Inheritance diagram for SkScalerContext_FreeType:

Public Member Functions
	SkScalerContext_FreeType (sk_sp< SkTypeface_FreeType >, const SkScalerContextEffects &, const SkDescriptor *desc)

	~SkScalerContext_FreeType () override

bool	success () const

Public Member Functions inherited from SkScalerContext
	SkScalerContext (sk_sp< SkTypeface >, const SkScalerContextEffects &, const SkDescriptor *)

virtual	~SkScalerContext ()

SkTypeface *	getTypeface () const

SkMask::Format	getMaskFormat () const

bool	isSubpixel () const

bool	isLinearMetrics () const

bool	isVertical () const

SkGlyph	makeGlyph (SkPackedGlyphID, SkArenaAlloc *)

void	getImage (const SkGlyph &)

void	getPath (SkGlyph &, SkArenaAlloc *)

sk_sp< SkDrawable >	getDrawable (SkGlyph &)

void	getFontMetrics (SkFontMetrics *)

const SkScalerContextRec &	getRec () const

SkScalerContextEffects	getEffects () const

SkAxisAlignment	computeAxisAlignmentForHText () const

Protected Member Functions
GlyphMetrics	generateMetrics (const SkGlyph &, SkArenaAlloc *) override

void	generateImage (const SkGlyph &, void *) override

bool	generatePath (const SkGlyph &glyph, SkPath *path) override

sk_sp< SkDrawable >	generateDrawable (const SkGlyph &) override

void	generateFontMetrics (SkFontMetrics *) override

Protected Member Functions inherited from SkScalerContext
void	forceGenerateImageFromPath ()

void	forceOffGenerateImageFromPath ()

Additional Inherited Members
Public Types inherited from SkScalerContext
enum	Flags { kFrameAndFill_Flag = 0x0001 , kUnused = 0x0002 , kEmbeddedBitmapText_Flag = 0x0004 , kEmbolden_Flag = 0x0008 , kSubpixelPositioning_Flag = 0x0010 , kForceAutohinting_Flag = 0x0020 , kHinting_Shift = 7 , kHintingBit1_Flag = 0x0080 , kHintingBit2_Flag = 0x0100 , kLCD_Vertical_Flag = 0x0200 , kLCD_BGROrder_Flag = 0x0400 , kGenA8FromLCD_Flag = 0x0800 , kLinearMetrics_Flag = 0x1000 , kBaselineSnap_Flag = 0x2000 , kNeedsForegroundColor_Flag = 0x4000 }

enum	{ kHinting_Mask = kHintingBit1_Flag \| kHintingBit2_Flag }

Static Public Member Functions inherited from SkScalerContext
static size_t	GetGammaLUTSize (SkScalar contrast, SkScalar paintGamma, SkScalar deviceGamma, int width, int height)

static bool	GetGammaLUTData (SkScalar contrast, SkScalar paintGamma, SkScalar deviceGamma, uint8_t *data)

static void	MakeRecAndEffects (const SkFont &font, const SkPaint &paint, const SkSurfaceProps &surfaceProps, SkScalerContextFlags scalerContextFlags, const SkMatrix &deviceMatrix, SkScalerContextRec rec, SkScalerContextEffects effects)

static void	MakeRecAndEffectsFromFont (const SkFont &font, SkScalerContextRec rec, SkScalerContextEffects effects)

static std::unique_ptr< SkScalerContext >	MakeEmpty (sk_sp< SkTypeface > typeface, const SkScalerContextEffects &effects, const SkDescriptor *desc)

static SkDescriptor *	AutoDescriptorGivenRecAndEffects (const SkScalerContextRec &rec, const SkScalerContextEffects &effects, SkAutoDescriptor *ad)

static std::unique_ptr< SkDescriptor >	DescriptorGivenRecAndEffects (const SkScalerContextRec &rec, const SkScalerContextEffects &effects)

static void	DescriptorBufferGiveRec (const SkScalerContextRec &rec, void *buffer)

static bool	CheckBufferSizeForRec (const SkScalerContextRec &rec, const SkScalerContextEffects &effects, size_t size)

static SkMaskGamma::PreBlend	GetMaskPreBlend (const SkScalerContextRec &rec)

static SkDescriptor *	CreateDescriptorAndEffectsUsingPaint (const SkFont &, const SkPaint &, const SkSurfaceProps &, SkScalerContextFlags scalerContextFlags, const SkMatrix &deviceMatrix, SkAutoDescriptor ad, SkScalerContextEffects effects)

Static Protected Member Functions inherited from SkScalerContext
static void	GenerateMetricsFromPath (SkGlyph *glyph, const SkPath &path, SkMask::Format format, bool verticalLCD, bool a8FromLCD, bool hairline)

static void	SaturateGlyphBounds (SkGlyph *glyph, SkRect &&)

static void	SaturateGlyphBounds (SkGlyph *glyph, SkIRect const &)

static void	GenerateImageFromPath (SkMaskBuilder &dst, const SkPath &path, const SkMaskGamma::PreBlend &maskPreBlend, bool doBGR, bool verticalLCD, bool a8FromLCD, bool hairline)

Protected Attributes inherited from SkScalerContext
SkScalerContextRec	fRec

const SkMaskGamma::PreBlend	fPreBlend

Detailed Description

Definition at line 440 of file SkFontHost_FreeType.cpp.

