#include <SkScalerContext.h>

Public Types
enum class	PreMatrixScale { kFull , kVertical , kVerticalInteger }

Public Member Functions
SkScalar	getDeviceGamma () const

void	setDeviceGamma (SkScalar dg)

SkScalar	getPaintGamma () const

void	setPaintGamma (SkScalar pg)

SkScalar	getContrast () const

void	setContrast (SkScalar c)

void	ignoreGamma ()

void	ignorePreBlend ()

SkString	dump () const

void	getMatrixFrom2x2 (SkMatrix *) const

void	getLocalMatrix (SkMatrix *) const

void	getSingleMatrix (SkMatrix *) const

bool	computeMatrices (PreMatrixScale preMatrixScale, SkVector scale, SkMatrix remaining, SkMatrix remainingWithoutRotation=nullptr, SkMatrix remainingRotation=nullptr, SkMatrix *total=nullptr)

SkAxisAlignment	computeAxisAlignmentForHText () const

SkFontHinting	getHinting () const

void	setHinting (SkFontHinting)

SkMask::Format	getFormat () const

SkColor	getLuminanceColor () const

void	setLuminanceColor (SkColor c)

Public Attributes
SkTypefaceID	fTypefaceID

SkScalar	fTextSize

SkScalar	fPreScaleX

SkScalar	fPreSkewX

SkScalar	fPost2x2 [2][2]

SkScalar	fFrameWidth

SkScalar	fMiterLimit

uint32_t	fForegroundColor {SK_ColorBLACK}

SkMask::Format	fMaskFormat

uint16_t	fFlags

Friends
class	SkScalerContext

Detailed Description

Definition at line 61 of file SkScalerContext.h.

Member Enumeration Documentation

◆ PreMatrixScale

enum class SkScalerContextRec::PreMatrixScale

strong

The kind of scale which will be applied by the underlying port (pre-matrix).

Enumerator
kFull
kVertical
kVerticalInteger

Definition at line 162 of file SkScalerContext.h.

                              {
        kFull,  // The underlying port can apply both x and y scale.
        kVertical,  // The underlying port can only apply a y scale.
        kVerticalInteger  // The underlying port can only apply an integer y scale.
    };

Member Function Documentation

◆ computeAxisAlignmentForHText()

SkAxisAlignment SkScalerContextRec::computeAxisAlignmentForHText ( ) const

Definition at line 973 of file SkScalerContext.cpp.

                                                                       {
    // Why fPost2x2 can be used here.
    // getSingleMatrix multiplies in getLocalMatrix, which consists of
    // * fTextSize (a scale, which has no effect)
    // * fPreScaleX (a scale in x, which has no effect)
    // * fPreSkewX (has no effect, but would on vertical text alignment).
    // In other words, making the text bigger, stretching it along the
    // horizontal axis, or fake italicizing it does not move the baseline.
    if (!SkToBool(fFlags & SkScalerContext::kBaselineSnap_Flag)) {
        return SkAxisAlignment::kNone;
    }
 
    if (0 == fPost2x2[1][0]) {
        // The x axis is mapped onto the x axis.
        return SkAxisAlignment::kX;
    }
    if (0 == fPost2x2[0][0]) {
        // The x axis is mapped onto the y axis.
        return SkAxisAlignment::kY;
    }
    return SkAxisAlignment::kNone;
}

◆ computeMatrices()

bool SkScalerContextRec::computeMatrices	(	PreMatrixScale	preMatrixScale,
		SkVector *	scale,
		SkMatrix *	remaining,
		SkMatrix *	remainingWithoutRotation = `nullptr`,
		SkMatrix *	remainingRotation = `nullptr`,
		SkMatrix *	total = `nullptr`
	)

Compute useful matrices for use with sizing in underlying libraries.

There are two kinds of text size, a 'requested/logical size' which is like asking for size '12' and a 'real' size which is the size after the matrix is applied. The matrices produced by this method are based on the 'real' size. This method effectively finds the total device matrix and decomposes it in various ways.

