std::vector<Handler<BitmapGlyph> > FreeType::lookupBitmap(Font& font, float size, std::vector<unsigned int> const& ucs4, float& ascent, float& descent, float& height)
{
Font::RawFaceSession rfs(font);
FT_Face face = rfs.face();
FT_Face face__;
FTC_ScalerRec scaler;
{
scaler.face_id = face;
scaler.width = 0;
scaler.height = FLOAT_TO_26_6( size );
scaler.pixel = 0;
scaler.x_res=72; //XXX
scaler.y_res=72; //XXX
}
FTC_Manager_LookupFace(this->cache_, face, &face__);
{
FT_Size size;
FTC_Manager_LookupSize(this->cache_, &scaler, &size);
ascent = FLOAT_FROM_26_6(size->metrics.ascender);
descent = FLOAT_FROM_26_6(size->metrics.descender);
height = FLOAT_FROM_26_6(size->metrics.height);
}
std::vector<Handler<BitmapGlyph> > ret;
ret.reserve(ucs4.size());
for(unsigned int const& u : ucs4) {
unsigned int const gindex = FTC_CMapCache_Lookup(this->cmap_, face, font.unicodeCharmapIndex(), u);
FT_Glyph glyph;
{
FT_Glyph glyph_orig;
FTC_ImageCache_LookupScaler(this->image_, &scaler, 0, gindex, &glyph_orig, nullptr);
FT_Glyph_Copy(glyph_orig, &glyph);
}
if(glyph->format != FT_GLYPH_FORMAT_BITMAP ) {
FT_Vector_ vec;
vec.x = 0;
vec.y = 0;
FT_Glyph_To_Bitmap(&glyph, FT_RENDER_MODE_NORMAL, &vec, 1);
}
ret.push_back( Handler<BitmapGlyph>(new BitmapGlyph(reinterpret_cast<FT_BitmapGlyph>(glyph))) );
}
return ret;
}
void
gfxFT2LockedFace::GetMetrics(gfxFont::Metrics* aMetrics,
PRUint32* aSpaceGlyph)
{
NS_PRECONDITION(aMetrics != NULL, "aMetrics must not be NULL");
NS_PRECONDITION(aSpaceGlyph != NULL, "aSpaceGlyph must not be NULL");
if (NS_UNLIKELY(!mFace)) {
// No face. This unfortunate situation might happen if the font
// file is (re)moved at the wrong time.
aMetrics->emHeight = mGfxFont->GetStyle()->size;
aMetrics->emAscent = 0.8 * aMetrics->emHeight;
aMetrics->emDescent = 0.2 * aMetrics->emHeight;
aMetrics->maxAscent = aMetrics->emAscent;
aMetrics->maxDescent = aMetrics->maxDescent;
aMetrics->maxHeight = aMetrics->emHeight;
aMetrics->internalLeading = 0.0;
aMetrics->externalLeading = 0.2 * aMetrics->emHeight;
aSpaceGlyph = 0;
aMetrics->spaceWidth = 0.5 * aMetrics->emHeight;
aMetrics->maxAdvance = aMetrics->spaceWidth;
aMetrics->aveCharWidth = aMetrics->spaceWidth;
aMetrics->zeroOrAveCharWidth = aMetrics->spaceWidth;
aMetrics->xHeight = 0.5 * aMetrics->emHeight;
aMetrics->underlineSize = aMetrics->emHeight / 14.0;
aMetrics->underlineOffset = -aMetrics->underlineSize;
aMetrics->strikeoutOffset = 0.25 * aMetrics->emHeight;
aMetrics->strikeoutSize = aMetrics->underlineSize;
aMetrics->superscriptOffset = aMetrics->xHeight;
aMetrics->subscriptOffset = aMetrics->xHeight;
return;
}
const FT_Size_Metrics& ftMetrics = mFace->size->metrics;
gfxFloat emHeight;
// Scale for vertical design metric conversion: pixels per design unit.
gfxFloat yScale;
if (FT_IS_SCALABLE(mFace)) {
// Prefer FT_Size_Metrics::x_scale to x_ppem as x_ppem does not
// have subpixel accuracy.