Constructor & Destructor Documentation

◆ SkScalerContext_FreeType()

SkScalerContext_FreeType::SkScalerContext_FreeType	(	sk_sp< SkTypeface_FreeType >	typeface,
		const SkScalerContextEffects &	effects,
		const SkDescriptor *	desc
	)

Definition at line 892 of file SkFontHost_FreeType.cpp.

    : SkScalerContext(std::move(typeface), effects, desc)
    , fFace(nullptr)
    , fFTSize(nullptr)
    , fStrikeIndex(-1)
{
    SkAutoMutexExclusive  ac(f_t_mutex());
    fFaceRec = static_cast<SkTypeface_FreeType*>(this->getTypeface())->getFaceRec();
 
    // load the font file
    if (nullptr == fFaceRec) {
        LOG_INFO("Could not create FT_Face.\n");
        return;
    }
 
    fLCDIsVert = SkToBool(fRec.fFlags & SkScalerContext::kLCD_Vertical_Flag);
 
    // compute the flags we send to Load_Glyph
    bool linearMetrics = this->isLinearMetrics();
    {
        FT_Int32 loadFlags = FT_LOAD_DEFAULT;
 
        if (SkMask::kBW_Format == fRec.fMaskFormat) {
            // See http://code.google.com/p/chromium/issues/detail?id=43252#c24
            loadFlags = FT_LOAD_TARGET_MONO;
            if (fRec.getHinting() == SkFontHinting::kNone) {
                loadFlags |= FT_LOAD_NO_HINTING;
                linearMetrics = true;
            }
        } else {
            switch (fRec.getHinting()) {
            case SkFontHinting::kNone:
                loadFlags = FT_LOAD_NO_HINTING;
                linearMetrics = true;
                break;
            case SkFontHinting::kSlight:
                loadFlags = FT_LOAD_TARGET_LIGHT;  // This implies FORCE_AUTOHINT
                linearMetrics = true;
                break;
            case SkFontHinting::kNormal:
                loadFlags = FT_LOAD_TARGET_NORMAL;
                break;
            case SkFontHinting::kFull:
                loadFlags = FT_LOAD_TARGET_NORMAL;
                if (isLCD(fRec)) {
                    if (fLCDIsVert) {
                        loadFlags = FT_LOAD_TARGET_LCD_V;
                    } else {
                        loadFlags = FT_LOAD_TARGET_LCD;
                    }
                }
                break;
            default:
                LOG_INFO("---------- UNKNOWN hinting %d\n", fRec.getHinting());
                break;
            }
        }
 
        if (fRec.fFlags & SkScalerContext::kForceAutohinting_Flag) {
            loadFlags |= FT_LOAD_FORCE_AUTOHINT;
#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
        } else {
            loadFlags |= FT_LOAD_NO_AUTOHINT;
#endif
        }
 
        if ((fRec.fFlags & SkScalerContext::kEmbeddedBitmapText_Flag) == 0) {
            loadFlags |= FT_LOAD_NO_BITMAP;
        }
 
        // Always using FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH to get correct
        // advances, as fontconfig and cairo do.
        // See http://code.google.com/p/skia/issues/detail?id=222.
        loadFlags |= FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH;
 
        // Use vertical layout if requested.
        if (this->isVertical()) {
            loadFlags |= FT_LOAD_VERTICAL_LAYOUT;
        }
 
        fLoadGlyphFlags = loadFlags;
    }
 
    SkUniqueFTSize ftSize([this]() -> FT_Size {
        FT_Size size;
        FT_Error err = FT_New_Size(fFaceRec->fFace.get(), &size);
        if (err != 0) {
            SK_TRACEFTR(err, "FT_New_Size(%s) failed.", fFaceRec->fFace->family_name);
            return nullptr;
        }
        return size;
    }());
    if (nullptr == ftSize) {
        LOG_INFO("Could not create FT_Size.\n");
        return;
    }
 
    FT_Error err = FT_Activate_Size(ftSize.get());
    if (err != 0) {
        SK_TRACEFTR(err, "FT_Activate_Size(%s) failed.", fFaceRec->fFace->family_name);
        return;
    }
 
    fRec.computeMatrices(SkScalerContextRec::PreMatrixScale::kFull, &fScale, &fMatrix22Scalar);
    FT_F26Dot6 scaleX = SkScalarToFDot6(fScale.fX);
    FT_F26Dot6 scaleY = SkScalarToFDot6(fScale.fY);
 
    if (FT_IS_SCALABLE(fFaceRec->fFace)) {
        err = FT_Set_Char_Size(fFaceRec->fFace.get(), scaleX, scaleY, 72, 72);
        if (err != 0) {
            SK_TRACEFTR(err, "FT_Set_CharSize(%s, %f, %f) failed.",
                        fFaceRec->fFace->family_name, fScale.fX, fScale.fY);
            return;
        }
 
