image package - image - Go Packages

Documentation ¶ Overview ¶ Package image implements a basic 2-D image library. The fundamental interface is called Image. An Image contains colors, which are described in the image/color package. Values of the Image interface are created either by calling functions such as NewRGBA and NewPaletted, or by calling Decode on an io.Reader containing image data in a format such as GIF, JPEG or PNG. Decoding any particular image format requires the prior registration of a decoder function. Registration is typically automatic as a side effect of initializing that format's package so that, to decode a PNG image, it suffices to have import _ "image/png" in a program's main package. The _ means to import a package purely for its initialization side effects. See "The Go image package" for more details: https://golang.org/doc/articles/image_package.html Security Considerations ¶The image package can be used to parse arbitrarily large images, which can cause resource exhaustion on machines which do not have enough memory to store them. When operating on arbitrary images, DecodeConfig should be called before Decode, so that the program can decide whether the image, as defined in the returned header, can be safely decoded with the available resources. A call to Decode which produces an extremely large image, as defined in the header returned by DecodeConfig, is not considered a security issue, regardless of whether the image is itself malformed or not. A call to DecodeConfig which returns a header which does not match the image returned by Decode may be considered a security issue, and should be reported per the Go Security Policy. Example ¶ package main import ( "encoding/base64" "fmt" "image" "log" "strings" // Package image/jpeg is not used explicitly in the code below, // but is imported for its initialization side-effect, which allows // image.Decode to understand JPEG formatted images. Uncomment these // two lines to also understand GIF and PNG images: // _ "image/gif" // _ "image/png" _ "image/jpeg" ) func main() { // Decode the JPEG data. If reading from file, create a reader with // // reader, err := os.Open("testdata/video-001.q50.420.jpeg") // if err != nil { // log.Fatal(err) // } // defer reader.Close() reader := base64.NewDecoder(base64.StdEncoding, strings.NewReader(data)) m, _, err := image.Decode(reader) if err != nil { log.Fatal(err) } bounds := m.Bounds() // Calculate a 16-bin histogram for m's red, green, blue and alpha components. // // An image's bounds do not necessarily start at (0, 0), so the two loops start // at bounds.Min.Y and bounds.Min.X. Looping over Y first and X second is more // likely to result in better memory access patterns than X first and Y second. var histogram [16][4]int for y := bounds.Min.Y; y < bounds.Max.Y; y++ { for x := bounds.Min.X; x < bounds.Max.X; x++ { r, g, b, a := m.At(x, y).RGBA() // A color's RGBA method returns values in the range [0, 65535]. // Shifting by 12 reduces this to the range [0, 15]. histogram[r>>12][0]++ histogram[g>>12][1]++ histogram[b>>12][2]++ histogram[a>>12][3]++ } } // Print the results. fmt.Printf("%-14s %6s %6s %6s %6s\n", "bin", "red", "green", "blue", "alpha") for i, x := range histogram { fmt.Printf("0x%04x-0x%04x: %6d %6d %6d %6d\n", i<<12, (i+1)<<12-1, x[0], x[1], x[2], x[3]) } } const data = ` /9j/4AAQSkZJRgABAQIAHAAcAAD/2wBDABALDA4MChAODQ4SERATGCgaGBYWGDEjJR0oOjM9PDkzODdA SFxOQERXRTc4UG1RV19iZ2hnPk1xeXBkeFxlZ2P/2wBDARESEhgVGC8aGi9jQjhCY2NjY2NjY2NjY2Nj Y2NjY2NjY2NjY2NjY2NjY2NjY2NjY2NjY2NjY2NjY2NjY2NjY2P/wAARCABnAJYDASIAAhEBAxEB/8QA 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Run Example (DecodeConfig) ¶ package main import ( "encoding/base64" "fmt" "image" "log" "strings" // Package image/jpeg is not used explicitly in the code below, // but is imported for its initialization side-effect, which allows // image.Decode to understand JPEG formatted images. Uncomment these // two lines to also understand