cairo: Improve comment.

diff --git a/src/output/cairo.c b/src/output/cairo.c
index 3e824607f2377f6fb0ed0f0f67a7e684df96c219..85c8f67b938fb77b77b13246d0279122953eb30e 100644 (file)
--- a/src/output/cairo.c
+++ b/src/output/cairo.c
@@ -71,7 +71,8 @@
 #define H TABLE_HORZ
 #define V TABLE_VERT
 
-/* The unit used for internal measurements is inch/(72 * XR_POINT). */
+/* The unit used for internal measurements is inch/(72 * XR_POINT).
+   (Thus, XR_POINT units represent one point.) */
 #define XR_POINT PANGO_SCALE
 
 /* Conversions to and from points. */