Add cap height and x height metrics to Font

Since FreeType (and consequently ttf2png) doesn't provide these metrics,
they are estimated by the makefont script.

diff --git a/scripts/makefont.py b/scripts/makefont.py
index 64c8e68459732ce964aa44290180ff4e961837d0..1d7a4332906a55e02dc0df2f8009648b4ee6408b 100755 (executable)
--- a/scripts/makefont.py
+++ b/scripts/makefont.py
@@ -1,8 +1,15 @@
 #!/usr/bin/python
 
+caps = list(range(ord("A"), ord("Z")+1))
+xchars = [ord(c) for c in "acemnorsuvwxz"]
+
 def convert_def(fn):
        src = file(fn)
 
+       result = ""
+       header = ""
+       cap_height = []
+       x_height = []
        for line in src.readlines():
                line = line.strip()
                if not line or line[0]=='#':
@@ -12,9 +19,9 @@ def convert_def(fn):
 
                if parts[0]=="font":
                        tw, th, fh, fa, fd = map(int, parts[1:])
-                       result = "native_size %d;\n"%fh
-                       result += "ascent %.3f;\n"%(float(fa)/fh)
-                       result += "descent %.3f;\n"%(float(fd)/fh)
+                       header += "native_size %d;\n"%fh
+                       header += "ascent %.3f;\n"%(float(fa)/fh)
+                       header += "descent %.3f;\n"%(float(fd)/fh)
                elif parts[0]=="glyph":
                        g, x, y, w, h, ox, oy, a = map(int, parts[1:])
                        result += "glyph %d\n{\n"%g
@@ -23,11 +30,21 @@ def convert_def(fn):
                        result += "\toffset %.3f %.3f;\n"%(float(ox)/fh, float(oy)/fh)
                        result += "\tadvance %.3f;\n"%(float(a)/fh)
                        result += "};\n"
+
+                       if g in caps:
+                               cap_height.append(h)
+                       elif g in xchars:
+                               x_height.append(h)
                elif parts[0]=="kern":
                        l, r, d = map(int, parts[1:])
                        result += "kerning %d %d %.3f;\n"%(l, r, float(d)/fh)
 
-       return result
+       if cap_height:
+               header += "cap_height %.3f;\n"%(float(cap_height[len(cap_height)*2/3])/fh)
+       if x_height:
+               header += "x_height %.3f;\n"%(float(x_height[len(x_height)*2/3])/fh)
+
+       return header+result
 
 def make_font(fn, size, ch_range, autohinter, margin, padding):
        import maketex

diff --git a/source/font.cpp b/source/font.cpp
index 6780f5fa8679f2ab73df72902d79e8d729b11a55..54631926e4e1b3ae22da55afff111450fc9719e0 100644 (file)
--- a/source/font.cpp
+++ b/source/font.cpp
@@ -15,7 +15,9 @@ namespace GL {
 Font::Font():
        native_size(1),
        ascent(1),
-       descent(0)
+       descent(0),
+       cap_height(1),
+       x_height(0.5)
 { }
 
 // Avoid synthesizing ~RefPtr in files including font.h
@@ -139,11 +141,13 @@ void Font::Loader::init()
 {
        add("native_size", &Font::native_size);
        add("ascent",      &Font::ascent);
+       add("cap_height",  &Font::cap_height);
        add("descent",     &Font::descent);
        add("texture",     &Loader::texture);
        add("texture",     &Loader::texture_ref);
        add("glyph",       &Loader::glyph);
        add("kerning",     &Loader::kerning);
+       add("x_height",    &Font::x_height);
 }
 
 void Font::Loader::glyph(unsigned c)

diff --git a/source/font.h b/source/font.h
index efef8351830bd45425dc8045ed144884bca3eac5..4eaed9635361ecca51ae5604b84c3c0d533c1109 100644 (file)
--- a/source/font.h
+++ b/source/font.h
@@ -60,6 +60,8 @@ private:
        float native_size;
        float ascent;
        float descent;
+       float cap_height;
+       float x_height;
        GlyphMap glyphs;
        KerningMap kerning;
 
@@ -81,6 +83,8 @@ public:
 
        float get_ascent() const { return ascent; }
        float get_descent() const { return descent; }
+       float get_cap_height() const { return cap_height; }
+       float get_x_height() const { return x_height; }
 
        /** Returns the width of a string, in multiples of the font size.  Scale the
        result according to the size used in rendering. */