ref: 297fc906899f4c1f9b37edca27a7e610ac8bf004
parent: 8c778d1a462baf17fb0094c3f9e1018443dcb85a
author: Ali Gholami Rudi <ali@rudi.ir>
date: Sun Aug 3 19:52:41 EDT 2014
font: support gsub/gpos context glyphs For instance, the line gsub feat 5 =a -x -y -z +xyz tells neatroff to replace the glyphs x y z with glyph xyz only if they follow an a and font feature feat is enabled. This patch also supports matching one of the many glyphs in the patterns. Also the rule gsub feat 5 -a |b |c -y +axy matches any of the strings ay, by and cy; neatroff replaces any of them with the glyph axy if feat is enabled.
--- a/font.c
+++ b/font.c
@@ -6,10 +6,15 @@
#define GHASH(g1, g2) ((((g2) + 1) << 16) | ((g1) + 1))
+#define GF_PAT 1 /* gsub/gpos pattern glyph */
+#define GF_REP 2 /* gsub replacement glyph */
+#define GF_CON 4 /* context glyph */
+#define GF_ALT 8 /* pattern followed by alternative patterns */
+
/* glyph pattern for gsub and gpos tables; each grule has some gpats */
struct gpat {short g; /* glyph index */
- short rep; /* ignore this glyph; gsub replacement */
+ short flg; /* pattern flags; GF_* */
short x, y, xadv, yadv; /* gpos data */
};
@@ -118,13 +123,13 @@
{int g1 = -1, g2 = -1;
int i = 0;
- while (i < rule->len && rule->pats[i].rep)
+ while (i < rule->len && rule->pats[i].flg == GF_REP)
i++;
- g1 = i < rule->len ? rule->pats[i++].g : -1;
- while (i < rule->len && rule->pats[i].rep)
+ g1 = i < rule->len && rule->pats[i].flg == GF_PAT ? rule->pats[i++].g : -1;
+ while (i < rule->len && rule->pats[i].flg == GF_REP)
i++;
- g2 = i < rule->len ? rule->pats[i++].g : -1;
- return GHASH(g1, g2);
+ g2 = i < rule->len && rule->pats[i].flg == GF_PAT ? rule->pats[i++].g : -1;
+ return GHASH(g1, g1 < 0 ? -1 : g2);
}
static int grule_find(struct grule *rules, int n, int hash)
@@ -141,29 +146,60 @@
return rules[l].hash == hash ? l : -1;
}
-static int font_rulematches(struct font *fn, struct grule *rule, int *src, int len)
+static int font_rulematches(struct font *fn, struct grule *rule,
+ int *src, int slen, int *dst, int dlen)
{- int j, sidx = 0;
+ int sidx = 0; /* the index of matched glyphs in src */
+ int didx = 0; /* the index of matched glyphs in dst */
+ int ncon = 0; /* number of initial context glyphs */
+ struct gpat *pats = rule->pats;
+ int j;
if (!fn->feat_set[rule->feat])
return 0;
- for (j = 0; j < rule->len; j++)
- if (!rule->pats[j].rep)
- if (sidx >= len || rule->pats[j].g != src[sidx++])
- return 0;
- return j == rule->len;
+ /* the number of initial context glyphs */
+ for (j = 0; j < rule->len && pats[j].flg & GF_CON; j++)
+ if (pats[j].flg == GF_CON)
+ ncon++;
+ if (dlen < ncon)
+ return 0;
+ /* matching the base pattern */
+ for (; j < rule->len; j++) {+ if (pats[j].flg & GF_REP)
+ continue;
+ if (sidx < slen && pats[j].g == src[sidx]) {+ sidx++;
+ while (pats[j].flg & GF_ALT)
+ j++;
+ } else if (!(pats[j].flg & GF_ALT)) {+ return 0;
+ }
+ }
+ if (j != rule->len)
+ return 0;
+ /* matching the initial context */
