hsvimage

README

hsvimage and hsvcolor

The Go programming language's standard library provides support for manipulating graphical images represented using RGB, CMYK, YCbCr, and grayscale color models and variations such as 8- vs. 16-bit channels, premultiplied alpha vs. non-premultiplied alpha vs. no alpha, and paletted color. hsvimage augments the Go standard library with support for the HSV color model.

Usage

hsvimage provides an hsvimage.NHSVA image type (Non-alpha-premultiplied Hue, Saturation, and Value with Alpha) that implements the image.Image interface. The underlying NHSVA color model and NHSVA data type are provided by hsvimage/hsvcolor. hsvimage and hsvimage/hsvcolor can be imported in the usual manner:

import (
	"github.com/spakin/hsvimage"
	"github.com/spakin/hsvimage/hsvcolor"
)

Author

Scott Pakin, scott+hsv@pakin.org

Documentation

Overview

Package hsvimage implements the image.Image interface with HSV + alpha images. The code was largely adapted from code in the Go standard library.

Index

• type NHSVA
  • func NewNHSVA(r image.Rectangle) *NHSVA
  • func (p *NHSVA) At(x, y int) color.Color
  • func (p *NHSVA) Bounds() image.Rectangle
  • func (p *NHSVA) ColorModel() color.Model
  • func (p *NHSVA) NHSVAAt(x, y int) hsvcolor.NHSVA
  • func (p *NHSVA) Opaque() bool
  • func (p *NHSVA) PixOffset(x, y int) int
  • func (p *NHSVA) Set(x, y int, c color.Color)
  • func (p *NHSVA) SetNHSVA(x, y int, c hsvcolor.NHSVA)
  • func (p *NHSVA) SubImage(r image.Rectangle) image.Image

Types

type NHSVA

type NHSVA struct {
	// Pix holds the image's pixels, in H, S, V, A order. The pixel at
	// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*4].
	Pix []uint8
	// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
	Stride int
	// Rect is the image's bounds.
	Rect image.Rectangle
}

NHSVA is an in-memory image whose At method returns hsvcolor.NHSVA values.

func NewNHSVA

func NewNHSVA(r image.Rectangle) *NHSVA

NewNHSVA returns a new NHSVA image with the given bounds.

func (*NHSVA) At

func (p *NHSVA) At(x, y int) color.Color

At returns the color at the given image coordinates.

func (*NHSVA) Bounds

func (p *NHSVA) Bounds() image.Rectangle

Bounds returns the image's bounding rectangle.

func (*NHSVA) ColorModel

func (p *NHSVA) ColorModel() color.Model

ColorModel states that an NHSVA image uses the hsvcolor.NHSVA color model.

func (*NHSVA) NHSVAAt

func (p *NHSVA) NHSVAAt(x, y int) hsvcolor.NHSVA

NHSVAAt returns the color at the given image coordinates as specifically an hsvcolor.NHSVA color.

func (*NHSVA) Opaque

func (p *NHSVA) Opaque() bool

Opaque scans the entire image and reports whether it is fully opaque.

func (*NHSVA) PixOffset

func (p *NHSVA) PixOffset(x, y int) int

PixOffset returns the index of the first element of Pix that corresponds to the pixel at (x, y).

func (*NHSVA) Set

func (p *NHSVA) Set(x, y int, c color.Color)

Set assigns an arbitrary color to a given coordinate.

func (*NHSVA) SetNHSVA

func (p *NHSVA) SetNHSVA(x, y int, c hsvcolor.NHSVA)

SetNHSVA assigns an NHSVA color to a given coordinate.

func (*NHSVA) SubImage

func (p *NHSVA) SubImage(r image.Rectangle) image.Image

SubImage returns an image representing the portion of the image p visible through r. The returned value shares pixels with the original image.