        // Adjust the matrix to reflect the actually chosen scale.
        // FreeType currently does not allow requesting sizes less than 1, this allow for scaling.
        // Don't do this at all sizes as that will interfere with hinting.
        if (fScale.fX < 1 || fScale.fY < 1) {
            SkScalar upem = fFaceRec->fFace->units_per_EM;
            FT_Size_Metrics& ftmetrics = fFaceRec->fFace->size->metrics;
            SkScalar x_ppem = upem * SkFT_FixedToScalar(ftmetrics.x_scale) / 64.0f;
            SkScalar y_ppem = upem * SkFT_FixedToScalar(ftmetrics.y_scale) / 64.0f;
            fMatrix22Scalar.preScale(fScale.x() / x_ppem, fScale.y() / y_ppem);
        }
 
        // FT_LOAD_COLOR with scalable fonts means allow SVG.
        // It also implies attempt to render COLR if available, but this is not used.
#if defined(FT_CONFIG_OPTION_SVG)
        if (SkGraphics::GetOpenTypeSVGDecoderFactory()) {
            fLoadGlyphFlags |= FT_LOAD_COLOR;
        }
#endif
    } else if (FT_HAS_FIXED_SIZES(fFaceRec->fFace)) {
        fStrikeIndex = chooseBitmapStrike(fFaceRec->fFace.get(), scaleY);
        if (fStrikeIndex == -1) {
            LOG_INFO("No glyphs for font \"%s\" size %f.\n",
                     fFaceRec->fFace->family_name, fScale.fY);
            return;
        }
 
        err = FT_Select_Size(fFaceRec->fFace.get(), fStrikeIndex);
        if (err != 0) {
            SK_TRACEFTR(err, "FT_Select_Size(%s, %d) failed.",
                        fFaceRec->fFace->family_name, fStrikeIndex);
            fStrikeIndex = -1;
            return;
        }
 
        // Adjust the matrix to reflect the actually chosen scale.
        // It is likely that the ppem chosen was not the one requested, this allows for scaling.
        fMatrix22Scalar.preScale(fScale.x() / fFaceRec->fFace->size->metrics.x_ppem,
                                 fScale.y() / fFaceRec->fFace->size->metrics.y_ppem);
 
        // FreeType does not provide linear metrics for bitmap fonts.
        linearMetrics = false;
 
        // FreeType documentation says:
        // FT_LOAD_NO_BITMAP -- Ignore bitmap strikes when loading.
        // Bitmap-only fonts ignore this flag.
        //
        // However, in FreeType 2.5.1 color bitmap only fonts do not ignore this flag.
        // Force this flag off for bitmap only fonts.
        fLoadGlyphFlags &= ~FT_LOAD_NO_BITMAP;
 
        // Color bitmaps are supported.
        fLoadGlyphFlags |= FT_LOAD_COLOR;
    } else {
        LOG_INFO("Unknown kind of font \"%s\" size %f.\n", fFaceRec->fFace->family_name, fScale.fY);
        return;
    }
 
    fMatrix22.xx = SkScalarToFixed(fMatrix22Scalar.getScaleX());
    fMatrix22.xy = SkScalarToFixed(-fMatrix22Scalar.getSkewX());
    fMatrix22.yx = SkScalarToFixed(-fMatrix22Scalar.getSkewY());
    fMatrix22.yy = SkScalarToFixed(fMatrix22Scalar.getScaleY());
 
    fFTSize = ftSize.release();
    fFace = fFaceRec->fFace.get();
    fDoLinearMetrics = linearMetrics;
    fUtils.init(fRec.fForegroundColor, (SkScalerContext::Flags)fRec.fFlags);
}

◆ ~SkScalerContext_FreeType()

SkScalerContext_FreeType::~SkScalerContext_FreeType ( )

override

Definition at line 1077 of file SkFontHost_FreeType.cpp.

                                                    {
    SkAutoMutexExclusive  ac(f_t_mutex());
 
    if (fFTSize != nullptr) {
        FT_Done_Size(fFTSize);
    }
 
    fFaceRec = nullptr;
}

Member Function Documentation

◆ generateDrawable()

sk_sp< SkDrawable > SkScalerContext_FreeType::generateDrawable ( const SkGlyph & )

overrideprotectedvirtual

Returns the drawable for the glyph (if any).

The generated drawable will be lifetime scoped to the lifetime of this scaler context. This means the drawable may refer to the scaler context and associated font data.

The drawable does not need to be flattenable (e.g. implement getFactory and getTypeName). Any necessary serialization will be done with makePictureSnapshot.

Reimplemented from SkScalerContext.

Definition at line 1416 of file SkFontHost_FreeType.cpp.

