/*
* Copyright © 2018 Ebrahim Byagowi
* Copyright © 2020 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): Calder Kitagawa
*/
#ifndef OT_COLOR_SBIX_SBIX_HH
#define OT_COLOR_SBIX_SBIX_HH
#include "../../../hb-open-type.hh"
#include "../../../hb-paint.hh"
/*
* sbix -- Standard Bitmap Graphics
* https://docs.microsoft.com/en-us/typography/opentype/spec/sbix
* https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6sbix.html
*/
#define HB_OT_TAG_sbix HB_TAG('s','b','i','x')
namespace OT {
struct SBIXGlyph
{
SBIXGlyph* copy (hb_serialize_context_t *c, unsigned int data_length) const
{
TRACE_SERIALIZE (this);
SBIXGlyph* new_glyph = c->start_embed<SBIXGlyph> ();
if (unlikely (!c->extend_min (new_glyph))) return_trace (nullptr);
new_glyph->xOffset = xOffset;
new_glyph->yOffset = yOffset;
new_glyph->graphicType = graphicType;
data.copy (c, data_length);
return_trace (new_glyph);
}
HBINT16 xOffset; /* The horizontal (x-axis) offset from the left
* edge of the graphic to the glyph’s origin.
* That is, the x-coordinate of the point on the
* baseline at the left edge of the glyph. */
HBINT16 yOffset; /* The vertical (y-axis) offset from the bottom
* edge of the graphic to the glyph’s origin.
* That is, the y-coordinate of the point on the
* baseline at the left edge of the glyph. */
Tag graphicType; /* Indicates the format of the embedded graphic
* data: one of 'jpg ', 'png ' or 'tiff', or the
* special format 'dupe'. */
UnsizedArrayOf<HBUINT8>
data; /* The actual embedded graphic data. The total
* length is inferred from sequential entries in
* the glyphDataOffsets array and the fixed size
* (8 bytes) of the preceding fields. */
public:
DEFINE_SIZE_ARRAY (8, data);
};
struct SBIXStrike
{
static unsigned int get_size (unsigned num_glyphs)
{ return min_size + num_glyphs * HBUINT32::static_size; }
bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this) &&
imageOffsetsZ.sanitize_shallow (c, c->get_num_glyphs () + 1));
}
hb_blob_t *get_glyph_blob (unsigned int glyph_id,
hb_blob_t *sbix_blob,
hb_tag_t file_type,
int *x_offset,
int *y_offset,
unsigned int num_glyphs,
unsigned int *strike_ppem) const
{
if (unlikely (!ppem)) return hb_blob_get_empty (); /* To get Null() object out of the way. */
unsigned int retry_count = 8;
unsigned int sbix_len = sbix_blob->length;
unsigned int strike_offset = (const char *) this - (const char *) sbix_blob->data;
assert (strike_offset < sbix_len);
retry:
if (unlikely (glyph_id >= num_glyphs ||
imageOffsetsZ[glyph_id + 1] <= imageOffsetsZ[glyph_id] ||
imageOffsetsZ[glyph_id + 1] - imageOffsetsZ[glyph_id] <= SBIXGlyph::min_size ||
(unsigned int) imageOffsetsZ[glyph_id + 1] > sbix_len - strike_offset))
return hb_blob_get_empty ();
unsigned int glyph_offset = strike_offset + (unsigned int) imageOffsetsZ[glyph_id] + SBIXGlyph::min_size;
unsigned int glyph_length = imageOffsetsZ[glyph_id + 1] - imageOffsetsZ[glyph_id] - SBIXGlyph::min_size;
const SBIXGlyph *glyph = &(this+imageOffsetsZ[glyph_id]);
if (glyph->graphicType == HB_TAG ('d','u','p','e'))
{
if (glyph_length >= 2)
{
glyph_id = *((HBUINT16 *) &glyph->data);
if (retry_count--)
goto retry;
}
return hb_blob_get_empty ();
}
if (unlikely (file_type != glyph->graphicType))
return hb_blob_get_empty ();
if (strike_ppem) *strike_ppem = ppem;
if (x_offset) *x_offset = glyph->xOffset;
if (y_offset) *y_offset = glyph->yOffset;
return hb_blob_create_sub_blob (sbix_blob, glyph_offset, glyph_length);
}
bool subset (hb_subset_context_t *c, unsigned int available_len) const
{
TRACE_SUBSET (this);
unsigned int num_output_glyphs = c->plan->num_output_glyphs ();
auto* out = c->serializer->start_embed<SBIXStrike> ();
auto snap = c->serializer->snapshot ();
if (unlikely (!c->serializer->extend (out, num_output_glyphs + 1))) return_trace (false);
out->ppem = ppem;
out->resolution = resolution;
HBUINT32 head;
head = get_size (num_output_glyphs + 1);
bool has_glyphs = false;
for (unsigned new_gid = 0; new_gid < num_output_glyphs; new_gid++)
{
hb_codepoint_t old_gid;
if (!c->plan->old_gid_for_new_gid (new_gid, &old_gid) ||
