Behdad Esfahbod
3 years ago
parent
8ed78627f0
commit
f0ec2b728e
4 changed files with 203 additions and 183 deletions
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#ifndef OT_GLYF_SIMPLEGLYPH_HH |
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#define OT_GLYF_SIMPLEGLYPH_HH |
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#include "../../hb-open-type.hh" |
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namespace OT { |
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namespace glyf_impl { |
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struct SimpleGlyph |
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{ |
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enum simple_glyph_flag_t |
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{ |
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FLAG_ON_CURVE = 0x01, |
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FLAG_X_SHORT = 0x02, |
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FLAG_Y_SHORT = 0x04, |
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FLAG_REPEAT = 0x08, |
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FLAG_X_SAME = 0x10, |
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FLAG_Y_SAME = 0x20, |
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FLAG_OVERLAP_SIMPLE = 0x40, |
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FLAG_RESERVED2 = 0x80 |
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}; |
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const GlyphHeader &header; |
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hb_bytes_t bytes; |
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SimpleGlyph (const GlyphHeader &header_, hb_bytes_t bytes_) : |
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header (header_), bytes (bytes_) {} |
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unsigned int instruction_len_offset () const |
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{ return GlyphHeader::static_size + 2 * header.numberOfContours; } |
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unsigned int length (unsigned int instruction_len) const |
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{ return instruction_len_offset () + 2 + instruction_len; } |
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unsigned int instructions_length () const |
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{ |
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unsigned int instruction_length_offset = instruction_len_offset (); |
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if (unlikely (instruction_length_offset + 2 > bytes.length)) return 0; |
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const HBUINT16 &instructionLength = StructAtOffset<HBUINT16> (&bytes, instruction_length_offset); |
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/* Out of bounds of the current glyph */ |
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if (unlikely (length (instructionLength) > bytes.length)) return 0; |
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return instructionLength; |
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} |
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const hb_bytes_t trim_padding () const |
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{ |
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/* based on FontTools _g_l_y_f.py::trim */ |
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const uint8_t *glyph = (uint8_t*) bytes.arrayZ; |
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const uint8_t *glyph_end = glyph + bytes.length; |
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/* simple glyph w/contours, possibly trimmable */ |
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glyph += instruction_len_offset (); |
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if (unlikely (glyph + 2 >= glyph_end)) return hb_bytes_t (); |
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unsigned int num_coordinates = StructAtOffset<HBUINT16> (glyph - 2, 0) + 1; |
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unsigned int num_instructions = StructAtOffset<HBUINT16> (glyph, 0); |
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glyph += 2 + num_instructions; |
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unsigned int coord_bytes = 0; |
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unsigned int coords_with_flags = 0; |
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while (glyph < glyph_end) |
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{ |
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uint8_t flag = *glyph; |
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glyph++; |
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unsigned int repeat = 1; |
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if (flag & FLAG_REPEAT) |
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{ |
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if (unlikely (glyph >= glyph_end)) return hb_bytes_t (); |
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repeat = *glyph + 1; |
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glyph++; |
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} |
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unsigned int xBytes, yBytes; |
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xBytes = yBytes = 0; |
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if (flag & FLAG_X_SHORT) xBytes = 1; |
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else if ((flag & FLAG_X_SAME) == 0) xBytes = 2; |
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if (flag & FLAG_Y_SHORT) yBytes = 1; |
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else if ((flag & FLAG_Y_SAME) == 0) yBytes = 2; |
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coord_bytes += (xBytes + yBytes) * repeat; |
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coords_with_flags += repeat; |
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if (coords_with_flags >= num_coordinates) break; |
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} |
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if (unlikely (coords_with_flags != num_coordinates)) return hb_bytes_t (); |
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return bytes.sub_array (0, bytes.length + coord_bytes - (glyph_end - glyph)); |
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} |
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/* zero instruction length */ |
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void drop_hints () |
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{ |
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GlyphHeader &glyph_header = const_cast<GlyphHeader &> (header); |
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(HBUINT16 &) StructAtOffset<HBUINT16> (&glyph_header, instruction_len_offset ()) = 0; |
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} |
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void drop_hints_bytes (hb_bytes_t &dest_start, hb_bytes_t &dest_end) const |
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{ |
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unsigned int instructions_len = instructions_length (); |
