Shaders specify the source color(s) for what is being drawn. More...

#include <SkShader.h>

Inheritance diagram for SkShader:

Classes
struct	GradientInfo

Public Types
enum	TileMode { kClamp_TileMode, kRepeat_TileMode, kMirror_TileMode }

enum	{ kTileModeCount = kMirror_TileMode + 1 }

enum	GradientType { kNone_GradientType, kColor_GradientType, kLinear_GradientType, kRadial_GradientType, kSweep_GradientType, kConical_GradientType, kLast_GradientType = kConical_GradientType }
	If the shader subclass can be represented as a gradient, asAGradient returns the matching GradientType enum (or kNone_GradientType if it cannot). More...

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

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

Public Member Functions
const SkMatrix &	getLocalMatrix () const
	Returns the local matrix. More...

virtual bool	isOpaque () const
	Returns true if the shader is guaranteed to produce only opaque colors, subject to the SkPaint using the shader to apply an opaque alpha value. More...

SkImage *	isAImage (SkMatrix *localMatrix, TileMode xy[2]) const
	Iff this shader is backed by a single SkImage, return its ptr (the caller must ref this if they want to keep it longer than the lifetime of the shader). More...

bool	isAImage () const

virtual GradientType	asAGradient (GradientInfo *info) const

sk_sp< SkShader >	makeWithLocalMatrix (const SkMatrix &) const
	Return a shader that will apply the specified localMatrix to this shader. More...

sk_sp< SkShader >	makeWithColorFilter (sk_sp< SkColorFilter >) const
	Create a new shader that produces the same colors as invoking this shader and then applying the colorfilter.

virtual sk_sp< SkShader >	makeAsALocalMatrixShader (SkMatrix *localMatrix) const
	If this shader can be represented by another shader + a localMatrix, return that shader and the localMatrix. 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 sk_sp< SkShader >	MakeEmptyShader ()
	Call this to create a new "empty" shader, that will not draw anything.

static sk_sp< SkShader >	MakeColorShader (SkColor)
	Call this to create a new shader that just draws the specified color. More...

static sk_sp< SkShader >	MakeColorShader (const SkColor4f &, sk_sp< SkColorSpace >)
	Create a shader that draws the specified color (in the specified colorspace). More...

static sk_sp< SkShader >	MakeCompose (sk_sp< SkShader > dst, sk_sp< SkShader > src, SkBlendMode mode, float lerp=1)
	Compose two shaders together, using two operators: mode and lerp. More...

static sk_sp< SkShader >	MakeComposeShader (sk_sp< SkShader > dst, sk_sp< SkShader > src, SkBlendMode mode)

static sk_sp< SkShader >	MakeMixer (sk_sp< SkShader > dst, sk_sp< SkShader > src, float lerp)
	Compose two shaders together using a weighted average. More...

static sk_sp< SkShader >	MakeBitmapShader (const SkBitmap &src, TileMode tmx, TileMode tmy, const SkMatrix *localMatrix=nullptr)
	Call this to create a new shader that will draw with the specified bitmap. More...

static sk_sp< SkShader >	MakePictureShader (sk_sp< SkPicture > src, TileMode tmx, TileMode tmy, const SkMatrix localMatrix, const SkRect tile)
	Call this to create a new shader that will draw with the specified picture. More...

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)

Private Types
typedef SkFlattenable	INHERITED

Friends
class	SkShaderBase

Additional Inherited Members
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...

Detailed Description

Shaders specify the source color(s) for what is being drawn.

If a paint has no shader, then the paint's color is used. If the paint has a shader, then the shader's color(s) are use instead, but they are modulated by the paint's alpha. This makes it easy to create a shader once (e.g. bitmap tiling or gradient) and then change its transparency w/o having to modify the original shader... only the paint's alpha needs to be modified.

Member Enumeration Documentation

enum SkShader::GradientType

If the shader subclass can be represented as a gradient, asAGradient returns the matching GradientType enum (or kNone_GradientType if it cannot).

Also, if info is not null, asAGradient populates info with the relevant (see below) parameters for the gradient. fColorCount is both an input and output parameter. On input, it indicates how many entries in fColors and fColorOffsets can be used, if they are non-NULL. After asAGradient has run, fColorCount indicates how many color-offset pairs there are in the gradient. If there is insufficient space to store all of the color-offset pairs, fColors and fColorOffsets will not be altered. fColorOffsets specifies where on the range of 0 to 1 to transition to the given color. The meaning of fPoint and fRadius is dependant on the type of gradient.

