better glyph offset computation

[mussa.git] / alg / glsequence.cpp

diff --git a/alg/glsequence.cpp b/alg/glsequence.cpp
index 3a9df4d3e0e4669445197d5044c8ab9698a2bcd8..6cb1b578fc211c59bcd39c68f721b816116c27fc 100644 (file)
--- a/alg/glsequence.cpp
+++ b/alg/glsequence.cpp
@@ -284,7 +284,7 @@ CP Xdata[] = {{ 0, 5, PT}, {5, -5,STROKE},{0,-5,PT},{5, 5, END}};
 CP Ndata[] = {{ 0, -5, PT}, {0, 5, PT}, {5, -5, PT}, {5, 5, END}};
 
 //! the maximum width used for a charcter glyph
-const int max_glyph_width = 5;
+const int max_glyph_width = 5; // unit ( glyph_coord )
 
 static void drawLetter(CP *l, GLfloat z)
 {
@@ -321,8 +321,11 @@ void GlSequence::draw_sequence(GLfloat left, GLfloat right) const
   Sequence::const_iterator seq_itor = sequence_begin(left, right);
   Sequence::const_iterator seq_end = sequence_end(left, right);
   Sequence::size_type basepair = 0;
-  const float glyph_x_scale = 0.1;
-  const float glyph_margin = ((1.0 / glyph_x_scale) - max_glyph_width) / 4.0;  
+  const float bp_per_world = 1.0; //( world coord )
+  const float glyph_x_scale = 0.125; // unit = ( world coord / glyph coord )
+  // compute how much space there should be to either size of a letter
+  const float glyph_margin = (bp_per_world - glyph_x_scale * max_glyph_width) 
+                           / 2.0;  
 
   assert(seq_end - seq_itor >= 0);
   while(seq_itor != seq_end)