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Diffstat (limited to 'gfx/harfbuzz/src/hb-kern.hh')
-rw-r--r-- | gfx/harfbuzz/src/hb-kern.hh | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/gfx/harfbuzz/src/hb-kern.hh b/gfx/harfbuzz/src/hb-kern.hh new file mode 100644 index 0000000000..9ea945caed --- /dev/null +++ b/gfx/harfbuzz/src/hb-kern.hh @@ -0,0 +1,145 @@ +/* + * Copyright © 2017 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_KERN_HH +#define HB_KERN_HH + +#include "hb-open-type.hh" +#include "hb-aat-layout-common.hh" +#include "hb-ot-layout-gpos-table.hh" + + +namespace OT { + + +template <typename Driver> +struct hb_kern_machine_t +{ + hb_kern_machine_t (const Driver &driver_, + bool crossStream_ = false) : + driver (driver_), + crossStream (crossStream_) {} + + HB_NO_SANITIZE_SIGNED_INTEGER_OVERFLOW + void kern (hb_font_t *font, + hb_buffer_t *buffer, + hb_mask_t kern_mask, + bool scale = true) const + { + if (!buffer->message (font, "start kern")) + return; + + buffer->unsafe_to_concat (); + OT::hb_ot_apply_context_t c (1, font, buffer); + c.set_lookup_mask (kern_mask); + c.set_lookup_props (OT::LookupFlag::IgnoreMarks); + auto &skippy_iter = c.iter_input; + + bool horizontal = HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction); + unsigned int count = buffer->len; + hb_glyph_info_t *info = buffer->info; + hb_glyph_position_t *pos = buffer->pos; + for (unsigned int idx = 0; idx < count;) + { + if (!(info[idx].mask & kern_mask)) + { + idx++; + continue; + } + + skippy_iter.reset (idx, 1); + unsigned unsafe_to; + if (!skippy_iter.next (&unsafe_to)) + { + idx++; + continue; + } + + unsigned int i = idx; + unsigned int j = skippy_iter.idx; + + hb_position_t kern = driver.get_kerning (info[i].codepoint, + info[j].codepoint); + + + if (likely (!kern)) + goto skip; + + if (horizontal) + { + if (scale) + kern = font->em_scale_x (kern); + if (crossStream) + { + pos[j].y_offset = kern; + buffer->scratch_flags |= HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT; + } + else + { + hb_position_t kern1 = kern >> 1; + hb_position_t kern2 = kern - kern1; + pos[i].x_advance += kern1; + pos[j].x_advance += kern2; + pos[j].x_offset += kern2; + } + } + else + { + if (scale) + kern = font->em_scale_y (kern); + if (crossStream) + { + pos[j].x_offset = kern; + buffer->scratch_flags |= HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT; + } + else + { + hb_position_t kern1 = kern >> 1; + hb_position_t kern2 = kern - kern1; + pos[i].y_advance += kern1; + pos[j].y_advance += kern2; + pos[j].y_offset += kern2; + } + } + + buffer->unsafe_to_break (i, j + 1); + + skip: + idx = skippy_iter.idx; + } + + (void) buffer->message (font, "end kern"); + } + + const Driver &driver; + bool crossStream; +}; + + +} /* namespace OT */ + + +#endif /* HB_KERN_HH */ |