                                                                                 {
    // Because FreeType's FT_Face is stateful (not thread safe) and the current design of this
    // SkTypeface and SkScalerContext does not work around this, it is necessary lock at least the
    // FT_Face when using it (this implementation currently locks the whole FT_Library).
    // It should be possible to draw the drawable straight out of the FT_Face. However, this would
    // mean locking each time any such drawable is drawn. To avoid locking, this implementation
    // creates drawables backed as pictures so that they can be played back later without locking.
    SkAutoMutexExclusive  ac(f_t_mutex());
 
    if (this->setupSize()) {
        return nullptr;
    }
 
#if defined(FT_COLOR_H) || defined(TT_SUPPORT_COLRV1) || defined(FT_CONFIG_OPTION_SVG)
    if (glyph.extraBits() == ScalerContextBits::COLRv0 ||
        glyph.extraBits() == ScalerContextBits::COLRv1 ||
        glyph.extraBits() == ScalerContextBits::SVG     )
    {
        SkSpan<SkColor> palette(fFaceRec->fSkPalette.get(), fFaceRec->fFTPaletteEntryCount);
        SkPictureRecorder recorder;
        SkCanvas* recordingCanvas = recorder.beginRecording(SkRect::Make(glyph.mask().fBounds));
        if (glyph.extraBits() == ScalerContextBits::COLRv0) {
#ifdef FT_COLOR_H
            if (!fUtils.drawCOLRv0Glyph(fFace, glyph, fLoadGlyphFlags, palette, recordingCanvas)) {
                return nullptr;
            }
#else
            return nullptr;
#endif
        } else if (glyph.extraBits() == ScalerContextBits::COLRv1) {
#ifdef TT_SUPPORT_COLRV1
            if (!fUtils.drawCOLRv1Glyph(fFace, glyph, fLoadGlyphFlags, palette, recordingCanvas)) {
                return nullptr;
            }
#else
            return nullptr;
#endif
        } else if (glyph.extraBits() == ScalerContextBits::SVG) {
#if defined(FT_CONFIG_OPTION_SVG)
            if (FT_Load_Glyph(fFace, glyph.getGlyphID(), fLoadGlyphFlags)) {
                return nullptr;
            }
            if (!fUtils.drawSVGGlyph(fFace, glyph, fLoadGlyphFlags, palette, recordingCanvas)) {
                return nullptr;
            }
#else
            return nullptr;
#endif
        }
        return recorder.finishRecordingAsDrawable();
    }
#endif
    return nullptr;
}

◆ generateFontMetrics()

void SkScalerContext_FreeType::generateFontMetrics ( SkFontMetrics * )

overrideprotectedvirtual

Retrieves font metrics.

Implements SkScalerContext.

Definition at line 1511 of file SkFontHost_FreeType.cpp.

                                                                         {
    if (nullptr == metrics) {
        return;
    }
 
    SkAutoMutexExclusive ac(f_t_mutex());
 
    if (this->setupSize()) {
        sk_bzero(metrics, sizeof(*metrics));
        return;
    }
 
    FT_Face face = fFace;
    metrics->fFlags = 0;
 
    SkScalar upem = SkIntToScalar(SkTypeface_FreeType::GetUnitsPerEm(face));
 
    // use the os/2 table as a source of reasonable defaults.
    SkScalar x_height = 0.0f;
    SkScalar avgCharWidth = 0.0f;
    SkScalar cap_height = 0.0f;
    SkScalar strikeoutThickness = 0.0f, strikeoutPosition = 0.0f;
    TT_OS2* os2 = (TT_OS2*) FT_Get_Sfnt_Table(face, ft_sfnt_os2);
    if (os2) {
        x_height = SkIntToScalar(os2->sxHeight) / upem * fScale.y();
        avgCharWidth = SkIntToScalar(os2->xAvgCharWidth) / upem;
        strikeoutThickness = SkIntToScalar(os2->yStrikeoutSize) / upem;
        strikeoutPosition = -SkIntToScalar(os2->yStrikeoutPosition) / upem;
        metrics->fFlags |= SkFontMetrics::kStrikeoutThicknessIsValid_Flag;
        metrics->fFlags |= SkFontMetrics::kStrikeoutPositionIsValid_Flag;
        if (os2->version != 0xFFFF && os2->version >= 2) {
            cap_height = SkIntToScalar(os2->sCapHeight) / upem * fScale.y();
        }
    }
 
    // pull from format-specific metrics as needed
    SkScalar ascent, descent, leading, xmin, xmax, ymin, ymax;
    SkScalar underlineThickness, underlinePosition;
    if (face->face_flags & FT_FACE_FLAG_SCALABLE) { // scalable outline font
        // FreeType will always use HHEA metrics if they're not zero.
        // It completely ignores the OS/2 fsSelection::UseTypoMetrics bit.
        // It also ignores the VDMX tables, which are also of interest here
        // (and override everything else when they apply).
        static const int kUseTypoMetricsMask = (1 << 7);
        if (os2 && os2->version != 0xFFFF && (os2->fsSelection & kUseTypoMetricsMask)) {
            ascent = -SkIntToScalar(os2->sTypoAscender) / upem;
            descent = -SkIntToScalar(os2->sTypoDescender) / upem;
            leading = SkIntToScalar(os2->sTypoLineGap) / upem;
        } else {
            ascent = -SkIntToScalar(face->ascender) / upem;
            descent = -SkIntToScalar(face->descender) / upem;
            leading = SkIntToScalar(face->height + (face->descender - face->ascender)) / upem;
        }
        xmin = SkIntToScalar(face->bbox.xMin) / upem;
        xmax = SkIntToScalar(face->bbox.xMax) / upem;
        ymin = -SkIntToScalar(face->bbox.yMin) / upem;
        ymax = -SkIntToScalar(face->bbox.yMax) / upem;
        underlineThickness = SkIntToScalar(face->underline_thickness) / upem;
        underlinePosition = -SkIntToScalar(face->underline_position +
                                           face->underline_thickness / 2) / upem;
 
        metrics->fFlags |= SkFontMetrics::kUnderlineThicknessIsValid_Flag;
        metrics->fFlags |= SkFontMetrics::kUnderlinePositionIsValid_Flag;
 
