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-rw-r--r--vendor/golang.org/x/image/webp/decode.go270
1 files changed, 0 insertions, 270 deletions
diff --git a/vendor/golang.org/x/image/webp/decode.go b/vendor/golang.org/x/image/webp/decode.go
deleted file mode 100644
index f77a4eb..0000000
--- a/vendor/golang.org/x/image/webp/decode.go
+++ /dev/null
@@ -1,270 +0,0 @@
-// 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 webp
-
-import (
- "bytes"
- "errors"
- "image"
- "image/color"
- "io"
-
- "golang.org/x/image/riff"
- "golang.org/x/image/vp8"
- "golang.org/x/image/vp8l"
-)
-
-var errInvalidFormat = errors.New("webp: invalid format")
-
-var (
- fccALPH = riff.FourCC{'A', 'L', 'P', 'H'}
- fccVP8 = riff.FourCC{'V', 'P', '8', ' '}
- fccVP8L = riff.FourCC{'V', 'P', '8', 'L'}
- fccVP8X = riff.FourCC{'V', 'P', '8', 'X'}
- fccWEBP = riff.FourCC{'W', 'E', 'B', 'P'}
-)
-
-func decode(r io.Reader, configOnly bool) (image.Image, image.Config, error) {
- formType, riffReader, err := riff.NewReader(r)
- if err != nil {
- return nil, image.Config{}, err
- }
- if formType != fccWEBP {
- return nil, image.Config{}, errInvalidFormat
- }
-
- var (
- alpha []byte
- alphaStride int
- wantAlpha bool
- widthMinusOne uint32
- heightMinusOne uint32
- buf [10]byte
- )
- for {
- chunkID, chunkLen, chunkData, err := riffReader.Next()
- if err == io.EOF {
- err = errInvalidFormat
- }
- if err != nil {
- return nil, image.Config{}, err
- }
-
- switch chunkID {
- case fccALPH:
- if !wantAlpha {
- return nil, image.Config{}, errInvalidFormat
- }
- wantAlpha = false
- // Read the Pre-processing | Filter | Compression byte.
- if _, err := io.ReadFull(chunkData, buf[:1]); err != nil {
- if err == io.EOF {
- err = errInvalidFormat
- }
- return nil, image.Config{}, err
- }
- alpha, alphaStride, err = readAlpha(chunkData, widthMinusOne, heightMinusOne, buf[0]&0x03)
- if err != nil {
- return nil, image.Config{}, err
- }
- unfilterAlpha(alpha, alphaStride, (buf[0]>>2)&0x03)
-
- case fccVP8:
- if wantAlpha || int32(chunkLen) < 0 {
- return nil, image.Config{}, errInvalidFormat
- }
- d := vp8.NewDecoder()
- d.Init(chunkData, int(chunkLen))
- fh, err := d.DecodeFrameHeader()
- if err != nil {
- return nil, image.Config{}, err
- }
- if configOnly {
- return nil, image.Config{
- ColorModel: color.YCbCrModel,
- Width: fh.Width,
- Height: fh.Height,
- }, nil
- }
- m, err := d.DecodeFrame()
- if err != nil {
- return nil, image.Config{}, err
- }
- if alpha != nil {
- return &image.NYCbCrA{
- YCbCr: *m,
- A: alpha,
- AStride: alphaStride,
- }, image.Config{}, nil
- }
- return m, image.Config{}, nil
-
- case fccVP8L:
- if wantAlpha || alpha != nil {
- return nil, image.Config{}, errInvalidFormat
- }
- if configOnly {
- c, err := vp8l.DecodeConfig(chunkData)
- return nil, c, err
- }
- m, err := vp8l.Decode(chunkData)
- return m, image.Config{}, err
-
- case fccVP8X:
- if chunkLen != 10 {
- return nil, image.Config{}, errInvalidFormat
- }
- if _, err := io.ReadFull(chunkData, buf[:10]); err != nil {
- return nil, image.Config{}, err
- }
- const (
- animationBit = 1 << 1
- xmpMetadataBit = 1 << 2
- exifMetadataBit = 1 << 3
- alphaBit = 1 << 4
- iccProfileBit = 1 << 5
- )
- if buf[0] != alphaBit {
- return nil, image.Config{}, errors.New("webp: non-Alpha VP8X is not implemented")
- }
- widthMinusOne = uint32(buf[4]) | uint32(buf[5])<<8 | uint32(buf[6])<<16
- heightMinusOne = uint32(buf[7]) | uint32(buf[8])<<8 | uint32(buf[9])<<16
- if configOnly {
- return nil, image.Config{
- ColorModel: color.NYCbCrAModel,
- Width: int(widthMinusOne) + 1,
- Height: int(heightMinusOne) + 1,
- }, nil
- }
- wantAlpha = true
-
- default:
- return nil, image.Config{}, errInvalidFormat
- }
- }
-}
-
-func readAlpha(chunkData io.Reader, widthMinusOne, heightMinusOne uint32, compression byte) (
- alpha []byte, alphaStride int, err error) {
-
- switch compression {
- case 0:
- w := int(widthMinusOne) + 1
- h := int(heightMinusOne) + 1
- alpha = make([]byte, w*h)
- if _, err := io.ReadFull(chunkData, alpha); err != nil {
- return nil, 0, err
- }
- return alpha, w, nil
-
- case 1:
- // Read the VP8L-compressed alpha values. First, synthesize a 5-byte VP8L header:
- // a 1-byte magic number, a 14-bit widthMinusOne, a 14-bit heightMinusOne,
- // a 1-bit (ignored, zero) alphaIsUsed and a 3-bit (zero) version.
