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Diffstat (limited to 'src/3rdparty/harfbuzz-ng/src/hb-aat-layout-trak-table.hh')
| -rw-r--r-- | src/3rdparty/harfbuzz-ng/src/hb-aat-layout-trak-table.hh | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/src/3rdparty/harfbuzz-ng/src/hb-aat-layout-trak-table.hh b/src/3rdparty/harfbuzz-ng/src/hb-aat-layout-trak-table.hh new file mode 100644 index 0000000000..99dddd8826 --- /dev/null +++ b/src/3rdparty/harfbuzz-ng/src/hb-aat-layout-trak-table.hh @@ -0,0 +1,230 @@ +/* + * Copyright © 2018 Ebrahim Byagowi + * Copyright © 2018 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 + */ + +#ifndef HB_AAT_LAYOUT_TRAK_TABLE_HH +#define HB_AAT_LAYOUT_TRAK_TABLE_HH + +#include "hb-aat-layout-common.hh" +#include "hb-ot-layout.hh" +#include "hb-open-type.hh" + +/* + * trak -- Tracking + * https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6trak.html + */ +#define HB_AAT_TAG_trak HB_TAG('t','r','a','k') + + +namespace AAT { + + +struct TrackTableEntry +{ + friend struct TrackData; + + float get_track_value () const { return track.to_float (); } + + int get_value (const void *base, unsigned int index, + unsigned int table_size) const + { return (base+valuesZ).as_array (table_size)[index]; } + + public: + bool sanitize (hb_sanitize_context_t *c, const void *base, + unsigned int table_size) const + { + TRACE_SANITIZE (this); + return_trace (likely (c->check_struct (this) && + (valuesZ.sanitize (c, base, table_size)))); + } + + protected: + HBFixed track; /* Track value for this record. */ + NameID trackNameID; /* The 'name' table index for this track. + * (a short word or phrase like "loose" + * or "very tight") */ + NNOffsetTo<UnsizedArrayOf<FWORD>> + valuesZ; /* Offset from start of tracking table to + * per-size tracking values for this track. */ + + public: + DEFINE_SIZE_STATIC (8); +}; + +struct TrackData +{ + float interpolate_at (unsigned int idx, + float target_size, + const TrackTableEntry &trackTableEntry, + const void *base) const + { + unsigned int sizes = nSizes; + hb_array_t<const HBFixed> size_table ((base+sizeTable).arrayZ, sizes); + + float s0 = size_table[idx].to_float (); + float s1 = size_table[idx + 1].to_float (); + float t = unlikely (s0 == s1) ? 0.f : (target_size - s0) / (s1 - s0); + return t * trackTableEntry.get_value (base, idx + 1, sizes) + + (1.f - t) * trackTableEntry.get_value (base, idx, sizes); + } + + int get_tracking (const void *base, float ptem) const + { + /* + * Choose track. + */ + const TrackTableEntry *trackTableEntry = nullptr; + unsigned int count = nTracks; + for (unsigned int i = 0; i < count; i++) + { + /* Note: Seems like the track entries are sorted by values. But the + * spec doesn't explicitly say that. It just mentions it in the example. */ + + /* For now we only seek for track entries with zero tracking value */ + + if (trackTable[i].get_track_value () == 0.f) + { + trackTableEntry = &trackTable[i]; + break; + } + } + if (!trackTableEntry) return 0.; + + /* + * Choose size. + */ + unsigned int sizes = nSizes; + if (!sizes) return 0.; + if (sizes == 1) return trackTableEntry->get_value (base, 0, sizes); + + hb_array_t<const HBFixed> size_table ((base+sizeTable).arrayZ, sizes); + unsigned int size_index; + for (size_index = 0; size_index < sizes - 1; size_index++) + if (size_table[size_index].to_float () >= ptem) + break; + + return roundf (interpolate_at (size_index ? size_index - 1 : 0, ptem, + *trackTableEntry, base)); + } + + bool sanitize (hb_sanitize_context_t *c, const void *base) const + { + TRACE_SANITIZE (this); + return_trace (likely (c->check_struct (this) && + sizeTable.sanitize (c, base, nSizes) && + trackTable.sanitize (c, nTracks, base, nSizes))); + } + + protected: + HBUINT16 nTracks; /* Number of separate tracks included in this table. */ + HBUINT16 nSizes; /* Number of point sizes included in this table. */ + LOffsetTo<UnsizedArrayOf<HBFixed>, false> + sizeTable; /* Offset from start of the tracking table to + * Array[nSizes] of size values.. */ + UnsizedArrayOf<TrackTableEntry> + trackTable; /* Array[nTracks] of TrackTableEntry records. */ + + public: + DEFINE_SIZE_ARRAY (8, trackTable); +}; + +struct trak +{ + static constexpr hb_tag_t tableTag = HB_AAT_TAG_trak; + + bool has_data () const { return version.to_int (); } + + bool apply (hb_aat_apply_context_t *c) const + { + TRACE_APPLY (this); + + hb_mask_t trak_mask = c->plan->trak_mask; + + const float ptem = c->font->ptem; + if (unlikely (ptem <= 0.f)) + return_trace (false); + + hb_buffer_t *buffer = c->buffer; + if (HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction)) + { + const TrackData &trackData = this+horizData; + int tracking = trackData.get_tracking (this, ptem); + hb_position_t offset_to_add = c->font->em_scalef_x (tracking / 2); + hb_position_t advance_to_add = c->font->em_scalef_x (tracking); + foreach_grapheme (buffer, start, end) + { + if (!(buffer->info[start].mask & trak_mask)) continue; + buffer->pos[start].x_advance += advance_to_add; + buffer->pos[start].x_offset += offset_to_add; + } + } + else + { + const TrackData &trackData = this+vertData; + int tracking = trackData.get_tracking (this, ptem); + hb_position_t offset_to_add = c->font->em_scalef_y (tracking / 2); + hb_position_t advance_to_add = c->font->em_scalef_y (tracking); + foreach_grapheme (buffer, start, end) + { + if (!(buffer->info[start].mask & trak_mask)) continue; + buffer->pos[start].y_advance += advance_to_add; + buffer->pos[start].y_offset += offset_to_add; + } + } + + return_trace (true); + } + + bool sanitize (hb_sanitize_context_t *c) const + { + TRACE_SANITIZE (this); + + return_trace (likely (c->check_struct (this) && + version.major == 1 && + horizData.sanitize (c, this, this) && + vertData.sanitize (c, this, this))); + } + + protected: + FixedVersion<>version; /* Version of the tracking table + * (0x00010000u for version 1.0). */ + HBUINT16 format; /* Format of the tracking table (set to 0). */ + OffsetTo<TrackData> + horizData; /* Offset from start of tracking table to TrackData + * for horizontal text (or 0 if none). */ + OffsetTo<TrackData> + vertData; /* Offset from start of tracking table to TrackData + * for vertical text (or 0 if none). */ + HBUINT16 reserved; /* Reserved. Set to 0. */ + + public: + DEFINE_SIZE_STATIC (12); +}; + +} /* namespace AAT */ + + +#endif /* HB_AAT_LAYOUT_TRAK_TABLE_HH */ |