[ot-font] Implement glyph_extents() for TrueType fonts This brings ot-fonts into almost-complete shape and mostly in par with ft font.
diff --git a/src/Makefile.am b/src/Makefile.am index 856aae6..5699782 100644 --- a/src/Makefile.am +++ b/src/Makefile.am
@@ -41,6 +41,7 @@ hb-open-file-private.hh \ hb-open-type-private.hh \ hb-ot-cmap-table.hh \ + hb-ot-glyf-table.hh \ hb-ot-head-table.hh \ hb-ot-hhea-table.hh \ hb-ot-hmtx-table.hh \
diff --git a/src/hb-font.h b/src/hb-font.h index cf22589..5d28b8f 100644 --- a/src/hb-font.h +++ b/src/hb-font.h
@@ -80,12 +80,13 @@ /* glyph extents */ +/* Note that height is negative in coordinate systems that grow up. */ typedef struct hb_glyph_extents_t { - hb_position_t x_bearing; - hb_position_t y_bearing; - hb_position_t width; - hb_position_t height; + hb_position_t x_bearing; /* left side of glyph from origin. */ + hb_position_t y_bearing; /* top side of glyph from origin. */ + hb_position_t width; /* distance from left to right side. */ + hb_position_t height; /* distance from top to bottom side. */ } hb_glyph_extents_t;
diff --git a/src/hb-ot-font.cc b/src/hb-ot-font.cc index df6514d..f5bf6cc 100644 --- a/src/hb-ot-font.cc +++ b/src/hb-ot-font.cc
@@ -31,6 +31,8 @@ #include "hb-font-private.hh" #include "hb-ot-cmap-table.hh" +#include "hb-ot-glyf-table.hh" +#include "hb-ot-head-table.hh" #include "hb-ot-hhea-table.hh" #include "hb-ot-hmtx-table.hh" @@ -76,8 +78,8 @@ if (unlikely (glyph >= this->num_metrics)) { /* If this->num_metrics is zero, it means we don't have the metrics table - * for this direction: return one EM. Otherwise, it means that the glyph - * index is out of bound: return zero. */ + * for this direction: return default advance. Otherwise, it means that the + * glyph index is out of bound: return zero. */ if (this->num_metrics) return 0; else @@ -91,6 +93,79 @@ } }; +struct hb_ot_face_glyf_accelerator_t +{ + bool short_offset; + unsigned int num_glyphs; + const OT::loca *loca; + const OT::glyf *glyf; + hb_blob_t *loca_blob; + hb_blob_t *glyf_blob; + unsigned int glyf_len; + + inline void init (hb_face_t *face) + { + hb_blob_t *head_blob = OT::Sanitizer<OT::head>::sanitize (face->reference_table (HB_OT_TAG_head)); + const OT::head *head = OT::Sanitizer<OT::head>::lock_instance (head_blob); + if ((unsigned int) head->indexToLocFormat > 1 || head->glyphDataFormat != 0) + { + /* Unknown format. Leave num_glyphs=0, that takes care of disabling us. */ + hb_blob_destroy (head_blob); + return; + } + this->short_offset = 0 == head->indexToLocFormat; + hb_blob_destroy (head_blob); + + this->loca_blob = OT::Sanitizer<OT::loca>::sanitize (face->reference_table (HB_OT_TAG_loca)); + this->loca = OT::Sanitizer<OT::loca>::lock_instance (this->loca_blob); + this->glyf_blob = OT::Sanitizer<OT::glyf>::sanitize (face->reference_table (HB_OT_TAG_glyf)); + this->glyf = OT::Sanitizer<OT::glyf>::lock_instance (this->glyf_blob); + + this->num_glyphs = MAX (1u, hb_blob_get_length (this->loca_blob) / (this->short_offset ? 2 : 4)) - 1; + this->glyf_len = hb_blob_get_length (this->glyf_blob); + } + + inline void fini (void) + { + hb_blob_destroy (this->loca_blob); + hb_blob_destroy (this->glyf_blob); + } + + inline bool get_extents (hb_codepoint_t glyph, + hb_glyph_extents_t *extents) const + { + if (unlikely (glyph >= this->num_glyphs)) + return false; + + unsigned int start_offset, end_offset; + if (this->short_offset) + { + start_offset = this->loca->u.shortsZ[glyph]; + end_offset = this->loca->u.shortsZ[glyph + 1]; + } + else + { + start_offset = this->loca->u.longsZ[glyph]; + end_offset = this->loca->u.longsZ[glyph + 1]; + } + + if (start_offset > end_offset || end_offset > this->glyf_len) + return false; + + if (end_offset - start_offset < OT::glyfGlyphHeader::static_size) + return