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[Indic] Towards better Reph positioning 

Fixed for Deva cases with two full-form consonants.  Failures **way** down.
Not much left to go :-).
This commit is contained in:
Behdad Esfahbod 2012-05-10 21:44:50 +02:00
parent 74e54cf446
commit 02b2922fbf
1 changed files with 81 additions and 32 deletions
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113
src/hb-ot-shape-complex-indic.cc
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@ -541,10 +541,26 @@ final_reordering_syllable (hb_buffer_t *buffer,
info[start].indic_position() == POS_RA_TO_BECOME_REPH &&
info[start + 1].indic_position() != POS_RA_TO_BECOME_REPH)
{
unsigned int new_reph_pos;
enum reph_position_t {
REPH_AFTER_MAIN, /* Malayalam, Oriya */
REPH_BEFORE_SUBSCRIPT, /* Gurmukhi */
REPH_AFTER_SUBSCRIPT, /* Bengali */
REPH_BEFORE_POSTSCRIPT, /* Devanagari, Gujarati */
REPH_AFTER_POSTSCRIPT, /* Kannada, Tamil, Telugu */
} reph_pos = REPH_BEFORE_POSTSCRIPT; /* XXX */ /* XXX Figure out old behavior too */
/* 1. If reph should be positioned after post-base consonant forms,
* proceed to step 5.
*
* 2. If the reph repositioning class is not after post-base: target
*/
reph_step_1:
{
if (reph_pos == REPH_AFTER_POSTSCRIPT)
goto reph_step_5;
}
/* 2. If the reph repositioning class is not after post-base: target
* position is after the first explicit halant glyph between the
* first post-reph consonant and last main consonant. If ZWJ or ZWNJ
* are following this halant, position is moved after it. If such
@ -554,49 +570,82 @@ final_reordering_syllable (hb_buffer_t *buffer,
* Note: in old-implementation fonts, where classifications were
* fixed in shaping engine, there was no case where reph position
* will be found on this step.
*
* 3. If reph should be repositioned after the main consonant: from the
*/
reph_step_2:
{
new_reph_pos = start + 1;
while (new_reph_pos < base && info[new_reph_pos].indic_category() != OT_H)
new_reph_pos++;
if (new_reph_pos < base && info[new_reph_pos].indic_category() == OT_H) {
/* ->If ZWJ or ZWNJ are following this halant, position is moved after it. */
if (new_reph_pos + 1 < base && is_joiner (info[new_reph_pos + 1]))
new_reph_pos++;
goto reph_move;
}
}
/* 3. If reph should be repositioned after the main consonant: find the
* first consonant not ligated with main, or find the first
* consonant that is not a potential pre-base reordering Ra.
*
*
* 4. If reph should be positioned before post-base consonant, find
*/
reph_step_3:
{
/* XXX */
}
/* 4. If reph should be positioned before post-base consonant, find
* first post-base classified consonant not ligated with main. If no
* consonant is found, the target position should be before the
* first matra, syllable modifier sign or vedic sign.
*
* 5. If no consonant is found in steps 3 or 4, move reph to a position
*/
reph_step_4:
{
/* XXX */
}
/* 5. If no consonant is found in steps 3 or 4, move reph to a position
* immediately before the first post-base matra, syllable modifier
* sign or vedic sign that has a reordering class after the intended
* reph position. For example, if the reordering position for reph
* is post-main, it will skip above-base matras that also have a
* post-main position.
*
* 6. Otherwise, reorder reph to the end of the syllable.
*/
/* Now let's go shopping for a position. */
unsigned int new_reph_pos = end - 1;
while (new_reph_pos > start && (FLAG (info[new_reph_pos].indic_position()) & (FLAG (POS_SMVD))))
new_reph_pos--;
if (unlikely (info[new_reph_pos].indic_category() == OT_H)) {
/* *If* the Reph is to be ending up after a Matra,Halant sequence,
* position it before that Halant so it can interact with the Matra.
* However, if it's a plain Consonant,Halant we shouldn't do that.
*/
for (unsigned int i = base + 1; i < new_reph_pos; i++)
if (info[i].indic_category() == OT_M) {
/* Ok, got it. */
new_reph_pos--;
}
reph_step_5:
{
/* XXX */
}
/* Move */
hb_glyph_info_t reph = info[start];
memmove (&info[start], &info[start + 1], (new_reph_pos - start) * sizeof (info[0]));
info[new_reph_pos] = reph;
start_of_last_cluster = start; /* Yay, one big cluster! */
/* 6. Otherwise, reorder reph to the end of the syllable.
*/
reph_step_6:
{
new_reph_pos = end - 1;
while (new_reph_pos > start && info[new_reph_pos].indic_position() == POS_SMVD)
new_reph_pos--;
if (unlikely (info[new_reph_pos].indic_category() == OT_H)) {
/* *If* the Reph is to be ending up after a Matra,Halant sequence,
* position it before that Halant so it can interact with the Matra.
* However, if it's a plain Consonant,Halant we shouldn't do that.
*/
for (unsigned int i = base + 1; i < new_reph_pos; i++)
if (info[i].indic_category() == OT_M) {
/* Ok, got it. */
new_reph_pos--;
}
}
goto reph_move;
}
reph_move:
{
/* Move */
hb_glyph_info_t reph = info[start];
memmove (&info[start], &info[start + 1], (new_reph_pos - start) * sizeof (info[0]));
info[new_reph_pos] = reph;
start_of_last_cluster = start; /* Yay, one big cluster! */
}
}