▹ Example
var (
// Black is an opaque black uniform image.
Black = NewUniform(color.Black)
// White is an opaque white uniform image.
White = NewUniform(color.White)
// Transparent is a fully transparent uniform image.
Transparent = NewUniform(color.Transparent)
// Opaque is a fully opaque uniform image.
Opaque = NewUniform(color.Opaque)
)
var ErrFormat = errors.New("image: unknown format")
ErrFormat indicates that decoding encountered an unknown format.
func RegisterFormat(name, magic string, decode func(io.Reader) (Image, error), decodeConfig func(io.Reader) (Config, error))
RegisterFormat registers an image format for use by Decode. Name is the name of the format, like "jpeg" or "png". Magic is the magic prefix that identifies the format's encoding. The magic string can contain "?" wildcards that each match any one byte. Decode is the function that decodes the encoded image. DecodeConfig is the function that decodes just its configuration.
type Alpha struct {
// Pix holds the image's pixels, as alpha values. The pixel at
// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*1].
Pix []uint8
// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
Stride int
// Rect is the image's bounds.
Rect Rectangle
}
Alpha is an in-memory image whose At method returns color.Alpha values.
func NewAlpha(r Rectangle) *Alpha
NewAlpha returns a new Alpha with the given bounds.
func (p *Alpha) AlphaAt(x, y int) color.Alpha
func (p *Alpha) At(x, y int) color.Color
func (p *Alpha) Bounds() Rectangle
func (p *Alpha) ColorModel() color.Model
func (p *Alpha) Opaque() bool
Opaque scans the entire image and reports whether it is fully opaque.
func (p *Alpha) PixOffset(x, y int) int
PixOffset returns the index of the first element of Pix that corresponds to the pixel at (x, y).
func (p *Alpha) Set(x, y int, c color.Color)
func (p *Alpha) SetAlpha(x, y int, c color.Alpha)
func (p *Alpha) SubImage(r Rectangle) Image
SubImage returns an image representing the portion of the image p visible through r. The returned value shares pixels with the original image.
type Alpha16 struct {
// Pix holds the image's pixels, as alpha values in big-endian format. The pixel at
// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*2].
Pix []uint8
// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
Stride int
// Rect is the image's bounds.
Rect Rectangle
}
Alpha16 is an in-memory image whose At method returns color.Alpha64 values.
func NewAlpha16(r Rectangle) *Alpha16
NewAlpha16 returns a new Alpha16 with the given bounds.
func (p *Alpha16) Alpha16At(x, y int) color.Alpha16
func (p *Alpha16) At(x, y int) color.Color
func (p *Alpha16) Bounds() Rectangle
func (p *Alpha16) ColorModel() color.Model
func (p *Alpha16) Opaque() bool
Opaque scans the entire image and reports whether it is fully opaque.
func (p *Alpha16) PixOffset(x, y int) int
PixOffset returns the index of the first element of Pix that corresponds to the pixel at (x, y).
func (p *Alpha16) Set(x, y int, c color.Color)
func (p *Alpha16) SetAlpha16(x, y int, c color.Alpha16)
func (p *Alpha16) SubImage(r Rectangle) Image
SubImage returns an image representing the portion of the image p visible through r. The returned value shares pixels with the original image.
type Config struct {
ColorModel color.Model
Width, Height int
}
Config holds an image's color model and dimensions.
func DecodeConfig(r io.Reader) (Config, string, error)
DecodeConfig decodes the color model and dimensions of an image that has been encoded in a registered format. The string returned is the format name used during format registration. Format registration is typically done by an init function in the codec-specific package.
type Gray struct {
// Pix holds the image's pixels, as gray values. The pixel at
// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*1].
Pix []uint8
// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
Stride int
// Rect is the image's bounds.
Rect Rectangle
}
Gray is an in-memory image whose At method returns color.Gray values.
func NewGray(r Rectangle) *Gray
NewGray returns a new Gray with the given bounds.
func (p *Gray) At(x, y int) color.Color
func (p *Gray) Bounds() Rectangle
func (p *Gray) ColorModel() color.Model
func (p *Gray) GrayAt(x, y int) color.Gray
func (p *Gray) Opaque() bool
Opaque scans the entire image and reports whether it is fully opaque.
func (p *Gray) PixOffset(x, y int) int
PixOffset returns the index of the first element of Pix that corresponds to the pixel at (x, y).
func (p *Gray) Set(x, y int, c color.Color)
func (p *Gray) SetGray(x, y int, c color.Gray)
func (p *Gray) SubImage(r Rectangle) Image
SubImage returns an image representing the portion of the image p visible through r. The returned value shares pixels with the original image.
type Gray16 struct {
// Pix holds the image's pixels, as gray values in big-endian format. The pixel at
// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*2].
