1 files changed, 463 insertions, 0 deletions
diff --git a/vendor/github.com/disintegration/imaging/io.go b/vendor/github.com/disintegration/imaging/io.go
new file mode 100644
index 000000000..557bf2f3d
--- /dev/null
+++ b/vendor/github.com/disintegration/imaging/io.go
@@ -0,0 +1,463 @@
+package imaging
+
+import (
+	"encoding/binary"
+	"errors"
+	"image"
+	"image/draw"
+	"image/gif"
+	"image/jpeg"
+	"image/png"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"golang.org/x/image/bmp"
+	"golang.org/x/image/tiff"
+)
+
+// Format is an image file format.
+type Format int
+
+// Image file formats.
+const (
+	JPEG Format = iota
+	PNG
+	GIF
+	TIFF
+	BMP
+)
+
+func (f Format) String() string {
+	switch f {
+	case JPEG:
+		return "JPEG"
+	case PNG:
+		return "PNG"
+	case GIF:
+		return "GIF"
+	case TIFF:
+		return "TIFF"
+	case BMP:
+		return "BMP"
+	default:
+		return "Unsupported"
+	}
+}
+
+var formatFromExt = map[string]Format{
+	"jpg":  JPEG,
+	"jpeg": JPEG,
+	"png":  PNG,
+	"tif":  TIFF,
+	"tiff": TIFF,
+	"bmp":  BMP,
+	"gif":  GIF,
+}
+
+// FormatFromExtension parses image format from extension:
+// "jpg" (or "jpeg"), "png", "gif", "tif" (or "tiff") and "bmp" are supported.
+func FormatFromExtension(ext string) (Format, error) {
+	if f, ok := formatFromExt[strings.ToLower(strings.TrimPrefix(ext, "."))]; ok {
+		return f, nil
+	}
+	return -1, ErrUnsupportedFormat
+}
+
+// FormatFromFilename parses image format from filename extension:
+// "jpg" (or "jpeg"), "png", "gif", "tif" (or "tiff") and "bmp" are supported.
+func FormatFromFilename(filename string) (Format, error) {
+	ext := filepath.Ext(filename)
+	return FormatFromExtension(ext)
+}
+
+var (
+	// ErrUnsupportedFormat means the given image format (or file extension) is unsupported.
+	ErrUnsupportedFormat = errors.New("imaging: unsupported image format")
+)
+
+type fileSystem interface {
+	Create(string) (io.WriteCloser, error)
+	Open(string) (io.ReadCloser, error)
+}
+
+type localFS struct{}
+
+func (localFS) Create(name string) (io.WriteCloser, error) { return os.Create(name) }
+func (localFS) Open(name string) (io.ReadCloser, error)    { return os.Open(name) }
+
+var fs fileSystem = localFS{}
+
+type decodeConfig struct {
+	autoOrientation bool
+}
+
+var defaultDecodeConfig = decodeConfig{
+	autoOrientation: false,
+}
+
+// DecodeOption sets an optional parameter for the Decode and Open functions.
+type DecodeOption func(*decodeConfig)
+
+// AutoOrientation returns a DecodeOption that sets the auto-orientation mode.
+// If auto-orientation is enabled, the image will be transformed after decoding
+// according to the EXIF orientation tag (if present). By default it's disabled.
+func AutoOrientation(enabled bool) DecodeOption {
+	return func(c *decodeConfig) {
+		c.autoOrientation = enabled
+	}
+}
+
+// Decode reads an image from r.
+func Decode(r io.Reader, opts ...DecodeOption) (image.Image, error) {
+	cfg := defaultDecodeConfig
+	for _, option := range opts {
+		option(&cfg)
+	}
+
+	if !cfg.autoOrientation {
+		img, _, err := image.Decode(r)
+		return img, err
+	}
+
+	var orient orientation
+	pr, pw := io.Pipe()
+	r = io.TeeReader(r, pw)
+	done := make(chan struct{})
+	go func() {
+		defer close(done)
+		orient = readOrientation(pr)
+		io.Copy(ioutil.Discard, pr)
+	}()
+
+	img, _, err := image.Decode(r)
+	pw.Close()
+	<-done
+	if err != nil {
+		return nil, err
+	}
+
+	return fixOrientation(img, orient), nil
+}
+
+// Open loads an image from file.
+//
+// Examples:
+//
+//	// Load an image from file.
+//	img, err := imaging.Open("test.jpg")
+//
+//	// Load an image and transform it depending on the EXIF orientation tag (if present).
+//	img, err := imaging.Open("test.jpg", imaging.AutoOrientation(true))
+//
+func Open(filename string, opts ...DecodeOption) (image.Image, error) {
+	file, err := fs.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+	return Decode(file, opts...)
