ston1th/glyphosat
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ston1th 2019-05-08 20:50:37 +02:00
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.gitignore vendored Normal file
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convert
new
orig
glyphosat_bfr.odt
glyphosat_bfr.pdf
glyphosat_bfr.txt

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README.md Normal file
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# BfR Glyphosat Image Converter
Use this tool to convert the grayscale images to more readable black/white images.
These are then combined into a single tiff image and OCR scanned with tesseract to produce a good machine readable form.
The `convert.sh` script does all the nessesary steps and leaves the two files:
* glyphosat_bfr.pdf
* glyphosat_bfr.txt
# Requirenments
* go (golang)
* tesseract version 4
* german langaue
* poppler-utils (for `tiffcp`)
# Usage
Place the downloaded glyphosat images in a new directory named `orig` and use the original file names.
Run the convert script: `./convert.sh`
# Hashes
The sha1 and sha256 hashes of the original image files.
```
sha1sum orig/*
01c0378d14bff41e92433bc5b2c49f4800ce55ba orig/glypo-0.jpg
31ff6e6dd3a6117f898a98c45f4c991ce3a79668 orig/glypo-1.jpg
f14ae8bed3044150023b1b0b4010376b1797ddce orig/glypo-2.jpg
2a8435cbaa05d86ea2129acf3145980170624316 orig/glypo-3.jpg
afc23087d309186314261eaf860b81a10a2e5c0f orig/glypo-4.jpg
9b75b546ee15a93c8fb1495f51c78e0edad5b4d1 orig/glypo-5.jpg
```
```
sha256sum orig/*
6451b51f44d590eb891ab1c1c02630072e89f6a1b6c096be54018377f42c2e85 orig/glypo-0.jpg
0b7c2565fd1cad0da4cd91e5df98e191f873eaa21c3bdfd53072adf79ebef767 orig/glypo-1.jpg
09c7db92ff06130843fd0c94900589fbf5ac7ef6f745183b622034efb3e1b40e orig/glypo-2.jpg
a4ce38aee94878d2c52261ad4b4c52c56352efe88346d8a12180e8e66429c07a orig/glypo-3.jpg
a192041d87c234273dd774da559437ab1cb54a4340f526de990f3f72c8d75464 orig/glypo-4.jpg
d84bbc84ce6507048a8f2ae5b16dd803083979cdcf6fa7cc50b9b27244818750 orig/glypo-5.jpg
```

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convert.go Normal file
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package main
import (
"fmt"
"golang.org/x/image/tiff"
"image"
"image/color"
_ "image/jpeg"
"os"
)
func convert(i image.Image) image.Image {
rect := i.Bounds()
n := image.NewGray(rect)
for x := 0; x < rect.Max.X; x++ {
for y := 0; y < rect.Max.Y; y++ {
p := color.GrayModel.Convert(i.At(x, y)).(color.Gray)
if p.Y <= 130 {
n.Set(x, y, p)
} else {
n.Set(x, y, color.White)
}
}
}
return n
}
func main() {
in, err := os.Open(os.Args[1])
if err != nil {
fmt.Println(err)
return
}
out, err := os.OpenFile(os.Args[2], os.O_RDWR|os.O_CREATE, 0644)
if err != nil {
fmt.Println(err)
return
}
i, _, err := image.Decode(in)
if err != nil {
fmt.Println(err)
return
}
err = tiff.Encode(out, convert(i), &tiff.Options{tiff.Uncompressed, false})
if err != nil {
fmt.Println(err)
}
}

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convert.sh Executable file
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#!/bin/sh
[ -d new ] || mkdir new
go build convert.go
./convert orig/glypo-0.jpg new/glypo-0.tif
./convert orig/glypo-1.jpg new/glypo-1.tif
./convert orig/glypo-2.jpg new/glypo-2.tif
./convert orig/glypo-3.jpg new/glypo-3.tif
./convert orig/glypo-4.jpg new/glypo-4.tif
./convert orig/glypo-5.jpg new/glypo-5.tif
tiffcp new/*.tif new/combined.tif
tesseract --oem 1 -l deu new/combined.tif glyphosat_bfr pdf
tesseract --oem 1 -l deu new/combined.tif glyphosat_bfr txt

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module git.giftfish.de/ston1th/glyphosat
go 1.12
require golang.org/x/image v0.0.0-20190507092727-e4e5bf290fec

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golang.org/x/image v0.0.0-20190507092727-e4e5bf290fec h1:arXJwtMuk5vqI1NHX0UTnNw977rYk5Sl4jQqHj+hun4=
golang.org/x/image v0.0.0-20190507092727-e4e5bf290fec/go.mod h1:kZ7UVZpmo3dzQBMxlp+ypCbDeSB+sBbTgSJuh5dn5js=
golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

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vendor/golang.org/x/image/AUTHORS generated vendored Normal file
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# This source code refers to The Go Authors for copyright purposes.
# The master list of authors is in the main Go distribution,
# visible at http://tip.golang.org/AUTHORS.

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vendor/golang.org/x/image/CONTRIBUTORS generated vendored Normal file
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# This source code was written by the Go contributors.
# The master list of contributors is in the main Go distribution,
# visible at http://tip.golang.org/CONTRIBUTORS.

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Copyright (c) 2009 The Go Authors. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
distribution.
* Neither the name of Google Inc. nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

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vendor/golang.org/x/image/PATENTS generated vendored Normal file
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Additional IP Rights Grant (Patents)
"This implementation" means the copyrightable works distributed by
Google as part of the Go project.
Google hereby grants to You a perpetual, worldwide, non-exclusive,
no-charge, royalty-free, irrevocable (except as stated in this section)
patent license to make, have made, use, offer to sell, sell, import,
transfer and otherwise run, modify and propagate the contents of this
implementation of Go, where such license applies only to those patent
claims, both currently owned or controlled by Google and acquired in
the future, licensable by Google that are necessarily infringed by this
implementation of Go. This grant does not include claims that would be
infringed only as a consequence of further modification of this
implementation. If you or your agent or exclusive licensee institute or
order or agree to the institution of patent litigation against any
entity (including a cross-claim or counterclaim in a lawsuit) alleging
that this implementation of Go or any code incorporated within this
implementation of Go constitutes direct or contributory patent
infringement, or inducement of patent infringement, then any patent
rights granted to you under this License for this implementation of Go
shall terminate as of the date such litigation is filed.

