SkShaper::SkShaper(sk_sp<SkTypeface> tf) : fImpl(new Impl) {
fImpl->fTypeface = tf ? std::move(tf) : SkTypeface::MakeDefault();
int index;
std::unique_ptr<SkStreamAsset> asset(fImpl->fTypeface->openStream(&index));
size_t size = asset->getLength();
SkAutoMalloc autoMalloc(size); // TODO(halcanary): Avoid this malloc+copy.
asset->read(autoMalloc.get(), size);
asset = nullptr;
void* ptr = autoMalloc.get();
hb_blob_t* blob = hb_blob_create((char*)autoMalloc.release(), size,
HB_MEMORY_MODE_READONLY, ptr, sk_free);
SkASSERT(blob);
hb_blob_make_immutable(blob);
struct HBFaceDel {
void operator()(hb_face_t* f) { hb_face_destroy(f); }
};
std::unique_ptr<hb_face_t, HBFaceDel> face(hb_face_create(blob, (unsigned)index));
hb_blob_destroy(blob);
SkASSERT(face);
if (!face) {
return;
}
hb_face_set_index(face.get(), (unsigned)index);
hb_face_set_upem(face.get(), fImpl->fTypeface->getUnitsPerEm());
fImpl->fHarfBuzzFont.reset(hb_font_create(face.get()));
SkASSERT(fImpl->fHarfBuzzFont);
hb_font_set_scale(fImpl->fHarfBuzzFont.get(), FONT_SIZE_SCALE, FONT_SIZE_SCALE);
hb_ot_font_set_funcs(fImpl->fHarfBuzzFont.get());
fImpl->fBuffer.reset(hb_buffer_create());
}
void* ScFace::ScFaceData::hbFont()
{
if (!m_hbFont)
{
if (!ftFace())
return NULL;
if (formatCode == ScFace::SFNT || formatCode == ScFace::TTCF || formatCode == ScFace::TYPE42)
{
// use HarfBuzz internal font functions for formats it supports,
// gives us more consistent glyph metrics.
FT_Reference_Face(ftFace());
hb_face_t *hbFace = hb_face_create_for_tables(referenceTable, ftFace(), (hb_destroy_func_t) FT_Done_Face);
hb_face_set_index(hbFace, ftFace()->face_index);
hb_face_set_upem(hbFace, ftFace()->units_per_EM);
m_hbFont = hb_font_create(hbFace);
hb_ot_font_set_funcs(reinterpret_cast<hb_font_t*>(m_hbFont));
hb_face_destroy(hbFace);
}
else
{
m_hbFont = hb_ft_font_create_referenced(ftFace());
}
}
return m_hbFont;
}
int shape (lua_State *L) {
size_t font_l;
const char * text = luaL_checkstring(L, 1);
const char * font_s = luaL_checklstring(L, 2, &font_l);
unsigned int font_index = luaL_checknumber(L, 3);
const char * script = luaL_checkstring(L, 4);
const char * direction_s = luaL_checkstring(L, 5);
const char * lang = luaL_checkstring(L, 6);
double point_size = luaL_checknumber(L, 7);
const char * featurestring = luaL_checkstring(L, 8);
hb_segment_properties_t segment_props;
hb_shape_plan_t *shape_plan;
hb_direction_t direction;
hb_feature_t* features;
int nFeatures = 0;
unsigned int glyph_count = 0;
hb_font_t *hbFont;
hb_buffer_t *buf;
hb_glyph_info_t *glyph_info;
hb_glyph_position_t *glyph_pos;
unsigned int j;
features = scan_feature_string(featurestring, &nFeatures);
if (!strcasecmp(direction_s,"RTL"))
direction = HB_DIRECTION_RTL;
else if (!strcasecmp(direction_s,"TTB"))
direction = HB_DIRECTION_TTB;
else
direction = HB_DIRECTION_LTR;
hb_blob_t* blob = hb_blob_create (font_s, font_l, HB_MEMORY_MODE_WRITABLE, (void*)font_s, NULL);
hb_face_t* hbFace = hb_face_create (blob, font_index);
hbFont = hb_font_create (hbFace);
unsigned int upem = hb_face_get_upem(hbFace);
hb_font_set_scale(hbFont, upem, upem);
/* Harfbuzz's support for OT fonts is great, but
there's currently no support for CFF fonts, so
downgrade to Freetype for those. */
if (strncmp(font_s, "OTTO", 4) == 0) {