        // we may be able to synthesize x_height and cap_height from outline
        if (!x_height) {
            FT_BBox bbox;
            if (getCBoxForLetter('x', &bbox)) {
                x_height = SkIntToScalar(bbox.yMax) / 64.0f;
            }
        }
        if (!cap_height) {
            FT_BBox bbox;
            if (getCBoxForLetter('H', &bbox)) {
                cap_height = SkIntToScalar(bbox.yMax) / 64.0f;
            }
        }
    } else if (fStrikeIndex != -1) { // bitmap strike metrics
        SkScalar xppem = SkIntToScalar(face->size->metrics.x_ppem);
        SkScalar yppem = SkIntToScalar(face->size->metrics.y_ppem);
        ascent = -SkIntToScalar(face->size->metrics.ascender) / (yppem * 64.0f);
        descent = -SkIntToScalar(face->size->metrics.descender) / (yppem * 64.0f);
        leading = (SkIntToScalar(face->size->metrics.height) / (yppem * 64.0f)) + ascent - descent;
 
        xmin = 0.0f;
        xmax = SkIntToScalar(face->available_sizes[fStrikeIndex].width) / xppem;
        ymin = descent;
        ymax = ascent;
        // The actual bitmaps may be any size and placed at any offset.
        metrics->fFlags |= SkFontMetrics::kBoundsInvalid_Flag;
 
        underlineThickness = 0;
        underlinePosition = 0;
        metrics->fFlags &= ~SkFontMetrics::kUnderlineThicknessIsValid_Flag;
        metrics->fFlags &= ~SkFontMetrics::kUnderlinePositionIsValid_Flag;
 
        TT_Postscript* post = (TT_Postscript*) FT_Get_Sfnt_Table(face, ft_sfnt_post);
        if (post) {
            underlineThickness = SkIntToScalar(post->underlineThickness) / upem;
            underlinePosition = -SkIntToScalar(post->underlinePosition) / upem;
            metrics->fFlags |= SkFontMetrics::kUnderlineThicknessIsValid_Flag;
            metrics->fFlags |= SkFontMetrics::kUnderlinePositionIsValid_Flag;
        }
    } else {
        sk_bzero(metrics, sizeof(*metrics));
        return;
    }
 
    // synthesize elements that were not provided by the os/2 table or format-specific metrics
    if (!x_height) {
        x_height = -ascent * fScale.y();
    }
    if (!avgCharWidth) {
        avgCharWidth = xmax - xmin;
    }
    if (!cap_height) {
      cap_height = -ascent * fScale.y();
    }
 
    // disallow negative linespacing
    if (leading < 0.0f) {
        leading = 0.0f;
    }
 
    metrics->fTop = ymax * fScale.y();
    metrics->fAscent = ascent * fScale.y();
    metrics->fDescent = descent * fScale.y();
    metrics->fBottom = ymin * fScale.y();
    metrics->fLeading = leading * fScale.y();
    metrics->fAvgCharWidth = avgCharWidth * fScale.y();
    metrics->fXMin = xmin * fScale.y();
    metrics->fXMax = xmax * fScale.y();
    metrics->fMaxCharWidth = metrics->fXMax - metrics->fXMin;
    metrics->fXHeight = x_height;
    metrics->fCapHeight = cap_height;
    metrics->fUnderlineThickness = underlineThickness * fScale.y();
    metrics->fUnderlinePosition = underlinePosition * fScale.y();
    metrics->fStrikeoutThickness = strikeoutThickness * fScale.y();
    metrics->fStrikeoutPosition = strikeoutPosition * fScale.y();
 
    if (face->face_flags & FT_FACE_FLAG_MULTIPLE_MASTERS
#if defined(FT_CONFIG_OPTION_SVG)
        || face->face_flags & FT_FACE_FLAG_SVG
#endif  // FT_CONFIG_OPTION_SVG
    ) {
        // The bounds are only valid for the default variation of variable glyphs.
        // https://docs.microsoft.com/en-us/typography/opentype/spec/head
        // For SVG glyphs this number is often incorrect for its non-`glyf` points.
        // https://github.com/fonttools/fonttools/issues/2566
        metrics->fFlags |= SkFontMetrics::kBoundsInvalid_Flag;
    }
}

◆ generateImage()

void SkScalerContext_FreeType::generateImage	(	const SkGlyph &	glyph,
		void *	imageBuffer
	)

overrideprotectedvirtual

Generates the contents of glyph.fImage. When called, glyph.fImage will be pointing to a pre-allocated, uninitialized region of memory of size glyph.imageSize(). This method may not change glyph.fMaskFormat.

Because glyph.imageSize() will determine the size of fImage, generateMetrics will be called before generateImage.

Implements SkScalerContext.

