Get missing width for the font metrics

1 files changed, 9 insertions, 0 deletions

diff --git a/README.md b/README.md
index 457e673..50010aa 100644
--- a/README.md
+++ b/README.md
@@ -40,3 +40,12 @@ fountainhead --help
 for help.
 
 ## Usage
+
+TrueType and OpenType fonts consist of a sequence of tables and various
+informations about the font are encoded in these tables. There are both
+required and optional tables. The first table is a font directory and it
+describes the overall structure of the font, what tables it contains and at what
+offset other tables can be found.
+
+This library doesn't parse the whole font at once. The font directory has to be
+parsed first and can be used then to parse further tables as needed.