gobmp

README

gobmp

A Go package for reading and writing BMP image files.

Installation

To download and install, at a command prompt type:

go get github.com/jsummers/gobmp

Documentation

Gobmp is designed to work the same as Go's standard image modules. Importing it will automatically cause the image.Decode function to support reading BMP files.

The documentation may be read online at GoDoc.

Or, after installing, type:

godoc github.com/jsummers/gobmp | more

Status

The decoder supports almost all types of BMP images.

By default, the encoder will write a 24-bit RGB image, or a 1-, 4-, or 8-bit paletted image. Support for 32-bit RGBA images can optionally be enabled. Writing compressed images is not supported.

License

Gobmp is distributed under an MIT-style license.

Copyright © 2012-2013 Jason Summers <jason1@pobox.com>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.

Documentation

Overview

Package gobmp implements a BMP image decoder and encoder.

Index

• func Decode(r io.Reader) (image.Image, error)
• func DecodeConfig(r io.Reader) (image.Config, error)
• func Encode(w io.Writer, m image.Image) error
• func EncodeWithOptions(w io.Writer, m image.Image, opts *EncoderOptions) error
• type EncoderOptions
  • func (opts *EncoderOptions) SetDensity(xDens, yDens int)
  • func (opts *EncoderOptions) SupportTransparency(t bool)
• type FormatError
  • func (e FormatError) Error() string
• type UnsupportedError
  • func (e UnsupportedError) Error() string

Functions

func Decode

func Decode(r io.Reader) (image.Image, error)

Decode reads a BMP image from r and returns it as an image.Image.

func DecodeConfig

func DecodeConfig(r io.Reader) (image.Config, error)

DecodeConfig returns the color model and dimensions of the BMP image without decoding the entire image.

func Encode

func Encode(w io.Writer, m image.Image) error

Encode writes the Image m to w in BMP format.

func EncodeWithOptions

func EncodeWithOptions(w io.Writer, m image.Image, opts *EncoderOptions) error

EncodeWithOptions writes the Image m to w in BMP format, using the options recorded in opts. opts may be nil, in which case it behaves the same as Encode.

Types

type EncoderOptions

type EncoderOptions struct {
	// contains filtered or unexported fields
}

EncoderOptions stores options that can be passed to EncodeWithOptions(). Create an EncoderOptions object with new().

func (*EncoderOptions) SetDensity

func (opts *EncoderOptions) SetDensity(xDens, yDens int)

SetDensity sets the density to write to the output image's metadata, in pixels per meter.

func (*EncoderOptions) SupportTransparency

func (opts *EncoderOptions) SupportTransparency(t bool)

SupportTransparency indicates whether to retain transparency information when writing the BMP file. Transparency requires the use of a not-so-portable version of BMP.

type FormatError

type FormatError string

A FormatError reports that the input is not a valid BMP file.

func (FormatError) Error

func (e FormatError) Error() string

type UnsupportedError

type UnsupportedError string

An UnsupportedError reports that the input uses a valid but unimplemented BMP feature.

func (UnsupportedError) Error

func (e UnsupportedError) Error() string