SkPoint Struct Reference

#include <SkPoint_impl.h>

Public Member Functions
constexpr float	x () const
constexpr float	y () const
bool	isZero () const
void	set (float x, float y)
void	iset (int32_t x, int32_t y)
void	iset (const SkIPoint &p)
void	setAbs (const SkPoint &pt)
void	offset (float dx, float dy)
float	length () const
float	distanceToOrigin () const
bool	normalize ()
bool	setNormalize (float x, float y)
bool	setLength (float length)
bool	setLength (float x, float y, float length)
void	scale (float scale, SkPoint *dst) const
void	scale (float value)
void	negate ()
SkPoint	operator- () const
void	operator+= (const SkVector &v)
void	operator-= (const SkVector &v)
SkPoint	operator* (float scale) const
SkPoint &	operator*= (float scale)
bool	isFinite () const
bool	equals (float x, float y) const
float	cross (const SkVector &vec) const
float	dot (const SkVector &vec) const

Static Public Member Functions
static constexpr SkPoint	Make (float x, float y)
static void	Offset (SkPoint points[], int count, const SkVector &offset)
static void	Offset (SkPoint points[], int count, float dx, float dy)
static float	Length (float x, float y)
static float	Normalize (SkVector *vec)
static float	Distance (const SkPoint &a, const SkPoint &b)
static float	DotProduct (const SkVector &a, const SkVector &b)
static float	CrossProduct (const SkVector &a, const SkVector &b)

Public Attributes
float	fX
	x-axis value
float	fY
	y-axis value

Friends
bool	operator== (const SkPoint &a, const SkPoint &b)
bool	operator!= (const SkPoint &a, const SkPoint &b)
SkVector	operator- (const SkPoint &a, const SkPoint &b)
SkPoint	operator+ (const SkPoint &a, const SkVector &b)

Detailed Description

SkPoint holds two 32-bit floating point coordinates.

Definition at line 163 of file SkPoint_impl.h.

Member Function Documentation

cross()

float SkPoint::cross ( const SkVector &  vec ) const

inline

Returns the cross product of vector and vec.

Vector and vec form three-dimensional vectors with z-axis value equal to zero. The cross product is a three-dimensional vector with x-axis and y-axis values equal to zero. The cross product z-axis component is returned.

Parameters

vec	right side of cross product

Returns

area spanned by vectors signed by angle direction

Definition at line 545 of file SkPoint_impl.h.

                                           {
        return CrossProduct(*this, vec);
    }

CrossProduct()

static float SkPoint::CrossProduct ( const SkVector &  a, const SkVector &  b  )

inlinestatic

Returns the cross product of vector a and vector b.

a and b form three-dimensional vectors with z-axis value equal to zero. The cross product is a three-dimensional vector with x-axis and y-axis values equal to zero. The cross product z-axis component is returned.

Parameters

a	left side of cross product
b	right side of cross product

Returns

area spanned by vectors signed by angle direction

Definition at line 532 of file SkPoint_impl.h.

                                                                    {
        return a.fX * b.fY - a.fY * b.fX;
    }

Distance()

static float SkPoint::Distance ( const SkPoint &  a, const SkPoint &  b  )

inlinestatic

Returns the Euclidean distance between a and b.

Parameters

a	line end point
b	line end point

Returns

straight-line distance from a to b

Definition at line 508 of file SkPoint_impl.h.

                                                              {
        return Length(a.fX - b.fX, a.fY - b.fY);
    }

distanceToOrigin()

float SkPoint::distanceToOrigin ( ) const

inline

Returns the Euclidean distance from origin, computed as:

sqrt(fX * fX + fY * fY)

Returns

straight-line distance to origin

Definition at line 292 of file SkPoint_impl.h.

{ return this->length(); }

dot()

float SkPoint::dot ( const SkVector &  vec ) const

inline

Returns the dot product of vector and vector vec.

Parameters

vec	right side of dot product

Returns

product of input magnitudes and cosine of the angle between them

Definition at line 554 of file SkPoint_impl.h.

                                         {
        return DotProduct(*this, vec);
    }

DotProduct()

static float SkPoint::DotProduct ( const SkVector &  a, const SkVector &  b  )

inlinestatic

Returns the dot product of vector a and vector b.

Parameters

a	left side of dot product
b	right side of dot product

Returns

product of input magnitudes and cosine of the angle between them

Definition at line 518 of file SkPoint_impl.h.