+}
+
+type encodeConfig struct {
+	jpegQuality         int
+	gifNumColors        int
+	gifQuantizer        draw.Quantizer
+	gifDrawer           draw.Drawer
+	pngCompressionLevel png.CompressionLevel
+}
+
+var defaultEncodeConfig = encodeConfig{
+	jpegQuality:         95,
+	gifNumColors:        256,
+	gifQuantizer:        nil,
+	gifDrawer:           nil,
+	pngCompressionLevel: png.DefaultCompression,
+}
+
+// EncodeOption sets an optional parameter for the Encode and Save functions.
+type EncodeOption func(*encodeConfig)
+
+// JPEGQuality returns an EncodeOption that sets the output JPEG quality.
+// Quality ranges from 1 to 100 inclusive, higher is better. Default is 95.
+func JPEGQuality(quality int) EncodeOption {
+	return func(c *encodeConfig) {
+		c.jpegQuality = quality
+	}
+}
+
+// GIFNumColors returns an EncodeOption that sets the maximum number of colors
+// used in the GIF-encoded image. It ranges from 1 to 256.  Default is 256.
+func GIFNumColors(numColors int) EncodeOption {
+	return func(c *encodeConfig) {
+		c.gifNumColors = numColors
+	}
+}
+
+// GIFQuantizer returns an EncodeOption that sets the quantizer that is used to produce
+// a palette of the GIF-encoded image.
+func GIFQuantizer(quantizer draw.Quantizer) EncodeOption {
+	return func(c *encodeConfig) {
+		c.gifQuantizer = quantizer
+	}
+}
+
+// GIFDrawer returns an EncodeOption that sets the drawer that is used to convert
+// the source image to the desired palette of the GIF-encoded image.
+func GIFDrawer(drawer draw.Drawer) EncodeOption {
+	return func(c *encodeConfig) {
+		c.gifDrawer = drawer
+	}
+}
+
+// PNGCompressionLevel returns an EncodeOption that sets the compression level
+// of the PNG-encoded image. Default is png.DefaultCompression.
+func PNGCompressionLevel(level png.CompressionLevel) EncodeOption {
+	return func(c *encodeConfig) {
+		c.pngCompressionLevel = level
+	}
+}
+
+// Encode writes the image img to w in the specified format (JPEG, PNG, GIF, TIFF or BMP).
+func Encode(w io.Writer, img image.Image, format Format, opts ...EncodeOption) error {
+	cfg := defaultEncodeConfig
+	for _, option := range opts {
+		option(&cfg)
+	}
+
+	var err error
+	switch format {
+	case JPEG:
+		var rgba *image.RGBA
+		if nrgba, ok := img.(*image.NRGBA); ok {
+			if nrgba.Opaque() {
+				rgba = &image.RGBA{
+					Pix:    nrgba.Pix,
+					Stride: nrgba.Stride,
+					Rect:   nrgba.Rect,
+				}
+			}
+		}
+		if rgba != nil {
+			err = jpeg.Encode(w, rgba, &jpeg.Options{Quality: cfg.jpegQuality})
+		} else {
+			err = jpeg.Encode(w, img, &jpeg.Options{Quality: cfg.jpegQuality})
+		}
+
+	case PNG:
+		enc := png.Encoder{CompressionLevel: cfg.pngCompressionLevel}
+		err = enc.Encode(w, img)
+
+	case GIF:
+		err = gif.Encode(w, img, &gif.Options{
+			NumColors: cfg.gifNumColors,
+			Quantizer: cfg.gifQuantizer,
+			Drawer:    cfg.gifDrawer,
+		})
+
+	case TIFF:
+		err = tiff.Encode(w, img, &tiff.Options{Compression: tiff.Deflate, Predictor: true})
+
+	case BMP:
+		err = bmp.Encode(w, img)
+
+	default:
+		err = ErrUnsupportedFormat
+	}
+	return err
+}
+
+// Save saves the image to file with the specified filename.
+// The format is determined from the filename extension:
+// "jpg" (or "jpeg"), "png", "gif", "tif" (or "tiff") and "bmp" are supported.
+//
+// Examples:
+//
+//	// Save the image as PNG.
+//	err := imaging.Save(img, "out.png")
+//
+//	// Save the image as JPEG with optional quality parameter set to 80.
+//	err := imaging.Save(img, "out.jpg", imaging.JPEGQuality(80))
+//
+func Save(img image.Image, filename string, opts ...EncodeOption) (err error) {
+	f, err := FormatFromFilename(filename)
+	if err != nil {
+		return err
+	}
+	file, err := fs.Create(filename)
+	if err != nil {
+		return err
+	}
+
+	defer func() {
+		cerr := file.Close()
+		if err == nil {
+			err = cerr
+		}
+	}()
+
+	return Encode(file, img, f, opts...)
+}
+
+// orientation is an EXIF flag that specifies the transformation
+// that should be applied to image to display it correctly.