Pix []uint8
// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
Stride int
// Rect is the image's bounds.
Rect Rectangle
}
Gray16 is an in-memory image whose At method returns color.Gray16 values.
func NewGray16(r Rectangle) *Gray16
NewGray16 returns a new Gray16 with the given bounds.
func (p *Gray16) At(x, y int) color.Color
func (p *Gray16) Bounds() Rectangle
func (p *Gray16) ColorModel() color.Model
func (p *Gray16) Gray16At(x, y int) color.Gray16
func (p *Gray16) Opaque() bool
Opaque scans the entire image and reports whether it is fully opaque.
func (p *Gray16) PixOffset(x, y int) int
PixOffset returns the index of the first element of Pix that corresponds to the pixel at (x, y).
func (p *Gray16) Set(x, y int, c color.Color)
func (p *Gray16) SetGray16(x, y int, c color.Gray16)
func (p *Gray16) SubImage(r Rectangle) Image
SubImage returns an image representing the portion of the image p visible through r. The returned value shares pixels with the original image.
type Image interface {
// ColorModel returns the Image's color model.
ColorModel() color.Model
// Bounds returns the domain for which At can return non-zero color.
// The bounds do not necessarily contain the point (0, 0).
Bounds() Rectangle
// At returns the color of the pixel at (x, y).
// At(Bounds().Min.X, Bounds().Min.Y) returns the upper-left pixel of the grid.
// At(Bounds().Max.X-1, Bounds().Max.Y-1) returns the lower-right one.
At(x, y int) color.Color
}
Image is a finite rectangular grid of color.Color values taken from a color model.
func Decode(r io.Reader) (Image, string, error)
Decode decodes an image that has been encoded in a registered format. The string returned is the format name used during format registration. Format registration is typically done by an init function in the codec- specific package.
type NRGBA struct {
// Pix holds the image's pixels, in R, G, B, 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 Rectangle
}
NRGBA is an in-memory image whose At method returns color.NRGBA values.
func NewNRGBA(r Rectangle) *NRGBA
NewNRGBA returns a new NRGBA with the given bounds.
func (p *NRGBA) At(x, y int) color.Color
func (p *NRGBA) Bounds() Rectangle
func (p *NRGBA) ColorModel() color.Model
func (p *NRGBA) NRGBAAt(x, y int) color.NRGBA
func (p *NRGBA) Opaque() bool
Opaque scans the entire image and reports whether it is fully opaque.
func (p *NRGBA) PixOffset(x, y int) int
PixOffset returns the index of the first element of Pix that corresponds to the pixel at (x, y).
func (p *NRGBA) Set(x, y int, c color.Color)
func (p *NRGBA) SetNRGBA(x, y int, c color.NRGBA)
func (p *NRGBA) SubImage(r Rectangle) Image
SubImage returns an image representing the portion of the image p visible through r. The returned value shares pixels with the original image.
type NRGBA64 struct {
// Pix holds the image's pixels, in R, G, B, A order and big-endian format. The pixel at
// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*8].
Pix []uint8
// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
Stride int
// Rect is the image's bounds.
Rect Rectangle
}
NRGBA64 is an in-memory image whose At method returns color.NRGBA64 values.
func NewNRGBA64(r Rectangle) *NRGBA64
NewNRGBA64 returns a new NRGBA64 with the given bounds.
func (p *NRGBA64) At(x, y int) color.Color
func (p *NRGBA64) Bounds() Rectangle
func (p *NRGBA64) ColorModel() color.Model
func (p *NRGBA64) NRGBA64At(x, y int) color.NRGBA64
func (p *NRGBA64) Opaque() bool
Opaque scans the entire image and reports whether it is fully opaque.
func (p *NRGBA64) PixOffset(x, y int) int
PixOffset returns the index of the first element of Pix that corresponds to the pixel at (x, y).
func (p *NRGBA64) Set(x, y int, c color.Color)
func (p *NRGBA64) SetNRGBA64(x, y int, c color.NRGBA64)
func (p *NRGBA64) SubImage(r Rectangle) Image
SubImage returns an image representing the portion of the image p visible through r. The returned value shares pixels with the original image.
type Paletted struct {
// Pix holds the image's pixels, as palette indices. The pixel at
// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*1].
Pix []uint8
// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
Stride int
// Rect is the image's bounds.
Rect Rectangle
// Palette is the image's palette.