                                                                  {
        return a.fX * b.fX + a.fY * b.fY;
    }

equals()

bool SkPoint::equals ( float  x, float  y  ) const

inline

Returns true if SkPoint is equivalent to SkPoint constructed from (x, y).

Parameters

x	value compared with fX
y	value compared with fY

Returns

true if SkPoint equals (x, y)

Definition at line 422 of file SkPoint_impl.h.

                                        {
        return fX == x && fY == y;
    }

iset() [1/2]

void SkPoint::iset ( const SkIPoint &  p )

inline

Sets fX to p.fX and fY to p.fY, promoting integers to float values.

Assigning an SkIPoint containing a large integer value directly to fX or fY may cause a compiler error, triggered by narrowing conversion of int to float. This safely casts p.fX and p.fY to avoid the error.

Parameters

p	SkIPoint members promoted to float

Definition at line 227 of file SkPoint_impl.h.

                                 {
        fX = static_cast<float>(p.fX);
        fY = static_cast<float>(p.fY);
    }

iset() [2/2]

void SkPoint::iset ( int32_t  x, int32_t  y  )

inline

Sets fX to x and fY to y, promoting integers to float values.

Assigning a large integer value directly to fX or fY may cause a compiler error, triggered by narrowing conversion of int to float. This safely casts x and y to avoid the error.

Parameters

x	new value for fX
y	new value for fY

Definition at line 214 of file SkPoint_impl.h.

                                    {
        fX = static_cast<float>(x);
        fY = static_cast<float>(y);
    }

isFinite()

bool SkPoint::isFinite ( ) const

inline

Returns true if both fX and fY are measurable values.

Returns

true for values other than infinities and NaN

Definition at line 412 of file SkPoint_impl.h.

                          {
        return SkIsFinite(fX, fY);
    }

isZero()

bool SkPoint::isZero ( ) const

inline

Returns true if fX and fY are both zero.

Returns

true if fX is zero and fY is zero

Definition at line 193 of file SkPoint_impl.h.

{ return (0 == fX) & (0 == fY); }

length()

float SkPoint::length ( ) const

inline

Returns the Euclidean distance from origin, computed as:

sqrt(fX * fX + fY * fY)

Returns

straight-line distance to origin

Definition at line 282 of file SkPoint_impl.h.

{ return SkPoint::Length(fX, fY); }

Length()

float SkPoint::Length ( float  x, float  y  )

static

Returns the Euclidean distance from origin, computed as:

sqrt(x * x + y * y)

Parameters

x	component of length
y	component of length

Returns

straight-line distance to origin

example: https://fiddle.skia.org/c/@Point_Length

Definition at line 79 of file SkPoint.cpp.

                                        {
    float mag2 = dx * dx + dy * dy;
    if (SkIsFinite(mag2)) {
        return std::sqrt(mag2);
    } else {
        double xx = dx;
        double yy = dy;
        return sk_double_to_float(sqrt(xx * xx + yy * yy));
    }
}

Make()

static constexpr SkPoint SkPoint::Make ( float  x, float  y  )

inlinestaticconstexpr

Sets fX to x, fY to y. Used both to set SkPoint and vector.

Parameters

x	float x-axis value of constructed SkPoint or vector
y	float y-axis value of constructed SkPoint or vector

Returns

SkPoint (x, y)

Definition at line 173 of file SkPoint_impl.h.

                                                    {
        return {x, y};
    }

negate()

void SkPoint::negate ( )

inline

Changes the sign of fX and fY.

Definition at line 357 of file SkPoint_impl.h.

                  {
        fX = -fX;
        fY = -fY;
    }

normalize()

bool SkPoint::normalize

(

)

Scales (fX, fY) so that length() returns one, while preserving ratio of fX to fY, if possible. If prior length is nearly zero, sets vector to (0, 0) and returns false; otherwise returns true.

Returns

true if former length is not zero or nearly zero

example: https://fiddle.skia.org/c/@Point_normalize_2

Definition at line 22 of file SkPoint.cpp.

                        {
    return this->setLength(fX, fY, 1);
}

Normalize()

float SkPoint::Normalize ( SkVector *  vec )

static

Scales (vec->fX, vec->fY) so that length() returns one, while preserving ratio of vec->fX to vec->fY, if possible. If original length is nearly zero, sets vec to (0, 0) and returns zero; otherwise, returns length of vec before vec is scaled.

Returned prior length may be INFINITY if it can not be represented by float.

Note that normalize() is faster if prior length is not required.