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vendor/golang.org/x/image/tiff/buffer.go generated vendored Normal file
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tiff
import "io"
// buffer buffers an io.Reader to satisfy io.ReaderAt.
type buffer struct {
r io.Reader
buf []byte
}
// fill reads data from b.r until the buffer contains at least end bytes.
func (b *buffer) fill(end int) error {
m := len(b.buf)
if end > m {
if end > cap(b.buf) {
newcap := 1024
for newcap < end {
newcap *= 2
}
newbuf := make([]byte, end, newcap)
copy(newbuf, b.buf)
b.buf = newbuf
} else {
b.buf = b.buf[:end]
}
if n, err := io.ReadFull(b.r, b.buf[m:end]); err != nil {
end = m + n
b.buf = b.buf[:end]
return err
}
}
return nil
}
func (b *buffer) ReadAt(p []byte, off int64) (int, error) {
o := int(off)
end := o + len(p)
if int64(end) != off+int64(len(p)) {
return 0, io.ErrUnexpectedEOF
}
err := b.fill(end)
return copy(p, b.buf[o:end]), err
}
// Slice returns a slice of the underlying buffer. The slice contains
// n bytes starting at offset off.
func (b *buffer) Slice(off, n int) ([]byte, error) {
end := off + n
if err := b.fill(end); err != nil {
return nil, err
}
return b.buf[off:end], nil
}
// newReaderAt converts an io.Reader into an io.ReaderAt.
func newReaderAt(r io.Reader) io.ReaderAt {
if ra, ok := r.(io.ReaderAt); ok {
return ra
}
return &buffer{
r: r,
buf: make([]byte, 0, 1024),
}
}

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vendor/golang.org/x/image/tiff/compress.go generated vendored Normal file
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tiff
import (
"bufio"
"io"
)
type byteReader interface {
io.Reader
io.ByteReader
}
// unpackBits decodes the PackBits-compressed data in src and returns the
// uncompressed data.
//
// The PackBits compression format is described in section 9 (p. 42)
// of the TIFF spec.
func unpackBits(r io.Reader) ([]byte, error) {
buf := make([]byte, 128)
dst := make([]byte, 0, 1024)
br, ok := r.(byteReader)
if !ok {
br = bufio.NewReader(r)
}
for {
b, err := br.ReadByte()
if err != nil {
if err == io.EOF {
return dst, nil
}
return nil, err
}
code := int(int8(b))
switch {
case code >= 0:
n, err := io.ReadFull(br, buf[:code+1])
if err != nil {
return nil, err
}
dst = append(dst, buf[:n]...)
case code == -128:
// No-op.
default:
if b, err = br.ReadByte(); err != nil {
return nil, err
}
for j := 0; j < 1-code; j++ {
buf[j] = b
}
dst = append(dst, buf[:1-code]...)
}
}
}

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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tiff
// A tiff image file contains one or more images. The metadata
// of each image is contained in an Image File Directory (IFD),
// which contains entries of 12 bytes each and is described
// on page 14-16 of the specification. An IFD entry consists of
//
// - a tag, which describes the signification of the entry,
// - the data type and length of the entry,
// - the data itself or a pointer to it if it is more than 4 bytes.
//
// The presence of a length means that each IFD is effectively an array.
const (
leHeader = "II\x2A\x00" // Header for little-endian files.
beHeader = "MM\x00\x2A" // Header for big-endian files.
ifdLen = 12 // Length of an IFD entry in bytes.
)
// Data types (p. 14-16 of the spec).
const (
dtByte = 1
dtASCII = 2
dtShort = 3
dtLong = 4
dtRational = 5
)
// The length of one instance of each data type in bytes.
var lengths = [...]uint32{0, 1, 1, 2, 4, 8}
// Tags (see p. 28-41 of the spec).
const (
tImageWidth = 256
tImageLength = 257
tBitsPerSample = 258
tCompression = 259
tPhotometricInterpretation = 262
tStripOffsets = 273
tSamplesPerPixel = 277
tRowsPerStrip = 278
tStripByteCounts = 279
tTileWidth = 322
tTileLength = 323
tTileOffsets = 324
tTileByteCounts = 325
tXResolution = 282
tYResolution = 283
tResolutionUnit = 296
tPredictor = 317
tColorMap = 320
tExtraSamples = 338
tSampleFormat = 339
)
// Compression types (defined in various places in the spec and supplements).
const (
cNone = 1
cCCITT = 2
cG3 = 3 // Group 3 Fax.
cG4 = 4 // Group 4 Fax.
cLZW = 5
cJPEGOld = 6 // Superseded by cJPEG.
cJPEG = 7
cDeflate = 8 // zlib compression.
cPackBits = 32773
cDeflateOld = 32946 // Superseded by cDeflate.
)
// Photometric interpretation values (see p. 37 of the spec).
const (
pWhiteIsZero = 0
pBlackIsZero = 1
pRGB = 2
pPaletted = 3
pTransMask = 4 // transparency mask
pCMYK = 5
pYCbCr = 6
pCIELab = 8
)
// Values for the tPredictor tag (page 64-65 of the spec).
const (
prNone = 1
prHorizontal = 2
)
// Values for the tResolutionUnit tag (page 18).
const (
resNone = 1
resPerInch = 2 // Dots per inch.
resPerCM = 3 // Dots per centimeter.
)
// imageMode represents the mode of the image.
type imageMode int
const (
mBilevel imageMode = iota
mPaletted
mGray
mGrayInvert
mRGB
mRGBA
mNRGBA
)
// CompressionType describes the type of compression used in Options.
type CompressionType int
const (
Uncompressed CompressionType = iota
Deflate
)
// specValue returns the compression type constant from the TIFF spec that
// is equivalent to c.
func (c CompressionType) specValue() uint32 {
switch c {
case Deflate:
return cDeflate
}
return cNone
}

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vendor/golang.org/x/image/tiff/fuzz.go generated vendored Normal file
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// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build gofuzz
package tiff
import "bytes"
func Fuzz(data []byte) int {
cfg, err := DecodeConfig(bytes.NewReader(data))
if err != nil {
return 0
}
if cfg.Width*cfg.Height > 1e6 {
return 0
}
img, err := Decode(bytes.NewReader(data))
if err != nil {
return 0
}
var w bytes.Buffer
err = Encode(&w, img, nil)
if err != nil {
panic(err)
}
return 1
}