Palette color.Palette
}
Paletted is an in-memory image of uint8 indices into a given palette.
func NewPaletted(r Rectangle, p color.Palette) *Paletted
NewPaletted returns a new Paletted with the given width, height and palette.
func (p *Paletted) At(x, y int) color.Color
func (p *Paletted) Bounds() Rectangle
func (p *Paletted) ColorIndexAt(x, y int) uint8
func (p *Paletted) ColorModel() color.Model
func (p *Paletted) Opaque() bool
Opaque scans the entire image and reports whether it is fully opaque.
func (p *Paletted) PixOffset(x, y int) int
PixOffset returns the index of the first element of Pix that corresponds to the pixel at (x, y).
func (p *Paletted) Set(x, y int, c color.Color)
func (p *Paletted) SetColorIndex(x, y int, index uint8)
func (p *Paletted) SubImage(r Rectangle) Image
SubImage returns an image representing the portion of the image p visible through r. The returned value shares pixels with the original image.
type PalettedImage interface {
// ColorIndexAt returns the palette index of the pixel at (x, y).
ColorIndexAt(x, y int) uint8
Image
}
PalettedImage is an image whose colors may come from a limited palette. If m is a PalettedImage and m.ColorModel() returns a PalettedColorModel p, then m.At(x, y) should be equivalent to p[m.ColorIndexAt(x, y)]. If m's color model is not a PalettedColorModel, then ColorIndexAt's behavior is undefined.
type Point struct {
X, Y int
}
A Point is an X, Y coordinate pair. The axes increase right and down.
var ZP Point
ZP is the zero Point.
func Pt(X, Y int) Point
Pt is shorthand for Point{X, Y}.
func (p Point) Add(q Point) Point
Add returns the vector p+q.
func (p Point) Div(k int) Point
Div returns the vector p/k.
func (p Point) Eq(q Point) bool
Eq reports whether p and q are equal.
func (p Point) In(r Rectangle) bool
In reports whether p is in r.
func (p Point) Mod(r Rectangle) Point
Mod returns the point q in r such that p.X-q.X is a multiple of r's width and p.Y-q.Y is a multiple of r's height.
func (p Point) Mul(k int) Point
Mul returns the vector p*k.
func (p Point) String() string
String returns a string representation of p like "(3,4)".
func (p Point) Sub(q Point) Point
Sub returns the vector p-q.
type RGBA struct {
// Pix holds the image's pixels, in R, G, B, 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 Rectangle
}
RGBA is an in-memory image whose At method returns color.RGBA values.
func NewRGBA(r Rectangle) *RGBA
NewRGBA returns a new RGBA with the given bounds.
func (p *RGBA) At(x, y int) color.Color
func (p *RGBA) Bounds() Rectangle
func (p *RGBA) ColorModel() color.Model
func (p *RGBA) Opaque() bool
Opaque scans the entire image and reports whether it is fully opaque.
func (p *RGBA) PixOffset(x, y int) int
PixOffset returns the index of the first element of Pix that corresponds to the pixel at (x, y).
func (p *RGBA) RGBAAt(x, y int) color.RGBA
func (p *RGBA) Set(x, y int, c color.Color)
func (p *RGBA) SetRGBA(x, y int, c color.RGBA)
func (p *RGBA) SubImage(r Rectangle) Image
SubImage returns an image representing the portion of the image p visible through r. The returned value shares pixels with the original image.
type RGBA64 struct {
// Pix holds the image's pixels, in R, G, B, A order and big-endian format. The pixel at
// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*8].
Pix []uint8
// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
Stride int
// Rect is the image's bounds.
Rect Rectangle
}
RGBA64 is an in-memory image whose At method returns color.RGBA64 values.
func NewRGBA64(r Rectangle) *RGBA64
NewRGBA64 returns a new RGBA64 with the given bounds.
func (p *RGBA64) At(x, y int) color.Color
func (p *RGBA64) Bounds() Rectangle
func (p *RGBA64) ColorModel() color.Model
func (p *RGBA64) Opaque() bool
Opaque scans the entire image and reports whether it is fully opaque.
func (p *RGBA64) PixOffset(x, y int) int
PixOffset returns the index of the first element of Pix that corresponds to the pixel at (x, y).
func (p *RGBA64) RGBA64At(x, y int) color.RGBA64
func (p *RGBA64) Set(x, y int, c color.Color)
func (p *RGBA64) SetRGBA64(x, y int, c color.RGBA64)
func (p *RGBA64) SubImage(r Rectangle) Image
SubImage returns an image representing the portion of the image p visible through r. The returned value shares pixels with the original image.
type Rectangle struct {
Min, Max Point
}
A Rectangle contains the points with Min.X <= X < Max.X, Min.Y <= Y < Max.Y. It is well-formed if Min.X <= Max.X and likewise for Y. Points are always well-formed. A rectangle's methods always return well-formed outputs for well-formed inputs.
var ZR Rectangle
ZR is the zero Rectangle.
func Rect(x0, y0, x1, y1 int) Rectangle
Rect is shorthand for Rectangle{Pt(x0, y0), Pt(x1, y1)}.