None: info is ignored. Color: fColorOffsets[0] is meaningless. Linear: fPoint[0] and fPoint[1] are the end-points of the gradient Radial: fPoint[0] and fRadius[0] are the center and radius Conical: fPoint[0] and fRadius[0] are the center and radius of the 1st circle fPoint[1] and fRadius[1] are the center and radius of the 2nd circle Sweep: fPoint[0] is the center of the sweep.

enum SkShader::TileMode

Enumerator
kClamp_TileMode	replicate the edge color if the shader draws outside of its original bounds
kRepeat_TileMode	repeat the shader's image horizontally and vertically
kMirror_TileMode	repeat the shader's image horizontally and vertically, alternating mirror images so that adjacent images always seam

Member Function Documentation

const SkMatrix& SkShader::getLocalMatrix ( ) const

Returns the local matrix.

FIXME: This can be incorrect for a Shader with its own local matrix that is also wrapped via CreateLocalMatrixShader.

SkImage* SkShader::isAImage	(	SkMatrix *	localMatrix,
		TileMode	xy[2]
	)		const

Iff this shader is backed by a single SkImage, return its ptr (the caller must ref this if they want to keep it longer than the lifetime of the shader).

If not, return nullptr.

virtual bool SkShader::isOpaque ( ) const

inlinevirtual

Returns true if the shader is guaranteed to produce only opaque colors, subject to the SkPaint using the shader to apply an opaque alpha value.

Subclasses should override this to allow some optimizations.

virtual sk_sp<SkShader> SkShader::makeAsALocalMatrixShader ( SkMatrix * localMatrix ) const

virtual

If this shader can be represented by another shader + a localMatrix, return that shader and the localMatrix.

If not, return nullptr and ignore the localMatrix parameter.

static sk_sp<SkShader> SkShader::MakeBitmapShader	(	const SkBitmap &	src,
		TileMode	tmx,
		TileMode	tmy,
		const SkMatrix *	localMatrix = `nullptr`
	)

static

Call this to create a new shader that will draw with the specified bitmap.

If the bitmap cannot be used (e.g. has no pixels, or its dimensions exceed implementation limits (currently at 64K - 1)) then SkEmptyShader may be returned.

If the src is kA8_Config then that mask will be colorized using the color on the paint.

Parameters

src	The bitmap to use inside the shader
tmx	The tiling mode to use when sampling the bitmap in the x-direction.
tmy	The tiling mode to use when sampling the bitmap in the y-direction.

Returns: Returns a new shader object. Note: this function never returns null.

static sk_sp<SkShader> SkShader::MakeColorShader ( SkColor )

static

Call this to create a new shader that just draws the specified color.

This should always draw the same as a paint with this color (and no shader).

static sk_sp<SkShader> SkShader::MakeColorShader	(	const SkColor4f &	,
		sk_sp< SkColorSpace >
	)

static

Create a shader that draws the specified color (in the specified colorspace).

This works around the limitation that SkPaint::setColor() only takes byte values, and does not support specific colorspaces.

static sk_sp<SkShader> SkShader::MakeCompose	(	sk_sp< SkShader >	dst,
		sk_sp< SkShader >	src,
		SkBlendMode	mode,
		float	lerp = `1`
	)

static

Compose two shaders together, using two operators: mode and lerp.

The resulting colors are computed by first combining the src and dst shaders using mode, and then linearly interpolating between the dst and result colors using lerp.

result = dst * (1 - lerp) + (src (mode) dst) * lerp

If either shader is nullptr, then this returns nullptr. If lerp is NaN then this returns nullptr, otherwise lerp is clamped to [0..1].

static sk_sp<SkShader> SkShader::MakeMixer	(	sk_sp< SkShader >	dst,
		sk_sp< SkShader >	src,
		float	lerp
	)

inlinestatic

Compose two shaders together using a weighted average.

result = dst * (1 - lerp) + src * lerp

If either shader is nullptr, then this returns nullptr. If lerp is NaN then this returns nullptr, otherwise lerp is clamped to [0..1].

static sk_sp<SkShader> SkShader::MakePictureShader	(	sk_sp< SkPicture >	src,
		TileMode	tmx,
		TileMode	tmy,
		const SkMatrix *	localMatrix,
		const SkRect *	tile
	)

static

Call this to create a new shader that will draw with the specified picture.

Parameters

src	The picture to use inside the shader (if not NULL, its ref count is incremented). The SkPicture must not be changed after successfully creating a picture shader.
tmx	The tiling mode to use when sampling the bitmap in the x-direction.
tmy	The tiling mode to use when sampling the bitmap in the y-direction.
tile	The tile rectangle in picture coordinates: this represents the subset (or superset) of the picture used when building a tile. It is not affected by localMatrix and does not imply scaling (only translation and cropping). If null, the tile rect is considered equal to the picture bounds.

Returns: Returns a new shader object. Note: this function never returns null.

sk_sp<SkShader> SkShader::makeWithLocalMatrix ( const SkMatrix & ) const

Return a shader that will apply the specified localMatrix to this shader.

The specified matrix will be applied before any matrix associated with this shader.

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

include/core/SkShader.h

Classes

Public Types

Public Member Functions

Static Public Member Functions

Private Types

Friends

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

Member Function Documentation