transform

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v0.0.0-...-fb73569 Latest Latest Go to latest Published: Feb 24, 2023 License: Apache-2.0 Imports: 3 Imported by: 0

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Repository

github.com/xwc1125/gopdf

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Documentation ¶

Constants ¶

This section is empty.

Variables ¶

This section is empty.

Functions ¶

This section is empty.

Types ¶

type Matrix ¶

type Matrix [9]float64

Matrix is a linear transform matrix in homogenous coordinates. PDF coordinate transforms are always affine so we only need 6 of these. See newMatrix.

func IdentityMatrix ¶

func IdentityMatrix() Matrix

IdentityMatrix returns the identity transform.

func NewMatrix ¶

func NewMatrix(a, b, c, d, tx, ty float64) Matrix

NewMatrix returns an affine transform matrix laid out in homogenous coordinates as

a  b  0
c  d  0
tx ty 1

func TranslationMatrix ¶

func TranslationMatrix(tx, ty float64) Matrix

TranslationMatrix returns a matrix that translates by `tx`, `ty`.

func (*Matrix) Angle ¶

func (m *Matrix) Angle() float64

Angle returns the angle of the affine transform in `m` in degrees.

func (*Matrix) Concat ¶

func (m *Matrix) Concat(b Matrix)

Concat sets `m` to `b` × `m`. `b` needs to be created by newMatrix. i.e. It must be an affine transform.

b00 b01 0     m00 m01 0     b00*m00 + b01*m01        b00*m10 + b01*m11        0
b10 b11 0  ×  m10 m11 0  ➔  b10*m00 + b11*m01        b10*m10 + b11*m11        0
b20 b21 1     m20 m21 1     b20*m00 + b21*m10 + m20  b20*m01 + b21*m11 + m21  1

func (Matrix) Mult ¶

func (m Matrix) Mult(b Matrix) Matrix

Mult returns `b` × `m`.

func (*Matrix) ScalingFactorX ¶

func (m *Matrix) ScalingFactorX() float64

ScalingFactorX returns the X scaling of the affine transform.

func (*Matrix) ScalingFactorY ¶

func (m *Matrix) ScalingFactorY() float64

ScalingFactorY returns the Y scaling of the affine transform.

func (*Matrix) Set ¶

func (m *Matrix) Set(a, b, c, d, tx, ty float64)

Set sets `m` to affine transform a,b,c,d,tx,ty.

func (Matrix) String ¶

func (m Matrix) String() string

String returns a string describing `m`.

func (*Matrix) Transform ¶

func (m *Matrix) Transform(x, y float64) (float64, float64)

Transform returns coordinates `x`,`y` transformed by `m`.

func (*Matrix) Translate ¶

func (m *Matrix) Translate(dx, dy float64)

Translate appends a translation of `dx`,`dy` to `m`. m.Translate(dx, dy) is equivalent to m.Concat(NewMatrix(1, 0, 0, 1, dx, dy))

func (*Matrix) Translation ¶

func (m *Matrix) Translation() (float64, float64)

Translation returns the translation part of `m`.

func (*Matrix) Unrealistic ¶

func (m *Matrix) Unrealistic() bool

Unrealistic returns true if `m` is too small to have been created intentionally. If it returns true then `m` probably contains junk values, due to some processing error in the PDF generator or our code.

type Point ¶

type Point struct {
	X float64
	Y float64
}

Point defines a point (X,Y) in Cartesian coordinates.

func NewPoint ¶

func NewPoint(x, y float64) Point

NewPoint returns a Point at `(x,y)`.

func (Point) Displace ¶

func (p Point) Displace(delta Point) Point

Displace returns a new Point at location `p` + `delta`.

func (Point) Rotate ¶

func (p Point) Rotate(theta float64) Point

Rotate returns a new Point at `p` rotated by `theta` degrees.

func (*Point) Set ¶

func (p *Point) Set(x, y float64)

Set mutates `p` and sets to coordinates `(x, y)`.

func (Point) String ¶

func (p Point) String() string

String returns a string describing `p`.

func (*Point) Transform ¶

func (p *Point) Transform(a, b, c, d, tx, ty float64)

Transform mutates and transforms `p` by the affine transformation a, b, c, d, tx, ty.

Source Files ¶

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