Documentation ¶
Overview ¶
Package gif implements a GIF image decoder and encoder.
The GIF specification is at https://www.w3.org/Graphics/GIF/spec-gif89a.txt.
Index ¶
- Constants
- func Decode(r io.Reader) (image.Image, error)
- func DecodeConfig(r io.Reader) (image.Config, error)
- func Encode(w io.Writer, m image.Image, o *Options) error
- func EncodeAll(w io.Writer, g *GIF) error
- func EncodeAllConcurrent(w io.Writer, c chan GIFFrame) error
- type GIF
- type GIFFrame
- type Options
Constants ¶
View Source
const ( DisposalNone = 0x01 DisposalBackground = 0x02 DisposalPrevious = 0x03 )
Disposal Methods.
Variables ¶
This section is empty.
Functions ¶
func Decode ¶
Decode reads a GIF image from r and returns the first embedded image as an image.Image.
func DecodeConfig ¶
DecodeConfig returns the global color model and dimensions of a GIF image without decoding the entire image.
Types ¶
type GIF ¶
type GIF struct { Image []*image.Paletted // The successive images. Delay []int // The successive delay times, one per frame, in 100ths of a second. // LoopCount controls the number of times an animation will be // restarted during display. // A LoopCount of 0 means to loop forever. // A LoopCount of -1 means to show each frame only once. // Otherwise, the animation is looped LoopCount+1 times. LoopCount int // Disposal is the successive disposal methods, one per frame. For // backwards compatibility, a nil Disposal is valid to pass to EncodeAll, // and implies that each frame's disposal method is 0 (no disposal // specified). Disposal []byte // Config is the global color table (palette), width and height. A nil or // empty-color.Palette Config.ColorModel means that each frame has its own // color table and there is no global color table. Each frame's bounds must // be within the rectangle defined by the two points (0, 0) and // (Config.Width, Config.Height). // // For backwards compatibility, a zero-valued Config is valid to pass to // EncodeAll, and implies that the overall GIF's width and height equals // the first frame's bounds' Rectangle.Max point. Config image.Config // BackgroundIndex is the background index in the global color table, for // use with the DisposalBackground disposal method. BackgroundIndex byte }
GIF represents the possibly multiple images stored in a GIF file.
type Options ¶
type Options struct { // NumColors is the maximum number of colors used in the image. // It ranges from 1 to 256. NumColors int // Quantizer is used to produce a palette with size NumColors. // palette.Plan9 is used in place of a nil Quantizer. Quantizer draw.Quantizer // Drawer is used to convert the source image to the desired palette. // draw.FloydSteinberg is used in place of a nil Drawer. Drawer draw.Drawer }
Options are the encoding parameters.
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