Parameters

vec	normalized to unit length

Returns

original vec length

example: https://fiddle.skia.org/c/@Point_Normalize

Definition at line 71 of file SkPoint.cpp.

                                    {
    float mag;
    if (set_point_length<false>(pt, pt->fX, pt->fY, 1.0f, &mag)) {
        return mag;
    }
    return 0;
}

offset()

void SkPoint::offset ( float  dx, float  dy  )

inline

Adds offset (dx, dy) to SkPoint.

Parameters

dx	added to fX
dy	added to fY

Definition at line 269 of file SkPoint_impl.h.

                                    {
        fX += dx;
        fY += dy;
    }

Offset() [1/2]

static void SkPoint::Offset ( SkPoint  points[], int  count, const SkVector &  offset  )

inlinestatic

Adds offset to each SkPoint in points array with count entries.

Parameters

points	SkPoint array
count	entries in array
offset	vector added to points

Definition at line 247 of file SkPoint_impl.h.

                                                                            {
        Offset(points, count, offset.fX, offset.fY);
    }

Offset() [2/2]

static void SkPoint::Offset ( SkPoint  points[], int  count, float  dx, float  dy  )

inlinestatic

Adds offset (dx, dy) to each SkPoint in points array of length count.

Parameters

points	SkPoint array
count	entries in array
dx	added to fX in points
dy	added to fY in points

Definition at line 258 of file SkPoint_impl.h.

                                                                        {
        for (int i = 0; i < count; ++i) {
            points[i].offset(dx, dy);
        }
    }

operator*()

SkPoint SkPoint::operator* ( float  scale ) const

inline

Returns SkPoint multiplied by scale.

Parameters

scale

float to multiply by

Returns

SkPoint as (fX * scale, fY * scale)

Definition at line 393 of file SkPoint_impl.h.

                                         {
        return {fX * scale, fY * scale};
    }

operator*=()

SkPoint & SkPoint::operator*= ( float  scale )

inline

Multiplies SkPoint by scale. Sets SkPoint to: (fX * scale, fY * scale).

Parameters

scale

float to multiply by

Returns

reference to SkPoint

Definition at line 402 of file SkPoint_impl.h.

                                     {
        fX *= scale;
        fY *= scale;
        return *this;
    }

operator+=()

void SkPoint::operator+= ( const SkVector &  v )

inline

Adds vector v to SkPoint. Sets SkPoint to: (fX + v.fX, fY + v.fY).

Parameters

v	vector to add

Definition at line 374 of file SkPoint_impl.h.

                                       {
        fX += v.fX;
        fY += v.fY;
    }

operator-()

SkPoint SkPoint::operator- ( ) const

inline

Returns SkPoint changing the signs of fX and fY.

Returns

SkPoint as (-fX, -fY)

Definition at line 366 of file SkPoint_impl.h.

                              {
        return {-fX, -fY};
    }

operator-=()

void SkPoint::operator-= ( const SkVector &  v )

inline

Subtracts vector v from SkPoint. Sets SkPoint to: (fX - v.fX, fY - v.fY).

Parameters

v	vector to subtract

Definition at line 383 of file SkPoint_impl.h.

                                       {
        fX -= v.fX;
        fY -= v.fY;
    }

scale() [1/2]

void SkPoint::scale	(	float	scale,
		SkPoint *	dst
	)		const

Sets dst to SkPoint times scale. dst may be SkPoint to modify SkPoint in place.

Parameters

scale	factor to multiply SkPoint by
dst	storage for scaled SkPoint

example: https://fiddle.skia.org/c/@Point_scale

Definition at line 17 of file SkPoint.cpp.

                                                   {
    SkASSERT(dst);
    dst->set(fX * scale, fY * scale);
}

scale() [2/2]

void SkPoint::scale ( float  value )

inline

Scales SkPoint in place by scale.

Parameters

value

factor to multiply SkPoint by

Definition at line 353 of file SkPoint_impl.h.

{ this->scale(value, this); }

set()

void SkPoint::set ( float  x, float  y  )

inline

Sets fX to x and fY to y.

Parameters

x	new value for fX
y	new value for fY

Definition at line 200 of file SkPoint_impl.h.

                               {
        fX = x;
        fY = y;
    }

setAbs()

void SkPoint::setAbs ( const SkPoint &  pt )

inline

Sets fX to absolute value of pt.fX; and fY to absolute value of pt.fY.

Parameters

pt	members providing magnitude for fX and fY

Definition at line 236 of file SkPoint_impl.h.

