| /* |
| * 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, hb_blob_get_empty ()); |
| 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 */ |