From fa48ccbe127a2e61ab316f3638e4056940964dae Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Thu, 12 Oct 2017 14:07:37 +0200
Subject: [PATCH] [indic] Special-case Kannada Ra,H,ZWJ sequence

Fixes https://github.com/behdad/harfbuzz/issues/435
---
 src/hb-ot-shape-complex-indic.cc                 |  15 +++++++++++++++
 test/shaping/Makefile.am                         |   1 +
 .../3cae6bfe5b57c07ba81ddbd54c02fe4f3a1e3bf6.ttf | Bin 0 -> 2984 bytes
 test/shaping/tests/indic-special-cases.tests     |   3 +++
 4 files changed, 19 insertions(+)
 create mode 100644 test/shaping/fonts/sha1sum/3cae6bfe5b57c07ba81ddbd54c02fe4f3a1e3bf6.ttf
 create mode 100644 test/shaping/tests/indic-special-cases.tests

diff --git a/src/hb-ot-shape-complex-indic.cc b/src/hb-ot-shape-complex-indic.cc
index 31dc1c0eb..e520f38f4 100644
--- a/src/hb-ot-shape-complex-indic.cc
+++ b/src/hb-ot-shape-complex-indic.cc
@@ -691,6 +691,21 @@ initial_reordering_consonant_syllable (const hb_ot_shape_plan_t *plan,
   const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data;
   hb_glyph_info_t *info = buffer->info;
 
+  /* https://github.com/behdad/harfbuzz/issues/435#issuecomment-335560167
+   * // For compatibility with legacy useage in Kannada,
+   * // Ra+h+ZWJ must behave like Ra+ZWJ+h...
+   */
+  if (buffer->props.script == HB_SCRIPT_KANNADA &&
+      start + 3 <= end &&
+      is_one_of (info[start  ], FLAG (OT_Ra)) &&
+      is_one_of (info[start+1], FLAG (OT_H)) &&
+      is_one_of (info[start+2], FLAG (OT_ZWJ)))
+  {
+    buffer->merge_clusters (start+1, start+3);
+    hb_glyph_info_t tmp = info[start+1];
+    info[start+1] = info[start+2];
+    info[start+2] = tmp;
+  }
 
