(reference-point-alist): Doc fixed.

(encode-composition-rule): Handle a rule (GREF NREF XOFF YOFF).
(decode-composition-rule): Likewise.

diff --git a/lisp/composite.el b/lisp/composite.el
index 0b91656d477ca25e66155b87b3d3b5bf90943fd4..657bfa8658e7c5ac6106785fc2bb8783069ffc58 100644 (file)
--- a/lisp/composite.el
+++ b/lisp/composite.el
@@ -73,7 +73,12 @@ follows (the point `*' corresponds to both reference points):
     |    | new |
     |    |glyph|
     +----+-----+ <--- new descent
-")
+
+A composition rule may have the form \(GLOBAL-REF-POINT
+NEW-REF-POINT XOFF YOFF), where XOFF and YOFF specifies how much
+to shift NEW-REF-POINT from GLOBAL-REF-POINT.  In this case, XOFF
+and YOFF are integers in the range -100..100 representing the
+shifting percentage against the font size.")
 
 ;; Encode composition rule RULE into an integer value.  RULE is a cons
 ;; of global and new reference point symbols.
@@ -84,17 +89,29 @@ follows (the point `*' corresponds to both reference points):
   (if (and (integerp rule) (< rule 144))
       ;; Already encoded.
       rule
-    (or (consp rule)
-       (error "Invalid composition rule: %S" rule))
-    (let ((gref (car rule))
-         (nref (cdr rule)))
-      (or (integerp gref)
-         (setq gref (cdr (assq gref reference-point-alist))))
-      (or (integerp nref)
-         (setq nref (cdr (assq nref reference-point-alist))))
-      (or (and (>= gref 0) (< gref 12) (>= nref 0) (< nref 12))
-         (error "Invalid composition rule: %S" rule))
-      (+ (* gref 12) nref))))
+    (if (consp rule)
+       (let ((gref (car rule))
+             (nref (cdr rule))
+             xoff yoff)
+         (if (consp nref)              ; (GREF NREF XOFF YOFF)
+             (progn
+               (setq xoff (nth 1 nref)
+                     yoff (nth 2 nref)
+                     nref (car nref))
+               (or (and (>= xoff -100) (<= xoff 100)
+                        (>= yoff -100) (<= yoff 100))
+                   (error "Invalid compostion rule: %s" rule))
+               (setq xoff (+ xoff 128) yoff (+ yoff 128)))
+           ;; (GREF . NREF)
+           (setq xoff 0 yoff 0))
+         (or (integerp gref)
+             (setq gref (cdr (assq gref reference-point-alist))))
+         (or (integerp nref)
+             (setq nref (cdr (assq nref reference-point-alist))))
+         (or (and (>= gref 0) (< gref 12) (>= nref 0) (< nref 12))
+             (error "Invalid composition rule: %S" rule))
+         (logior (lsh xoff 16) (lsh yoff 8) (+ (* gref 12) nref)))
+      (error "Invalid composition rule: %S" rule))))
 
 ;; Decode encoded composition rule RULE-CODE.  The value is a cons of
 ;; global and new reference point symbols.
@@ -102,13 +119,20 @@ follows (the point `*' corresponds to both reference points):
 ;; defined in composite.h.
 
 (defun decode-composition-rule (rule-code)
-  (or (and (natnump rule-code) (< rule-code 144))
+  (or (and (natnump rule-code) (< rule-code #x1000000))
       (error "Invalid encoded composition rule: %S" rule-code))
-  (let ((gref (car (rassq (/ rule-code 12) reference-point-alist)))
-       (nref (car (rassq (% rule-code 12) reference-point-alist))))
+  (let ((xoff (lsh rule-code -16))
+       (yoff (logand (lsh rule-code -8) #xFF))
+       gref nref)
+    (setq rule-code (logand rule-code #xFF)
+         gref (car (rassq (/ rule-code 12) reference-point-alist))
+         nref (car (rassq (% rule-code 12) reference-point-alist)))
     (or (and gref (symbolp gref) nref (symbolp nref))
        (error "Invalid composition rule code: %S" rule-code))
-    (cons gref nref)))
+    (if (and (= xoff 0) (= yoff 0))
+       (cons gref nref)
+      (setq xoff (- xoff 128) yoff (- yoff 128))
+      (list gref xoff yoff nref))))
 
 ;; Encode composition rules in composition components COMPONENTS.  The
 ;; value is a copy of COMPONENTS, where composition rules (cons of