mirror of
https://github.com/chrislusf/seaweedfs
synced 2024-08-22 01:30:43 +02:00
183 lines
4.2 KiB
Go
183 lines
4.2 KiB
Go
package images
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import (
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"bytes"
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"image"
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"image/draw"
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"image/jpeg"
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"log"
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"github.com/seaweedfs/goexif/exif"
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)
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//many code is copied from http://camlistore.org/pkg/images/images.go
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func FixJpgOrientation(data []byte) (oriented []byte) {
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ex, err := exif.Decode(bytes.NewReader(data))
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if err != nil {
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return data
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}
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tag, err := ex.Get(exif.Orientation)
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if err != nil {
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return data
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}
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angle := 0
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flipMode := FlipDirection(0)
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orient, err := tag.Int(0)
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if err != nil {
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return data
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}
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switch orient {
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case topLeftSide:
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// do nothing
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return data
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case topRightSide:
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flipMode = 2
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case bottomRightSide:
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angle = 180
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case bottomLeftSide:
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angle = 180
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flipMode = 2
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case leftSideTop:
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angle = -90
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flipMode = 2
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case rightSideTop:
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angle = -90
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case rightSideBottom:
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angle = 90
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flipMode = 2
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case leftSideBottom:
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angle = 90
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}
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if srcImage, _, err := image.Decode(bytes.NewReader(data)); err == nil {
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dstImage := flip(rotate(srcImage, angle), flipMode)
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var buf bytes.Buffer
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jpeg.Encode(&buf, dstImage, nil)
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return buf.Bytes()
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}
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return data
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}
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// Exif Orientation Tag values
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// http://sylvana.net/jpegcrop/exif_orientation.html
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const (
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topLeftSide = 1
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topRightSide = 2
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bottomRightSide = 3
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bottomLeftSide = 4
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leftSideTop = 5
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rightSideTop = 6
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rightSideBottom = 7
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leftSideBottom = 8
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)
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// The FlipDirection type is used by the Flip option in DecodeOpts
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// to indicate in which direction to flip an image.
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type FlipDirection int
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// FlipVertical and FlipHorizontal are two possible FlipDirections
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// values to indicate in which direction an image will be flipped.
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const (
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FlipVertical FlipDirection = 1 << iota
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FlipHorizontal
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)
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type DecodeOpts struct {
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// Rotate specifies how to rotate the image.
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// If nil, the image is rotated automatically based on EXIF metadata.
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// If an int, Rotate is the number of degrees to rotate
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// counter clockwise and must be one of 0, 90, -90, 180, or
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// -180.
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Rotate interface{}
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// Flip specifies how to flip the image.
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// If nil, the image is flipped automatically based on EXIF metadata.
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// Otherwise, Flip is a FlipDirection bitfield indicating how to flip.
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Flip interface{}
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}
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func rotate(im image.Image, angle int) image.Image {
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var rotated *image.NRGBA
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// trigonometric (i.e counter clock-wise)
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switch angle {
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case 90:
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newH, newW := im.Bounds().Dx(), im.Bounds().Dy()
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rotated = image.NewNRGBA(image.Rect(0, 0, newW, newH))
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for y := 0; y < newH; y++ {
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for x := 0; x < newW; x++ {
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rotated.Set(x, y, im.At(newH-1-y, x))
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}
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}
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case -90:
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newH, newW := im.Bounds().Dx(), im.Bounds().Dy()
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rotated = image.NewNRGBA(image.Rect(0, 0, newW, newH))
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for y := 0; y < newH; y++ {
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for x := 0; x < newW; x++ {
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rotated.Set(x, y, im.At(y, newW-1-x))
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}
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}
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case 180, -180:
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newW, newH := im.Bounds().Dx(), im.Bounds().Dy()
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rotated = image.NewNRGBA(image.Rect(0, 0, newW, newH))
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for y := 0; y < newH; y++ {
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for x := 0; x < newW; x++ {
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rotated.Set(x, y, im.At(newW-1-x, newH-1-y))
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}
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}
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default:
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return im
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}
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return rotated
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}
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// flip returns a flipped version of the image im, according to
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// the direction(s) in dir.
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// It may flip the imput im in place and return it, or it may allocate a
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// new NRGBA (if im is an *image.YCbCr).
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func flip(im image.Image, dir FlipDirection) image.Image {
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if dir == 0 {
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return im
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}
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ycbcr := false
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var nrgba image.Image
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dx, dy := im.Bounds().Dx(), im.Bounds().Dy()
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di, ok := im.(draw.Image)
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if !ok {
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if _, ok := im.(*image.YCbCr); !ok {
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log.Printf("failed to flip image: input does not satisfy draw.Image")
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return im
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}
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// because YCbCr does not implement Set, we replace it with a new NRGBA
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ycbcr = true
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nrgba = image.NewNRGBA(image.Rect(0, 0, dx, dy))
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di, ok = nrgba.(draw.Image)
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if !ok {
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log.Print("failed to flip image: could not cast an NRGBA to a draw.Image")
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return im
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}
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}
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if dir&FlipHorizontal != 0 {
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for y := 0; y < dy; y++ {
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for x := 0; x < dx/2; x++ {
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old := im.At(x, y)
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di.Set(x, y, im.At(dx-1-x, y))
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di.Set(dx-1-x, y, old)
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}
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}
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}
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if dir&FlipVertical != 0 {
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for y := 0; y < dy/2; y++ {
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for x := 0; x < dx; x++ {
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old := im.At(x, y)
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di.Set(x, y, im.At(x, dy-1-y))
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di.Set(x, dy-1-y, old)
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}
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}
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}
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if ycbcr {
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return nrgba
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}
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return im
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}
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