The most useful decomposition is into 'scale' and 'remaining'. The 'scale' is applied first and then the 'remaining' to fully apply the total matrix. This decomposition is useful when the text size ('scale') may have meaning apart from the total matrix. This is true when hinting, and sometimes true for other properties as well.

The second (optional) decomposition is of 'remaining' into a non-rotational part 'remainingWithoutRotation' and a rotational part 'remainingRotation'. The 'scale' is applied first, then 'remainingWithoutRotation', then 'remainingRotation' to fully apply the total matrix. This decomposition is helpful when only horizontal metrics can be trusted, so the 'scale' and 'remainingWithoutRotation' will be handled by the underlying library, but the final rotation 'remainingRotation' will be handled manually.

The 'total' matrix is also (optionally) available. This is useful in cases where the underlying library will not be used, often when working directly with font data.

The parameters 'scale' and 'remaining' are required, the other pointers may be nullptr.

Parameters

preMatrixScale	the kind of scale to extract from the total matrix.
scale	the scale extracted from the total matrix (both values positive).
remaining	apply after scale to apply the total matrix.
remainingWithoutRotation	apply after scale to apply the total matrix sans rotation.
remainingRotation	apply after remainingWithoutRotation to apply the total matrix.
total	the total matrix.

Returns: false if the matrix was singular. The output will be valid but not invertible.

Definition at line 854 of file SkScalerContext.cpp.

{
    // A is the 'total' matrix.
    SkMatrix A;
    this->getSingleMatrix(&A);
 
    // The caller may find the 'total' matrix useful when dealing directly with EM sizes.
    if (A_out) {
        *A_out = A;
    }
 
    // GA is the matrix A with rotation removed.
    SkMatrix GA;
    bool skewedOrFlipped = A.getSkewX() || A.getSkewY() || A.getScaleX() < 0 || A.getScaleY() < 0;
    if (skewedOrFlipped) {
        // QR by Givens rotations. G is Q^T and GA is R. G is rotational (no reflections).
        // h is where A maps the horizontal baseline.
        SkPoint h = SkPoint::Make(SK_Scalar1, 0);
        A.mapPoints(&h, 1);
 
        // G is the Givens Matrix for A (rotational matrix where GA[0][1] == 0).
        SkMatrix G;
        SkComputeGivensRotation(h, &G);
 
        GA = G;
        GA.preConcat(A);
 
        // The 'remainingRotation' is G inverse, which is fairly simple since G is 2x2 rotational.
        if (G_inv) {
            G_inv->setAll(
                G.get(SkMatrix::kMScaleX), -G.get(SkMatrix::kMSkewX), G.get(SkMatrix::kMTransX),
                -G.get(SkMatrix::kMSkewY), G.get(SkMatrix::kMScaleY), G.get(SkMatrix::kMTransY),
                G.get(SkMatrix::kMPersp0), G.get(SkMatrix::kMPersp1), G.get(SkMatrix::kMPersp2));
        }
    } else {
        GA = A;
        if (G_inv) {
            G_inv->reset();
        }
    }
 
    // If the 'total' matrix is singular, set the 'scale' to something finite and zero the matrices.
    // All underlying ports have issues with zero text size, so use the matricies to zero.
    // If one of the scale factors is less than 1/256 then an EM filling square will
    // never affect any pixels.
    // If there are any nonfinite numbers in the matrix, bail out and set the matrices to zero.
    if (SkScalarAbs(GA.get(SkMatrix::kMScaleX)) <= SK_ScalarNearlyZero ||
        SkScalarAbs(GA.get(SkMatrix::kMScaleY)) <= SK_ScalarNearlyZero ||
        !GA.isFinite())
    {
        s->fX = SK_Scalar1;
        s->fY = SK_Scalar1;
        sA->setScale(0, 0);
        if (GsA) {
            GsA->setScale(0, 0);
        }
        if (G_inv) {
            G_inv->reset();
        }
        return false;
    }
 
