacing at the left edge, there are several approaches.  In
+// order to get to predictable behavior, we want to have at least a
+// continuous approach.  An obvious idea is to do a "translate" by the
+// appropriate amount.  Doing that while retaining the nominal left
+// edge seems like the most straightforward way.
+
+void
+Stencil::stack (Axis a, Direction d, Stencil const &s, Real padding, Real mindist)
+{
+  // Material that is empty in the axis of reference can't be sensibly
+  // stacked.  We just revert to add_at_edge behavior then.
+
+  if (is_empty (a))
+    {
+      Stencil toadd (s);
+      toadd.add_stencil (*this);
+      expr_ = toadd.expr ();
+      dim_ = toadd.extent_box ();
+      return;
+    }
+
+  Interval first_extent = extent (a);
+
+  if (s.is_empty (a))
+    {
+      Stencil toadd (s);
+      toadd.translate_axis (first_extent[d], a);
+      toadd.add_stencil (*this);
+      expr_ = toadd.expr ();
+      dim_ = toadd.extent_box ();
+      return;
+    }
+
+  Interval next_extent = s.extent (a);
+
+  // It is somewhat tedious to special-case all spacing, but it turns
+  // out that not doing so makes it astonishingly hard to make the
+  // code do the correct thing.
+
+  // If first is spacing, we translate second accordingly without
+  // letting this affect its backward edge.
+  if (is_empty (other_axis (a)))
+    {
+      Stencil toadd (s);
+      Real offset = d * first_extent.delta ();
+      toadd.translate_axis (offset, a);
+      toadd.add_stencil (*this);
+      expr_ = toadd.expr ();
+      dim_ = toadd.extent_box ();
+      dim_[a][-d] = next_extent[-d];
+      dim_[a][d] = next_extent[d] + offset;
+      return;
+    }
+
+  // If next is spacing, similar action:
+  if (s.is_empty (other_axis (a)))
+    {
+      Stencil toadd (s);
+      Real offset = first_extent [d];
+      toadd.translate_axis (offset, a);
+      toadd.add_stencil (*this);
+      expr_ = toadd.expr ();
+      dim_ = toadd.extent_box ();
+      dim_[a][-d] = first_extent[-d];
+      dim_[a][d] = first_extent[d] + d * next_extent.delta ();
+      return;
+    }
+
+
+  Real offset = first_extent[d];
+
+  // If the added stencil has a backwardly protruding edge, we make
+  // room for it when combining.
+
+  if (d * next_extent [-d] < 0)
+    offset -= next_extent [-d];
+
+  offset += d * padding;
+
+  if (offset * d < mindist)
+    offset = d * mindist;
+
+  Stencil toadd (s);
+  toadd.translate_axis (offset, a);
+  toadd.add_stencil (*this);
+  expr_ = toadd.expr ();
+  dim_ = toadd.extent_box ();
+  dim_[a][-d] = first_extent [-d];
+  dim_[a][d] = next_extent [d] + offset;
+}
+
+
 Stencil
 Stencil::in_color (Real r, Real g, Real b) const
 {