SkXfermode is the base class for objects that are called to implement custom "transfer-modes" in the drawing pipeline. More...

#include <SkXfermode.h>

Inheritance diagram for SkXfermode:

Public Types
enum	Coeff { kZero_Coeff, kOne_Coeff, kSC_Coeff, kISC_Coeff, kDC_Coeff, kIDC_Coeff, kSA_Coeff, kISA_Coeff, kDA_Coeff, kIDA_Coeff, kCoeffCount }
	Enum of possible coefficients to describe some xfermodes. More...

enum	Mode { kClear_Mode, kSrc_Mode, kDst_Mode, kSrcOver_Mode, kDstOver_Mode, kSrcIn_Mode, kDstIn_Mode, kSrcOut_Mode, kDstOut_Mode, kSrcATop_Mode, kDstATop_Mode, kXor_Mode, kPlus_Mode, kModulate_Mode, kScreen_Mode, kLastCoeffMode = kScreen_Mode, kOverlay_Mode, kDarken_Mode, kLighten_Mode, kColorDodge_Mode, kColorBurn_Mode, kHardLight_Mode, kSoftLight_Mode, kDifference_Mode, kExclusion_Mode, kMultiply_Mode, kLastSeparableMode = kMultiply_Mode, kHue_Mode, kSaturation_Mode, kColor_Mode, kLuminosity_Mode, kLastMode = kLuminosity_Mode }
	List of predefined xfermodes. More...

enum	SrcColorOpacity { kOpaque_SrcColorOpacity = 0, kTransparentBlack_SrcColorOpacity = 1, kTransparentAlpha_SrcColorOpacity = 2, kUnknown_SrcColorOpacity = 3 }

enum	D32Flags { kSrcIsOpaque_D32Flag = 1 << 0, kSrcIsSingle_D32Flag = 1 << 1, kDstIsSRGB_D32Flag = 1 << 2 }

enum	F16Flags { kSrcIsOpaque_F16Flag = 1 << 0, kSrcIsSingle_F16Flag = 1 << 1 }

enum	LCDFlags { kSrcIsOpaque_LCDFlag = 1 << 0, kSrcIsSingle_LCDFlag = 1 << 1, kDstIsSRGB_LCDFlag = 1 << 2 }

typedef void(*	D32Proc )(const SkXfermode *, uint32_t dst[], const SkPM4f src[], int count, const SkAlpha coverage[])

typedef void(*	F16Proc )(const SkXfermode *, uint64_t dst[], const SkPM4f src[], int count, const SkAlpha coverage[])

typedef void(*	LCD32Proc )(uint32_t dst, const SkPM4f src, int count, const uint16_t lcd[])

typedef void(*	LCDF16Proc )(uint64_t dst, const SkPM4f src, int count, const uint16_t lcd[])

Public Types inherited from SkFlattenable
enum	Type { kSkColorFilter_Type, kSkDrawable_Type, kSkDrawLooper_Type, kSkImageFilter_Type, kSkMaskFilter_Type, kSkPathEffect_Type, kSkPixelRef_Type, kSkRasterizer_Type, kSkShader_Type, kSkUnused_Type, kSkXfermode_Type, kSkNormalSource_Type }

typedef sk_sp< SkFlattenable >(*	Factory )(SkReadBuffer &)

Public Member Functions
virtual void	xfer32 (SkPMColor dst[], const SkPMColor src[], int count, const SkAlpha aa[]) const

virtual void	xfer16 (uint16_t dst[], const SkPMColor src[], int count, const SkAlpha aa[]) const

virtual void	xferA8 (SkAlpha dst[], const SkPMColor src[], int count, const SkAlpha aa[]) const

virtual bool	asMode (Mode *mode) const
	If the xfermode is one of the modes in the Mode enum, then asMode() returns true and sets (if not null) mode accordingly. More...

virtual SkXfermodeProc4f	getProc4f () const

bool	appendStages (SkRasterPipeline *) const

virtual bool	supportsCoverageAsAlpha () const
	Returns whether or not the xfer mode can support treating coverage as alpha.

virtual bool	isOpaque (SrcColorOpacity opacityType) const
	Returns whether or not the result of the draw with the xfer mode will be opaque or not. More...

virtual sk_sp < GrFragmentProcessor >	makeFragmentProcessorForImageFilter (sk_sp< GrFragmentProcessor > dst) const
	Used by the SkXfermodeImageFilter to blend two colors via a GrFragmentProcessor. More...

virtual sk_sp< GrXPFactory >	asXPFactory () const
	A subclass must implement this factory function to work with the GPU backend. More...

