132 lines
3.3 KiB
Go
132 lines
3.3 KiB
Go
package utils
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import (
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"bytes"
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"encoding/base64"
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"golang.org/x/image/bmp"
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"golang.org/x/image/tiff"
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"image"
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"image/color"
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"image/jpeg"
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"image/png"
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)
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func BuffToImage(in []byte) image.Image {
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buff := bytes.NewBuffer(in)
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m, _, _ := image.Decode(buff)
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return m
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}
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// Clip 图片裁剪
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func Clip(in []byte, wi, hi int, equalProportion bool) (out image.Image, imageType string, err error) {
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buff := bytes.NewBuffer(in)
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m, imgType, _ := image.Decode(buff)
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rgbImg := m.(*image.YCbCr)
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if equalProportion {
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w := m.Bounds().Max.X
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h := m.Bounds().Max.Y
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if w > 0 && h > 0 && wi > 0 && hi > 0 {
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wi, hi = fixSize(w, h, wi, hi)
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}
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}
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return rgbImg.SubImage(image.Rect(0, 0, wi, hi)), imgType, nil
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}
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func fixSize(img1W, img2H, wi, hi int) (new1W, new2W int) {
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var ( //为了方便计算，将图片的宽转为 float64
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imgWidth, imgHeight = float64(img1W), float64(img2H)
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ratio float64
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)
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if imgWidth >= imgHeight {
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ratio = imgWidth / float64(wi)
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return int(imgWidth * ratio), int(imgHeight * ratio)
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}
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ratio = imgHeight / float64(hi)
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return int(imgWidth * ratio), int(imgHeight * ratio)
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}
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func Gray(in []byte) (out image.Image, err error) {
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m := BuffToImage(in)
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bounds := m.Bounds()
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dx := bounds.Dx()
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dy := bounds.Dy()
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newRgba := image.NewRGBA(bounds)
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for i := 0; i < dx; i++ {
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for j := 0; j < dy; j++ {
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colorRgb := m.At(i, j)
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_, g, _, a := colorRgb.RGBA()
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gUint8 := uint8(g >> 8)
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aUint8 := uint8(a >> 8)
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newRgba.SetRGBA(i, j, color.RGBA{R: gUint8, G: gUint8, B: gUint8, A: aUint8})
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}
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}
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r := image.Rect(0, 0, dx, dy)
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return newRgba.SubImage(r), nil
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}
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func Rotate90(in []byte) image.Image {
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m := BuffToImage(in)
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rotate90 := image.NewRGBA(image.Rect(0, 0, m.Bounds().Dy(), m.Bounds().Dx()))
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// 矩阵旋转
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for x := m.Bounds().Min.Y; x < m.Bounds().Max.Y; x++ {
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for y := m.Bounds().Max.X - 1; y >= m.Bounds().Min.X; y-- {
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// 设置像素点
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rotate90.Set(m.Bounds().Max.Y-x, y, m.At(y, x))
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}
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}
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return rotate90
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}
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// Rotate180 旋转180度
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func Rotate180(in []byte) image.Image {
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m := BuffToImage(in)
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rotate180 := image.NewRGBA(image.Rect(0, 0, m.Bounds().Dx(), m.Bounds().Dy()))
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// 矩阵旋转
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for x := m.Bounds().Min.X; x < m.Bounds().Max.X; x++ {
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for y := m.Bounds().Min.Y; y < m.Bounds().Max.Y; y++ {
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// 设置像素点
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rotate180.Set(m.Bounds().Max.X-x, m.Bounds().Max.Y-y, m.At(x, y))
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}
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}
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return rotate180
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}
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// Rotate270 旋转270度
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func Rotate270(in []byte) image.Image {
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m := BuffToImage(in)
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rotate270 := image.NewRGBA(image.Rect(0, 0, m.Bounds().Dy(), m.Bounds().Dx()))
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// 矩阵旋转
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for x := m.Bounds().Min.Y; x < m.Bounds().Max.Y; x++ {
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for y := m.Bounds().Max.X - 1; y >= m.Bounds().Min.X; y-- {
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// 设置像素点
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rotate270.Set(x, m.Bounds().Max.X-y, m.At(y, x))
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}
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}
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return rotate270
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}
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func ImageToBase64(img image.Image, imgType string) string {
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buff := ImageToBuff(img, imgType)
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return base64.StdEncoding.EncodeToString(buff.Bytes())
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}
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func ImageToBuff(img image.Image, imgType string) *bytes.Buffer {
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buff := bytes.NewBuffer(nil)
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switch imgType {
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case "bmp":
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imgType = "bmp"
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_ = bmp.Encode(buff, img)
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case "png":
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imgType = "png"
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_ = png.Encode(buff, img)
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case "tiff":
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imgType = "tiff"
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_ = tiff.Encode(buff, img, nil)
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default:
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imgType = "jpeg"
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_ = jpeg.Encode(buff, img, nil)
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}
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return buff
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}
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