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vendor/golang.org/x/image/tiff/lzw/reader.go generated vendored Normal file
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package lzw implements the Lempel-Ziv-Welch compressed data format,
// described in T. A. Welch, ``A Technique for High-Performance Data
// Compression'', Computer, 17(6) (June 1984), pp 8-19.
//
// In particular, it implements LZW as used by the TIFF file format, including
// an "off by one" algorithmic difference when compared to standard LZW.
package lzw // import "golang.org/x/image/tiff/lzw"
/*
This file was branched from src/pkg/compress/lzw/reader.go in the
standard library. Differences from the original are marked with "NOTE".
The tif_lzw.c file in the libtiff C library has this comment:
----
The 5.0 spec describes a different algorithm than Aldus
implements. Specifically, Aldus does code length transitions
one code earlier than should be done (for real LZW).
Earlier versions of this library implemented the correct
LZW algorithm, but emitted codes in a bit order opposite
to the TIFF spec. Thus, to maintain compatibility w/ Aldus
we interpret MSB-LSB ordered codes to be images written w/
old versions of this library, but otherwise adhere to the
Aldus "off by one" algorithm.
----
The Go code doesn't read (invalid) TIFF files written by old versions of
libtiff, but the LZW algorithm in this package still differs from the one in
Go's standard package library to accomodate this "off by one" in valid TIFFs.
*/
import (
"bufio"
"errors"
"fmt"
"io"
)
// Order specifies the bit ordering in an LZW data stream.
type Order int
const (
// LSB means Least Significant Bits first, as used in the GIF file format.
LSB Order = iota
// MSB means Most Significant Bits first, as used in the TIFF and PDF
// file formats.
MSB
)
const (
maxWidth = 12
decoderInvalidCode = 0xffff
flushBuffer = 1 << maxWidth
)
// decoder is the state from which the readXxx method converts a byte
// stream into a code stream.
type decoder struct {
r io.ByteReader
bits uint32
nBits uint
width uint
read func(*decoder) (uint16, error) // readLSB or readMSB
litWidth int // width in bits of literal codes
err error
// The first 1<<litWidth codes are literal codes.
// The next two codes mean clear and EOF.
// Other valid codes are in the range [lo, hi] where lo := clear + 2,
// with the upper bound incrementing on each code seen.
// overflow is the code at which hi overflows the code width. NOTE: TIFF's LZW is "off by one".
// last is the most recently seen code, or decoderInvalidCode.
clear, eof, hi, overflow, last uint16
// Each code c in [lo, hi] expands to two or more bytes. For c != hi:
// suffix[c] is the last of these bytes.
// prefix[c] is the code for all but the last byte.
// This code can either be a literal code or another code in [lo, c).
// The c == hi case is a special case.
suffix [1 << maxWidth]uint8
prefix [1 << maxWidth]uint16
// output is the temporary output buffer.
// Literal codes are accumulated from the start of the buffer.
// Non-literal codes decode to a sequence of suffixes that are first
// written right-to-left from the end of the buffer before being copied
// to the start of the buffer.
// It is flushed when it contains >= 1<<maxWidth bytes,
// so that there is always room to decode an entire code.
output [2 * 1 << maxWidth]byte
o int // write index into output
toRead []byte // bytes to return from Read
}
// readLSB returns the next code for "Least Significant Bits first" data.
func (d *decoder) readLSB() (uint16, error) {
for d.nBits < d.width {
x, err := d.r.ReadByte()
if err != nil {
return 0, err
}
d.bits |= uint32(x) << d.nBits
d.nBits += 8
}
code := uint16(d.bits & (1<<d.width - 1))
d.bits >>= d.width
d.nBits -= d.width
return code, nil
}
// readMSB returns the next code for "Most Significant Bits first" data.
func (d *decoder) readMSB() (uint16, error) {
for d.nBits < d.width {
x, err := d.r.ReadByte()
if err != nil {
return 0, err
}
d.bits |= uint32(x) << (24 - d.nBits)
d.nBits += 8
}
code := uint16(d.bits >> (32 - d.width))
d.bits <<= d.width
d.nBits -= d.width
return code, nil
}
func (d *decoder) Read(b []byte) (int, error) {
for {
if len(d.toRead) > 0 {
n := copy(b, d.toRead)
d.toRead = d.toRead[n:]
return n, nil
}
if d.err != nil {
return 0, d.err
}
d.decode()
}
}
// decode decompresses bytes from r and leaves them in d.toRead.
// read specifies how to decode bytes into codes.
// litWidth is the width in bits of literal codes.
func (d *decoder) decode() {
// Loop over the code stream, converting codes into decompressed bytes.
loop:
for {
code, err := d.read(d)
if err != nil {
if err == io.EOF {
err = io.ErrUnexpectedEOF
}
d.err = err
break
}
switch {
case code < d.clear:
// We have a literal code.
d.output[d.o] = uint8(code)
d.o++
if d.last != decoderInvalidCode {
// Save what the hi code expands to.
d.suffix[d.hi] = uint8(code)
d.prefix[d.hi] = d.last
}
case code == d.clear:
d.width = 1 + uint(d.litWidth)
d.hi = d.eof
d.overflow = 1 << d.width
d.last = decoderInvalidCode
continue
case code == d.eof:
d.err = io.EOF
break loop
case code <= d.hi:
c, i := code, len(d.output)-1
if code == d.hi {
// code == hi is a special case which expands to the last expansion
// followed by the head of the last expansion. To find the head, we walk
// the prefix chain until we find a literal code.
c = d.last
for c >= d.clear {
c = d.prefix[c]
}
d.output[i] = uint8(c)
i--
c = d.last
}
// Copy the suffix chain into output and then write that to w.
for c >= d.clear {
d.output[i] = d.suffix[c]
i--
c = d.prefix[c]
}
d.output[i] = uint8(c)
d.o += copy(d.output[d.o:], d.output[i:])
if d.last != decoderInvalidCode {
// Save what the hi code expands to.
d.suffix[d.hi] = uint8(c)
d.prefix[d.hi] = d.last
}
default:
d.err = errors.New("lzw: invalid code")
break loop
}
d.last, d.hi = code, d.hi+1
if d.hi+1 >= d.overflow { // NOTE: the "+1" is where TIFF's LZW differs from the standard algorithm.
if d.width == maxWidth {
d.last = decoderInvalidCode
} else {
d.width++
d.overflow <<= 1
}
}
if d.o >= flushBuffer {
break
}
}
// Flush pending output.
d.toRead = d.output[:d.o]
d.o = 0
}
var errClosed = errors.New("lzw: reader/writer is closed")
func (d *decoder) Close() error {
d.err = errClosed // in case any Reads come along
return nil
}
// NewReader creates a new io.ReadCloser.
// Reads from the returned io.ReadCloser read and decompress data from r.
// If r does not also implement io.ByteReader,
// the decompressor may read more data than necessary from r.
// It is the caller's responsibility to call Close on the ReadCloser when
// finished reading.
// The number of bits to use for literal codes, litWidth, must be in the
// range [2,8] and is typically 8. It must equal the litWidth
// used during compression.
func NewReader(r io.Reader, order Order, litWidth int) io.ReadCloser {
d := new(decoder)
switch order {
case LSB:
d.read = (*decoder).readLSB
case MSB:
d.read = (*decoder).readMSB
default:
d.err = errors.New("lzw: unknown order")
return d
}
if litWidth < 2 || 8 < litWidth {
d.err = fmt.Errorf("lzw: litWidth %d out of range", litWidth)
return d
}
if br, ok := r.(io.ByteReader); ok {
d.r = br
} else {
d.r = bufio.NewReader(r)
}
d.litWidth = litWidth
d.width = 1 + uint(litWidth)
d.clear = uint16(1) << uint(litWidth)
d.eof, d.hi = d.clear+1, d.clear+1
d.overflow = uint16(1) << d.width
d.last = decoderInvalidCode
return d
}