true; /* Empty glyph; zero extents. */ + + const OT::glyfGlyphHeader &glyph_header = OT::StructAtOffset<OT::glyfGlyphHeader> (this->glyf, start_offset); + + extents->x_bearing = MIN (glyph_header.xMin, glyph_header.xMax); + extents->y_bearing = MAX (glyph_header.yMin, glyph_header.yMax); + extents->width = MAX (glyph_header.xMin, glyph_header.xMax) - extents->x_bearing; + extents->height = MIN (glyph_header.yMin, glyph_header.yMax) - extents->y_bearing; + + return true; + } +}; + struct hb_ot_face_cmap_accelerator_t { const OT::CmapSubtable *table; @@ -158,6 +233,7 @@ hb_ot_face_cmap_accelerator_t cmap; hb_ot_face_metrics_accelerator_t h_metrics; hb_ot_face_metrics_accelerator_t v_metrics; + hb_ot_face_glyf_accelerator_t glyf; }; @@ -175,6 +251,7 @@ ot_font->cmap.init (face); ot_font->h_metrics.init (face, HB_OT_TAG_hhea, HB_OT_TAG_hmtx, upem>>1); ot_font->v_metrics.init (face, HB_OT_TAG_vhea, HB_OT_TAG_vmtx, upem); /* TODO Can we do this lazily? */ + ot_font->glyf.init (face); return ot_font; } @@ -276,8 +353,13 @@ hb_glyph_extents_t *extents, void *user_data HB_UNUSED) { - /* TODO */ - return false; + const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data; + bool ret = ot_font->glyf.get_extents (glyph, extents); + extents->x_bearing = font->em_scale_x (extents->x_bearing); + extents->y_bearing = font->em_scale_y (extents->y_bearing); + extents->width = font->em_scale_x (extents->width); + extents->height = font->em_scale_y (extents->height); + return ret; } static hb_bool_t
diff --git a/src/hb-ot-glyf-table.hh b/src/hb-ot-glyf-table.hh new file mode 100644 index 0000000..40b54fd --- /dev/null +++ b/src/hb-ot-glyf-table.hh
@@ -0,0 +1,104 @@ +/* + * Copyright © 2015 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_GLYF_TABLE_HH +#define HB_OT_GLYF_TABLE_HH + +#include "hb-open-type-private.hh" + + +namespace OT { + + +/* + * loca -- Index to Location + */ + +#define HB_OT_TAG_loca HB_TAG('l','o','c','a') + + +struct loca +{ + static const hb_tag_t tableTag = HB_OT_TAG_loca; + + inline bool sanitize (hb_sanitize_context_t *c) const + { + TRACE_SANITIZE (this); + return TRACE_RETURN (true); + } + + public: + union { + USHORT shortsZ[VAR]; /* Location offset divided by 2. */ + ULONG longsZ[VAR]; /* Location offset. */ + } u; + DEFINE_SIZE_ARRAY (0, u.longsZ); +}; + + +/* + * glyf -- TrueType Glyph Data + */ + +#define HB_OT_TAG_glyf HB_TAG('g','l','y','f') + + +struct glyf +{ + static const hb_tag_t tableTag = HB_OT_TAG_glyf; + + inline bool sanitize (hb_sanitize_context_t *c) const + { + TRACE_SANITIZE (this); + /* We don't check for anything specific here. The users of the + * struct do all the hard work... */ + return TRACE_RETURN (true); + } + + public: + BYTE dataX[VAR]; /* Glyphs data. */ + + DEFINE_SIZE_ARRAY (0, dataX); +}; + +struct glyfGlyphHeader +{ + SHORT numberOfContours; /* If the number of contours is + * greater than or equal to zero, + * this is a simple glyph; if negative, + * this is a composite glyph. */ + SHORT xMin; /* Minimum x for coordinate data. */ + SHORT yMin; /* Minimum y for coordinate data. */ + SHORT xMax; /* Maximum x for coordinate data. */ + SHORT yMax; /* Maximum y for coordinate data. */ + + DEFINE_SIZE_STATIC (10); +}; + +} /* namespace OT */ + + +#endif /* HB_OT_GLYF_TABLE_HH */
diff --git a/src/hb-ot-head-table.hh b/src/hb-ot-head-table.hh index 268f133..157961c 100644 --- a/src/hb-ot-head-table.hh +++ b/src/hb-ot-head-table.hh
@@ -138,9 +138,10 @@ * 2: Like 1 but also contains neutrals; * -1: Only strongly right to left; * -2: Like -1 but also contains neutrals. */ + public: SHORT indexToLocFormat; /* 0 for short offsets, 1 for long. */ SHORT glyphDataFormat; /* 0 for current format. */ - public: + DEFINE_SIZE_STATIC (54); };