Public Member Functions inherited from SkFlattenable
virtual Factory	getFactory () const =0
	Implement this to return a factory function pointer that can be called to recreate your class given a buffer (previously written to by your override of flatten().

virtual const char *	getTypeName () const
	Returns the name of the object's class. More...

virtual void	flatten (SkWriteBuffer &) const
	Override this if your subclass needs to record data that it will need to recreate itself from its CreateProc (returned by getFactory()).

Public Member Functions inherited from SkRefCntBase
	SkRefCntBase ()
	Default construct, initializing the reference count to 1.

virtual	~SkRefCntBase ()
	Destruct, asserting that the reference count is 1.

int32_t	getRefCnt () const
	Return the reference count. More...

void	validate () const

bool	unique () const
	May return true if the caller is the only owner. More...

void	ref () const
	Increment the reference count. More...

void	unref () const
	Decrement the reference count. More...

Static Public Member Functions
static const char *	ModeName (Mode)
	Gets the name of the Mode as a string.

static bool	AsMode (const SkXfermode , Mode mode)
	The same as calling xfermode->asMode(mode), except that this also checks if the xfermode is NULL, and if so, treats it as kSrcOver_Mode.

static bool	AsMode (const sk_sp< SkXfermode > &xfer, Mode *mode)

static bool	IsMode (const SkXfermode *xfer, Mode mode)
	Returns true if the xfermode claims to be the specified Mode. More...

static bool	IsMode (const sk_sp< SkXfermode > &xfer, Mode mode)

static sk_sp< SkXfermode >	Make (Mode)
	Return an SkXfermode object for the specified mode.

static SkXfermodeProc	GetProc (Mode mode)
	Return a function pointer to a routine that applies the specified porter-duff transfer mode.

static SkXfermodeProc4f	GetProc4f (Mode)

static bool	ModeAsCoeff (Mode mode, Coeff src, Coeff dst)
	If the specified mode can be represented by a pair of Coeff, then return true and set (if not NULL) the corresponding coeffs. More...

static bool	SupportsCoverageAsAlpha (const SkXfermode *xfer)
	The same as calling xfermode->supportsCoverageAsAlpha(), except that this also checks if the xfermode is NULL, and if so, treats it as kSrcOver_Mode.

static bool	SupportsCoverageAsAlpha (const sk_sp< SkXfermode > &xfer)

static bool	IsOpaque (const SkXfermode *xfer, SrcColorOpacity opacityType)
	The same as calling xfermode->isOpaque(...), except that this also checks if the xfermode is NULL, and if so, treats it as kSrcOver_Mode.

static bool	IsOpaque (const sk_sp< SkXfermode > &xfer, SrcColorOpacity opacityType)

static D32Proc	GetD32Proc (SkXfermode *, uint32_t flags)

static D32Proc	GetD32Proc (const sk_sp< SkXfermode > &xfer, uint32_t flags)

static F16Proc	GetF16Proc (SkXfermode *, uint32_t flags)

static F16Proc	GetF16Proc (const sk_sp< SkXfermode > &xfer, uint32_t flags)

static LCD32Proc	GetLCD32Proc (uint32_t flags)

static LCDF16Proc	GetLCDF16Proc (uint32_t)

Static Public Member Functions inherited from SkFlattenable
static Factory	NameToFactory (const char name[])

static const char *	FactoryToName (Factory)

static bool	NameToType (const char name[], Type *type)

static void	Register (const char name[], Factory, Type)

Protected Member Functions
virtual SkPMColor	xferColor (SkPMColor src, SkPMColor dst) const
	The default implementation of xfer32/xfer16/xferA8 in turn call this method, 1 color at a time (upscaled to a SkPMColor). More...

virtual D32Proc	onGetD32Proc (uint32_t flags) const

virtual F16Proc	onGetF16Proc (uint32_t flags) const

virtual bool	onAppendStages (SkRasterPipeline *) const

Protected Member Functions inherited from SkRefCntBase
void	internal_dispose_restore_refcnt_to_1 () const
	Allow subclasses to call this if they've overridden internal_dispose so they can reset fRefCnt before the destructor is called or if they choose not to call the destructor (e.g. More...

Private Types
enum	{ kModeCount = kLastMode + 1 }

typedef SkFlattenable	INHERITED

Detailed Description

SkXfermode is the base class for objects that are called to implement custom "transfer-modes" in the drawing pipeline.

The static function Create(Modes) can be called to return an instance of any of the predefined subclasses as specified in the Modes enum. When an SkXfermode is assigned to an SkPaint, then objects drawn with that paint have the xfermode applied.

All subclasses are required to be reentrant-safe : it must be legal to share the same instance between several threads.

Member Enumeration Documentation

enum SkXfermode::Coeff

Enum of possible coefficients to describe some xfermodes.

