diff --git a/truetype/truetype.go b/truetype/truetype.go
index 75cb733..8d040c7 100644
--- a/truetype/truetype.go
+++ b/truetype/truetype.go
@@ -574,14 +574,15 @@ func parse(ttf []byte, offset int) (font *Font, err error) {
 		return
 	}
 	n, offset := int(u16(ttf, offset)), offset+2
-	if len(ttf) < 16*n+12 {
+	offset = offset + 2*3 // skip 3 short fields
+	if len(ttf) < 16*n+offset {
 		err = FormatError("TTF data is too short")
 		return
 	}
 	f := new(Font)
 	// Assign the table slices.
 	for i := 0; i < n; i++ {
-		x := 16*i + 12
+		x := 16*i + offset
 		switch string(ttf[x : x+4]) {
 		case "cmap":
 			f.cmap, err = readTable(ttf, ttf[x+8:x+16])