    // At this point, given GA, create s.
    switch (preMatrixScale) {
        case PreMatrixScale::kFull:
            s->fX = SkScalarAbs(GA.get(SkMatrix::kMScaleX));
            s->fY = SkScalarAbs(GA.get(SkMatrix::kMScaleY));
            break;
        case PreMatrixScale::kVertical: {
            SkScalar yScale = SkScalarAbs(GA.get(SkMatrix::kMScaleY));
            s->fX = yScale;
            s->fY = yScale;
            break;
        }
        case PreMatrixScale::kVerticalInteger: {
            SkScalar realYScale = SkScalarAbs(GA.get(SkMatrix::kMScaleY));
            SkScalar intYScale = SkScalarRoundToScalar(realYScale);
            if (intYScale == 0) {
                intYScale = SK_Scalar1;
            }
            s->fX = intYScale;
            s->fY = intYScale;
            break;
        }
    }
 
    // The 'remaining' matrix sA is the total matrix A without the scale.
    if (!skewedOrFlipped && (
            (PreMatrixScale::kFull == preMatrixScale) ||
            (PreMatrixScale::kVertical == preMatrixScale && A.getScaleX() == A.getScaleY())))
    {
        // If GA == A and kFull, sA is identity.
        // If GA == A and kVertical and A.scaleX == A.scaleY, sA is identity.
        sA->reset();
    } else if (!skewedOrFlipped && PreMatrixScale::kVertical == preMatrixScale) {
        // If GA == A and kVertical, sA.scaleY is SK_Scalar1.
        sA->reset();
        sA->setScaleX(A.getScaleX() / s->fY);
    } else {
        // TODO: like kVertical, kVerticalInteger with int scales.
        *sA = A;
        sA->preScale(SkScalarInvert(s->fX), SkScalarInvert(s->fY));
    }
 
    // The 'remainingWithoutRotation' matrix GsA is the non-rotational part of A without the scale.
    if (GsA) {
        *GsA = GA;
         // G is rotational so reorders with the scale.
        GsA->preScale(SkScalarInvert(s->fX), SkScalarInvert(s->fY));
    }
 
    return true;
}

◆ dump()

SkString SkScalerContextRec::dump ( ) const

inline

Definition at line 143 of file SkScalerContext.h.

                          {
        SkString msg;
        msg.appendf("    Rec\n");
        msg.appendf("      textsize %a prescale %a preskew %a post [%a %a %a %a]\n",
                   fTextSize, fPreScaleX, fPreSkewX, fPost2x2[0][0],
                   fPost2x2[0][1], fPost2x2[1][0], fPost2x2[1][1]);
        msg.appendf("      frame %g miter %g format %d join %d cap %d flags %#hx\n",
                   fFrameWidth, fMiterLimit, fMaskFormat, fStrokeJoin, fStrokeCap, fFlags);
        msg.appendf("      lum bits %x, device gamma %d, paint gamma %d contrast %d\n", fLumBits,
                    fDeviceGamma, fPaintGamma, fContrast);
        msg.appendf("      foreground color %x\n", fForegroundColor);
        return msg;
    }

◆ getContrast()

SkScalar SkScalerContextRec::getContrast ( ) const

inline

Definition at line 100 of file SkScalerContext.h.

                                 {
        sk_ignore_unused_variable(fReservedAlign);
        return SkIntToScalar(fContrast) / ((1 << 8) - 1);
    }

◆ getDeviceGamma()

SkScalar SkScalerContextRec::getDeviceGamma ( ) const

inline

Definition at line 82 of file SkScalerContext.h.

                                    {
        return SkIntToScalar(fDeviceGamma) / (1 << 6);
    }

◆ getFormat()

SkMask::Format SkScalerContextRec::getFormat ( ) const

inline

Definition at line 211 of file SkScalerContext.h.