func (r Rectangle) Add(p Point) Rectangle
Add returns the rectangle r translated by p.
func (r Rectangle) Canon() Rectangle
Canon returns the canonical version of r. The returned rectangle has minimum and maximum coordinates swapped if necessary so that it is well-formed.
func (r Rectangle) Dx() int
Dx returns r's width.
func (r Rectangle) Dy() int
Dy returns r's height.
func (r Rectangle) Empty() bool
Empty reports whether the rectangle contains no points.
func (r Rectangle) Eq(s Rectangle) bool
Eq reports whether r and s are equal.
func (r Rectangle) In(s Rectangle) bool
In reports whether every point in r is in s.
func (r Rectangle) Inset(n int) Rectangle
Inset returns the rectangle r inset by n, which may be negative. If either of r's dimensions is less than 2*n then an empty rectangle near the center of r will be returned.
func (r Rectangle) Intersect(s Rectangle) Rectangle
Intersect returns the largest rectangle contained by both r and s. If the two rectangles do not overlap then the zero rectangle will be returned.
func (r Rectangle) Overlaps(s Rectangle) bool
Overlaps reports whether r and s have a non-empty intersection.
func (r Rectangle) Size() Point
Size returns r's width and height.
func (r Rectangle) String() string
String returns a string representation of r like "(3,4)-(6,5)".
func (r Rectangle) Sub(p Point) Rectangle
Sub returns the rectangle r translated by -p.
func (r Rectangle) Union(s Rectangle) Rectangle
Union returns the smallest rectangle that contains both r and s.
type Uniform struct {
C color.Color
}
Uniform is an infinite-sized Image of uniform color. It implements the color.Color, color.Model, and Image interfaces.
func NewUniform(c color.Color) *Uniform
func (c *Uniform) At(x, y int) color.Color
func (c *Uniform) Bounds() Rectangle
func (c *Uniform) ColorModel() color.Model
func (c *Uniform) Convert(color.Color) color.Color
func (c *Uniform) Opaque() bool
Opaque scans the entire image and reports whether it is fully opaque.
func (c *Uniform) RGBA() (r, g, b, a uint32)
type YCbCr struct {
Y, Cb, Cr []uint8
YStride int
CStride int
SubsampleRatio YCbCrSubsampleRatio
Rect Rectangle
}
YCbCr is an in-memory image of Y'CbCr colors. There is one Y sample per pixel, but each Cb and Cr sample can span one or more pixels. YStride is the Y slice index delta between vertically adjacent pixels. CStride is the Cb and Cr slice index delta between vertically adjacent pixels that map to separate chroma samples. It is not an absolute requirement, but YStride and len(Y) are typically multiples of 8, and:
For 4:4:4, CStride == YStride/1 && len(Cb) == len(Cr) == len(Y)/1. For 4:2:2, CStride == YStride/2 && len(Cb) == len(Cr) == len(Y)/2. For 4:2:0, CStride == YStride/2 && len(Cb) == len(Cr) == len(Y)/4. For 4:4:0, CStride == YStride/1 && len(Cb) == len(Cr) == len(Y)/2.
func NewYCbCr(r Rectangle, subsampleRatio YCbCrSubsampleRatio) *YCbCr
NewYCbCr returns a new YCbCr with the given bounds and subsample ratio.
func (p *YCbCr) At(x, y int) color.Color
func (p *YCbCr) Bounds() Rectangle
func (p *YCbCr) COffset(x, y int) int
COffset returns the index of the first element of Cb or Cr that corresponds to the pixel at (x, y).
func (p *YCbCr) ColorModel() color.Model
func (p *YCbCr) Opaque() bool
func (p *YCbCr) SubImage(r Rectangle) Image
SubImage returns an image representing the portion of the image p visible through r. The returned value shares pixels with the original image.
func (p *YCbCr) YCbCrAt(x, y int) color.YCbCr
func (p *YCbCr) YOffset(x, y int) int
YOffset returns the index of the first element of Y that corresponds to the pixel at (x, y).
type YCbCrSubsampleRatio int
YCbCrSubsampleRatio is the chroma subsample ratio used in a YCbCr image.
const (
YCbCrSubsampleRatio444 YCbCrSubsampleRatio = iota
YCbCrSubsampleRatio422
YCbCrSubsampleRatio420
YCbCrSubsampleRatio440
)
func (s YCbCrSubsampleRatio) String() string
| Name | Synopsis |
|---|---|
| .. | |
| color | Package color implements a basic color library. |
| palette | Package palette provides standard color palettes. |
| draw | Package draw provides image composition functions. |
| gif | Package gif implements a GIF image decoder and encoder. |
| jpeg | Package jpeg implements a JPEG image decoder and encoder. |
| png | Package png implements a PNG image decoder and encoder. |