GIF and PNG images: // _ "image/gif" // _ "image/png" _ "image/jpeg" ) func main() { reader := base64.NewDecoder(base64.StdEncoding, strings.NewReader(data)) config, format, err := image.DecodeConfig(reader) if err != nil { log.Fatal(err) } fmt.Println("Width:", config.Width, "Height:", config.Height, "Format:", format) } const data = ` /9j/4AAQSkZJRgABAQIAHAAcAAD/2wBDABALDA4MChAODQ4SERATGCgaGBYWGDEjJR0oOjM9PDkzODdA SFxOQERXRTc4UG1RV19iZ2hnPk1xeXBkeFxlZ2P/2wBDARESEhgVGC8aGi9jQjhCY2NjY2NjY2NjY2Nj Y2NjY2NjY2NjY2NjY2NjY2NjY2NjY2NjY2NjY2NjY2NjY2NjY2P/wAARCABnAJYDASIAAhEBAxEB/8QA HwAAAQUBAQEBAQEAAAAAAAAAAAECAwQFBgcICQoL/8QAtRAAAgEDAwIEAwUFBAQAAAF9AQIDAAQRBRIh MUEGE1FhByJxFDKBkaEII0KxwRVS0fAkM2JyggkKFhcYGRolJicoKSo0NTY3ODk6Q0RFRkdISUpTVFVW V1hZWmNkZWZnaGlqc3R1dnd4eXqDhIWGh4iJipKTlJWWl5iZmqKjpKWmp6ipqrKztLW2t7i5usLDxMXG x8jJytLT1NXW19jZ2uHi4+Tl5ufo6erx8vP09fb3+Pn6/8QAHwEAAwEBAQEBAQEBAQAAAAAAAAECAwQF 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3uyVGNthuq3Eei6DK8H7sRR7YuMgHtXkc8rzTNLM26RyWY+p70UVnLY0iEsUipG7rhZBlDkc1HgYoorM 0HwyBXGeRjmrcUhMg2ghezd//rUUVcTKW5s2jZtY/QDaOKKKK8ip8bPRj8KP/9k= ` Share Format Run Index ¶ Variables func RegisterFormat(name, magic string, decode func(io.Reader) (Image, error), ...) type Alpha func NewAlpha(r Rectangle) *Alpha 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 func (p *Alpha) PixOffset(x, y int) int func (p *Alpha) RGBA64At(x, y int) color.RGBA64 func (p *Alpha) Set(x, y int, c color.Color) func (p *Alpha) SetAlpha(x, y int, c color.Alpha) func (p *Alpha) SetRGBA64(x, y int, c color.RGBA64) func (p *Alpha) SubImage(r Rectangle) Image type Alpha16 func NewAlpha16(r Rectangle) *Alpha16 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 func (p *Alpha16) PixOffset(x, y int) int func (p *Alpha16) RGBA64At(x, y int) color.RGBA64 func (p *Alpha16) Set(x, y int, c color.Color) func (p *Alpha16) SetAlpha16(x, y int, c color.Alpha16) func (p *Alpha16) SetRGBA64(x, y int, c color.RGBA64) func (p *Alpha16) SubImage(r Rectangle) Image type CMYK func NewCMYK(r Rectangle) *CMYK func (p *CMYK) At(x, y int) color.Color func (p *CMYK) Bounds() Rectangle func (p *CMYK) CMYKAt(x, y int) color.CMYK func (p *CMYK) ColorModel() color.Model func (p *CMYK) Opaque() bool func (p *CMYK) PixOffset(x, y int) int func (p *CMYK) RGBA64At(x, y int) color.RGBA64 func (p *CMYK) Set(x, y int, c color.Color) func (p *CMYK) SetCMYK(x, y int, c color.CMYK) func (p *CMYK) SetRGBA64(x, y int, c color.RGBA64) func (p *CMYK) SubImage(r Rectangle) Image type Config func DecodeConfig(r io.Reader) (Config, string, error) type Gray func NewGray(r Rectangle) *Gray 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 func (p *Gray) PixOffset(x, y int) int func (p *Gray) RGBA64At(x, y int) color.RGBA64 func (p *Gray) Set(x, y int, c color.Color) func (p *Gray) SetGray(x, y int, c color.Gray) func (p *Gray) SetRGBA64(x, y int, c color.RGBA64) func (p *Gray) SubImage(r Rectangle) Image type Gray16 func NewGray16(r Rectangle) *Gray16 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 func (p *Gray16) PixOffset(x, y int) int func (p *Gray16) RGBA64At(x, y int) color.RGBA64 func (p *Gray16) Set(x, y int, c color.Color) func (p *Gray16) SetGray16(x, y int, c color.Gray16) func (p *Gray16) SetRGBA64(x, y int, c color.RGBA64) func (p *Gray16) SubImage(r Rectangle) Image type Image func Decode(r io.Reader) (Image, string, error) type NRGBA func NewNRGBA(r Rectangle) *NRGBA 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 func (p *NRGBA) PixOffset(x, y int) int func (p *NRGBA) RGBA64At(x, y int) color.RGBA64 func (p *NRGBA) Set(x, y int, c color.Color) func (p *NRGBA) SetNRGBA(x, y int, c color.NRGBA) func (p *NRGBA) SetRGBA64(x, y int, c color.RGBA64) func (p *NRGBA) SubImage(r Rectangle) Image type NRGBA64 func NewNRGBA64(r Rectangle) *NRGBA64 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 func (p *NRGBA64) PixOffset(x, y int) int func (p *NRGBA64) RGBA64At(x, y int) color.RGBA64 func (p *NRGBA64) Set(x, y