                                   {
        return fMaskFormat;
    }

◆ getHinting()

SkFontHinting SkScalerContextRec::getHinting ( ) const

inline

Definition at line 478 of file SkScalerContext.h.

                                                   {
    unsigned hint = (fFlags & SkScalerContext::kHinting_Mask) >>
                                            SkScalerContext::kHinting_Shift;
    return static_cast<SkFontHinting>(hint);
}

◆ getLocalMatrix()

void SkScalerContextRec::getLocalMatrix ( SkMatrix * m ) const

Definition at line 841 of file SkScalerContext.cpp.

                                                         {
    *m = SkFontPriv::MakeTextMatrix(fTextSize, fPreScaleX, fPreSkewX);
}

◆ getLuminanceColor()

SkColor SkScalerContextRec::getLuminanceColor ( ) const

inline

Definition at line 215 of file SkScalerContext.h.

                                      {
        return fLumBits;
    }

◆ getMatrixFrom2x2()

void SkScalerContextRec::getMatrixFrom2x2 ( SkMatrix * dst ) const

Definition at line 835 of file SkScalerContext.cpp.

                                                             {
    dst->setAll(fPost2x2[0][0], fPost2x2[0][1], 0,
                fPost2x2[1][0], fPost2x2[1][1], 0,
                0,              0,              1);
}

◆ getPaintGamma()

SkScalar SkScalerContextRec::getPaintGamma ( ) const

inline

Definition at line 91 of file SkScalerContext.h.

                                   {
        return SkIntToScalar(fPaintGamma) / (1 << 6);
    }

◆ getSingleMatrix()

void SkScalerContextRec::getSingleMatrix ( SkMatrix * m ) const

Definition at line 845 of file SkScalerContext.cpp.

                                                          {
    this->getLocalMatrix(m);
 
    //  now concat the device matrix
    SkMatrix    deviceMatrix;
    this->getMatrixFrom2x2(&deviceMatrix);
    m->postConcat(deviceMatrix);
}

◆ ignoreGamma()

void SkScalerContextRec::ignoreGamma ( )

inline

Causes the luminance color to be ignored, and the paint and device gamma to be effectively 1.0

Definition at line 114 of file SkScalerContext.h.

                       {
        setLuminanceColor(SK_ColorTRANSPARENT);
        setPaintGamma(SK_Scalar1);
        setDeviceGamma(SK_Scalar1);
    }

◆ ignorePreBlend()

void SkScalerContextRec::ignorePreBlend ( )

inline

Causes the luminance color and contrast to be ignored, and the paint and device gamma to be effectively 1.0.

Definition at line 124 of file SkScalerContext.h.

                          {
        ignoreGamma();
        setContrast(0);
    }

◆ setContrast()

void SkScalerContextRec::setContrast ( SkScalar c )

inline

Definition at line 104 of file SkScalerContext.h.

                                 {
        SkASSERT(SkSurfaceProps::kMinContrastInclusive <= c &&
                 c <= SkIntToScalar(SkSurfaceProps::kMaxContrastInclusive));
        fContrast = SkScalarRoundToInt(c * ((1 << 8) - 1));
    }

◆ setDeviceGamma()

void SkScalerContextRec::setDeviceGamma ( SkScalar dg )

inline

Definition at line 85 of file SkScalerContext.h.

                                     {
        SkASSERT(SkSurfaceProps::kMinGammaInclusive <= dg &&
                 dg < SkIntToScalar(SkSurfaceProps::kMaxGammaExclusive));
        fDeviceGamma = SkScalarFloorToInt(dg * (1 << 6));
    }

◆ setHinting()

void SkScalerContextRec::setHinting ( SkFontHinting hinting )

inline

Definition at line 484 of file SkScalerContext.h.