+ for (j = 0; j < rule->len && pats[j].flg & GF_CON; j++) {+ if (pats[j].g == dst[didx - ncon]) {+ didx++;
+ while (pats[j].flg & GF_ALT)
+ j++;
+ } else if (!(pats[j].flg & GF_ALT)) {+ return 0;
+ }
+ }
+ return 1;
}
-static struct grule *font_findrule(struct font *fn, struct grule *rules,
- int n, int *src, int len)
+static struct grule *font_findrule(struct font *fn, struct grule *rules, int n,
+ int *src, int slen, int *dst, int dlen)
{+ int hash[] = {GHASH(-1, -1), GHASH(src[0], -1), GHASH(src[0], src[1])};int i, j;
- for (j = 0; j < 2 && j < len; j++) {- int hash = GHASH(src[0], j == 0 ? -1 : src[1]);
- int idx = grule_find(rules, n, hash);
+ for (j = 0; j < LEN(hash) && j <= slen; j++) {+ int idx = grule_find(rules, n, hash[j]);
if (idx < 0)
continue;
- for (i = idx; i < n && rules[i].hash == hash; i++)
- if (font_rulematches(fn, rules + i, src, len))
+ for (i = idx; i < n && rules[i].hash == hash[j]; i++)
+ if (font_rulematches(fn, rules + i, src, slen, dst, dlen))
return rules + i;
}
return NULL;
@@ -179,14 +215,14 @@
for (i = 0; i < nsrc; i++)
src[i] = font_idx(fn, gsrc[i]);
for (i = 0; i < nsrc; i++) {- struct grule *rule = font_findrule(fn, fn->gsub,
- fn->gsub_n, src + i, nsrc - i);
+ struct grule *rule = font_findrule(fn, fn->gsub, fn->gsub_n,
+ src + i, nsrc - i, dst + ndst, ndst);
dmap[ndst] = i;
if (rule) { for (j = 0; j < rule->len; j++) {- if (rule->pats[j].rep)
+ if (rule->pats[j].flg == GF_REP)
dst[ndst++] = rule->pats[j].g;
- else
+ if (rule->pats[j].flg == GF_PAT)
i++;
}
i--;
@@ -201,8 +237,8 @@
for (i = 0; i < ndst; i++)
gdst[i] = fn->glyphs + dst[i];
for (i = 0; i < ndst; i++) {- struct grule *rule = font_findrule(fn, fn->gpos,
- fn->gpos_n, dst + i, ndst - i);
+ struct grule *rule = font_findrule(fn, fn->gpos, fn->gpos_n,
+ dst + i, ndst - i, dst + i, i);
if (!rule)
continue;
for (j = 0; j < rule->len; j++) {@@ -319,7 +355,16 @@
if (!tok[0] || !(g = font_glyph(fn, tok + 1)))
return 0;
rule->pats[i].g = font_idx(fn, g);
- rule->pats[i].rep = tok[0] == '+';
+ if (tok[0] == '-')
+ rule->pats[i].flg = GF_PAT;
+ if (tok[0] == '=')
+ rule->pats[i].flg = GF_CON;
+ if (tok[0] == '+')
+ rule->pats[i].flg = GF_REP;
+ if (i > 0 && tok[0] == '|') {+ rule->pats[i].flg = rule->pats[i - 1].flg;
+ rule->pats[i - 1].flg |= GF_ALT;
+ }
}
return 0;
}
@@ -364,6 +409,8 @@
rule->pats[0].g = font_idx(fn, font_glyph(fn, c1));
rule->pats[1].g = font_idx(fn, font_glyph(fn, c2));
rule->pats[0].xadv = val;
+ rule->pats[0].flg = GF_PAT;
+ rule->pats[1].flg = GF_PAT;
return 0;
}
@@ -378,10 +425,12 @@
g[n++] = font_idx(fn, font_find(fn, c));
if (!(rule = font_gsub(fn, "liga", n + 1)))
return;
- for (j = 0; j < n; j++)
+ for (j = 0; j < n; j++) {rule->pats[j].g = g[j];
- rule->pats[n].g = font_idx(fn, font_glyph(fn, lig));
- rule->pats[n].rep = 1;
+ rule->pats[j].flg = GF_PAT;
+ }
+ rule->pats[n].g = font_idx(fn, font_find(fn, lig));
+ rule->pats[n].flg = GF_REP;
}
static void skipline(FILE* filp)