140 lines
3.4 KiB
C++
140 lines
3.4 KiB
C++
/*
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* Copyright © 2017 Google, Inc.
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*
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* This is part of HarfBuzz, a text shaping library.
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*
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* Permission is hereby granted, without written agreement and without
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* license or royalty fees, to use, copy, modify, and distribute this
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* software and its documentation for any purpose, provided that the
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* above copyright notice and the following two paragraphs appear in
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* all copies of this software.
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*
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* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
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* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
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* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
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* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
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* DAMAGE.
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*
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* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
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* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
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* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
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* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*
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* Google Author(s): Behdad Esfahbod
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*/
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#ifndef HB_KERN_HH
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#define HB_KERN_HH
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#include "hb-open-type.hh"
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#include "hb-aat-layout-common.hh"
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#include "hb-ot-layout-gpos-table.hh"
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namespace OT {
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template <typename Driver>
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struct hb_kern_machine_t
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{
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hb_kern_machine_t (const Driver &driver_,
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bool crossStream_ = false) :
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driver (driver_),
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crossStream (crossStream_) {}
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HB_NO_SANITIZE_SIGNED_INTEGER_OVERFLOW
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void kern (hb_font_t *font,
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hb_buffer_t *buffer,
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hb_mask_t kern_mask,
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bool scale = true) const
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{
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OT::hb_ot_apply_context_t c (1, font, buffer);
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c.set_lookup_mask (kern_mask);
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c.set_lookup_props (OT::LookupFlag::IgnoreMarks);
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OT::hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c.iter_input;
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skippy_iter.init (&c);
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bool horizontal = HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction);
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unsigned int count = buffer->len;
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hb_glyph_info_t *info = buffer->info;
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hb_glyph_position_t *pos = buffer->pos;
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for (unsigned int idx = 0; idx < count;)
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{
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if (!(info[idx].mask & kern_mask))
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{
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idx++;
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continue;
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}
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skippy_iter.reset (idx, 1);
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if (!skippy_iter.next ())
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{
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idx++;
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continue;
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}
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unsigned int i = idx;
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unsigned int j = skippy_iter.idx;
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hb_position_t kern = driver.get_kerning (info[i].codepoint,
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info[j].codepoint);
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if (likely (!kern))
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goto skip;
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if (horizontal)
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{
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if (scale)
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kern = font->em_scale_x (kern);
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if (crossStream)
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{
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pos[j].y_offset = kern;
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buffer->scratch_flags |= HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT;
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}
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else
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{
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hb_position_t kern1 = kern >> 1;
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hb_position_t kern2 = kern - kern1;
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pos[i].x_advance += kern1;
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pos[j].x_advance += kern2;
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pos[j].x_offset += kern2;
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}
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}
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else
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{
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if (scale)
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kern = font->em_scale_y (kern);
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if (crossStream)
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{
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pos[j].x_offset = kern;
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buffer->scratch_flags |= HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT;
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}
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else
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{
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hb_position_t kern1 = kern >> 1;
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hb_position_t kern2 = kern - kern1;
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pos[i].y_advance += kern1;
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pos[j].y_advance += kern2;
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pos[j].y_offset += kern2;
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}
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}
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buffer->unsafe_to_break (i, j + 1);
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skip:
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idx = skippy_iter.idx;
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}
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}
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const Driver &driver;
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bool crossStream;
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};
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} /* namespace OT */
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#endif /* HB_KERN_HH */
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