Definition at line 1349 of file SkFontHost_FreeType.cpp.

                                                                                    {
    SkAutoMutexExclusive  ac(f_t_mutex());
 
    if (this->setupSize()) {
        sk_bzero(imageBuffer, glyph.imageSize());
        return;
    }
 
    if (glyph.extraBits() == ScalerContextBits::COLRv0 ||
        glyph.extraBits() == ScalerContextBits::COLRv1 ||
        glyph.extraBits() == ScalerContextBits::SVG     )
    {
        SkASSERT(glyph.maskFormat() == SkMask::kARGB32_Format);
        SkBitmap dstBitmap;
        // TODO: mark this as sRGB when the blits will be sRGB.
        dstBitmap.setInfo(SkImageInfo::Make(glyph.width(), glyph.height(),
                                            kN32_SkColorType,
                                            kPremul_SkAlphaType),
                                            glyph.rowBytes());
        dstBitmap.setPixels(imageBuffer);
 
        SkCanvas canvas(dstBitmap);
        if constexpr (kSkShowTextBlitCoverage) {
            canvas.clear(0x33FF0000);
        } else {
            canvas.clear(SK_ColorTRANSPARENT);
        }
        canvas.translate(-glyph.left(), -glyph.top());
 
        SkSpan<SkColor> palette(fFaceRec->fSkPalette.get(), fFaceRec->fFTPaletteEntryCount);
        if (glyph.extraBits() == ScalerContextBits::COLRv0) {
#ifdef FT_COLOR_H
            fUtils.drawCOLRv0Glyph(fFace, glyph, fLoadGlyphFlags, palette, &canvas);
#endif
        } else if (glyph.extraBits() == ScalerContextBits::COLRv1) {
#ifdef TT_SUPPORT_COLRV1
            fUtils.drawCOLRv1Glyph(fFace, glyph, fLoadGlyphFlags, palette, &canvas);
#endif
        } else if (glyph.extraBits() == ScalerContextBits::SVG) {
#if defined(FT_CONFIG_OPTION_SVG)
            if (FT_Load_Glyph(fFace, glyph.getGlyphID(), fLoadGlyphFlags)) {
                return;
            }
            fUtils.drawSVGGlyph(fFace, glyph, fLoadGlyphFlags, palette, &canvas);
#endif
        }
        return;
    }
 
    if (FT_Load_Glyph(fFace, glyph.getGlyphID(), fLoadGlyphFlags)) {
        sk_bzero(imageBuffer, glyph.imageSize());
        return;
    }
    emboldenIfNeeded(fFace, fFace->glyph, glyph.getGlyphID());
 
    SkMatrix* bitmapMatrix = &fMatrix22Scalar;
    SkMatrix subpixelBitmapMatrix;
    if (this->shouldSubpixelBitmap(glyph, *bitmapMatrix)) {
        subpixelBitmapMatrix = fMatrix22Scalar;
        subpixelBitmapMatrix.postTranslate(SkFixedToScalar(glyph.getSubXFixed()),
                                           SkFixedToScalar(glyph.getSubYFixed()));
        bitmapMatrix = &subpixelBitmapMatrix;
    }
 
    fUtils.generateGlyphImage(fFace, glyph, imageBuffer, *bitmapMatrix, fPreBlend);
}

◆ generateMetrics()

SkScalerContext::GlyphMetrics SkScalerContext_FreeType::generateMetrics	(	const SkGlyph &	glyph,
		SkArenaAlloc *	alloc
	)

overrideprotectedvirtual

Implements SkScalerContext.

Definition at line 1169 of file SkFontHost_FreeType.cpp.

                                                                                             {
    SkAutoMutexExclusive  ac(f_t_mutex());
 
    GlyphMetrics mx(glyph.maskFormat());
 
    if (this->setupSize()) {
        return mx;
    }
 
    FT_Bool haveLayers = false;
#ifdef FT_COLOR_H
    // See https://skbug.com/12945, if the face isn't marked scalable then paths cannot be loaded.
    if (FT_IS_SCALABLE(fFace)) {
        SkRect bounds = SkRect::MakeEmpty();
#ifdef TT_SUPPORT_COLRV1
        FT_OpaquePaint opaqueLayerPaint{nullptr, 1};
        if (FT_Get_Color_Glyph_Paint(fFace, glyph.getGlyphID(),
                                     FT_COLOR_INCLUDE_ROOT_TRANSFORM, &opaqueLayerPaint)) {
            haveLayers = true;
            mx.extraBits = ScalerContextBits::COLRv1;
 
