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Diffstat (limited to 'gfx/harfbuzz/src/hb-ot-kern-table.hh')
| -rw-r--r-- | gfx/harfbuzz/src/hb-ot-kern-table.hh | 359 |
1 files changed, 359 insertions, 0 deletions
diff --git a/gfx/harfbuzz/src/hb-ot-kern-table.hh b/gfx/harfbuzz/src/hb-ot-kern-table.hh new file mode 100644 index 0000000000..ffa11bc249 --- /dev/null +++ b/gfx/harfbuzz/src/hb-ot-kern-table.hh @@ -0,0 +1,359 @@ +/* + * 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_OT_KERN_TABLE_HH +#define HB_OT_KERN_TABLE_HH + +#include "hb-aat-layout-kerx-table.hh" + + +/* + * kern -- Kerning + * https://docs.microsoft.com/en-us/typography/opentype/spec/kern + * https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6kern.html + */ +#define HB_OT_TAG_kern HB_TAG('k','e','r','n') + + +namespace OT { + + +template <typename KernSubTableHeader> +struct KernSubTableFormat3 +{ + int get_kerning (hb_codepoint_t left, hb_codepoint_t right) const + { + hb_array_t<const FWORD> kernValue = kernValueZ.as_array (kernValueCount); + hb_array_t<const HBUINT8> leftClass = StructAfter<const UnsizedArrayOf<HBUINT8>> (kernValue).as_array (glyphCount); + hb_array_t<const HBUINT8> rightClass = StructAfter<const UnsizedArrayOf<HBUINT8>> (leftClass).as_array (glyphCount); + hb_array_t<const HBUINT8> kernIndex = StructAfter<const UnsizedArrayOf<HBUINT8>> (rightClass).as_array (leftClassCount * rightClassCount); + + unsigned int leftC = leftClass[left]; + unsigned int rightC = rightClass[right]; + if (unlikely (leftC >= leftClassCount || rightC >= rightClassCount)) + return 0; + unsigned int i = leftC * rightClassCount + rightC; + return kernValue[kernIndex[i]]; + } + + bool apply (AAT::hb_aat_apply_context_t *c) const + { + TRACE_APPLY (this); + + if (!c->plan->requested_kerning) + return false; + + if (header.coverage & header.Backwards) + return false; + + hb_kern_machine_t<KernSubTableFormat3> machine (*this, header.coverage & header.CrossStream); + machine.kern (c->font, c->buffer, c->plan->kern_mask); + + return_trace (true); + } + + bool sanitize (hb_sanitize_context_t *c) const + { + TRACE_SANITIZE (this); + return_trace (c->check_struct (this) && + c->check_range (kernValueZ, + kernValueCount * sizeof (FWORD) + + glyphCount * 2 + + leftClassCount * rightClassCount)); + } + + protected: + KernSubTableHeader + header; + HBUINT16 glyphCount; /* The number of glyphs in this font. */ + HBUINT8 kernValueCount; /* The number of kerning values. */ + HBUINT8 leftClassCount; /* The number of left-hand classes. */ + HBUINT8 rightClassCount;/* The number of right-hand classes. */ + HBUINT8 flags; /* Set to zero (reserved for future use). */ + UnsizedArrayOf<FWORD> + kernValueZ; /* The kerning values. + * Length kernValueCount. */ +#if 0 + UnsizedArrayOf<HBUINT8> + leftClass; /* The left-hand classes. + * Length glyphCount. */ + UnsizedArrayOf<HBUINT8> + rightClass; /* The right-hand classes. + * Length glyphCount. */ + UnsizedArrayOf<HBUINT8>kernIndex; + /* The indices into the kernValue array. + * Length leftClassCount * rightClassCount */ +#endif + public: + DEFINE_SIZE_ARRAY (KernSubTableHeader::static_size + 6, kernValueZ); +}; + +template <typename KernSubTableHeader> +struct KernSubTable +{ + unsigned int get_size () const { return u.header.length; } + unsigned int get_type () const { return u.header.format; } + + int get_kerning (hb_codepoint_t left, hb_codepoint_t right) const + { + switch (get_type ()) { + /* This method hooks up to hb_font_t's get_h_kerning. Only support Format0. */ + case 0: return u.format0.get_kerning (left, right); + default:return 0; + } + } + + template <typename context_t, typename ...Ts> + typename context_t::return_t dispatch (context_t *c, Ts&&... ds) const + { + unsigned int subtable_type = get_type (); + TRACE_DISPATCH (this, subtable_type); + switch (subtable_type) { + case 0: return_trace (c->dispatch (u.format0)); +#ifndef HB_NO_AAT_SHAPE + case 1: return_trace (u.header.apple ? c->dispatch (u.format1, std::forward<Ts> (ds)...) : c->default_return_value ()); +#endif + case 2: return_trace (c->dispatch (u.format2)); +#ifndef HB_NO_AAT_SHAPE + case 3: return_trace (u.header.apple ? c->dispatch (u.format3, std::forward<Ts> (ds)...) : c->default_return_value ()); +#endif + default: return_trace (c->default_return_value ()); + } + } + + bool sanitize (hb_sanitize_context_t *c) const + { + TRACE_SANITIZE (this); + if (unlikely (!u.header.sanitize (c) || + u.header.length < u.header.min_size || + !c->check_range (this, u.header.length))) return_trace (false); + + return_trace (dispatch (c)); + } + + public: + union { + KernSubTableHeader