From 486e1683dde5aafeb37ba8a979d4c893a098e717 Mon Sep 17 00:00:00 2001
From: R?my Oudompheng <oudomphe@phare.normalesup.org>
Date: Fri, 25 Oct 2013 11:01:57 +1100
Subject: [PATCH] freetype/truetype: handle control value cut-in in MIRP.

The difference is quite large on glyph 509 (period character)
of Adobe Source Sans Pro Bold Italic.

R=golang-dev, nigeltao, bsiegert
CC=golang-dev
https://codereview.appspot.com/16820043

Committer: Nigel Tao <nigeltao@golang.org>
---
 freetype/truetype/hint.go | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/freetype/truetype/hint.go b/freetype/truetype/hint.go
index e7b6d11..1312f54 100644
--- a/freetype/truetype/hint.go
+++ b/freetype/truetype/hint.go
@@ -1023,7 +1023,11 @@ func (h *Hinter) run(program []byte, pCurrent, pUnhinted, pInFontUnits []Point,
 			// TODO: metrics compensation.
 			distance := cvtDist
 			if opcode&0x04 != 0 {
-				distance = h.round(cvtDist)
+				// The CVT value is only used if close enough to oldDist.
+				if (cvtDist - oldDist).abs() > h.gs.controlValueCutIn {
+					distance = oldDist
+				}
+				distance = h.round(distance)
 			}
 
 			// Minimum distance bit.