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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package tiff implements a TIFF image decoder and encoder.
//
// The TIFF specification is at http://partners.adobe.com/public/developer/en/tiff/TIFF6.pdf
package tiff // import "golang.org/x/image/tiff"
import (
"compress/zlib"
"encoding/binary"
"fmt"
"image"
"image/color"
"io"
"io/ioutil"
"math"
"golang.org/x/image/tiff/lzw"
)
// A FormatError reports that the input is not a valid TIFF image.
type FormatError string
func (e FormatError) Error() string {
return "tiff: invalid format: " + string(e)
}
// An UnsupportedError reports that the input uses a valid but
// unimplemented feature.
type UnsupportedError string
func (e UnsupportedError) Error() string {
return "tiff: unsupported feature: " + string(e)
}
var errNoPixels = FormatError("not enough pixel data")
type decoder struct {
r io.ReaderAt
byteOrder binary.ByteOrder
config image.Config
mode imageMode
bpp uint
features map[int][]uint
palette []color.Color
buf []byte
off int // Current offset in buf.
v uint32 // Buffer value for reading with arbitrary bit depths.
nbits uint // Remaining number of bits in v.
}
// firstVal returns the first uint of the features entry with the given tag,
// or 0 if the tag does not exist.
func (d *decoder) firstVal(tag int) uint {
f := d.features[tag]
if len(f) == 0 {
return 0
}
return f[0]
}
// ifdUint decodes the IFD entry in p, which must be of the Byte, Short
// or Long type, and returns the decoded uint values.
func (d *decoder) ifdUint(p []byte) (u []uint, err error) {
var raw []byte
if len(p) < ifdLen {
return nil, FormatError("bad IFD entry")
}
datatype := d.byteOrder.Uint16(p[2:4])
if dt := int(datatype); dt <= 0 || dt >= len(lengths) {
return nil, UnsupportedError("IFD entry datatype")
}
count := d.byteOrder.Uint32(p[4:8])
if count > math.MaxInt32/lengths[datatype] {
return nil, FormatError("IFD data too large")
}
if datalen := lengths[datatype] * count; datalen > 4 {
// The IFD contains a pointer to the real value.
raw = make([]byte, datalen)
_, err = d.r.ReadAt(raw, int64(d.byteOrder.Uint32(p[8:12])))
} else {
raw = p[8 : 8+datalen]
}
if err != nil {
return nil, err
}
u = make([]uint, count)
switch datatype {
case dtByte:
for i := uint32(0); i < count; i++ {
u[i] = uint(raw[i])
}
case dtShort:
for i := uint32(0); i < count; i++ {
u[i] = uint(d.byteOrder.Uint16(raw[2*i : 2*(i+1)]))
}
case dtLong:
for i := uint32(0); i < count; i++ {
u[i] = uint(d.byteOrder.Uint32(raw[4*i : 4*(i+1)]))
}
default:
return nil, UnsupportedError("data type")
}
return u, nil
}
// parseIFD decides whether the IFD entry in p is "interesting" and
// stows away the data in the decoder. It returns the tag number of the
// entry and an error, if any.
func (d *decoder) parseIFD(p []byte) (int, error) {
tag := d.byteOrder.Uint16(p[0:2])
switch tag {
case tBitsPerSample,
tExtraSamples,
tPhotometricInterpretation,
tCompression,
tPredictor,
tStripOffsets,
tStripByteCounts,
tRowsPerStrip,
tTileWidth,
tTileLength,
tTileOffsets,
tTileByteCounts,
tImageLength,
tImageWidth:
val, err := d.ifdUint(p)
if err != nil {
return 0, err
}
d.features[int(tag)] = val
case tColorMap:
val, err := d.ifdUint(p)
if err != nil {
return 0, err
}
numcolors := len(val) / 3
if len(val)%3 != 0 || numcolors <= 0 || numcolors > 256 {
return 0, FormatError("bad ColorMap length")
}
d.palette = make([]color.Color, numcolors)
for i := 0; i < numcolors; i++ {
d.palette[i] = color.RGBA64{
uint16(val[i]),
uint16(val[i+numcolors]),
uint16(val[i+2*numcolors]),
0xffff,
}
}
case tSampleFormat:
// Page 27 of the spec: If the SampleFormat is present and
// the value is not 1 [= unsigned integer data], a Baseline
// TIFF reader that cannot handle the SampleFormat value
// must terminate the import process gracefully.
val, err := d.ifdUint(p)
if err != nil {
return 0, err
}
for _, v := range val {
if v != 1 {
return 0, UnsupportedError("sample format")
}
}
}
return int(tag), nil
}
// readBits reads n bits from the internal buffer starting at the current offset.
func (d *decoder) readBits(n uint) (v uint32, ok bool) {
for d.nbits < n {
d.v <<= 8
if d.off >= len(d.buf) {
return 0, false
}
d.v |= uint32(d.buf[d.off])
d.off++
d.nbits += 8
}
d.nbits -= n
rv := d.v >> d.nbits
d.v &^= rv << d.nbits
return rv, true
}
// flushBits discards the unread bits in the buffer used by readBits.
// It is used at the end of a line.
func (d *decoder) flushBits() {
d.v = 0
d.nbits = 0
}
// minInt returns the smaller of x or y.
func minInt(a, b int) int {
if a <= b {
return a
}
return b
}
// decode decodes the raw data of an image.
// It reads from d.buf and writes the strip or tile into dst.
func (d *decoder) decode(dst image.Image, xmin, ymin, xmax, ymax int) error {
d.off = 0
// Apply horizontal predictor if necessary.
// In this case, p contains the color difference to the preceding pixel.
// See page 64-65 of the spec.
if d.firstVal(tPredictor) == prHorizontal {
switch d.bpp {
case 16:
var off int
n := 2 * len(d.features[tBitsPerSample]) // bytes per sample times samples per pixel
for y := ymin; y < ymax; y++ {
off += n
for x := 0; x < (xmax-xmin-1)*n; x += 2 {
if off+2 > len(d.buf) {
return errNoPixels
}