//
// FT_Size_Metrics::y_scale is in 16.16 fixed point format. Its
// (fractional) value is a factor that converts vertical metrics from
// design units to units of 1/64 pixels, so that the result may be
// interpreted as pixels in 26.6 fixed point format.
yScale = FLOAT_FROM_26_6(FLOAT_FROM_16_16(ftMetrics.y_scale));
emHeight = mFace->units_per_EM * yScale;
} else { // Not scalable.
// FT_Size_Metrics doc says x_scale is "only relevant for scalable
// font formats".
gfxFloat emUnit = mFace->units_per_EM;
emHeight = ftMetrics.y_ppem;
yScale = emHeight / emUnit;
}
TT_OS2 *os2 =
static_cast<TT_OS2*>(FT_Get_Sfnt_Table(mFace, ft_sfnt_os2));
aMetrics->maxAscent = FLOAT_FROM_26_6(ftMetrics.ascender);
aMetrics->maxDescent = -FLOAT_FROM_26_6(ftMetrics.descender);
aMetrics->maxAdvance = FLOAT_FROM_26_6(ftMetrics.max_advance);
gfxFloat lineHeight;
if (os2 && os2->sTypoAscender) {
aMetrics->emAscent = os2->sTypoAscender * yScale;
aMetrics->emDescent = -os2->sTypoDescender * yScale;
FT_Short typoHeight =
os2->sTypoAscender - os2->sTypoDescender + os2->sTypoLineGap;
lineHeight = typoHeight * yScale;
// maxAscent/maxDescent get used for frame heights, and some fonts
// don't have the HHEA table ascent/descent set (bug 279032).
if (aMetrics->emAscent > aMetrics->maxAscent)
aMetrics->maxAscent = aMetrics->emAscent;
if (aMetrics->emDescent > aMetrics->maxDescent)
aMetrics->maxDescent = aMetrics->emDescent;
} else {
aMetrics->emAscent = aMetrics->maxAscent;
aMetrics->emDescent = aMetrics->maxDescent;
lineHeight = FLOAT_FROM_26_6(ftMetrics.height);
}
cairo_text_extents_t extents;
*aSpaceGlyph = GetCharExtents(' ', &extents);
if (*aSpaceGlyph) {
aMetrics->spaceWidth = extents.x_advance;
} else {
aMetrics->spaceWidth = aMetrics->maxAdvance; // guess
}
aMetrics->zeroOrAveCharWidth = 0.0;
if (GetCharExtents('0', &extents)) {
aMetrics->zeroOrAveCharWidth = extents.x_advance;
}
// Prefering a measured x over sxHeight because sxHeight doesn't consider
// hinting, but maybe the x extents are not quite right in some fancy
// script fonts. CSS 2.1 suggests possibly using the height of an "o",
// which would have a more consistent glyph across fonts.
if (GetCharExtents('x', &extents) && extents.y_bearing < 0.0) {
aMetrics->xHeight = -extents.y_bearing;
aMetrics->aveCharWidth = extents.x_advance;
} else {
if (os2 && os2->sxHeight) {
aMetrics->xHeight = os2->sxHeight * yScale;
} else {
// CSS 2.1, section 4.3.2 Lengths: "In the cases where it is
// impossible or impractical to determine the x-height, a value of
// 0.5em should be used."
aMetrics->xHeight = 0.5 * emHeight;
}
aMetrics->aveCharWidth = 0.0; // updated below
}
// aveCharWidth is used for the width of text input elements so be
// liberal rather than conservative in the estimate.
if (os2 && os2->xAvgCharWidth) {
// Round to pixels as this is compared with maxAdvance to guess
// whether this is a fixed width font.
gfxFloat avgCharWidth =
ScaleRoundDesignUnits(os2->xAvgCharWidth, ftMetrics.x_scale);
aMetrics->aveCharWidth =
NS_MAX(aMetrics->aveCharWidth, avgCharWidth);
}
aMetrics->aveCharWidth =
NS_MAX(aMetrics->aveCharWidth, aMetrics->zeroOrAveCharWidth);
if (aMetrics->aveCharWidth == 0.0) {
aMetrics->aveCharWidth = aMetrics->spaceWidth;
}
if (aMetrics->zeroOrAveCharWidth == 0.0) {
aMetrics->zeroOrAveCharWidth = aMetrics->aveCharWidth;
}
// Apparently hinting can mean that max_advance is not always accurate.
aMetrics->maxAdvance =
NS_MAX(aMetrics->maxAdvance, aMetrics->aveCharWidth);
// gfxFont::Metrics::underlineOffset is the position of the top of the
// underline.