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unsigned int glyph_length = length (instructions_len); |
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dest_start = bytes.sub_array (0, glyph_length - instructions_len); |
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dest_end = bytes.sub_array (glyph_length, bytes.length - glyph_length); |
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} |
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void set_overlaps_flag () |
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{ |
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if (unlikely (!header.numberOfContours)) return; |
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unsigned flags_offset = length (instructions_length ()); |
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if (unlikely (flags_offset + 1 > bytes.length)) return; |
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HBUINT8 &first_flag = (HBUINT8 &) StructAtOffset<HBUINT16> (&bytes, flags_offset); |
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first_flag = (uint8_t) first_flag | FLAG_OVERLAP_SIMPLE; |
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} |
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static bool read_points (const HBUINT8 *&p /* IN/OUT */, |
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contour_point_vector_t &points_ /* IN/OUT */, |
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const hb_bytes_t &bytes, |
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void (* setter) (contour_point_t &_, float v), |
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const simple_glyph_flag_t short_flag, |
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const simple_glyph_flag_t same_flag) |
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{ |
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float v = 0; |
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for (unsigned i = 0; i < points_.length; i++) |
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{ |
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uint8_t flag = points_[i].flag; |
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if (flag & short_flag) |
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{ |
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if (unlikely (!bytes.check_range (p))) return false; |
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if (flag & same_flag) |
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v += *p++; |
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else |
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v -= *p++; |
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} |
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else |
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{ |
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if (!(flag & same_flag)) |
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{ |
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if (unlikely (!bytes.check_range ((const HBUINT16 *) p))) return false; |
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v += *(const HBINT16 *) p; |
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p += HBINT16::static_size; |
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} |
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} |
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setter (points_[i], v); |
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} |
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return true; |
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} |
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bool get_contour_points (contour_point_vector_t &points_ /* OUT */, |
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bool phantom_only = false) const |
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{ |
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const HBUINT16 *endPtsOfContours = &StructAfter<HBUINT16> (header); |
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int num_contours = header.numberOfContours; |
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if (unlikely (!bytes.check_range (&endPtsOfContours[num_contours + 1]))) return false; |
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unsigned int num_points = endPtsOfContours[num_contours - 1] + 1; |
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points_.resize (num_points); |
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for (unsigned int i = 0; i < points_.length; i++) points_[i].init (); |
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if (phantom_only) return true; |
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for (int i = 0; i < num_contours; i++) |
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points_[endPtsOfContours[i]].is_end_point = true; |
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/* Skip instructions */ |
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const HBUINT8 *p = &StructAtOffset<HBUINT8> (&endPtsOfContours[num_contours + 1], |
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endPtsOfContours[num_contours]); |
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/* Read flags */ |
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for (unsigned int i = 0; i < num_points; i++) |
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{ |
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if (unlikely (!bytes.check_range (p))) return false; |
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uint8_t flag = *p++; |
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points_[i].flag = flag; |
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if (flag & FLAG_REPEAT) |
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{ |
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if (unlikely (!bytes.check_range (p))) return false; |
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unsigned int repeat_count = *p++; |
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while ((repeat_count-- > 0) && (++i < num_points)) |
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points_[i].flag = flag; |
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} |
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} |
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/* Read x & y coordinates */ |
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return read_points (p, points_, bytes, [] (contour_point_t &p, float v) { p.x = v; }, |
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FLAG_X_SHORT, FLAG_X_SAME) |
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&& read_points (p, points_, bytes, [] (contour_point_t &p, float v) { p.y = v; }, |
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FLAG_Y_SHORT, FLAG_Y_SAME); |
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} |
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}; |
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} /* namespace glyf_impl */ |
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} /* namespace OT */ |
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#endif /* OT_GLYF_SIMPLEGLYPH_HH */ |
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