   /* 1. Find base consonant:
    *
diff --git a/test/shaping/Makefile.am b/test/shaping/Makefile.am
index ecb836db9..f788d42b7 100644
--- a/test/shaping/Makefile.am
+++ b/test/shaping/Makefile.am
@@ -61,6 +61,7 @@ TESTS = \
 	tests/indic-joiners.tests \
 	tests/indic-old-spec.tests \
 	tests/indic-pref-blocking.tests \
+	tests/indic-special-cases.tests \
 	tests/indic-syllable.tests \
 	tests/language-tags.tests \
 	tests/ligature-id.tests \
diff --git a/test/shaping/fonts/sha1sum/3cae6bfe5b57c07ba81ddbd54c02fe4f3a1e3bf6.ttf b/test/shaping/fonts/sha1sum/3cae6bfe5b57c07ba81ddbd54c02fe4f3a1e3bf6.ttf
new file mode 100644
index 0000000000000000000000000000000000000000..2cacb68166ceaa6b12174666c8cd06a03115b95f
GIT binary patch
literal 2984
zcmZuzeQ*=k5#RT8`mm6U9e+`VQcE(D!2}b@k~|b6*FzDq0DoZ$1qTacBaH9|wy{Y_
z!Nj<bX+qo>LX%+Aq%_2&fu>Vt(s2WBJ4q+h49zrY8M{q@q|;9Ghf^lRjqFo*-$}?0
zzMHqV``*6Y-|pMJJ755i42MAlwcgd=T>}fj0H9ldvkScCWmVqxf)ywiqI}O=Rb8_7
zk1HYoNy`CvXIWLgz30VadH~HNuGj9|8)z=JYia<r+fZJ;E6~~uTD(D*g0f*(_&|Nn
zD;Jg_{~3UKWvDI?)Ri(D?hoOdD})m%Vck-c|Aul-Xm4BRa^J*yl+U7E7;f4bnBz<u
zMR_gC3-<;(n_&^#fpRX&*^Pm{b<%aiW%N(_8=9M1+oHRn9_4Xb#~6Lle@Qi(PFMmi
za09T+jC8Fj!<LCpjm2zr7Pz%elgn9PGdWFm7cp+Jrm?8ZnvC>JhaKmvDn4kM&j#N0
zm3?*R!-*eXVHcccxrFa*2s@7+-B{^6`%2GqXI|>-JJWwfb<J%rTzo>c^qEb+dT-?Q
zH|qEa+sXpRK&Hp}<dH3p4hH>QW%8>%Z7qimwe0VfG>EYpG2TLq3m_L36Gj3jS<E?B
zXNuc06PJ2AD%E61<B#Nf7ca<P^p1}5(HNW#**WyjkA{awKfS5CS$X?R|HM;IPMl*8
zpGtrT_F6v~8Xmjzo1stmFYsvPOT30ZukM9;U_k^{i&>*}*yBlZVsczAhdqmlj9@~n
z7Vi1pw(92j?xBmP4)?t(zsYK?H=aM<BE#kl9eHcL(x3DF{!>rv@4j+gJ8<H(M?Nq&
z*s^CyVHQa82UE!`593XSxsU>>0BKoTTdE~hYjfM&S?;VwX{yp&{=x8||JE)4#~=IU
z7xT*1d1JoU{ukA-*L-6)ePd&#?e|Xc{~}Z<0g(1c4VXJ%=46ftGaZf$i^2-dipT77
z6J5m}rVL)b`{1U$qQ`#l**k%j@+ECuM*YC~Eo;_SR1`jTp`R~PUDMf$9j<le0sZ1t
z%PKa$?0b4gMMwU!<6DdNSDOaVoji^aybbSQwsK$*Sn15ZUQceE(K<3r)6R=!u}5mo
zz4YAAwjX7Vl|`q&^KDt~+qij4Rn_;m$`eNUd|_Mb<4-j1E0VgsHMLE79s4(L>0Vb{
zyvFM(DP`MQu!W}7=vjhyW0`vh(#W^No+Ao3BOOd;n>x+ro_hG%(=sz|c)Cu0L4NC}
zzhsebB>h(2YQ22!@uu}Xzy41Y^4{iMEe@qawE1}Q1>gZcT6^H^vnY~Td&WIWU9f2Z
zYyLW;Mp9J|G?7a7NZV%=&g5IMPMTgp%r#3-+1ZT3N;DNHJ*6GNsH|XzqS>PQdXp*j
zJq^4mQR~|F8FBojsUgvI(&qyHSMSGKjvsii0oMQhCy5>u%@A+CcvD29@_1yJe~L9_
z0R#IvzP&hT0HRSyk6h=sqdgdthULgtL7EChhM5O7?)MK?Kz1s<xiV6y0J4~B>PX;+
z+~s+uTs|hBJk)-JFa6f!kyJK#u*=u~y8Lf>Eb|e`Bmar)=SGI5Zz_KIKhP@qp|`*C
zoj416xQc_M#KmKBCG^32@Hxw4A=b+#c{LC42Hwm2QI&QueNm+A(PP`^uKWV#=*0e!
z)H}Z?=Kb7j<CB$<VdDV43Gf3G_aKeHuyh)HY8O=V!}28n`2*=Vl(2evoTW{vwe!HI
zy^L$e<Z+%4>2P~0q`HdTkNz~Bk&6JvHzzCQA>%;YqHs$j86@dT_AIEekzP<c5Z*!M
z$)AFHj$b`KN6jU*#JL2;_jd`#TUO?UV#CR7qvAu;DOKQt$cogU?m?cuHZ-FWvj&iW
zvZx0go+LM%G+Z)_WE(Nxkl^oz?^fP*ee|Vb2ep-p<2M<tNR$&ZPANP`{ASnyP0)rT
z8>%1xjnImmUvP~`gE%Uo4t7C1gpuDTb_=V~dipNTdU3*t$l}NqB}5&IMh!;6Q#3jF
zp5S{LgLX(p8laq#I_{=iu;A|2Hnc|7OSzyL4#jxNL$1)a!&-b&w!{^!jWLRJ1@##2
zGonaOkw4@pv&zlz1T{j7d@4C7s>87mR{-dbqX5SWScfOM4%XmMtZDG?L=SWDpT`J{
zeJD5Mp0h+%CPCAQvKBE9NNE?vy&7Jg5qHl0xXB_D@n{fNJR3BNUkXG?v$`GOj(V^Q
zT8Ok2Rw*<T2-m}Eq>WJ8+}hR(<@=gL^{`p^6&Xbfgn{f*28fbnPF96P=rZx|W*c<F
z8*rV?V=fkCzl-gloIHeso)YfiXoGUeQKC5<Y#~Z|>?G2lypo25UWiltlIDD&P4O6n
z7U588gm5MFZU}3c!iEl4XpQV8#rT9~0+$~5P!{RD>BI>ahfVl*kPUx84q!P_@=aQL
zIy<4O7EfFjPx3=IN%%5|ab(GWzGG*OoKgc4&c<sd5kF}w@h8PNsz&l0M-@a=R;(~W
kWfyC-LQ?!93<@%urM;Bf1TwNrR^v#Ocb|eKUf1gX17DAE_y7O^

literal 0
HcmV?d00001

diff --git a/test/shaping/tests/indic-special-cases.tests b/test/shaping/tests/indic-special-cases.tests
new file mode 100644
index 000000000..d45ee8c43
--- /dev/null
+++ b/test/shaping/tests/indic-special-cases.tests
@@ -0,0 +1,3 @@
+fonts/sha1sum/3cae6bfe5b57c07ba81ddbd54c02fe4f3a1e3bf6.ttf::U+0CB0,U+0CCD,U+0C95:[gid1=0+1176|gid5=0+1161]
+fonts/sha1sum/3cae6bfe5b57c07ba81ddbd54c02fe4f3a1e3bf6.ttf::U+0CB0,U+200D,U+0CCD,U+0C95:[gid2=0+1334|gid6=0+358]
+fonts/sha1sum/3cae6bfe5b57c07ba81ddbd54c02fe4f3a1e3bf6.ttf::U+0CB0,U+0CCD,U+200D,U+0C95:[gid2=0+1334|gid6=0+358]