Go文档查看帮助很方便，主要可以通过以下两种方式查看

第一种，Go本地运行（参考：#Go语言安装#）起来后，References下面：

• Package

  Go标准函数库说明。

• Command

  Go工具说明。

• Language Specification

  Go官方语言规范说明。

第二种，命令行中执行查看，如

• godoc image NewRGBA

  文档说明 image.NewRGBA()函数功能，输出结果如下：

  PACKAGE

  package image
      import "image"

  TYPES

  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.

  SUBDIRECTORIES

          color
          draw
          gif
          jpeg
          png

• godoc image/png

  输出整个 image/png包，输出结果如下：

  PACKAGE

  package png
      import "image/png"

      Package png implements a PNG image decoder and encoder.

      The PNG specification is at http://www.w3.org/TR/PNG/.

  FUNCTIONS

  func Decode(r io.Reader) (image.Image, error)
      Decode reads a PNG image from r and returns it as an image.Image. The
      type of Image returned depends on the PNG contents.

  func DecodeConfig(r io.Reader) (image.Config, error)
      DecodeConfig returns the color model and dimensions of a PNG image
      without decoding the entire image.

  func Encode(w io.Writer, m image.Image) error
      Encode writes the Image m to w in PNG format. Any Image may be encoded,
      but images that are not image.NRGBA might be encoded lossily.

  TYPES

  type FormatError string
      A FormatError reports that the input is not a valid PNG.

  func (e FormatError) Error() string

  type UnsupportedError string
      An UnsupportedError reports that the input uses a valid but
      unimplemented PNG feature.

  func (e UnsupportedError) Error() string