                                                         {
    fFlags = (fFlags & ~SkScalerContext::kHinting_Mask) |
                        (static_cast<unsigned>(hinting) << SkScalerContext::kHinting_Shift);
}

◆ setLuminanceColor()

void SkScalerContextRec::setLuminanceColor ( SkColor c )

Definition at line 996 of file SkScalerContext.cpp.

                                                    {
    fLumBits = SkMaskGamma::CanonicalColor(
            SkColorSetRGB(SkColorGetR(c), SkColorGetG(c), SkColorGetB(c)));
}

◆ setPaintGamma()

void SkScalerContextRec::setPaintGamma ( SkScalar pg )

inline

Definition at line 94 of file SkScalerContext.h.

                                    {
        SkASSERT(SkSurfaceProps::kMinGammaInclusive <= pg &&
                 pg < SkIntToScalar(SkSurfaceProps::kMaxGammaExclusive));
        fPaintGamma = SkScalarFloorToInt(pg * (1 << 6));
    }

Friends And Related Symbol Documentation

◆ SkScalerContext

friend class SkScalerContext

friend

Definition at line 225 of file SkScalerContext.h.

Member Data Documentation

◆ fFlags

uint16_t SkScalerContextRec::fFlags

Definition at line 136 of file SkScalerContext.h.

◆ fForegroundColor

uint32_t SkScalerContextRec::fForegroundColor {SK_ColorBLACK}

Definition at line 70 of file SkScalerContext.h.

70{SK_ColorBLACK};

SK_ColorBLACK

constexpr SkColor SK_ColorBLACK

Definition SkColor.h:103

◆ fFrameWidth

SkScalar SkScalerContextRec::fFrameWidth

Definition at line 65 of file SkScalerContext.h.

◆ fMaskFormat

SkMask::Format SkScalerContextRec::fMaskFormat

Definition at line 129 of file SkScalerContext.h.

◆ fMiterLimit

SkScalar SkScalerContextRec::fMiterLimit

Definition at line 65 of file SkScalerContext.h.

◆ fPost2x2

SkScalar SkScalerContextRec::fPost2x2[2][2]

Definition at line 64 of file SkScalerContext.h.

◆ fPreScaleX

SkScalar SkScalerContextRec::fPreScaleX

Definition at line 63 of file SkScalerContext.h.

◆ fPreSkewX

SkScalar SkScalerContextRec::fPreSkewX

Definition at line 63 of file SkScalerContext.h.

◆ fTextSize

SkScalar SkScalerContextRec::fTextSize

Definition at line 63 of file SkScalerContext.h.

◆ fTypefaceID

SkTypefaceID SkScalerContextRec::fTypefaceID

Definition at line 62 of file SkScalerContext.h.

The documentation for this struct was generated from the following files:

third_party/skia/src/core/SkScalerContext.h
third_party/skia/src/core/SkScalerContext.cpp

Public Types

Public Member Functions

Public Attributes

Friends

Detailed Description

Member Enumeration Documentation

◆ PreMatrixScale

Member Function Documentation

◆ computeAxisAlignmentForHText()

◆ computeMatrices()

◆ dump()

◆ getContrast()

◆ getDeviceGamma()

◆ getFormat()

◆ getHinting()

◆ getLocalMatrix()

◆ getLuminanceColor()

◆ getMatrixFrom2x2()

◆ getPaintGamma()

◆ getSingleMatrix()

◆ ignoreGamma()

◆ ignorePreBlend()

◆ setContrast()

◆ setDeviceGamma()

◆ setHinting()

◆ setLuminanceColor()

◆ setPaintGamma()

Friends And Related Symbol Documentation

◆ SkScalerContext

Member Data Documentation

◆ fFlags

◆ fForegroundColor

◆ fFrameWidth

◆ fMaskFormat

◆ fMiterLimit

◆ fPost2x2

◆ fPreScaleX

◆ fPreSkewX

◆ fTextSize

◆ fTypefaceID