unlikely (imageOffsetsZ[old_gid].is_null () ||
imageOffsetsZ[old_gid + 1].is_null () ||
imageOffsetsZ[old_gid + 1] <= imageOffsetsZ[old_gid] ||
imageOffsetsZ[old_gid + 1] - imageOffsetsZ[old_gid] <= SBIXGlyph::min_size) ||
(unsigned int) imageOffsetsZ[old_gid + 1] > available_len)
{
out->imageOffsetsZ[new_gid] = head;
continue;
}
has_glyphs = true;
unsigned int delta = imageOffsetsZ[old_gid + 1] - imageOffsetsZ[old_gid];
unsigned int glyph_data_length = delta - SBIXGlyph::min_size;
if (!(this+imageOffsetsZ[old_gid]).copy (c->serializer, glyph_data_length))
return_trace (false);
out->imageOffsetsZ[new_gid] = head;
head += delta;
}
if (has_glyphs)
out->imageOffsetsZ[num_output_glyphs] = head;
else
c->serializer->revert (snap);
return_trace (has_glyphs);
}
public:
HBUINT16 ppem; /* The PPEM size for which this strike was designed. */
HBUINT16 resolution; /* The device pixel density (in PPI) for which this
* strike was designed. (E.g., 96 PPI, 192 PPI.) */
protected:
UnsizedArrayOf<Offset32To<SBIXGlyph>>
imageOffsetsZ; /* Offset from the beginning of the strike data header
* to bitmap data for an individual glyph ID. */
public:
DEFINE_SIZE_ARRAY (4, imageOffsetsZ);
};
struct sbix
{
static constexpr hb_tag_t tableTag = HB_OT_TAG_sbix;
bool has_data () const { return version; }
const SBIXStrike &get_strike (unsigned int i) const { return this+strikes[i]; }
struct accelerator_t
{
accelerator_t (hb_face_t *face)
{
table = hb_sanitize_context_t ().reference_table<sbix> (face);
num_glyphs = face->get_num_glyphs ();
}
~accelerator_t () { table.destroy (); }
bool has_data () const { return table->has_data (); }
bool get_extents (hb_font_t *font,
hb_codepoint_t glyph,
hb_glyph_extents_t *extents,
bool scale = true) const
{
/* We only support PNG right now, and following function checks type. */
return get_png_extents (font, glyph, extents, scale);
}
hb_blob_t *reference_png (hb_font_t *font,
hb_codepoint_t glyph_id,
int *x_offset,
int *y_offset,
unsigned int *available_ppem) const
{
return choose_strike (font).get_glyph_blob (glyph_id, table.get_blob (),
HB_TAG ('p','n','g',' '),
x_offset, y_offset,
num_glyphs, available_ppem);
}
bool paint_glyph (hb_font_t *font, hb_codepoint_t glyph, hb_paint_funcs_t *funcs, void *data) const
{
if (!has_data ())
return false;
int x_offset = 0, y_offset = 0;
unsigned int strike_ppem = 0;
hb_blob_t *blob = reference_png (font, glyph, &x_offset, &y_offset, &strike_ppem);
hb_glyph_extents_t extents;
hb_glyph_extents_t pixel_extents;
if (blob == hb_blob_get_empty ())
return false;
if (!hb_font_get_glyph_extents (font, glyph, &extents))
return false;
if (unlikely (!get_extents (font, glyph, &pixel_extents, false)))
return false;
bool ret = funcs->image (data,
blob,
pixel_extents.width, -pixel_extents.height,
HB_PAINT_IMAGE_FORMAT_PNG,
font->slant_xy,
&extents);
hb_blob_destroy (blob);
return ret;
}
private:
const SBIXStrike &choose_strike (hb_font_t *font) const
{
unsigned count = table->strikes.len;
if (unlikely (!count))
return Null (SBIXStrike);
unsigned int requested_ppem = hb_max (font->x_ppem, font->y_ppem);
if (!requested_ppem)
requested_ppem = 1<<30; /* Choose largest strike. */
/* TODO Add DPI sensitivity as well? */
unsigned int best_i = 0;
unsigned int best_ppem = table->get_strike (0).ppem;
for (unsigned int i = 1; i < count; i++)
{
unsigned int ppem = (table->get_strike (i)).ppem;
if ((requested_ppem <= ppem && ppem < best_ppem) ||
(requested_ppem > best_ppem && ppem > best_ppem))
{
best_i = i;
best_ppem = ppem;
}
}
return table->get_strike (best_i);
}
struct PNGHeader
{
HBUINT8 signature[8];
struct
{
struct
{
HBUINT32 length;
Tag type;
} header;
HBUINT32 width;
HBUINT32 height;
HBUINT8 bitDepth;
HBUINT8 colorType;
HBUINT8 compressionMethod;
HBUINT8 filterMethod;
HBUINT8 interlaceMethod;
} IHDR;
public:
DEFINE_SIZE_STATIC (29);
};
bool get_png_extents (hb_font_t *font,
hb_codepoint_t glyph,
hb_glyph_extents_t *extents,
bool scale = true) const
{
/* Following code is safe to call even without data.