int, c color.Color) func (p *NRGBA64) SetNRGBA64(x, y int, c color.NRGBA64) func (p *NRGBA64) SetRGBA64(x, y int, c color.RGBA64) func (p *NRGBA64) SubImage(r Rectangle) Image type NYCbCrA func NewNYCbCrA(r Rectangle, subsampleRatio YCbCrSubsampleRatio) *NYCbCrA func (p *NYCbCrA) AOffset(x, y int) int func (p *NYCbCrA) At(x, y int) color.Color func (p *NYCbCrA) ColorModel() color.Model func (p *NYCbCrA) NYCbCrAAt(x, y int) color.NYCbCrA func (p *NYCbCrA) Opaque() bool func (p *NYCbCrA) RGBA64At(x, y int) color.RGBA64 func (p *NYCbCrA) SubImage(r Rectangle) Image type Paletted func NewPaletted(r Rectangle, p color.Palette) *Paletted 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 func (p *Paletted) PixOffset(x, y int) int func (p *Paletted) RGBA64At(x, y int) color.RGBA64 func (p *Paletted) Set(x, y int, c color.Color) func (p *Paletted) SetColorIndex(x, y int, index uint8) func (p *Paletted) SetRGBA64(x, y int, c color.RGBA64) func (p *Paletted) SubImage(r Rectangle) Image type PalettedImage type Point func Pt(X, Y int) Point func (p Point) Add(q Point) Point func (p Point) Div(k int) Point func (p Point) Eq(q Point) bool func (p Point) In(r Rectangle) bool func (p Point) Mod(r Rectangle) Point func (p Point) Mul(k int) Point func (p Point) String() string func (p Point) Sub(q Point) Point type RGBA func NewRGBA(r Rectangle) *RGBA 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 func (p *RGBA) PixOffset(x, y int) int func (p *RGBA) RGBA64At(x, y int) color.RGBA64 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) SetRGBA64(x, y int, c color.RGBA64) func (p *RGBA) SubImage(r Rectangle) Image type RGBA64 func NewRGBA64(r Rectangle) *RGBA64 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 func (p *RGBA64) PixOffset(x, y int) int 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 type RGBA64Image type Rectangle func Rect(x0, y0, x1, y1 int) Rectangle func (r Rectangle) Add(p Point) Rectangle func (r Rectangle) At(x, y int) color.Color func (r Rectangle) Bounds() Rectangle func (r Rectangle) Canon() Rectangle func (r Rectangle) ColorModel() color.Model func (r Rectangle) Dx() int func (r Rectangle) Dy() int func (r Rectangle) Empty() bool func (r Rectangle) Eq(s Rectangle) bool func (r Rectangle) In(s Rectangle) bool func (r Rectangle) Inset(n int) Rectangle func (r Rectangle) Intersect(s Rectangle) Rectangle func (r Rectangle) Overlaps(s Rectangle) bool func (r Rectangle) RGBA64At(x, y int) color.RGBA64 func (r Rectangle) Size() Point func (r Rectangle) String() string func (r Rectangle) Sub(p Point) Rectangle func (r Rectangle) Union(s Rectangle) Rectangle type Uniform 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 func (c *Uniform) RGBA() (r, g, b, a uint32) func (c *Uniform) RGBA64At(x, y int) color.RGBA64 type YCbCr func NewYCbCr(r Rectangle, subsampleRatio YCbCrSubsampleRatio) *YCbCr func (p *YCbCr) At(x, y int) color.Color func (p *YCbCr) Bounds() Rectangle func (p *YCbCr) COffset(x, y int) int func (p *YCbCr) ColorModel() color.Model func (p *YCbCr) Opaque() bool func (p *YCbCr) RGBA64At(x, y int) color.RGBA64 func (p *YCbCr) SubImage(r Rectangle) Image func (p *YCbCr) YCbCrAt(x, y int) color.YCbCr func (p *YCbCr) YOffset(x, y int) int type YCbCrSubsampleRatio func (s YCbCrSubsampleRatio) String() string Examples ¶ Package Package (DecodeConfig) Constants ¶ This section is empty. Variables ¶ View Source var ( Black = NewUniform(color.Black) White = NewUniform(color.White) Transparent = NewUniform(color.Transparent) Opaque = NewUniform(color.Opaque) ) View Source var ErrFormat = errors.New("image: unknown format") ErrFormat indicates that decoding encountered an unknown format. Functions ¶ func RegisterFormat ¶ 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. Types ¶ type Alpha ¶ type Alpha struct { Pix []uint8 Stride int Rect Rectangle } Alpha is an in-memory image whose At method returns color.Alpha values. func NewAlpha ¶ func NewAlpha(r Rectangle) *Alpha NewAlpha returns