v0 := d.byteOrder.Uint16(d.buf[off-n : off-n+2])
v1 := d.byteOrder.Uint16(d.buf[off : off+2])
d.byteOrder.PutUint16(d.buf[off:off+2], v1+v0)
off += 2
}
}
case 8:
var off int
n := 1 * len(d.features[tBitsPerSample]) // bytes per sample times samples per pixel
for y := ymin; y < ymax; y++ {
off += n
for x := 0; x < (xmax-xmin-1)*n; x++ {
if off >= len(d.buf) {
return errNoPixels
}
d.buf[off] += d.buf[off-n]
off++
}
}
case 1:
return UnsupportedError("horizontal predictor with 1 BitsPerSample")
}
}
rMaxX := minInt(xmax, dst.Bounds().Max.X)
rMaxY := minInt(ymax, dst.Bounds().Max.Y)
switch d.mode {
case mGray, mGrayInvert:
if d.bpp == 16 {
img := dst.(*image.Gray16)
for y := ymin; y < rMaxY; y++ {
for x := xmin; x < rMaxX; x++ {
if d.off+2 > len(d.buf) {
return errNoPixels
}
v := d.byteOrder.Uint16(d.buf[d.off : d.off+2])
d.off += 2
if d.mode == mGrayInvert {
v = 0xffff - v
}
img.SetGray16(x, y, color.Gray16{v})
}
if rMaxX == img.Bounds().Max.X {
d.off += 2 * (xmax - img.Bounds().Max.X)
}
}
} else {
img := dst.(*image.Gray)
max := uint32((1 << d.bpp) - 1)
for y := ymin; y < rMaxY; y++ {
for x := xmin; x < rMaxX; x++ {
v, ok := d.readBits(d.bpp)
if !ok {
return errNoPixels
}
v = v * 0xff / max
if d.mode == mGrayInvert {
v = 0xff - v
}
img.SetGray(x, y, color.Gray{uint8(v)})
}
d.flushBits()
}
}
case mPaletted:
img := dst.(*image.Paletted)
for y := ymin; y < rMaxY; y++ {
for x := xmin; x < rMaxX; x++ {
v, ok := d.readBits(d.bpp)
if !ok {
return errNoPixels
}
img.SetColorIndex(x, y, uint8(v))
}
d.flushBits()
}
case mRGB:
if d.bpp == 16 {
img := dst.(*image.RGBA64)
for y := ymin; y < rMaxY; y++ {
for x := xmin; x < rMaxX; x++ {
if d.off+6 > len(d.buf) {
return errNoPixels
}
r := d.byteOrder.Uint16(d.buf[d.off+0 : d.off+2])
g := d.byteOrder.Uint16(d.buf[d.off+2 : d.off+4])
b := d.byteOrder.Uint16(d.buf[d.off+4 : d.off+6])
d.off += 6
img.SetRGBA64(x, y, color.RGBA64{r, g, b, 0xffff})
}
}
} else {
img := dst.(*image.RGBA)
for y := ymin; y < rMaxY; y++ {
min := img.PixOffset(xmin, y)
max := img.PixOffset(rMaxX, y)
off := (y - ymin) * (xmax - xmin) * 3
for i := min; i < max; i += 4 {
if off+3 > len(d.buf) {
return errNoPixels
}
img.Pix[i+0] = d.buf[off+0]
img.Pix[i+1] = d.buf[off+1]
img.Pix[i+2] = d.buf[off+2]
img.Pix[i+3] = 0xff
off += 3
}
}
}
case mNRGBA:
if d.bpp == 16 {
img := dst.(*image.NRGBA64)
for y := ymin; y < rMaxY; y++ {
for x := xmin; x < rMaxX; x++ {
if d.off+8 > len(d.buf) {
return errNoPixels
}
r := d.byteOrder.Uint16(d.buf[d.off+0 : d.off+2])
g := d.byteOrder.Uint16(d.buf[d.off+2 : d.off+4])
b := d.byteOrder.Uint16(d.buf[d.off+4 : d.off+6])
a := d.byteOrder.Uint16(d.buf[d.off+6 : d.off+8])
d.off += 8
img.SetNRGBA64(x, y, color.NRGBA64{r, g, b, a})
}
}
} else {
img := dst.(*image.NRGBA)
for y := ymin; y < rMaxY; y++ {
min := img.PixOffset(xmin, y)
max := img.PixOffset(rMaxX, y)
i0, i1 := (y-ymin)*(xmax-xmin)*4, (y-ymin+1)*(xmax-xmin)*4
if i1 > len(d.buf) {
return errNoPixels
}
copy(img.Pix[min:max], d.buf[i0:i1])
}
}
case mRGBA:
if d.bpp == 16 {
img := dst.(*image.RGBA64)
for y := ymin; y < rMaxY; y++ {
for x := xmin; x < rMaxX; x++ {
if d.off+8 > len(d.buf) {
return errNoPixels
}
r := d.byteOrder.Uint16(d.buf[d.off+0 : d.off+2])
g := d.byteOrder.Uint16(d.buf[d.off+2 : d.off+4])
b := d.byteOrder.Uint16(d.buf[d.off+4 : d.off+6])
a := d.byteOrder.Uint16(d.buf[d.off+6 : d.off+8])
d.off += 8
img.SetRGBA64(x, y, color.RGBA64{r, g, b, a})
}
}
} else {
img := dst.(*image.RGBA)
for y := ymin; y < rMaxY; y++ {
min := img.PixOffset(xmin, y)
max := img.PixOffset(rMaxX, y)
i0, i1 := (y-ymin)*(xmax-xmin)*4, (y-ymin+1)*(xmax-xmin)*4
if i1 > len(d.buf) {
return errNoPixels
}
copy(img.Pix[min:max], d.buf[i0:i1])
}
}
}
return nil
}
func newDecoder(r io.Reader) (*decoder, error) {
d := &decoder{
r: newReaderAt(r),
features: make(map[int][]uint),
}
p := make([]byte, 8)
if _, err := d.r.ReadAt(p, 0); err != nil {
return nil, err
}
switch string(p[0:4]) {
case leHeader:
d.byteOrder = binary.LittleEndian
case beHeader:
d.byteOrder = binary.BigEndian
default:
return nil, FormatError("malformed header")
}
ifdOffset := int64(d.byteOrder.Uint32(p[4:8]))
// The first two bytes contain the number of entries (12 bytes each).
if _, err := d.r.ReadAt(p[0:2], ifdOffset); err != nil {
return nil, err
}
numItems := int(d.byteOrder.Uint16(p[0:2]))
// All IFD entries are read in one chunk.
p = make([]byte, ifdLen*numItems)
if _, err := d.r.ReadAt(p, ifdOffset+2); err != nil {
return nil, err
}
prevTag := -1
for i := 0; i < len(p); i += ifdLen {
tag, err := d.parseIFD(p[i : i+ifdLen])
if err != nil {
return nil, err
}
if tag <= prevTag {
return nil, FormatError("tags are not sorted in ascending order")
}
prevTag = tag
}
d.config.Width = int(d.firstVal(tImageWidth))
d.config.Height = int(d.firstVal(tImageLength))
if _, ok := d.features[tBitsPerSample]; !ok {
return nil, FormatError("BitsPerSample tag missing")
}
d.bpp = d.firstVal(tBitsPerSample)
switch d.bpp {
case 0:
return nil, FormatError("BitsPerSample must not be 0")
case 1, 8, 16:
// Nothing to do, these are accepted by this implementation.
default:
return nil, UnsupportedError(fmt.Sprintf("BitsPerSample of %v", d.bpp))
}
// Determine the image mode.
switch d.firstVal(tPhotometricInterpretation) {
case pRGB:
if d.bpp == 16 {
