AutoDetectHeight is passed as the height argument to NewReader to indicate that the image height (the number of rows) is not known in advance.
const AutoDetectHeight = -1
func DecodeIntoGray(dst *image.Gray, r io.Reader, order Order, sf SubFormat, opts *Options) error
DecodeIntoGray decodes the CCITT-formatted data in r into dst.
It returns an error if dst's width and height don't match the implied width and height of CCITT-formatted data.
func NewReader(r io.Reader, order Order, sf SubFormat, width int, height int, opts *Options) io.Reader
NewReader returns an io.Reader that decodes the CCITT-formatted data in r. The resultant byte stream is one bit per pixel (MSB first), with 1 meaning white and 0 meaning black. Each row in the result is byte-aligned.
A negative height, such as passing AutoDetectHeight, means that the image height is not known in advance. A negative width is invalid.
Options are optional parameters.
type Options struct {
// Align means that some variable-bit-width codes are byte-aligned.
Align bool
// Invert means that black is the 1 bit or 0xFF byte, and white is 0.
Invert bool
}
Order specifies the bit ordering in a CCITT data stream.
type Order uint32
const (
// LSB means Least Significant Bits first.
LSB Order = iota
// MSB means Most Significant Bits first.
MSB
)
SubFormat represents that the CCITT format consists of a number of sub-formats. Decoding or encoding a CCITT data stream requires knowing the sub-format context. It is not represented in the data stream per se.
type SubFormat uint32
const (
Group3 SubFormat = iota
Group4
)