hb_ft_font_set_funcs(hbFont);
} else {
hb_ot_font_set_funcs(hbFont);
}
buf = hb_buffer_create();
hb_buffer_add_utf8(buf, text, strlen(text), 0, strlen(text));
hb_buffer_set_script(buf, hb_tag_from_string(script, strlen(script)));
hb_buffer_set_direction(buf, direction);
hb_buffer_set_language(buf, hb_language_from_string(lang,strlen(lang)));
hb_buffer_guess_segment_properties(buf);
hb_buffer_get_segment_properties(buf, &segment_props);
shape_plan = hb_shape_plan_create_cached(hbFace, &segment_props, features, nFeatures, NULL);
int res = hb_shape_plan_execute(shape_plan, hbFont, buf, features, nFeatures);
if (direction == HB_DIRECTION_RTL) {
hb_buffer_reverse(buf); /* URGH */
}
glyph_info = hb_buffer_get_glyph_infos(buf, &glyph_count);
glyph_pos = hb_buffer_get_glyph_positions(buf, &glyph_count);
lua_checkstack(L, glyph_count);
for (j = 0; j < glyph_count; ++j) {
char namebuf[255];
hb_glyph_extents_t extents = {0,0,0,0};
hb_font_get_glyph_extents(hbFont, glyph_info[j].codepoint, &extents);
lua_newtable(L);
lua_pushstring(L, "name");
hb_font_get_glyph_name( hbFont, glyph_info[j].codepoint, namebuf, 255 );
lua_pushstring(L, namebuf);
lua_settable(L, -3);
/* We don't apply x-offset and y-offsets for TTB, which
is arguably a bug. We should. The reason we don't is that
Harfbuzz assumes that you want to shift the character from a
top-center baseline to a bottom-left baseline, and gives you
offsets which do that. We don't want to do that so we ignore the
offsets. I'm told there is a way of configuring HB's idea of the
baseline, and we should use that and take out this condition. */
if (direction != HB_DIRECTION_TTB) {
if (glyph_pos[j].x_offset) {
lua_pushstring(L, "x_offset");
lua_pushnumber(L, glyph_pos[j].x_offset * point_size / upem);
lua_settable(L, -3);
}
if (glyph_pos[j].y_offset) {
lua_pushstring(L, "y_offset");
lua_pushnumber(L, glyph_pos[j].y_offset * point_size / upem);
lua_settable(L, -3);
}
}
lua_pushstring(L, "codepoint");
lua_pushinteger(L, glyph_info[j].codepoint);
lua_settable(L, -3);
lua_pushstring(L, "index");
lua_pushinteger(L, glyph_info[j].cluster);
lua_settable(L, -3);
double height = extents.y_bearing * point_size / upem;
double tHeight = extents.height * point_size / upem;
double width = glyph_pos[j].x_advance * point_size / upem;
/* The PDF model expects us to make positioning adjustments
after a glyph is painted. For this we need to know the natural
glyph advance. libtexpdf will use this to compute the adjustment. */
double glyphAdvance = hb_font_get_glyph_h_advance(hbFont, glyph_info[j].codepoint) * point_size / upem;
if (direction == HB_DIRECTION_TTB) {
height = -glyph_pos[j].y_advance * point_size / upem;
tHeight = -height; /* Set depth to 0 - depth has no meaning for TTB */
width = glyphAdvance;
glyphAdvance = height;
}
lua_pushstring(L, "glyphAdvance");
lua_pushnumber(L, glyphAdvance);
lua_settable(L, -3);
lua_pushstring(L, "width");
lua_pushnumber(L, width);
lua_settable(L, -3);
lua_pushstring(L, "height");
lua_pushnumber(L, height);
lua_settable(L, -3);
lua_pushstring(L, "depth");
lua_pushnumber(L, -tHeight - height);
lua_settable(L, -3);
}
/* Cleanup */
hb_buffer_destroy(buf);
hb_font_destroy(hbFont);
hb_shape_plan_destroy(shape_plan);
free(features);
return glyph_count;
}