* But faster to short-circuit. */
if (!has_data ())
return false;
int x_offset = 0, y_offset = 0;
unsigned int strike_ppem = 0;
hb_blob_t *blob = reference_png (font, glyph, &x_offset, &y_offset, &strike_ppem);
const PNGHeader &png = *blob->as<PNGHeader>();
if (png.IHDR.height >= 65536 || png.IHDR.width >= 65536)
{
hb_blob_destroy (blob);
return false;
}
extents->x_bearing = x_offset;
extents->y_bearing = png.IHDR.height + y_offset;
extents->width = png.IHDR.width;
extents->height = -1 * png.IHDR.height;
/* Convert to font units. */
if (strike_ppem && scale)
{
float scale = font->face->get_upem () / (float) strike_ppem;
extents->x_bearing = roundf (extents->x_bearing * scale);
extents->y_bearing = roundf (extents->y_bearing * scale);
extents->width = roundf (extents->width * scale);
extents->height = roundf (extents->height * scale);
}
if (scale)
font->scale_glyph_extents (extents);
hb_blob_destroy (blob);
return strike_ppem;
}
private:
hb_blob_ptr_t<sbix> table;
unsigned int num_glyphs;
};
bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (likely (c->check_struct (this) &&
hb_barrier () &&
version >= 1 &&
strikes.sanitize (c, this)));
}
bool
add_strike (hb_subset_context_t *c, unsigned i) const
{
if (strikes[i].is_null () || c->source_blob->length < (unsigned) strikes[i])
return false;
return (this+strikes[i]).subset (c, c->source_blob->length - (unsigned) strikes[i]);
}
bool serialize_strike_offsets (hb_subset_context_t *c) const
{
TRACE_SERIALIZE (this);
auto *out = c->serializer->start_embed<Array32OfOffset32To<SBIXStrike>> ();
if (unlikely (!c->serializer->extend_min (out))) return_trace (false);
hb_vector_t<Offset32To<SBIXStrike>*> new_strikes;
hb_vector_t<hb_serialize_context_t::objidx_t> objidxs;
for (int i = strikes.len - 1; i >= 0; --i)
{
auto* o = out->serialize_append (c->serializer);
if (unlikely (!o)) return_trace (false);
*o = 0;
auto snap = c->serializer->snapshot ();
c->serializer->push ();
bool ret = add_strike (c, i);
if (!ret)
{
c->serializer->pop_discard ();
out->pop ();
c->serializer->revert (snap);
}
else
{
objidxs.push (c->serializer->pop_pack ());
new_strikes.push (o);
}
}
for (unsigned int i = 0; i < new_strikes.length; ++i)
c->serializer->add_link (*new_strikes[i], objidxs[new_strikes.length - 1 - i]);
return_trace (true);
}
bool subset (hb_subset_context_t* c) const
{
TRACE_SUBSET (this);
if (unlikely (!c->serializer->embed (this->version))) return_trace (false);
if (unlikely (!c->serializer->embed (this->flags))) return_trace (false);
return_trace (serialize_strike_offsets (c));
}
protected:
HBUINT16 version; /* Table version number — set to 1 */
HBUINT16 flags; /* Bit 0: Set to 1. Bit 1: Draw outlines.
* Bits 2 to 15: reserved (set to 0). */
Array32OfOffset32To<SBIXStrike>
strikes; /* Offsets from the beginning of the 'sbix'
* table to data for each individual bitmap strike. */
public:
DEFINE_SIZE_ARRAY (8, strikes);
};
struct sbix_accelerator_t : sbix::accelerator_t {
sbix_accelerator_t (hb_face_t *face) : sbix::accelerator_t (face) {}
};
} /* namespace OT */
#endif /* OT_COLOR_SBIX_SBIX_HH */