//
// FT_FaceRec documentation describes underline_position as "the
// center of the underlining stem". This was the original definition
// of the PostScript metric, but in the PostScript table of OpenType
// fonts the metric is "the top of the underline"
// (http://www.microsoft.com/typography/otspec/post.htm), and FreeType
// (up to version 2.3.7) doesn't make any adjustment.
//
// Therefore get the underline position directly from the table
// ourselves when this table exists. Use FreeType's metrics for
// other (including older PostScript) fonts.
if (mFace->underline_position && mFace->underline_thickness) {
aMetrics->underlineSize = mFace->underline_thickness * yScale;
TT_Postscript *post = static_cast<TT_Postscript*>
(FT_Get_Sfnt_Table(mFace, ft_sfnt_post));
if (post && post->underlinePosition) {
aMetrics->underlineOffset = post->underlinePosition * yScale;
} else {
aMetrics->underlineOffset = mFace->underline_position * yScale
+ 0.5 * aMetrics->underlineSize;
}
} else { // No underline info.
// Imitate Pango.
aMetrics->underlineSize = emHeight / 14.0;
aMetrics->underlineOffset = -aMetrics->underlineSize;
}
if (os2 && os2->yStrikeoutSize && os2->yStrikeoutPosition) {
aMetrics->strikeoutSize = os2->yStrikeoutSize * yScale;
aMetrics->strikeoutOffset = os2->yStrikeoutPosition * yScale;
} else { // No strikeout info.
aMetrics->strikeoutSize = aMetrics->underlineSize;
// Use OpenType spec's suggested position for Roman font.
aMetrics->strikeoutOffset = emHeight * 409.0 / 2048.0
+ 0.5 * aMetrics->strikeoutSize;
}
SnapLineToPixels(aMetrics->strikeoutOffset, aMetrics->strikeoutSize);
if (os2 && os2->ySuperscriptYOffset) {
gfxFloat val = ScaleRoundDesignUnits(os2->ySuperscriptYOffset,
ftMetrics.y_scale);
aMetrics->superscriptOffset = NS_MAX(1.0, val);
} else {
aMetrics->superscriptOffset = aMetrics->xHeight;
}
if (os2 && os2->ySubscriptYOffset) {
gfxFloat val = ScaleRoundDesignUnits(os2->ySubscriptYOffset,
ftMetrics.y_scale);
// some fonts have the incorrect sign.
val = fabs(val);
aMetrics->subscriptOffset = NS_MAX(1.0, val);
} else {
aMetrics->subscriptOffset = aMetrics->xHeight;
}
aMetrics->maxHeight = aMetrics->maxAscent + aMetrics->maxDescent;
// Make the line height an integer number of pixels so that lines will be
// equally spaced (rather than just being snapped to pixels, some up and
// some down). Layout calculates line height from the emHeight +
// internalLeading + externalLeading, but first each of these is rounded
// to layout units. To ensure that the result is an integer number of
// pixels, round each of the components to pixels.
aMetrics->emHeight = NS_floor(emHeight + 0.5);
// maxHeight will normally be an integer, but round anyway in case
// FreeType is configured differently.
aMetrics->internalLeading =
NS_floor(aMetrics->maxHeight - aMetrics->emHeight + 0.5);
// Text input boxes currently don't work well with lineHeight
// significantly less than maxHeight (with Verdana, for example).
lineHeight = NS_floor(NS_MAX(lineHeight, aMetrics->maxHeight) + 0.5);
aMetrics->externalLeading =
lineHeight - aMetrics->internalLeading - aMetrics->emHeight;
// Ensure emAscent + emDescent == emHeight
gfxFloat sum = aMetrics->emAscent + aMetrics->emDescent;
aMetrics->emAscent = sum > 0.0 ?
aMetrics->emAscent * aMetrics->emHeight / sum : 0.0;
aMetrics->emDescent = aMetrics->emHeight - aMetrics->emAscent;
}