for _, b := range d.features[tBitsPerSample] {
if b != 16 {
return nil, FormatError("wrong number of samples for 16bit RGB")
}
}
} else {
for _, b := range d.features[tBitsPerSample] {
if b != 8 {
return nil, FormatError("wrong number of samples for 8bit RGB")
}
}
}
// RGB images normally have 3 samples per pixel.
// If there are more, ExtraSamples (p. 31-32 of the spec)
// gives their meaning (usually an alpha channel).
//
// This implementation does not support extra samples
// of an unspecified type.
switch len(d.features[tBitsPerSample]) {
case 3:
d.mode = mRGB
if d.bpp == 16 {
d.config.ColorModel = color.RGBA64Model
} else {
d.config.ColorModel = color.RGBAModel
}
case 4:
switch d.firstVal(tExtraSamples) {
case 1:
d.mode = mRGBA
if d.bpp == 16 {
d.config.ColorModel = color.RGBA64Model
} else {
d.config.ColorModel = color.RGBAModel
}
case 2:
d.mode = mNRGBA
if d.bpp == 16 {
d.config.ColorModel = color.NRGBA64Model
} else {
d.config.ColorModel = color.NRGBAModel
}
default:
return nil, FormatError("wrong number of samples for RGB")
}
default:
return nil, FormatError("wrong number of samples for RGB")
}
case pPaletted:
d.mode = mPaletted
d.config.ColorModel = color.Palette(d.palette)
case pWhiteIsZero:
d.mode = mGrayInvert
if d.bpp == 16 {
d.config.ColorModel = color.Gray16Model
} else {
d.config.ColorModel = color.GrayModel
}
case pBlackIsZero:
d.mode = mGray
if d.bpp == 16 {
d.config.ColorModel = color.Gray16Model
} else {
d.config.ColorModel = color.GrayModel
}
default:
return nil, UnsupportedError("color model")
}
return d, nil
}
// DecodeConfig returns the color model and dimensions of a TIFF image without
// decoding the entire image.
func DecodeConfig(r io.Reader) (image.Config, error) {
d, err := newDecoder(r)
if err != nil {
return image.Config{}, err
}
return d.config, nil
}
// Decode reads a TIFF image from r and returns it as an image.Image.
// The type of Image returned depends on the contents of the TIFF.
func Decode(r io.Reader) (img image.Image, err error) {
d, err := newDecoder(r)
if err != nil {
return
}
blockPadding := false
blockWidth := d.config.Width
blockHeight := d.config.Height
blocksAcross := 1
blocksDown := 1
if d.config.Width == 0 {
blocksAcross = 0
}
if d.config.Height == 0 {
blocksDown = 0
}
var blockOffsets, blockCounts []uint
if int(d.firstVal(tTileWidth)) != 0 {
blockPadding = true
blockWidth = int(d.firstVal(tTileWidth))
blockHeight = int(d.firstVal(tTileLength))
if blockWidth != 0 {
blocksAcross = (d.config.Width + blockWidth - 1) / blockWidth
}
if blockHeight != 0 {
blocksDown = (d.config.Height + blockHeight - 1) / blockHeight
}
blockCounts = d.features[tTileByteCounts]
blockOffsets = d.features[tTileOffsets]
} else {
if int(d.firstVal(tRowsPerStrip)) != 0 {
blockHeight = int(d.firstVal(tRowsPerStrip))
}
if blockHeight != 0 {
blocksDown = (d.config.Height + blockHeight - 1) / blockHeight
}
blockOffsets = d.features[tStripOffsets]
blockCounts = d.features[tStripByteCounts]
}
// Check if we have the right number of strips/tiles, offsets and counts.
if n := blocksAcross * blocksDown; len(blockOffsets) < n || len(blockCounts) < n {
return nil, FormatError("inconsistent header")
}
imgRect := image.Rect(0, 0, d.config.Width, d.config.Height)
switch d.mode {
case mGray, mGrayInvert:
if d.bpp == 16 {
img = image.NewGray16(imgRect)
} else {
img = image.NewGray(imgRect)
}
case mPaletted:
img = image.NewPaletted(imgRect, d.palette)
case mNRGBA:
if d.bpp == 16 {
img = image.NewNRGBA64(imgRect)
} else {
img = image.NewNRGBA(imgRect)
}
case mRGB, mRGBA:
if d.bpp == 16 {
img = image.NewRGBA64(imgRect)
} else {
img = image.NewRGBA(imgRect)
}
}
for i := 0; i < blocksAcross; i++ {
blkW := blockWidth
if !blockPadding && i == blocksAcross-1 && d.config.Width%blockWidth != 0 {
blkW = d.config.Width % blockWidth
}
for j := 0; j < blocksDown; j++ {
blkH := blockHeight
if !blockPadding && j == blocksDown-1 && d.config.Height%blockHeight != 0 {
blkH = d.config.Height % blockHeight
}
offset := int64(blockOffsets[j*blocksAcross+i])
n := int64(blockCounts[j*blocksAcross+i])
switch d.firstVal(tCompression) {
// According to the spec, Compression does not have a default value,
// but some tools interpret a missing Compression value as none so we do
// the same.
case cNone, 0:
if b, ok := d.r.(*buffer); ok {
d.buf, err = b.Slice(int(offset), int(n))
} else {
d.buf = make([]byte, n)
_, err = d.r.ReadAt(d.buf, offset)
}
case cLZW:
r := lzw.NewReader(io.NewSectionReader(d.r, offset, n), lzw.MSB, 8)
d.buf, err = ioutil.ReadAll(r)
r.Close()
case cDeflate, cDeflateOld:
var r io.ReadCloser
r, err = zlib.NewReader(io.NewSectionReader(d.r, offset, n))
if err != nil {
return nil, err
}
d.buf, err = ioutil.ReadAll(r)
r.Close()
case cPackBits:
d.buf, err = unpackBits(io.NewSectionReader(d.r, offset, n))
default:
err = UnsupportedError(fmt.Sprintf("compression value %d", d.firstVal(tCompression)))
}
if err != nil {
return nil, err
}
xmin := i * blockWidth
ymin := j * blockHeight
xmax := xmin + blkW
ymax := ymin + blkH
err = d.decode(img, xmin, ymin, xmax, ymax)
if err != nil {
return nil, err
}
}
}
return
}
func init() {
image.RegisterFormat("tiff", leHeader, Decode, DecodeConfig)
image.RegisterFormat("tiff", beHeader, Decode, DecodeConfig)
}

