linear

Documentation

Overview

Package linear provides support for working with linearised colour.

Index

• func NormalisedTo16Bit(v float32) uint16
• func NormalisedTo8Bit(v float32) uint8
• func NormalisedTo9Bit(v float32) uint16
• func TransformImageColor(dst draw.Image, src image.Image, parallelism int, ...)
• type RGB
  • func RGBFromEncoded(c color.Color, trcDecode func(uint16) float32) (col RGB, alpha float32)
  • func RGBFromLinear(c color.Color) (col RGB, alpha float32)
  • func (c RGB) Luminance() float32
  • func (c RGB) ToEncodedNRGBA(alpha float32, trcEncode func(float32) uint8) color.NRGBA
  • func (c RGB) ToEncodedRGBA(alpha float32, trcEncode func(float32) uint8) color.RGBA
  • func (c RGB) ToEncodedRGBA64(alpha float32, trcEncode func(float32) uint16) color.RGBA64
  • func (c RGB) ToLinearRGBA64(alpha float32) color.RGBA64

Functions

func NormalisedTo16Bit

func NormalisedTo16Bit(v float32) uint16

NormalisedTo16Bit clamps and scales a normalised value to the range 0-65535.

func NormalisedTo8Bit

func NormalisedTo8Bit(v float32) uint8

NormalisedTo8Bit clamps and scales a normalised value to the range 0-255.

func NormalisedTo9Bit

func NormalisedTo9Bit(v float32) uint16

NormalisedTo9Bit clamps and scales a normalised value to the range 0-511.

func TransformImageColor

func TransformImageColor(dst draw.Image, src image.Image, parallelism int, transformColor func(color.Color) color.RGBA64)

TransformImageColor applies a colour transformation function to all pixels of src, writing the results to dst at its origin.

src and dst may be the same image.

parallelism specifies the degree of parallel processing; a value of 4 indicates that processing will be spread across four threads.

Types

type RGB

type RGB struct {
	R float32
	G float32
	B float32
}

RGB represents a linear normalised RGB colour value in an unspecified colour space.

func RGBFromEncoded

func RGBFromEncoded(c color.Color, trcDecode func(uint16) float32) (col RGB, alpha float32)

RGBFromEncoded returns a normalised RGB instance representing the specified color.Color value. The alpha component is returned as a normalised value in the range 0.0-1.0.

c is assumed to be an encoded colour.

func RGBFromLinear

func RGBFromLinear(c color.Color) (col RGB, alpha float32)

RGBFromLinear returns a normalised RGB instance representing the specified color.Color value. The alpha component is returned as a normalised value in the range 0.0-1.0.

c is assumed to be a linear colour.

func (RGB) Luminance

func (c RGB) Luminance() float32

Luminance returns the perceptual luminance of this colour.

func (RGB) ToEncodedNRGBA

func (c RGB) ToEncodedNRGBA(alpha float32, trcEncode func(float32) uint8) color.NRGBA

ToEncodedNRGBA returns an encoded 8-bit NRGBA representation of this colour suitable for use with instances of image.NRGBA.

alpha is the normalised alpha value and will be clipped to 0.0–1.0.

trcEncode is a tonal response curve encoding function.

func (RGB) ToEncodedRGBA

func (c RGB) ToEncodedRGBA(alpha float32, trcEncode func(float32) uint8) color.RGBA

ToEncodedRGBA returns an encoded 8-bit RGBA representation of this colour suitable for use with instances of image.RGBA.

alpha is the normalised alpha value and will be clipped to 0.0–1.0.

trcEncode is a tonal response curve encoding function.

func (RGB) ToEncodedRGBA64

func (c RGB) ToEncodedRGBA64(alpha float32, trcEncode func(float32) uint16) color.RGBA64

ToEncodedRGBA64 returns an encoded 16-bit RGBA representation of this colour suitable for use with instances of image.RGBA64.

alpha is the normalised alpha value and will be clipped to 0.0–1.0.

trcEncode is a tonal response curve encoding function.

func (RGB) ToLinearRGBA64

func (c RGB) ToLinearRGBA64(alpha float32) color.RGBA64

ToLinearRGBA64 returns a linear 16-bit RGBA representation of this colour suitable for use with instances of image.RGBA64.

alpha is the normalised alpha value and will be clipped to 0.0–1.0.