            // COLRv1 optionally provides a ClipBox.
            FT_ClipBox clipBox;
            if (FT_Get_Color_Glyph_ClipBox(fFace, glyph.getGlyphID(), &clipBox)) {
                // Find bounding box of clip box corner points, needed when clipbox is transformed.
                FT_BBox bbox;
                bbox.xMin = clipBox.bottom_left.x;
                bbox.xMax = clipBox.bottom_left.x;
                bbox.yMin = clipBox.bottom_left.y;
                bbox.yMax = clipBox.bottom_left.y;
                for (auto& corner : {clipBox.top_left, clipBox.top_right, clipBox.bottom_right}) {
                    bbox.xMin = std::min(bbox.xMin, corner.x);
                    bbox.yMin = std::min(bbox.yMin, corner.y);
                    bbox.xMax = std::max(bbox.xMax, corner.x);
                    bbox.yMax = std::max(bbox.yMax, corner.y);
                }
                bounds = SkRect::MakeLTRB(SkFDot6ToScalar(bbox.xMin), -SkFDot6ToScalar(bbox.yMax),
                                          SkFDot6ToScalar(bbox.xMax), -SkFDot6ToScalar(bbox.yMin));
            } else {
                // Traverse the glyph graph with a focus on measuring the required bounding box.
                // The call to computeColrV1GlyphBoundingBox may modify the face.
                // Reset the face to load the base glyph for metrics.
                if (!SkScalerContextFTUtils::computeColrV1GlyphBoundingBox(fFace,
                                                                           glyph.getGlyphID(),
                                                                           &bounds) ||
                    this->setupSize())
                {
                    return mx;
                }
            }
        }
#endif // #TT_SUPPORT_COLRV1
 
        if (!haveLayers) {
            FT_LayerIterator layerIterator = { 0, 0, nullptr };
            FT_UInt layerGlyphIndex;
            FT_UInt layerColorIndex;
            FT_Int32 flags = fLoadGlyphFlags;
            flags |= FT_LOAD_BITMAP_METRICS_ONLY;  // Don't decode any bitmaps.
            flags |= FT_LOAD_NO_BITMAP; // Ignore embedded bitmaps.
            flags &= ~FT_LOAD_RENDER;  // Don't scan convert.
            flags &= ~FT_LOAD_COLOR;  // Ignore SVG.
            // For COLRv0 compute the glyph bounding box from the union of layer bounding boxes.
            while (FT_Get_Color_Glyph_Layer(fFace, glyph.getGlyphID(), &layerGlyphIndex,
                                            &layerColorIndex, &layerIterator)) {
                haveLayers = true;
                if (FT_Load_Glyph(fFace, layerGlyphIndex, flags)) {
                    return mx;
                }
 
                SkRect currentBounds;
                if (getBoundsOfCurrentOutlineGlyph(fFace->glyph, &currentBounds)) {
                    bounds.join(currentBounds);
                }
            }
            if (haveLayers) {
                mx.extraBits = ScalerContextBits::COLRv0;
            }
        }
 
        if (haveLayers) {
            mx.maskFormat = SkMask::kARGB32_Format;
            mx.neverRequestPath = true;
            updateGlyphBoundsIfSubpixel(glyph, &bounds, this->isSubpixel());
            mx.bounds = bounds;
        }
    }
#endif  //FT_COLOR_H
 
    // Even if haveLayers, the base glyph must be loaded to get the metrics.
    if (FT_Load_Glyph(fFace, glyph.getGlyphID(), fLoadGlyphFlags | FT_LOAD_BITMAP_METRICS_ONLY)) {
        return mx;
    }
 
    if (!haveLayers) {
        emboldenIfNeeded(fFace, fFace->glyph, glyph.getGlyphID());
 
        if (fFace->glyph->format == FT_GLYPH_FORMAT_OUTLINE) {
            getBoundsOfCurrentOutlineGlyph(fFace->glyph, &mx.bounds);
            updateGlyphBoundsIfSubpixel(glyph, &mx.bounds, this->isSubpixel());
            updateGlyphBoundsIfLCD(&mx);
 
        } else if (fFace->glyph->format == FT_GLYPH_FORMAT_BITMAP) {
            mx.neverRequestPath = true;
 
            if (this->isVertical()) {
                FT_Vector vector;
                vector.x =  fFace->glyph->metrics.vertBearingX - fFace->glyph->metrics.horiBearingX;
                vector.y = -fFace->glyph->metrics.vertBearingY - fFace->glyph->metrics.horiBearingY;
                FT_Vector_Transform(&vector, &fMatrix22);
                fFace->glyph->bitmap_left += SkFDot6Floor(vector.x);
                fFace->glyph->bitmap_top  += SkFDot6Floor(vector.y);
            }
 
            if (fFace->glyph->bitmap.pixel_mode == FT_PIXEL_MODE_BGRA) {
                mx.maskFormat = SkMask::kARGB32_Format;
            }
 
            mx.bounds = SkRect::MakeXYWH(SkIntToScalar(fFace->glyph->bitmap_left ),
                                        -SkIntToScalar(fFace->glyph->bitmap_top  ),
                                         SkIntToScalar(fFace->glyph->bitmap.width),
                                         SkIntToScalar(fFace->glyph->bitmap.rows ));
            fMatrix22Scalar.mapRect(&mx.bounds);
            updateGlyphBoundsIfSubpixel(glyph, &mx.bounds,
                                        this->shouldSubpixelBitmap(glyph, fMatrix22Scalar));
 
#if defined(FT_CONFIG_OPTION_SVG)
        } else if (fFace->glyph->format == FT_GLYPH_FORMAT_SVG) {
            mx.extraBits = ScalerContextBits::SVG;
            mx.maskFormat = SkMask::kARGB32_Format;
            mx.neverRequestPath = true;
 