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vendor/golang.org/x/image/tiff/writer.go generated vendored Normal file
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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tiff
import (
"bytes"
"compress/zlib"
"encoding/binary"
"image"
"io"
"sort"
)
// The TIFF format allows to choose the order of the different elements freely.
// The basic structure of a TIFF file written by this package is:
//
// 1. Header (8 bytes).
// 2. Image data.
// 3. Image File Directory (IFD).
// 4. "Pointer area" for larger entries in the IFD.
// We only write little-endian TIFF files.
var enc = binary.LittleEndian
// An ifdEntry is a single entry in an Image File Directory.
// A value of type dtRational is composed of two 32-bit values,
// thus data contains two uints (numerator and denominator) for a single number.
type ifdEntry struct {
tag int
datatype int
data []uint32
}
func (e ifdEntry) putData(p []byte) {
for _, d := range e.data {
switch e.datatype {
case dtByte, dtASCII:
p[0] = byte(d)
p = p[1:]
case dtShort:
enc.PutUint16(p, uint16(d))
p = p[2:]
case dtLong, dtRational:
enc.PutUint32(p, uint32(d))
p = p[4:]
}
}
}
type byTag []ifdEntry
func (d byTag) Len() int { return len(d) }
func (d byTag) Less(i, j int) bool { return d[i].tag < d[j].tag }
func (d byTag) Swap(i, j int) { d[i], d[j] = d[j], d[i] }
func encodeGray(w io.Writer, pix []uint8, dx, dy, stride int, predictor bool) error {
if !predictor {
return writePix(w, pix, dy, dx, stride)
}
buf := make([]byte, dx)
for y := 0; y < dy; y++ {
min := y*stride + 0
max := y*stride + dx
off := 0
var v0 uint8
for i := min; i < max; i++ {
v1 := pix[i]
buf[off] = v1 - v0
v0 = v1
off++
}
if _, err := w.Write(buf); err != nil {
return err
}
}
return nil
}
func encodeGray16(w io.Writer, pix []uint8, dx, dy, stride int, predictor bool) error {
buf := make([]byte, dx*2)
for y := 0; y < dy; y++ {
min := y*stride + 0
max := y*stride + dx*2
off := 0
var v0 uint16
for i := min; i < max; i += 2 {
// An image.Gray16's Pix is in big-endian order.
v1 := uint16(pix[i])<<8 | uint16(pix[i+1])
if predictor {
v0, v1 = v1, v1-v0
}
// We only write little-endian TIFF files.
buf[off+0] = byte(v1)
buf[off+1] = byte(v1 >> 8)
off += 2
}
if _, err := w.Write(buf); err != nil {
return err
}
}
return nil
}
func encodeRGBA(w io.Writer, pix []uint8, dx, dy, stride int, predictor bool) error {
if !predictor {
return writePix(w, pix, dy, dx*4, stride)
}
buf := make([]byte, dx*4)
for y := 0; y < dy; y++ {
min := y*stride + 0
max := y*stride + dx*4
off := 0
var r0, g0, b0, a0 uint8
for i := min; i < max; i += 4 {
r1, g1, b1, a1 := pix[i+0], pix[i+1], pix[i+2], pix[i+3]
buf[off+0] = r1 - r0
buf[off+1] = g1 - g0
buf[off+2] = b1 - b0
buf[off+3] = a1 - a0
off += 4
r0, g0, b0, a0 = r1, g1, b1, a1
}
if _, err := w.Write(buf); err != nil {
return err
}
}
return nil
}
func encodeRGBA64(w io.Writer, pix []uint8, dx, dy, stride int, predictor bool) error {
buf := make([]byte, dx*8)
for y := 0; y < dy; y++ {
min := y*stride + 0
max := y*stride + dx*8
off := 0
var r0, g0, b0, a0 uint16
for i := min; i < max; i += 8 {
// An image.RGBA64's Pix is in big-endian order.
r1 := uint16(pix[i+0])<<8 | uint16(pix[i+1])
g1 := uint16(pix[i+2])<<8 | uint16(pix[i+3])
b1 := uint16(pix[i+4])<<8 | uint16(pix[i+5])
a1 := uint16(pix[i+6])<<8 | uint16(pix[i+7])
if predictor {
r0, r1 = r1, r1-r0
g0, g1 = g1, g1-g0
b0, b1 = b1, b1-b0
a0, a1 = a1, a1-a0
}
// We only write little-endian TIFF files.
buf[off+0] = byte(r1)
buf[off+1] = byte(r1 >> 8)
buf[off+2] = byte(g1)
buf[off+3] = byte(g1 >> 8)
buf[off+4] = byte(b1)
buf[off+5] = byte(b1 >> 8)
buf[off+6] = byte(a1)
buf[off+7] = byte(a1 >> 8)
off += 8
}
if _, err := w.Write(buf); err != nil {
return err
}
}
return nil
}
func encode(w io.Writer, m image.Image, predictor bool) error {
bounds := m.Bounds()
buf := make([]byte, 4*bounds.Dx())
for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
off := 0
if predictor {
var r0, g0, b0, a0 uint8
for x := bounds.Min.X; x < bounds.Max.X; x++ {
r, g, b, a := m.At(x, y).RGBA()
r1 := uint8(r >> 8)
g1 := uint8(g >> 8)
b1 := uint8(b >> 8)
a1 := uint8(a >> 8)
buf[off+0] = r1 - r0
buf[off+1] = g1 - g0
buf[off+2] = b1 - b0
buf[off+3] = a1 - a0
off += 4
r0, g0, b0, a0 = r1, g1, b1, a1
}
} else {
for x := bounds.Min.X; x < bounds.Max.X; x++ {
r, g, b, a := m.At(x, y).RGBA()
buf[off+0] = uint8(r >> 8)
buf[off+1] = uint8(g >> 8)
buf[off+2] = uint8(b >> 8)
buf[off+3] = uint8(a >> 8)
off += 4
}
}
if _, err := w.Write(buf); err != nil {
return err
}
}
return nil
}
// writePix writes the internal byte array of an image to w. It is less general
// but much faster then encode. writePix is used when pix directly
// corresponds to one of the TIFF image types.
func writePix(w io.Writer, pix []byte, nrows, length, stride int) error {
if length == stride {
_, err := w.Write(pix[:nrows*length])
return err
}
for ; nrows > 0; nrows-- {
if _, err := w.Write(pix[:length]); err != nil {
return err
}
pix = pix[stride:]
}
return nil
}
func writeIFD(w io.Writer, ifdOffset int, d []ifdEntry) error {
var buf [ifdLen]byte
// Make space for "pointer area" containing IFD entry data
// longer than 4 bytes.
parea := make([]byte, 1024)
pstart := ifdOffset + ifdLen*len(d) + 6
var o int // Current offset in parea.
// The IFD has to be written with the tags in ascending order.
sort.Sort(byTag(d))
// Write the number of entries in this IFD.
if err := binary.Write(w, enc, uint16(len(d))); err != nil {
return err
}
for _, ent := range d {
enc.PutUint16(buf[0:2], uint16(ent.tag))
enc.PutUint16(buf[2:4], uint16(ent.datatype))
count := uint32(len(ent.data))
if ent.datatype == dtRational {