a new Alpha image with the given bounds. func (*Alpha) AlphaAt ¶ added in go1.4 func (p *Alpha) AlphaAt(x, y int) color.Alpha func (*Alpha) At ¶ func (p *Alpha) At(x, y int) color.Color func (*Alpha) Bounds ¶ func (p *Alpha) Bounds() Rectangle func (*Alpha) ColorModel ¶ func (p *Alpha) ColorModel() color.Model func (*Alpha) Opaque ¶ func (p *Alpha) Opaque() bool Opaque scans the entire image and reports whether it is fully opaque. func (*Alpha) PixOffset ¶ 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 (*Alpha) RGBA64At ¶ added in go1.17 func (p *Alpha) RGBA64At(x, y int) color.RGBA64 func (*Alpha) Set ¶ func (p *Alpha) Set(x, y int, c color.Color) func (*Alpha) SetAlpha ¶ func (p *Alpha) SetAlpha(x, y int, c color.Alpha) func (*Alpha) SetRGBA64 ¶ added in go1.17 func (p *Alpha) SetRGBA64(x, y int, c color.RGBA64) func (*Alpha) SubImage ¶ 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 ¶ type Alpha16 struct { Pix []uint8 Stride int Rect Rectangle } Alpha16 is an in-memory image whose At method returns color.Alpha16 values. func NewAlpha16 ¶ func NewAlpha16(r Rectangle) *Alpha16 NewAlpha16 returns a new Alpha16 image with the given bounds. func (*Alpha16) Alpha16At ¶ added in go1.4 func (p *Alpha16) Alpha16At(x, y int) color.Alpha16 func (*Alpha16) At ¶ func (p *Alpha16) At(x, y int) color.Color func (*Alpha16) Bounds ¶ func (p *Alpha16) Bounds() Rectangle func (*Alpha16) ColorModel ¶ func (p *Alpha16) ColorModel() color.Model func (*Alpha16) Opaque ¶ func (p *Alpha16) Opaque() bool Opaque scans the entire image and reports whether it is fully opaque. func (*Alpha16) PixOffset ¶ 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 (*Alpha16) RGBA64At ¶ added in go1.17 func (p *Alpha16) RGBA64At(x, y int) color.RGBA64 func (*Alpha16) Set ¶ func (p *Alpha16) Set(x, y int, c color.Color) func (*Alpha16) SetAlpha16 ¶ func (p *Alpha16) SetAlpha16(x, y int, c color.Alpha16) func (*Alpha16) SetRGBA64 ¶ added in go1.17 func (p *Alpha16) SetRGBA64(x, y int, c color.RGBA64) func (*Alpha16) SubImage ¶ 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 CMYK ¶ added in go1.5 type CMYK struct { Pix []uint8 Stride int Rect Rectangle } CMYK is an in-memory image whose At method returns color.CMYK values. func NewCMYK ¶ added in go1.5 func NewCMYK(r Rectangle) *CMYK NewCMYK returns a new CMYK image with the given bounds. func (*CMYK) At ¶ added in go1.5 func (p *CMYK) At(x, y int) color.Color func (*CMYK) Bounds ¶ added in go1.5 func (p *CMYK) Bounds() Rectangle func (*CMYK) CMYKAt ¶ added in go1.5 func (p *CMYK) CMYKAt(x, y int) color.CMYK func (*CMYK) ColorModel ¶ added in go1.5 func (p *CMYK) ColorModel() color.Model func (*CMYK) Opaque ¶ added in go1.5 func (p *CMYK) Opaque() bool Opaque scans the entire image and reports whether it is fully opaque. func (*CMYK) PixOffset ¶ added in go1.5 func (p *CMYK) PixOffset(x, y int) int PixOffset returns the index of the first element of Pix that corresponds to the pixel at (x, y). func (*CMYK) RGBA64At ¶ added in go1.17 func (p *CMYK) RGBA64At(x, y int) color.RGBA64 func (*CMYK) Set ¶ added in go1.5 func (p *CMYK) Set(x, y int, c color.Color) func (*CMYK) SetCMYK ¶ added in go1.5 func (p *CMYK) SetCMYK(x, y int, c color.CMYK) func (*CMYK) SetRGBA64 ¶ added in go1.17 func (p *CMYK) SetRGBA64(x, y int, c color.RGBA64) func (*CMYK) SubImage ¶ added in go1.5 func (p *CMYK) 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 ¶ type Config struct { ColorModel color.Model Width, Height int } Config holds an image's color model and dimensions. func DecodeConfig ¶ 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 ¶ type Gray struct { Pix []uint8 Stride int Rect Rectangle } Gray is an in-memory image whose At method returns color.Gray values. func NewGray ¶ func NewGray(r Rectangle) *Gray NewGray returns a new Gray image with the given bounds. func (*Gray) At ¶ func (p *Gray) At(x, y int) color.Color func (*Gray) Bounds ¶ func (p *Gray) Bounds() Rectangle func (*Gray) ColorModel ¶ func (p *Gray) ColorModel() color.Model func (*Gray) GrayAt ¶ added in go1.4 func (p *Gray) GrayAt(x, y int) color.Gray func (*Gray) Opaque ¶ func (p *Gray) Opaque() bool Opaque scans the entire image and reports whether it is fully opaque. func (*Gray) PixOffset ¶ 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 (*Gray) RGBA64At ¶ added in go1.17 func (p *Gray) RGBA64At(x, y int) color.RGBA64 func (*Gray) Set ¶ func (p *Gray) Set(x, y int, c color.Color) func (*Gray) SetGray ¶ func (p *Gray) SetGray(x, y int, c color.Gray) func (*Gray) SetRGBA64 ¶ added in go1.17 func (p *Gray) SetRGBA64(x, y int, c color.RGBA64) func (*Gray) SubImage ¶ 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 ¶ type Gray16 struct { Pix []uint8 Stride int Rect Rectangle } Gray16 is an in-memory image whose At method returns color.Gray16 values. func NewGray16 ¶ func NewGray16(r Rectangle) *Gray16 NewGray16 returns a new Gray16 image with the given bounds. func (*Gray16) At ¶ func (p *Gray16) At(x, y int) color.Color func (*Gray16) Bounds ¶ func (p *Gray16) Bounds() Rectangle func (*Gray16) ColorModel ¶ func (p *Gray16) ColorModel() color.Model func (*Gray16) Gray16At ¶ added in go1.4 func (p *Gray16) Gray16At(x, y int) color.Gray16 func (*Gray16) Opaque ¶ func (p *Gray16) Opaque() bool Opaque scans the entire image and reports whether it is fully opaque. func (*Gray16) PixOffset ¶ 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 (*Gray16) RGBA64At ¶ added in go1.17 func (p *Gray16) RGBA64At(x, y int) color.RGBA64 func (*Gray16) Set ¶ func (p *Gray16) Set(x, y int, c color.Color) func (*Gray16) SetGray16 ¶ func (p *Gray16) SetGray16(x, y int, c color.Gray16) func (*Gray16) SetRGBA64 ¶ added in go1.17 func (p *Gray16) SetRGBA64(x, y int, c color.RGBA64) func (*Gray16) SubImage ¶ 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 ¶ type Image interface { ColorModel() color.Model Bounds() Rectangle At(x, y int) color.Color } Image is a finite rectangular grid of color.Color values taken from a color model. func Decode ¶ 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 ¶ type NRGBA struct { Pix []uint8 Stride int Rect Rectangle } NRGBA is an in-memory image whose At method returns color.NRGBA values. func NewNRGBA ¶ func NewNRGBA(r Rectangle) *NRGBA NewNRGBA returns a new NRGBA image with the given bounds. func (*NRGBA) At ¶ func (p *NRGBA) At(x, y int) color.Color func (*NRGBA) Bounds ¶ func (p *NRGBA) Bounds() Rectangle func (*NRGBA) ColorModel ¶ func (p *NRGBA) ColorModel() color.Model func (*NRGBA) NRGBAAt ¶ added in go1.4 func (p *NRGBA) NRGBAAt(x, y int) color.NRGBA func (*NRGBA) Opaque ¶ func (p *NRGBA) Opaque() bool Opaque scans the entire image and reports whether it is fully opaque. func (*NRGBA) PixOffset ¶ 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 (*NRGBA) RGBA64At ¶ added in go1.17 func (p *NRGBA) RGBA64At(x, y int) color.RGBA64 func (*NRGBA) Set ¶ func (p *NRGBA) Set(x, y int, c color.Color) func (*NRGBA) SetNRGBA ¶ func (p *NRGBA) SetNRGBA(x, y int, c color.NRGBA) func (*NRGBA) SetRGBA64 ¶ added in go1.17 func (p *NRGBA) SetRGBA64(x, y int, c color.RGBA64) func (*NRGBA) SubImage ¶ 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 ¶ type NRGBA64 struct { Pix []uint8 Stride int Rect Rectangle } NRGBA64 is an in-memory image whose At method returns color.NRGBA64 values. func NewNRGBA64 ¶ func NewNRGBA64(r Rectangle) *NRGBA64 NewNRGBA64 returns a new NRGBA64 image with the given bounds. func (*NRGBA64) At ¶ func (p *NRGBA64) At(x, y int) color.Color func (*NRGBA64) Bounds ¶ func (p *NRGBA64) Bounds() Rectangle func (*NRGBA64) ColorModel ¶ func (p *NRGBA64) ColorModel() color.Model func (*NRGBA64) NRGBA64At ¶ added in go1.4 func (p *NRGBA64) NRGBA64At(x, y int) color.NRGBA64 func (*NRGBA64) Opaque ¶ func (p *NRGBA64) Opaque() bool Opaque scans the entire image and reports whether it is fully opaque. func (*NRGBA64) PixOffset ¶ 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 (*NRGBA64) RGBA64At ¶ added in go1.17 func (p *NRGBA64) RGBA64At(x, y int) color.RGBA64 func (*NRGBA64) Set ¶ func (p *NRGBA64) Set(x, y int, c color.Color) func (*NRGBA64) SetNRGBA64 ¶ func (p *NRGBA64) SetNRGBA64(x, y int, c color.NRGBA64) func (*NRGBA64) SetRGBA64 ¶ added in go1.17 func (p *NRGBA64) SetRGBA64(x, y int, c color.RGBA64) func (*NRGBA64) SubImage ¶ 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 NYCbCrA ¶ added in go1.6 type NYCbCrA struct { YCbCr A []uint8 AStride int } NYCbCrA is an in-memory image of non-alpha-premultiplied Y'CbCr-with-alpha colors. A and AStride are analogous to the Y and YStride fields of the embedded YCbCr. func NewNYCbCrA ¶ added in go1.6 func NewNYCbCrA(r Rectangle, subsampleRatio YCbCrSubsampleRatio) *NYCbCrA NewNYCbCrA returns a new NYCbCrA image with the given bounds and subsample ratio. func (*NYCbCrA) AOffset ¶ added in go1.6 func (p *NYCbCrA) AOffset(x, y int) int AOffset returns the index of the first element of A that corresponds to the pixel at (x, y). func (*NYCbCrA) At ¶ added in go1.6 func (p *NYCbCrA) At(x, y int) color.Color func (*NYCbCrA) ColorModel ¶ added in go1.6 func (p *NYCbCrA) ColorModel() color.Model func (*NYCbCrA) NYCbCrAAt ¶ added in go1.6 func (p *NYCbCrA) NYCbCrAAt(x, y int) color.NYCbCrA func (*NYCbCrA) Opaque ¶ added in go1.6 func (p *NYCbCrA) Opaque() bool Opaque scans the entire image and reports whether it is fully opaque. func (*NYCbCrA) RGBA64At ¶ added in go1.17 func (p *NYCbCrA) RGBA64At(x, y int) color.RGBA64 func (*NYCbCrA) SubImage ¶ added in go1.6 func (p *NYCbCrA) 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 ¶ type Paletted struct { Pix []uint8 Stride int Rect Rectangle Palette color.Palette } Paletted is an in-memory image of uint8 indices into a given palette. func NewPaletted ¶ func NewPaletted(r Rectangle, p color.Palette) *Paletted NewPaletted returns a new Paletted image with the given width, height and palette. func (*Paletted) At ¶ func (p *Paletted) At(x, y int) color.Color func (*Paletted) Bounds ¶ func (p *Paletted) Bounds() Rectangle func (*Paletted) ColorIndexAt ¶ func (p *Paletted) ColorIndexAt(x, y int) uint8 func (*Paletted) ColorModel ¶ func (p *Paletted) ColorModel() color.Model func (*Paletted) Opaque ¶ func (p *Paletted) Opaque() bool Opaque scans the entire image and reports whether it is fully opaque. func (*Paletted) PixOffset ¶ 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 (*Paletted) RGBA64At ¶ added in go1.17 func (p *Paletted) RGBA64At(x, y int) color.RGBA64 func (*Paletted) Set ¶ func (p *Paletted) Set(x, y int, c color.Color) func (*Paletted) SetColorIndex ¶ func (p *Paletted) SetColorIndex(x, y int, index uint8) func (*Paletted) SetRGBA64 ¶ added in go1.17 func (p *Paletted) SetRGBA64(x, y int, c color.RGBA64) func (*Paletted) SubImage ¶ 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 ¶ type PalettedImage interface { 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 color.Palette p, then m.At(x, y) should be equivalent to p[m.ColorIndexAt(x, y)]. If m's color model is not a color.Palette, then ColorIndexAt's behavior is undefined. type Point ¶ 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. Deprecated: Use a literal image.Point instead. func Pt ¶ func Pt(X, Y int) Point Pt is shorthand for Point{X, Y}. func (Point) Add ¶ func (p Point) Add(q Point) Point Add returns the vector p+q. func (Point) Div ¶ func (p Point) Div(k int) Point Div returns the vector p/k. func (Point) Eq ¶ func (p Point) Eq(q Point) bool Eq reports whether p and q are equal. func (Point) In ¶ func (p Point) In(r Rectangle) bool In reports whether p is in r. func (Point) Mod ¶ 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 (Point) Mul ¶ func (p Point) Mul(k int) Point Mul returns the vector p*k. func (Point) String ¶ func (p Point) String() string String returns a string representation of p like "(3,4)". func (Point) Sub ¶ func (p Point) Sub(q Point) Point Sub returns the vector p-q. type RGBA ¶ type RGBA struct { Pix []uint8 Stride int Rect Rectangle } RGBA is an in-memory image whose At method returns color.RGBA values. func NewRGBA ¶ func NewRGBA(r Rectangle) *RGBA NewRGBA returns a new RGBA image with the given bounds. func (*RGBA) At ¶ func (p *RGBA) At(x, y int) color.Color func (*RGBA) Bounds ¶ func (p *RGBA) Bounds() Rectangle func (*RGBA) ColorModel ¶ func (p *RGBA) ColorModel() color.Model func (*RGBA) Opaque ¶ func (p *RGBA) Opaque() bool Opaque scans the entire image and reports whether it is fully opaque. func (*RGBA) PixOffset ¶ 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 (*RGBA) RGBA64At ¶ added in go1.17 func (p *RGBA) RGBA64At(x, y int) color.RGBA64 func (*RGBA) RGBAAt ¶ added in go1.4 func (p *RGBA) RGBAAt(x, y int) color.RGBA func (*RGBA) Set ¶ func (p *RGBA) Set(x, y int, c color.Color) func (*RGBA) SetRGBA ¶ func (p *RGBA) SetRGBA(x, y int, c color.RGBA) func (*RGBA) SetRGBA64 ¶ added in go1.17 func (p *RGBA) SetRGBA64(x, y int, c color.RGBA64) func (*RGBA) SubImage ¶ 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 ¶ type RGBA64 struct { Pix []uint8 Stride int Rect Rectangle } RGBA64 is an in-memory image whose At method returns color.RGBA64 values. func NewRGBA64 ¶ func NewRGBA64(r Rectangle) *RGBA64 NewRGBA64 returns a new RGBA64 image with the given bounds. func (*RGBA64) At ¶ func (p *RGBA64) At(x, y int) color.Color func (*RGBA64) Bounds ¶ func (p *RGBA64) Bounds() Rectangle func (*RGBA64) ColorModel ¶ func (p *RGBA64) ColorModel() color.Model func (*RGBA64) Opaque ¶ func (p *RGBA64) Opaque() bool Opaque scans the entire image and reports whether it is fully opaque. func (*RGBA64) PixOffset ¶ 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 (*RGBA64) RGBA64At ¶ added in go1.4 func (p *RGBA64) RGBA64At(x, y int) color.RGBA64 func (*RGBA64) Set ¶ func (p *RGBA64) Set(x, y int, c color.Color) func (*RGBA64) SetRGBA64 ¶ func (p *RGBA64) SetRGBA64(x, y int, c color.RGBA64) func (*RGBA64) SubImage ¶ 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 RGBA64Image ¶ added in go1.17 type RGBA64Image interface { RGBA64At(x, y int) color.RGBA64 Image } RGBA64Image is an Image whose pixels can be converted directly to a color.RGBA64. type Rectangle ¶ 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. A Rectangle is also an Image whose bounds are the rectangle itself. At returns color.Opaque for points in the rectangle and color.Transparent otherwise. var ZR Rectangle ZR is the zero Rectangle. Deprecated: Use a literal image.Rectangle instead. func Rect ¶ func Rect(x0, y0, x1, y1 int) Rectangle Rect is shorthand for Rectangle{Pt(x0, y0), Pt(x1, y1)}. The returned rectangle has minimum and maximum coordinates swapped if necessary so that it is well-formed. func (Rectangle) Add ¶ func (r Rectangle) Add(p Point) Rectangle Add returns the rectangle r translated by p. func (Rectangle) At ¶ added in go1.5 func (r Rectangle) At(x, y int) color.Color At implements the Image interface. func (Rectangle) Bounds ¶ added in go1.5 func (r Rectangle) Bounds() Rectangle Bounds implements the Image interface. func (Rectangle) Canon ¶ 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 (Rectangle) ColorModel ¶ added in go1.5 func (r Rectangle) ColorModel() color.Model ColorModel implements the Image interface. func (Rectangle) Dx ¶ func (r Rectangle) Dx() int Dx returns r's width. func (Rectangle) Dy ¶ func (r Rectangle) Dy() int Dy returns r's height. func (Rectangle) Empty ¶ func (r Rectangle) Empty() bool Empty reports whether the rectangle contains no points. func (Rectangle) Eq ¶ func (r Rectangle) Eq(s Rectangle) bool Eq reports whether r and s contain the same set of points. All empty rectangles are considered equal. func (Rectangle) In ¶ func (r Rectangle) In(s Rectangle) bool In reports whether every point in r is in s. func (Rectangle) Inset ¶ 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 (Rectangle) Intersect ¶ 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 (Rectangle) Overlaps ¶ func (r Rectangle) Overlaps(s Rectangle) bool Overlaps reports whether r and s have a non-empty intersection. func (Rectangle) RGBA64At ¶ added in go1.17 func (r Rectangle) RGBA64At(x, y int) color.RGBA64 RGBA64At implements the RGBA64Image interface. func (Rectangle) Size ¶ func (r Rectangle) Size() Point Size returns r's width and height. func (Rectangle) String ¶ func (r Rectangle) String() string String returns a string representation of r like "(3,4)-(6,5)". func (Rectangle) Sub ¶ func (r Rectangle) Sub(p Point) Rectangle Sub returns the rectangle r translated by -p. func (Rectangle) Union ¶ func (r Rectangle) Union(s Rectangle) Rectangle Union returns the smallest rectangle that contains both r and s. type Uniform ¶ 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 ¶ func NewUniform(c color.Color) *Uniform NewUniform returns a new Uniform image of the given color. func (*Uniform) At ¶ func (c *Uniform) At(x, y int) color.Color func (*Uniform) Bounds ¶ func (c *Uniform) Bounds() Rectangle func (*Uniform) ColorModel ¶ func (c *Uniform) ColorModel() color.Model func (*Uniform) Convert ¶ func (c *Uniform) Convert(color.Color) color.Color func (*Uniform) Opaque ¶ func (c *Uniform) Opaque() bool Opaque scans the entire image and reports whether it is fully opaque. func (*Uniform) RGBA ¶ func (c *Uniform) RGBA() (r, g, b, a uint32) func (*Uniform) RGBA64At ¶ added in go1.17 func (c *Uniform) RGBA64At(x, y int) color.RGBA64 type YCbCr ¶ 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. For 4:1:1, CStride == YStride/4 && len(Cb) == len(Cr) == len(Y)/4. For 4:1:0, CStride == YStride/4 && len(Cb) == len(Cr) == len(Y)/8. func NewYCbCr ¶ func NewYCbCr(r Rectangle, subsampleRatio YCbCrSubsampleRatio) *YCbCr NewYCbCr returns a new YCbCr image with the given bounds and subsample ratio. func (*YCbCr) At ¶ func (p *YCbCr) At(x, y int) color.Color func (*YCbCr) Bounds ¶ func (p *YCbCr) Bounds() Rectangle func (*YCbCr) COffset ¶ 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 (*YCbCr) ColorModel ¶ func (p *YCbCr) ColorModel() color.Model func (*YCbCr) Opaque ¶ func (p *YCbCr) Opaque() bool func (*YCbCr) RGBA64At ¶ added in go1.17 func (p *YCbCr) RGBA64At(x, y int) color.RGBA64 func (*YCbCr) SubImage ¶ 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 (*YCbCr) YCbCrAt ¶ added in go1.4 func (p *YCbCr) YCbCrAt(x, y int) color.YCbCr func (*YCbCr) YOffset ¶ 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 ¶ type YCbCrSubsampleRatio int YCbCrSubsampleRatio is the chroma subsample ratio used in a YCbCr image. const ( YCbCrSubsampleRatio444 YCbCrSubsampleRatio = iota YCbCrSubsampleRatio422 YCbCrSubsampleRatio420 YCbCrSubsampleRatio440 YCbCrSubsampleRatio411 YCbCrSubsampleRatio410 ) func (YCbCrSubsampleRatio) String ¶ func (s YCbCrSubsampleRatio) String() string Source Files ¶ View all Source files format.gogeom.goimage.gonames.goycbcr.go Directories ¶ Show internal Expand all Path Synopsis color Package color implements a basic color library. Package color implements a basic color library. palette Package palette provides standard color palettes. Package palette provides standard color palettes. draw Package draw provides image composition functions. Package draw provides image composition functions. gif Package gif implements a GIF image decoder and encoder. Package gif implements a GIF image decoder and encoder. internal imageutil Package imageutil contains code shared by image-related packages. Package imageutil contains code shared by image-related packages. jpeg Package jpeg implements a JPEG image decoder and encoder. Package jpeg implements a JPEG image decoder and encoder. png Package png implements a PNG image decoder and encoder. Package png implements a PNG image decoder and encoder. Click to show internal directories. Click to hide internal directories. go.dev uses cookies from Google to deliver and enhance the quality of its services and to analyze traffic. Learn more. Okay