            SkPictureRecorder recorder;
            SkRect infiniteRect = SkRect::MakeLTRB(-SK_ScalarInfinity, -SK_ScalarInfinity,
                                                    SK_ScalarInfinity,  SK_ScalarInfinity);
            sk_sp<SkBBoxHierarchy> bboxh = SkRTreeFactory()();
            SkSpan<SkColor> palette(fFaceRec->fSkPalette.get(), fFaceRec->fFTPaletteEntryCount);
            SkCanvas* recordingCanvas = recorder.beginRecording(infiniteRect, bboxh);
            if (!fUtils.drawSVGGlyph(fFace, glyph, fLoadGlyphFlags, palette, recordingCanvas)) {
                return mx;
            }
            sk_sp<SkPicture> pic = recorder.finishRecordingAsPicture();
            mx.bounds = pic->cullRect();
            SkASSERT(mx.bounds.isFinite());
            // drawSVGGlyph already applied the subpixel positioning.
#endif  // FT_CONFIG_OPTION_SVG
 
        } else {
            SkDEBUGFAIL("unknown glyph format");
            return mx;
        }
    }
 
    if (this->isVertical()) {
        if (fDoLinearMetrics) {
            const SkScalar advanceScalar = SkFT_FixedToScalar(fFace->glyph->linearVertAdvance);
            mx.advance.fX = fMatrix22Scalar.getSkewX() * advanceScalar;
            mx.advance.fY = fMatrix22Scalar.getScaleY() * advanceScalar;
        } else {
            mx.advance.fX = -SkFDot6ToFloat(fFace->glyph->advance.x);
            mx.advance.fY =  SkFDot6ToFloat(fFace->glyph->advance.y);
        }
    } else {
        if (fDoLinearMetrics) {
            const SkScalar advanceScalar = SkFT_FixedToScalar(fFace->glyph->linearHoriAdvance);
            mx.advance.fX = fMatrix22Scalar.getScaleX() * advanceScalar;
            mx.advance.fY = fMatrix22Scalar.getSkewY() * advanceScalar;
        } else {
            mx.advance.fX =  SkFDot6ToFloat(fFace->glyph->advance.x);
            mx.advance.fY = -SkFDot6ToFloat(fFace->glyph->advance.y);
        }
    }
 
#ifdef ENABLE_GLYPH_SPEW
    LOG_INFO("Metrics(glyph:%d flags:0x%x) w:%d\n", glyph->getGlyphID(), fLoadGlyphFlags, glyph->width());
#endif
    return mx;
}

◆ generatePath()

bool SkScalerContext_FreeType::generatePath	(	const SkGlyph &	,
		SkPath *
	)

overrideprotectedvirtual

Sets the passed path to the glyph outline. If this cannot be done the path is set to empty; Does not apply subpixel positioning to the path.

Returns: false if this glyph does not have any path.

Implements SkScalerContext.

Definition at line 1471 of file SkFontHost_FreeType.cpp.

                                                                              {
    SkASSERT(path);
 
    SkAutoMutexExclusive  ac(f_t_mutex());
 
    SkGlyphID glyphID = glyph.getGlyphID();
    // FT_IS_SCALABLE is documented to mean the face contains outline glyphs.
    if (!FT_IS_SCALABLE(fFace) || this->setupSize()) {
        path->reset();
        return false;
    }
 
    uint32_t flags = fLoadGlyphFlags;
    flags |= FT_LOAD_NO_BITMAP; // ignore embedded bitmaps so we're sure to get the outline
    flags &= ~FT_LOAD_RENDER;   // don't scan convert (we just want the outline)
 
    FT_Error err = FT_Load_Glyph(fFace, glyphID, flags);
    if (err != 0 || fFace->glyph->format != FT_GLYPH_FORMAT_OUTLINE) {
        path->reset();
        return false;
    }
    emboldenIfNeeded(fFace, fFace->glyph, glyphID);
 
    if (!fUtils.generateGlyphPath(fFace, path)) {
        path->reset();
        return false;
    }
 
    // The path's origin from FreeType is always the horizontal layout origin.
    // Offset the path so that it is relative to the vertical origin if needed.
    if (this->isVertical()) {
        FT_Vector vector;
        vector.x = fFace->glyph->metrics.vertBearingX - fFace->glyph->metrics.horiBearingX;
        vector.y = -fFace->glyph->metrics.vertBearingY - fFace->glyph->metrics.horiBearingY;
        FT_Vector_Transform(&vector, &fMatrix22);
        path->offset(SkFDot6ToScalar(vector.x), -SkFDot6ToScalar(vector.y));
    }
    return true;
}

◆ success()

bool SkScalerContext_FreeType::success ( ) const

inline

Definition at line 447 of file SkFontHost_FreeType.cpp.

                         {
        return fFTSize != nullptr && fFace != nullptr;
    }

The documentation for this class was generated from the following file:

third_party/skia/src/ports/SkFontHost_FreeType.cpp

Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ SkScalerContext_FreeType()

◆ ~SkScalerContext_FreeType()

Member Function Documentation

◆ generateDrawable()

◆ generateFontMetrics()

◆ generateImage()

◆ generateMetrics()

◆ generatePath()

◆ success()