Enumerator
kOne_Coeff	0
kSC_Coeff	1
kISC_Coeff	src color
kDC_Coeff	inverse src color (i.e. 1 - sc)
kIDC_Coeff	dst color
kSA_Coeff	inverse dst color (i.e. 1 - dc)
kISA_Coeff	src alpha
kDA_Coeff	inverse src alpha (i.e. 1 - sa)
kIDA_Coeff	dst alpha
kCoeffCount	inverse dst alpha (i.e. 1 - da)

enum SkXfermode::Mode

List of predefined xfermodes.

The algebra for the modes uses the following symbols: Sa, Sc - source alpha and color Da, Dc - destination alpha and color (before compositing) [a, c] - Resulting (alpha, color) values For these equations, the colors are in premultiplied state. If no xfermode is specified, kSrcOver is assumed. The modes are ordered by those that can be expressed as a pair of Coeffs, followed by those that aren't Coeffs but have separable r,g,b computations, and finally those that are not separable.

Enumerator
kClear_Mode	[0, 0]
kSrc_Mode	[Sa, Sc]
kDst_Mode	[Da, Dc]
kSrcOver_Mode	[Sa + Da * (1 - Sa), Sc + Dc * (1 - Sa)]
kDstOver_Mode	[Da + Sa * (1 - Da), Dc + Sc * (1 - Da)]
kSrcIn_Mode	[Sa * Da, Sc * Da]
kDstIn_Mode	[Da * Sa, Dc * Sa]
kSrcOut_Mode	[Sa * (1 - Da), Sc * (1 - Da)]
kDstOut_Mode	[Da * (1 - Sa), Dc * (1 - Sa)]
kSrcATop_Mode	[Da, Sc * Da + Dc * (1 - Sa)]
kDstATop_Mode	[Sa, Dc * Sa + Sc * (1 - Da)]
kXor_Mode	[Sa + Da - 2 * Sa * Da, Sc * (1 - Da) + Dc * (1 - Sa)]
kPlus_Mode	[Sa + Da, Sc + Dc]

Member Function Documentation

virtual bool SkXfermode::asMode ( Mode * mode ) const

virtual

If the xfermode is one of the modes in the Mode enum, then asMode() returns true and sets (if not null) mode accordingly.

Otherwise it returns false and ignores the mode parameter.

virtual sk_sp<GrXPFactory> SkXfermode::asXPFactory ( ) const

virtual

A subclass must implement this factory function to work with the GPU backend.

The xfermode will return a factory for which the caller will get a ref. It is up to the caller to install it. XferProcessors cannot use a background texture.

static bool SkXfermode::IsMode	(	const SkXfermode *	xfer,
		Mode	mode
	)

static

Returns true if the xfermode claims to be the specified Mode.

This works correctly even if the xfermode is NULL (which equates to kSrcOver.) Thus you can say this without checking for a null...

If (SkXfermode::IsMode(paint.getXfermode(), SkXfermode::kDstOver_Mode)) { ... }

virtual bool SkXfermode::isOpaque ( SrcColorOpacity opacityType ) const

virtual

Returns whether or not the result of the draw with the xfer mode will be opaque or not.

The input to this call is an enum describing known information about the opacity of the src color that will be given to the xfer mode.

virtual sk_sp<GrFragmentProcessor> SkXfermode::makeFragmentProcessorForImageFilter ( sk_sp< GrFragmentProcessor > dst ) const

virtual

Used by the SkXfermodeImageFilter to blend two colors via a GrFragmentProcessor.

The input to the returned FP is the src color. The dst color is provided by the dst param which becomes a child FP of the returned FP. It is legal for the function to return a null output. This indicates that the output of the blend is simply the src color.

static bool SkXfermode::ModeAsCoeff	(	Mode	mode,
		Coeff *	src,
		Coeff *	dst
	)

static

If the specified mode can be represented by a pair of Coeff, then return true and set (if not NULL) the corresponding coeffs.

If the mode is not representable as a pair of Coeffs, return false and ignore the src and dst parameters.

virtual SkPMColor SkXfermode::xferColor	(	SkPMColor	src,
		SkPMColor	dst
	)		const

protectedvirtual

The default implementation of xfer32/xfer16/xferA8 in turn call this method, 1 color at a time (upscaled to a SkPMColor).

The default implementation of this method just returns dst. If performance is important, your subclass should override xfer32/xfer16/xferA8 directly.

This method will not be called directly by the client, so it need not be implemented if your subclass has overridden xfer32/xfer16/xferA8

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

include/core/SkXfermode.h

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Private Types

Detailed Description

Member Enumeration Documentation

Member Function Documentation