153 lines
4.1 KiB
C++
153 lines
4.1 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_OT_VAR_AVAR_TABLE_HH
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#define HB_OT_VAR_AVAR_TABLE_HH
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#include "hb-open-type.hh"
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/*
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* avar -- Axis Variations
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* https://docs.microsoft.com/en-us/typography/opentype/spec/avar
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*/
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#define HB_OT_TAG_avar HB_TAG('a','v','a','r')
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namespace OT {
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struct AxisValueMap
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{
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bool sanitize (hb_sanitize_context_t *c) const
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{
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TRACE_SANITIZE (this);
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return_trace (c->check_struct (this));
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}
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public:
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F2DOT14 fromCoord; /* A normalized coordinate value obtained using
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* default normalization. */
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F2DOT14 toCoord; /* The modified, normalized coordinate value. */
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public:
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DEFINE_SIZE_STATIC (4);
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};
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struct SegmentMaps : ArrayOf<AxisValueMap>
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{
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int map (int value) const
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{
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/* The following special-cases are not part of OpenType, which requires
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* that at least -1, 0, and +1 must be mapped. But we include these as
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* part of a better error recovery scheme. */
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if (len < 2)
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{
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if (!len)
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return value;
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else /* len == 1*/
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return value - arrayZ[0].fromCoord + arrayZ[0].toCoord;
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}
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if (value <= arrayZ[0].fromCoord)
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return value - arrayZ[0].fromCoord + arrayZ[0].toCoord;
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unsigned int i;
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unsigned int count = len;
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for (i = 1; i < count && value > arrayZ[i].fromCoord; i++)
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;
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if (value >= arrayZ[i].fromCoord)
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return value - arrayZ[i].fromCoord + arrayZ[i].toCoord;
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if (unlikely (arrayZ[i-1].fromCoord == arrayZ[i].fromCoord))
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return arrayZ[i-1].toCoord;
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int denom = arrayZ[i].fromCoord - arrayZ[i-1].fromCoord;
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return arrayZ[i-1].toCoord +
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((arrayZ[i].toCoord - arrayZ[i-1].toCoord) *
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(value - arrayZ[i-1].fromCoord) + denom/2) / denom;
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}
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public:
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DEFINE_SIZE_ARRAY (2, *this);
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};
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struct avar
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{
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static constexpr hb_tag_t tableTag = HB_OT_TAG_avar;
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bool sanitize (hb_sanitize_context_t *c) const
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{
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TRACE_SANITIZE (this);
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if (unlikely (!(version.sanitize (c) &&
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version.major == 1 &&
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c->check_struct (this))))
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return_trace (false);
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const SegmentMaps *map = &firstAxisSegmentMaps;
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unsigned int count = axisCount;
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for (unsigned int i = 0; i < count; i++)
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{
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if (unlikely (!map->sanitize (c)))
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return_trace (false);
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map = &StructAfter<SegmentMaps> (*map);
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}
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return_trace (true);
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}
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void map_coords (int *coords, unsigned int coords_length) const
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{
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unsigned int count = hb_min (coords_length, axisCount);
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const SegmentMaps *map = &firstAxisSegmentMaps;
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for (unsigned int i = 0; i < count; i++)
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{
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coords[i] = map->map (coords[i]);
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map = &StructAfter<SegmentMaps> (*map);
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}
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}
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protected:
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FixedVersion<>version; /* Version of the avar table
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* initially set to 0x00010000u */
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HBUINT16 reserved; /* This field is permanently reserved. Set to 0. */
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HBUINT16 axisCount; /* The number of variation axes in the font. This
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* must be the same number as axisCount in the
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* 'fvar' table. */
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SegmentMaps firstAxisSegmentMaps;
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public:
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DEFINE_SIZE_MIN (8);
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};
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} /* namespace OT */
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#endif /* HB_OT_VAR_AVAR_TABLE_HH */
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