header; + AAT::KerxSubTableFormat0<KernSubTableHeader> format0; + AAT::KerxSubTableFormat1<KernSubTableHeader> format1; + AAT::KerxSubTableFormat2<KernSubTableHeader> format2; + KernSubTableFormat3<KernSubTableHeader> format3; + } u; + public: + DEFINE_SIZE_MIN (KernSubTableHeader::static_size); +}; + + +struct KernOTSubTableHeader +{ + static constexpr bool apple = false; + typedef AAT::ObsoleteTypes Types; + + unsigned tuple_count () const { return 0; } + bool is_horizontal () const { return (coverage & Horizontal); } + + enum Coverage + { + Horizontal = 0x01u, + Minimum = 0x02u, + CrossStream = 0x04u, + Override = 0x08u, + + /* Not supported: */ + Backwards = 0x00u, + Variation = 0x00u, + }; + + bool sanitize (hb_sanitize_context_t *c) const + { + TRACE_SANITIZE (this); + return_trace (c->check_struct (this)); + } + + public: + HBUINT16 versionZ; /* Unused. */ + HBUINT16 length; /* Length of the subtable (including this header). */ + HBUINT8 format; /* Subtable format. */ + HBUINT8 coverage; /* Coverage bits. */ + public: + DEFINE_SIZE_STATIC (6); +}; + +struct KernOT : AAT::KerxTable<KernOT> +{ + friend struct AAT::KerxTable<KernOT>; + + static constexpr hb_tag_t tableTag = HB_OT_TAG_kern; + static constexpr unsigned minVersion = 0u; + + typedef KernOTSubTableHeader SubTableHeader; + typedef SubTableHeader::Types Types; + typedef KernSubTable<SubTableHeader> SubTable; + + protected: + HBUINT16 version; /* Version--0x0000u */ + HBUINT16 tableCount; /* Number of subtables in the kerning table. */ + SubTable firstSubTable; /* Subtables. */ + public: + DEFINE_SIZE_MIN (4); +}; + + +struct KernAATSubTableHeader +{ + static constexpr bool apple = true; + typedef AAT::ObsoleteTypes Types; + + unsigned tuple_count () const { return 0; } + bool is_horizontal () const { return !(coverage & Vertical); } + + enum Coverage + { + Vertical = 0x80u, + CrossStream = 0x40u, + Variation = 0x20u, + + /* Not supported: */ + Backwards = 0x00u, + }; + + bool sanitize (hb_sanitize_context_t *c) const + { + TRACE_SANITIZE (this); + return_trace (c->check_struct (this)); + } + + public: + HBUINT32 length; /* Length of the subtable (including this header). */ + HBUINT8 coverage; /* Coverage bits. */ + HBUINT8 format; /* Subtable format. */ + HBUINT16 tupleIndex; /* The tuple index (used for variations fonts). + * This value specifies which tuple this subtable covers. + * Note: We don't implement. */ + public: + DEFINE_SIZE_STATIC (8); +}; + +struct KernAAT : AAT::KerxTable<KernAAT> +{ + friend struct AAT::KerxTable<KernAAT>; + + static constexpr hb_tag_t tableTag = HB_OT_TAG_kern; + static constexpr unsigned minVersion = 0x00010000u; + + typedef KernAATSubTableHeader SubTableHeader; + typedef SubTableHeader::Types Types; + typedef KernSubTable<SubTableHeader> SubTable; + + protected: + HBUINT32 version; /* Version--0x00010000u */ + HBUINT32 tableCount; /* Number of subtables in the kerning table. */ + SubTable firstSubTable; /* Subtables. */ + public: + DEFINE_SIZE_MIN (8); +}; + +struct kern +{ + static constexpr hb_tag_t tableTag = HB_OT_TAG_kern; + + bool has_data () const { return u.version32; } + unsigned get_type () const { return u.major; } + + bool has_state_machine () const + { + switch (get_type ()) { + case 0: return u.ot.has_state_machine (); +#ifndef HB_NO_AAT_SHAPE + case 1: return u.aat.has_state_machine (); +#endif + default:return false; + } + } + + bool has_cross_stream () const + { + switch (get_type ()) { + case 0: return u.ot.has_cross_stream (); +#ifndef HB_NO_AAT_SHAPE + case 1: return u.aat.has_cross_stream (); +#endif + default:return false; + } + } + + int get_h_kerning (hb_codepoint_t left, hb_codepoint_t right) const + { + switch (get_type ()) { + case 0: return u.ot.get_h_kerning (left, right); +#ifndef HB_NO_AAT_SHAPE + case 1: return u.aat.get_h_kerning (left, right); +#endif + default:return 0; + } + } + + bool apply (AAT::hb_aat_apply_context_t *c) const + { return dispatch (c); } + + template <typename context_t, typename ...Ts> + typename context_t::return_t dispatch (context_t *c, Ts&&... ds) const + { + unsigned int subtable_type = get_type (); + TRACE_DISPATCH (this, subtable_type); + switch (subtable_type) { + case 0: return_trace (c->dispatch (u.ot, std::forward<Ts> (ds)...)); +#ifndef HB_NO_AAT_SHAPE + case 1: return_trace (c->dispatch (u.aat, std::forward<Ts> (ds)...)); +#endif + default: return_trace (c->default_return_value ()); + } + } + + bool sanitize (hb_sanitize_context_t *c) const + { + TRACE_SANITIZE (this); + if (!u.version32.sanitize (c)) return_trace (false); + return_trace (dispatch (c)); + } + + protected: + union { + HBUINT32 version32; + HBUINT16 major; + KernOT ot; +#ifndef HB_NO_AAT_SHAPE + KernAAT aat; +#endif + } u; + public: + DEFINE_SIZE_UNION (4, version32); +}; + +} /* namespace OT */ + + +#endif /* HB_OT_KERN_TABLE_HH */ |