#include <rstransform.h>

Public Member Functions
constexpr	RSTransform ()

constexpr	RSTransform (Scalar scaled_cos, Scalar scaled_sin, Scalar translate_x, Scalar translate_y)

bool	IsAxisAligned () const

Matrix	GetMatrix () const

void	GetQuad (Scalar width, Scalar height, Quad &quad) const

Quad	GetQuad (Scalar width, Scalar height) const

Quad	GetQuad (Size size) const

std::optional< Rect >	GetBounds (Scalar width, Scalar height) const

std::optional< Rect >	GetBounds (Size size) const

Static Public Member Functions
static RSTransform	Make (Point origin, Scalar scale, Radians radians)

Public Attributes
Scalar	scaled_cos

Scalar	scaled_sin

Scalar	translate_x

Scalar	translate_y

Detailed Description

A utility struct that stores a simple transform composed of a translation, a rotation, and a uniform scale.

This transform is used by drawAtlas to transform the sprites. This structure mirrors the Flutter RSTransform class.

Definition at line 20 of file rstransform.h.

Constructor & Destructor Documentation

◆ RSTransform() [1/2]

constexpr impeller::RSTransform::RSTransform ( )

inlineconstexpr

Definition at line 21 of file rstransform.h.

       : scaled_cos(1.0f),
         scaled_sin(0.0f),
         translate_x(0.0f),
         translate_y(0.0f) {}

◆ RSTransform() [2/2]

constexpr impeller::RSTransform::RSTransform	(	Scalar	scaled_cos,
		Scalar	scaled_sin,
		Scalar	translate_x,
		Scalar	translate_y
	)

inlineconstexpr

Definition at line 27 of file rstransform.h.

       : scaled_cos(scaled_cos),
         scaled_sin(scaled_sin),
         translate_x(translate_x),
         translate_y(translate_y) {}

Member Function Documentation

◆ GetBounds() [1/2]

std::optional< Rect > impeller::RSTransform::GetBounds	(	Scalar	width,
		Scalar	height
	)		const

Returns the bounds of the 4 corner points of the transformed quad for a sub-image of the indicated size.

Definition at line 49 of file rstransform.cc.

                                                                           {
   return Rect::MakePointBounds(GetQuad(width, height));
 }

References GetQuad(), and impeller::TRect< Scalar >::MakePointBounds().

Referenced by impeller::DlAtlasGeometry::ComputeBoundingBox().

◆ GetBounds() [2/2]

std::optional< Rect > impeller::RSTransform::GetBounds ( Size size ) const

Definition at line 53 of file rstransform.cc.

                                                         {
   return Rect::MakePointBounds(GetQuad(size));
 }

References GetQuad(), and impeller::TRect< Scalar >::MakePointBounds().

◆ GetMatrix()

Matrix impeller::RSTransform::GetMatrix ( ) const

Definition at line 15 of file rstransform.cc.

                                     {
   // clang-format off
   return Matrix::MakeRow(scaled_cos, -scaled_sin, 0.0f, translate_x,
                          scaled_sin,  scaled_cos, 0.0f, translate_y,
                             0.0f,       0.0f,     1.0f,     0.0f,
                             0.0f,       0.0f,     0.0f,     1.0f);
   // clang-format on
 }

References impeller::Matrix::MakeRow(), scaled_cos, scaled_sin, translate_x, and translate_y.

◆ GetQuad() [1/3]

Quad impeller::RSTransform::GetQuad	(	Scalar	width,
		Scalar	height
	)		const

Definition at line 37 of file rstransform.cc.

                                                            {
   Quad quad;
   GetQuad(width, height, quad);
   return quad;
 }

References GetQuad().

◆ GetQuad() [2/3]

void impeller::RSTransform::GetQuad	(	Scalar	width,
		Scalar	height,
		Quad &	quad
	)		const

Returns the 4 corner points of the transformed quad for a sub-image of the indicated size in the same order as Rect::GetPoints.

The order is UpperLeft, UpperRight, LowerLeft, LowerRight

Definition at line 24 of file rstransform.cc.

                                                                        {
   Point origin = {translate_x, translate_y};
   Point dx = width * Point{scaled_cos, scaled_sin};
   Point dy = height * Point{-scaled_sin, scaled_cos};
   quad = {
       // Ordered in the same Z pattern as Rect::GetPoints()
       origin,
       origin + dx,
       origin + dy,
       origin + dx + dy,
   };
 }

References scaled_cos, scaled_sin, translate_x, and translate_y.

Referenced by impeller::DlAtlasGeometry::CreateBlendVertexBuffer(), impeller::DlAtlasGeometry::CreateSimpleVertexBuffer(), GetBounds(), and GetQuad().

◆ GetQuad() [3/3]

Quad impeller::RSTransform::GetQuad ( Size size ) const

Definition at line 43 of file rstransform.cc.

                                          {
   Quad quad;
   GetQuad(size.width, size.height, quad);
   return quad;
 }

References GetQuad(), impeller::TSize< T >::height, and impeller::TSize< T >::width.

◆ IsAxisAligned()

bool impeller::RSTransform::IsAxisAligned ( ) const

Returns true iff the resulting transformed quad will be aligned with the axes, even if rotated by a quadrant rotation.

Definition at line 11 of file rstransform.cc.

                                       {
   return scaled_cos == 0.0f || scaled_sin == 0.0f;
 }

References scaled_cos, and scaled_sin.

◆ Make()

static RSTransform impeller::RSTransform::Make	(	Point	origin,
		Scalar	scale,
		Radians	radians
	)

inlinestatic

Constructs an RSTransform from the indicated origin, uniform scale, and radians rotation.

Definition at line 38 of file rstransform.h.

                                                                               {
     auto scaled_cos_sin = Matrix::CosSin(radians) * scale;
     return {scaled_cos_sin.x, scaled_cos_sin.y, origin.x, origin.y};
   }

References impeller::Matrix::CosSin(), impeller::TPoint< T >::x, and impeller::TPoint< T >::y.

Referenced by impeller::testing::TEST().

Member Data Documentation

◆ scaled_cos

Scalar impeller::RSTransform::scaled_cos

Definition at line 43 of file rstransform.h.

Referenced by GetMatrix(), GetQuad(), IsAxisAligned(), and std::operator<<().

◆ scaled_sin

Scalar impeller::RSTransform::scaled_sin

Definition at line 44 of file rstransform.h.

Referenced by GetMatrix(), GetQuad(), IsAxisAligned(), and std::operator<<().

◆ translate_x

Scalar impeller::RSTransform::translate_x

Definition at line 45 of file rstransform.h.

Referenced by GetMatrix(), GetQuad(), and std::operator<<().

◆ translate_y

Scalar impeller::RSTransform::translate_y

Definition at line 46 of file rstransform.h.