                                   {
        fX = std::abs(pt.fX);
        fY = std::abs(pt.fY);
    }

setLength() [1/2]

bool SkPoint::setLength

(

float

length

)

Scales vector so that distanceToOrigin() returns length, if possible. If former length is nearly zero, sets vector to (0, 0) and return false; otherwise returns true.

Parameters

length

straight-line distance to origin

Returns

true if former length is not zero or nearly zero

example: https://fiddle.skia.org/c/@Point_setLength

Definition at line 30 of file SkPoint.cpp.

                                    {
    return this->setLength(fX, fY, length);
}

setLength() [2/2]

bool SkPoint::setLength	(	float	x,
		float	y,
		float	length
	)

Sets vector to (x, y) scaled to length, if possible. If former length is nearly zero, sets vector to (0, 0) and return false; otherwise returns true.

Parameters

x	proportional value for fX
y	proportional value for fY
length	straight-line distance to origin

Returns

true if (x, y) length is not zero or nearly zero

example: https://fiddle.skia.org/c/@Point_setLength_2

Definition at line 90 of file SkPoint.cpp.

                                                      {
    return set_point_length<false>(this, x, y, length);
}

setNormalize()

bool SkPoint::setNormalize	(	float	x,
		float	y
	)

Sets vector to (x, y) scaled so length() returns one, and so that (fX, fY) is proportional to (x, y). If (x, y) length is nearly zero, sets vector to (0, 0) and returns false; otherwise returns true.

Parameters

x	proportional value for fX
y	proportional value for fY

Returns

true if (x, y) length is not zero or nearly zero

example: https://fiddle.skia.org/c/@Point_setNormalize

Definition at line 26 of file SkPoint.cpp.

                                           {
    return this->setLength(x, y, 1);
}

x()

constexpr float SkPoint::x ( ) const

inlineconstexpr

Returns x-axis value of SkPoint or vector.

Returns

fX

Definition at line 181 of file SkPoint_impl.h.

{ return fX; }

y()

constexpr float SkPoint::y ( ) const

inlineconstexpr

Returns y-axis value of SkPoint or vector.

Returns

fY

Definition at line 187 of file SkPoint_impl.h.

{ return fY; }

Friends And Related Symbol Documentation

operator!=

bool operator!= ( const SkPoint &  a, const SkPoint &  b  )

friend

Returns true if a is not equivalent to b.

Parameters

a	SkPoint to compare
b	SkPoint to compare

Returns

true if a.fX != b.fX or a.fY != b.fY

Definition at line 442 of file SkPoint_impl.h.

                                                               {
        return a.fX != b.fX || a.fY != b.fY;
    }

operator+

SkPoint operator+ ( const SkPoint &  a, const SkVector &  b  )

friend

Returns SkPoint resulting from SkPoint a offset by vector b, computed as: (a.fX + b.fX, a.fY + b.fY).

Can also be used to offset SkPoint b by vector a, returning SkPoint. Can also be used to add vector to vector, returning vector.

Parameters

a	SkPoint or vector to add to
b	SkPoint or vector to add

Returns

SkPoint equal to a offset by b

Definition at line 469 of file SkPoint_impl.h.

                                                                  {
        return {a.fX + b.fX, a.fY + b.fY};
    }

operator-

SkVector operator- ( const SkPoint &  a, const SkPoint &  b  )

friend

Returns vector from b to a, computed as (a.fX - b.fX, a.fY - b.fY).

Can also be used to subtract vector from SkPoint, returning SkPoint. Can also be used to subtract vector from vector, returning vector.

Parameters

a	SkPoint to subtract from
b	SkPoint to subtract

Returns

vector from b to a

Definition at line 455 of file SkPoint_impl.h.

                                                                  {
        return {a.fX - b.fX, a.fY - b.fY};
    }

operator==

bool operator== ( const SkPoint &  a, const SkPoint &  b  )

friend

Returns true if a is equivalent to b.

Parameters

a	SkPoint to compare
b	SkPoint to compare

Returns

true if a.fX == b.fX and a.fY == b.fY

Definition at line 432 of file SkPoint_impl.h.

                                                               {
        return a.fX == b.fX && a.fY == b.fY;
    }

Member Data Documentation

fX

float SkPoint::fX

x-axis value

Definition at line 164 of file SkPoint_impl.h.

fY

float SkPoint::fY

y-axis value

Definition at line 165 of file SkPoint_impl.h.

---

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

• third_party/skia/include/private/base/SkPoint_impl.h
• third_party/skia/src/core/SkPoint.cpp