ucolor

Documentation

Overview

Package ucolor extends image/color.

Index

• Variables
• func Premultiply(ur, ug, ub, ua uint32) (r, g, b, a uint32)
• func ToRGBA(c color.Color) color.RGBA
• func Transparent(c color.Color) bool
• func Unpremultiply(r, g, b, a uint32) (ur, ug, ub, ua uint32)
• type HSV
  • func (hsv HSV) Canon() HSV
  • func (hsv HSV) RGBA() (r, g, b, a uint32)
• type HSVA
  • func (hsva HSVA) Canon() HSVA
  • func (hsva HSVA) RGBA() (r, g, b, a uint32)

Variables

var (
	HSVModel  color.Model = color.ModelFunc(hsvModel)
	HSVAModel color.Model = color.ModelFunc(hsvaModel)
)

Functions

func Premultiply

func Premultiply(ur, ug, ub, ua uint32) (r, g, b, a uint32)

Premultiply applies alpha-premultiplication that colors must apply as per color.Color.RGBA. This is an intrinsically lossy proccess.

func ToRGBA

func ToRGBA(c color.Color) color.RGBA

ToRGBA converts any color to a color.RGBA value.

func Transparent

func Transparent(c color.Color) bool

Transparent returns whether or not a color has transparency.

func Unpremultiply

func Unpremultiply(r, g, b, a uint32) (ur, ug, ub, ua uint32)

Unpremultiply reverses alpha-premultiplication that colors must apply as per color.Color.RGBA. This may or may not return the precise original color.

Types

type HSV

type HSV struct {
	H float64
	S float64
	V float64
}

HSV represents a color with hue, saturation, and value components. Each component C is in range 0 <= C <= 1.

func (HSV) Canon

func (hsv HSV) Canon() HSV

Canon returns the color but with the H, S, and V fields are constrained to the range 0.0-1.0

func (HSV) RGBA

func (hsv HSV) RGBA() (r, g, b, a uint32)

type HSVA

type HSVA struct {
	H float64
	S float64
	V float64
	A uint16
}

HSVA is an HSV color with an added 8-bit alpha component. The alpha component ranges from 0x0000 (fully transparent) to 0xFFFF (opaque), and has no bearing on the other components.

func (HSVA) Canon

func (hsva HSVA) Canon() HSVA

Canon returns the color but with the H, S, and V fields are constrained to the range 0.0-1.0

func (HSVA) RGBA

func (hsva HSVA) RGBA() (r, g, b, a uint32)