count /= 2
}
enc.PutUint32(buf[4:8], count)
datalen := int(count * lengths[ent.datatype])
if datalen <= 4 {
ent.putData(buf[8:12])
} else {
if (o + datalen) > len(parea) {
newlen := len(parea) + 1024
for (o + datalen) > newlen {
newlen += 1024
}
newarea := make([]byte, newlen)
copy(newarea, parea)
parea = newarea
}
ent.putData(parea[o : o+datalen])
enc.PutUint32(buf[8:12], uint32(pstart+o))
o += datalen
}
if _, err := w.Write(buf[:]); err != nil {
return err
}
}
// The IFD ends with the offset of the next IFD in the file,
// or zero if it is the last one (page 14).
if err := binary.Write(w, enc, uint32(0)); err != nil {
return err
}
_, err := w.Write(parea[:o])
return err
}
// Options are the encoding parameters.
type Options struct {
// Compression is the type of compression used.
Compression CompressionType
// Predictor determines whether a differencing predictor is used;
// if true, instead of each pixel's color, the color difference to the
// preceding one is saved. This improves the compression for certain
// types of images and compressors. For example, it works well for
// photos with Deflate compression.
Predictor bool
}
// Encode writes the image m to w. opt determines the options used for
// encoding, such as the compression type. If opt is nil, an uncompressed
// image is written.
func Encode(w io.Writer, m image.Image, opt *Options) error {
d := m.Bounds().Size()
compression := uint32(cNone)
predictor := false
if opt != nil {
compression = opt.Compression.specValue()
// The predictor field is only used with LZW. See page 64 of the spec.
predictor = opt.Predictor && compression == cLZW
}
_, err := io.WriteString(w, leHeader)
if err != nil {
return err
}
// Compressed data is written into a buffer first, so that we
// know the compressed size.
var buf bytes.Buffer
// dst holds the destination for the pixel data of the image --
// either w or a writer to buf.
var dst io.Writer
// imageLen is the length of the pixel data in bytes.
// The offset of the IFD is imageLen + 8 header bytes.
var imageLen int
switch compression {
case cNone:
dst = w
// Write IFD offset before outputting pixel data.
switch m.(type) {
case *image.Paletted:
imageLen = d.X * d.Y * 1
case *image.Gray:
imageLen = d.X * d.Y * 1
case *image.Gray16:
imageLen = d.X * d.Y * 2
case *image.RGBA64:
imageLen = d.X * d.Y * 8
case *image.NRGBA64:
imageLen = d.X * d.Y * 8
default:
imageLen = d.X * d.Y * 4
}
err = binary.Write(w, enc, uint32(imageLen+8))
if err != nil {
return err
}
case cDeflate:
dst = zlib.NewWriter(&buf)
}
pr := uint32(prNone)
photometricInterpretation := uint32(pRGB)
samplesPerPixel := uint32(4)
bitsPerSample := []uint32{8, 8, 8, 8}
extraSamples := uint32(0)
colorMap := []uint32{}
if predictor {
pr = prHorizontal
}
switch m := m.(type) {
case *image.Paletted:
photometricInterpretation = pPaletted
samplesPerPixel = 1
bitsPerSample = []uint32{8}
colorMap = make([]uint32, 256*3)
for i := 0; i < 256 && i < len(m.Palette); i++ {
r, g, b, _ := m.Palette[i].RGBA()
colorMap[i+0*256] = uint32(r)
colorMap[i+1*256] = uint32(g)
colorMap[i+2*256] = uint32(b)
}
err = encodeGray(dst, m.Pix, d.X, d.Y, m.Stride, predictor)
case *image.Gray:
photometricInterpretation = pBlackIsZero
samplesPerPixel = 1
bitsPerSample = []uint32{8}
err = encodeGray(dst, m.Pix, d.X, d.Y, m.Stride, predictor)
case *image.Gray16:
photometricInterpretation = pBlackIsZero
samplesPerPixel = 1
bitsPerSample = []uint32{16}
err = encodeGray16(dst, m.Pix, d.X, d.Y, m.Stride, predictor)
case *image.NRGBA:
extraSamples = 2 // Unassociated alpha.
err = encodeRGBA(dst, m.Pix, d.X, d.Y, m.Stride, predictor)
case *image.NRGBA64:
extraSamples = 2 // Unassociated alpha.
bitsPerSample = []uint32{16, 16, 16, 16}
err = encodeRGBA64(dst, m.Pix, d.X, d.Y, m.Stride, predictor)
case *image.RGBA:
extraSamples = 1 // Associated alpha.
err = encodeRGBA(dst, m.Pix, d.X, d.Y, m.Stride, predictor)
case *image.RGBA64:
extraSamples = 1 // Associated alpha.
bitsPerSample = []uint32{16, 16, 16, 16}
err = encodeRGBA64(dst, m.Pix, d.X, d.Y, m.Stride, predictor)
default:
extraSamples = 1 // Associated alpha.
err = encode(dst, m, predictor)
}
if err != nil {
return err
}
if compression != cNone {
if err = dst.(io.Closer).Close(); err != nil {
return err
}
imageLen = buf.Len()
if err = binary.Write(w, enc, uint32(imageLen+8)); err != nil {
return err
}
if _, err = buf.WriteTo(w); err != nil {
return err
}
}
ifd := []ifdEntry{
{tImageWidth, dtShort, []uint32{uint32(d.X)}},
{tImageLength, dtShort, []uint32{uint32(d.Y)}},
{tBitsPerSample, dtShort, bitsPerSample},
{tCompression, dtShort, []uint32{compression}},
{tPhotometricInterpretation, dtShort, []uint32{photometricInterpretation}},
{tStripOffsets, dtLong, []uint32{8}},
{tSamplesPerPixel, dtShort, []uint32{samplesPerPixel}},
{tRowsPerStrip, dtShort, []uint32{uint32(d.Y)}},
{tStripByteCounts, dtLong, []uint32{uint32(imageLen)}},
// There is currently no support for storing the image
// resolution, so give a bogus value of 72x72 dpi.
{tXResolution, dtRational, []uint32{72, 1}},
{tYResolution, dtRational, []uint32{72, 1}},
{tResolutionUnit, dtShort, []uint32{resPerInch}},
}
if pr != prNone {
ifd = append(ifd, ifdEntry{tPredictor, dtShort, []uint32{pr}})
}
if len(colorMap) != 0 {
ifd = append(ifd, ifdEntry{tColorMap, dtShort, colorMap})
}
if extraSamples > 0 {
ifd = append(ifd, ifdEntry{tExtraSamples, dtShort, []uint32{extraSamples}})
}
return writeIFD(w, imageLen+8, ifd)
}

3
vendor/modules.txt vendored Normal file
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@ -0,0 +1,3 @@
# golang.org/x/image v0.0.0-20190507092727-e4e5bf290fec
golang.org/x/image/tiff
golang.org/x/image/tiff/lzw