+type orientation int
+
+const (
+	orientationUnspecified = 0
+	orientationNormal      = 1
+	orientationFlipH       = 2
+	orientationRotate180   = 3
+	orientationFlipV       = 4
+	orientationTranspose   = 5
+	orientationRotate270   = 6
+	orientationTransverse  = 7
+	orientationRotate90    = 8
+)
+
+// readOrientation tries to read the orientation EXIF flag from image data in r.
+// If the EXIF data block is not found or the orientation flag is not found
+// or any other error occures while reading the data, it returns the
+// orientationUnspecified (0) value.
+func readOrientation(r io.Reader) orientation {
+	const (
+		markerSOI      = 0xffd8
+		markerAPP1     = 0xffe1
+		exifHeader     = 0x45786966
+		byteOrderBE    = 0x4d4d
+		byteOrderLE    = 0x4949
+		orientationTag = 0x0112
+	)
+
+	// Check if JPEG SOI marker is present.
+	var soi uint16
+	if err := binary.Read(r, binary.BigEndian, &soi); err != nil {
+		return orientationUnspecified
+	}
+	if soi != markerSOI {
+		return orientationUnspecified // Missing JPEG SOI marker.
+	}
+
+	// Find JPEG APP1 marker.
+	for {
+		var marker, size uint16
+		if err := binary.Read(r, binary.BigEndian, &marker); err != nil {
+			return orientationUnspecified
+		}
+		if err := binary.Read(r, binary.BigEndian, &size); err != nil {
+			return orientationUnspecified
+		}
+		if marker>>8 != 0xff {
+			return orientationUnspecified // Invalid JPEG marker.
+		}
+		if marker == markerAPP1 {
+			break
+		}
+		if size < 2 {
+			return orientationUnspecified // Invalid block size.
+		}
+		if _, err := io.CopyN(ioutil.Discard, r, int64(size-2)); err != nil {
+			return orientationUnspecified
+		}
+	}
+
+	// Check if EXIF header is present.
+	var header uint32
+	if err := binary.Read(r, binary.BigEndian, &header); err != nil {
+		return orientationUnspecified
+	}
+	if header != exifHeader {
+		return orientationUnspecified
+	}
+	if _, err := io.CopyN(ioutil.Discard, r, 2); err != nil {
+		return orientationUnspecified
+	}
+
+	// Read byte order information.
+	var (
+		byteOrderTag uint16
+		byteOrder    binary.ByteOrder
+	)
+	if err := binary.Read(r, binary.BigEndian, &byteOrderTag); err != nil {
+		return orientationUnspecified
+	}
+	switch byteOrderTag {
+	case byteOrderBE:
+		byteOrder = binary.BigEndian
+	case byteOrderLE:
+		byteOrder = binary.LittleEndian
+	default:
+		return orientationUnspecified // Invalid byte order flag.
+	}
+	if _, err := io.CopyN(ioutil.Discard, r, 2); err != nil {
+		return orientationUnspecified
+	}
+
+	// Skip the EXIF offset.
+	var offset uint32
+	if err := binary.Read(r, byteOrder, &offset); err != nil {
+		return orientationUnspecified
+	}
+	if offset < 8 {
+		return orientationUnspecified // Invalid offset value.
+	}
+	if _, err := io.CopyN(ioutil.Discard, r, int64(offset-8)); err != nil {
+		return orientationUnspecified
+	}
+
+	// Read the number of tags.
+	var numTags uint16
+	if err := binary.Read(r, byteOrder, &numTags); err != nil {
+		return orientationUnspecified
+	}
+
+	// Find the orientation tag.
+	for i := 0; i < int(numTags); i++ {
+		var tag uint16
+		if err := binary.Read(r, byteOrder, &tag); err != nil {
+			return orientationUnspecified
+		}
+		if tag != orientationTag {
+			if _, err := io.CopyN(ioutil.Discard, r, 10); err != nil {
+				return orientationUnspecified
+			}
+			continue
+		}
+		if _, err := io.CopyN(ioutil.Discard, r, 6); err != nil {
+			return orientationUnspecified
+		}
+		var val uint16
+		if err := binary.Read(r, byteOrder, &val); err != nil {
+			return orientationUnspecified
+		}
+		if val < 1 || val > 8 {
+			return orientationUnspecified // Invalid tag value.
+		}
+		return orientation(val)
+	}
+	return orientationUnspecified // Missing orientation tag.
+}
+
+// fixOrientation applies a transform to img corresponding to the given orientation flag.
+func fixOrientation(img image.Image, o orientation) image.Image {
+	switch o {
+	case orientationNormal:
+	case orientationFlipH:
+		img = FlipH(img)
+	case orientationFlipV:
+		img = FlipV(img)
+	case orientationRotate90:
+		img = Rotate90(img)
+	case orientationRotate180:
+		img = Rotate180(img)
+	case orientationRotate270:
+		img = Rotate270(img)
+	case orientationTranspose:
+		img = Transpose(img)
+	case orientationTransverse:
+		img = Transverse(img)
+	}
+	return img
+}