/*
* Copyright © 2010 Google, Inc.
*
* This is part of HarfBuzz, a text shaping library.
*
* Permission is hereby granted, without written agreement and without
* license or royalty fees, to use, copy, modify, and distribute this
* software and its documentation for any purpose, provided that the
* above copyright notice and the following two paragraphs appear in
* all copies of this software.
*
* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*
* Google Author(s): Behdad Esfahbod
*/
#include "hb-ot-shape-complex-private.hh"
/* TODO Add kana, and other small shapers here */
/* When adding trivial shapers, eg. kana, hangul, etc, we can either
* add a full shaper enum value for them, or switch on the script in
* the default complex shaper. The former is faster, so I think that's
* what we would do, and hence the default complex shaper shall remain
* empty.
*/
void
_hb_ot_shape_complex_collect_features_default (hb_ot_map_builder_t *map, const hb_segment_properties_t *props)
{
}
hb_ot_shape_normalization_mode_t
_hb_ot_shape_complex_normalization_preference_default (void)
{
return HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS;
}
void
_hb_ot_shape_complex_setup_masks_default (hb_ot_map_t *map, hb_buffer_t *buffer, hb_font_t *font)
{
}
/* Hangul shaper */
static const hb_tag_t hangul_features[] =
{
HB_TAG('l','j','m','o'),
HB_TAG('v','j','m','o'),
HB_TAG('t','j','m','o'),
};
void
_hb_ot_shape_complex_collect_features_hangul (hb_ot_map_builder_t *map, const hb_segment_properties_t *props)
{
for (unsigned int i = 0; i < ARRAY_LENGTH (hangul_features); i++)
map->add_bool_feature (hangul_features[i]);
}
hb_ot_shape_normalization_mode_t
_hb_ot_shape_complex_normalization_preference_hangul (void)
{
return HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_FULL;
}
void
_hb_ot_shape_complex_setup_masks_hangul (hb_ot_map_t *map, hb_buffer_t *buffer, hb_font_t *font)
{
}
/* Thai / Lao shaper */
void
_hb_ot_shape_complex_collect_features_thai (hb_ot_map_builder_t *map, const hb_segment_properties_t *props)
{
}
hb_ot_shape_normalization_mode_t
_hb_ot_shape_complex_normalization_preference_thai (void)
{
return HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_FULL;
}
void
_hb_ot_shape_complex_setup_masks_thai (hb_ot_map_t *map, hb_buffer_t *buffer, hb_font_t *font)
{
/* The following is NOT specified in the MS OT Thai spec, however, it seems
* to be what Uniscribe and other engines implement. According to Eric Muller:
*
* When you have a sara am, decompose it in nikhahit + sara a, *and* mode the
* nihka hit backwards over any *tone* mark (0E48-0E4B).
*
* <0E14, 0E4B, 0E33> -> <0E14, 0E4D, 0E4B, 0E32>
*
* This reordering is legit only when the nikhahit comes from a sara am, not
* when it's there to start with. The string <0E14, 0E4B, 0E4D> is probably
* not what a u↪ser wanted, but the rendering is nevertheless nikhahit above
* chattawa.
*
* Same for Lao.
*/
/*
* Here are the characters of significance:
*
* Thai Lao
* SARA AM: U+0E33 U+0EB3
* SARA AA: U+0E32 U+0EB2
* Nikhahit: U+0E4D U+0ECD
*
* Tone marks:
* Thai: <0E48..0E4B> CCC=107
* Lao: <0EC8..0ECB> CCC=122
*
* Note how the Lao versions are the same as Thai + 0x80.
*/
/* We only get one script at a time, so a script-agnostic implementation
* is adequate here. */
#define IS_SARA_AM(x) (((x) & ~0x0080) == 0x0E33)
#define NIKHAHIT_FROM_SARA_AM(x) ((x) - 0xE33 + 0xE4D)
#define SARA_AA_FROM_SARA_AM(x) ((x) - 1)
#define IS_TONE_MARK(x) (((x) & ~0x0083) == 0x0E48)
buffer->clear_output ();
unsigned int count = buffer->len;
for (buffer->idx = 0; buffer->idx < count;)
{
hb_codepoint_t u = buffer->info[buffer->idx].codepoint;
if (likely (!IS_SARA_AM (u))) {
buffer->next_glyph ();
continue;
}
/* Is SARA AM. Decompose and reorder. */
hb_codepoint_t decomposed[2] = {hb_codepoint_t (NIKHAHIT_FROM_SARA_AM (u)),
hb_codepoint_t (SARA_AA_FROM_SARA_AM (u))};
buffer->replace_glyphs (1, 2, decomposed);
if (unlikely (buffer->in_error))
return;
/* Ok, let's see... */
unsigned int end = buffer->out_len;
unsigned int start = end - 2;
while (start > 0 && IS_TONE_MARK (buffer->out_info[start - 1].codepoint))
start--;
/* Move Nikhahit (end-2) to the beginning */
hb_glyph_info_t t = buffer->out_info[end - 2];
memmove (buffer->out_info + start + 1,
buffer->out_info + start,
sizeof (buffer->out_info[0]) * (end - start - 2));
buffer->out_info[start] = t;
/* Make cluster */
for (; start > 0 && buffer->out_info[start - 1].cluster == buffer->out_info[start].cluster; start--)
;
for (; buffer->idx < count;)
if (buffer->info[buffer->idx].cluster == buffer->out_info[buffer->out_len - 1].cluster)
buffer->next_glyph ();
else
break;
end = buffer->out_len;
buffer->merge_out_clusters (start, end);
}
buffer->swap_buffers ();
}