- // TODO(nigeltao): be more efficient than decoding an *image.NRGBA just to
- // extract the green values to a separately allocated []byte. Fixing this
- // will require changes to the vp8l package's API.
- if widthMinusOne > 0x3fff || heightMinusOne > 0x3fff {
- return nil, 0, errors.New("webp: invalid format")
- }
- alphaImage, err := vp8l.Decode(io.MultiReader(
- bytes.NewReader([]byte{
- 0x2f, // VP8L magic number.
- uint8(widthMinusOne),
- uint8(widthMinusOne>>8) | uint8(heightMinusOne<<6),
- uint8(heightMinusOne >> 2),
- uint8(heightMinusOne >> 10),
- }),
- chunkData,
- ))
- if err != nil {
- return nil, 0, err
- }
- // The green values of the inner NRGBA image are the alpha values of the
- // outer NYCbCrA image.
- pix := alphaImage.(*image.NRGBA).Pix
- alpha = make([]byte, len(pix)/4)
- for i := range alpha {
- alpha[i] = pix[4*i+1]
- }
- return alpha, int(widthMinusOne) + 1, nil
- }
- return nil, 0, errInvalidFormat
-}
-
-func unfilterAlpha(alpha []byte, alphaStride int, filter byte) {
- if len(alpha) == 0 || alphaStride == 0 {
- return
- }
- switch filter {
- case 1: // Horizontal filter.
- for i := 1; i < alphaStride; i++ {
- alpha[i] += alpha[i-1]
- }
- for i := alphaStride; i < len(alpha); i += alphaStride {
- // The first column is equivalent to the vertical filter.
- alpha[i] += alpha[i-alphaStride]
-
- for j := 1; j < alphaStride; j++ {
- alpha[i+j] += alpha[i+j-1]
- }
- }
-
- case 2: // Vertical filter.
- // The first row is equivalent to the horizontal filter.
- for i := 1; i < alphaStride; i++ {
- alpha[i] += alpha[i-1]
- }
-
- for i := alphaStride; i < len(alpha); i++ {
- alpha[i] += alpha[i-alphaStride]
- }
-
- case 3: // Gradient filter.
- // The first row is equivalent to the horizontal filter.
- for i := 1; i < alphaStride; i++ {
- alpha[i] += alpha[i-1]
- }
-
- for i := alphaStride; i < len(alpha); i += alphaStride {
- // The first column is equivalent to the vertical filter.
- alpha[i] += alpha[i-alphaStride]
-
- // The interior is predicted on the three top/left pixels.
- for j := 1; j < alphaStride; j++ {
- c := int(alpha[i+j-alphaStride-1])
- b := int(alpha[i+j-alphaStride])
- a := int(alpha[i+j-1])
- x := a + b - c
- if x < 0 {
- x = 0
- } else if x > 255 {
- x = 255
- }
- alpha[i+j] += uint8(x)
- }
- }
- }
-}
-
-// Decode reads a WEBP image from r and returns it as an image.Image.
-func Decode(r io.Reader) (image.Image, error) {
- m, _, err := decode(r, false)
- if err != nil {
- return nil, err
- }
- return m, err
-}
-
-// DecodeConfig returns the color model and dimensions of a WEBP image without
-// decoding the entire image.
-func DecodeConfig(r io.Reader) (image.Config, error) {
- _, c, err := decode(r, true)
- return c, err
-}
-
-func init() {
- image.RegisterFormat("webp", "RIFF????WEBPVP8", Decode, DecodeConfig)
-}
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-28 23:53:18 +0000