website/pkg/photo/upload.go
2022-09-26 19:41:07 -07:00

241 lines
6.0 KiB
Go

package photo
import (
"bytes"
"errors"
"fmt"
"image"
"image/jpeg"
"image/png"
"io"
"os"
"path/filepath"
"strconv"
"strings"
"code.nonshy.com/nonshy/website/pkg/config"
"code.nonshy.com/nonshy/website/pkg/log"
"code.nonshy.com/nonshy/website/pkg/models"
"github.com/edwvee/exiffix"
"golang.org/x/image/draw"
)
type UploadConfig struct {
User *models.User
Extension string // 'jpg' or 'png' only.
Data []byte
Crop []int // x, y, w, h
}
// UploadPhoto handles an incoming photo to add to a user's account.
//
// Returns:
// - NewFilename() of the created photo file on disk.
// - NewFilename() of the cropped version, or "" if not cropping.
// - error on errors
func UploadPhoto(cfg UploadConfig) (string, string, error) {
// Validate and normalize the extension.
var extension = strings.ToLower(cfg.Extension)
switch extension {
case ".jpg":
fallthrough
case ".jpe":
fallthrough
case ".jpeg":
extension = ".jpg"
case ".png":
extension = ".png"
default:
return "", "", errors.New("unsupported image extension, must be jpg or png")
}
// Decide on a filename for this photo.
var (
filename = NewFilename(extension)
cropFilename = NewFilename(extension)
)
// Decode the image using exiffix, which will auto-rotate jpeg images
// based on their EXIF tags.
reader := bytes.NewReader(cfg.Data)
origImage, _, err := exiffix.Decode(reader)
if err != nil {
return "", "", err
}
// Read the config to get the image width.
reader.Seek(0, io.SeekStart)
var width, height = origImage.Bounds().Max.X, origImage.Bounds().Max.Y
// Find the longest edge, if it's too large (over 1280px)
// cap it to the max and scale the other dimension proportionally.
log.Debug("UploadPhoto: taking a w=%d by h=%d image to name it %s", width, height, filename)
if width >= height {
log.Debug("Its width(%d) is >= its height (%d)", width, height)
if width > config.MaxPhotoWidth {
newWidth := config.MaxPhotoWidth
log.Debug("\tnewWidth=%d", newWidth)
log.Debug("\tnewHeight=(%d / %d) * %d", width, height, newWidth)
height = int((float64(height) / float64(width)) * float64(newWidth))
width = newWidth
log.Debug("Its longest is width, scale to %dx%d", width, height)
}
} else {
if height > config.MaxPhotoWidth {
newHeight := config.MaxPhotoWidth
width = int((float64(width) / float64(height)) * float64(newHeight))
height = newHeight
log.Debug("Its longest is height, scale to %dx%d", width, height)
}
}
// Scale the image.
scaledImg := Scale(origImage, image.Rect(0, 0, width, height), draw.ApproxBiLinear)
// Write the image to disk.
if err := ToDisk(filename, extension, scaledImg); err != nil {
return "", "", err
}
// Are we producing a cropped image, too?
log.Error("Are we to crop? %+v", cfg.Crop)
if cfg.Crop != nil && len(cfg.Crop) >= 4 {
log.Debug("Also cropping this image to %+v", cfg.Crop)
var (
x = cfg.Crop[0]
y = cfg.Crop[1]
w = cfg.Crop[2]
h = cfg.Crop[3]
)
croppedImg := Crop(origImage, x, y, w, h)
// Write that to disk, too.
log.Debug("Writing cropped image to disk: %s", cropFilename)
if err := ToDisk(cropFilename, extension, croppedImg); err != nil {
return filename, "", err
}
// Return both filenames!
return filename, cropFilename, nil
}
// Not cropping, return only the first filename.
return filename, "", nil
}
// Scale down an image. Example:
//
// scaled := Scale(src, image.Rect(0, 0, 200, 200), draw.ApproxBiLinear)
func Scale(src image.Image, rect image.Rectangle, scale draw.Scaler) image.Image {
dst := image.NewRGBA(rect)
copyRect := image.Rect(
rect.Min.X,
rect.Min.Y,
rect.Min.X+rect.Max.X,
rect.Min.Y+rect.Max.Y,
)
scale.Scale(dst, copyRect, src, src.Bounds(), draw.Over, nil)
return dst
}
// Crop an image, returning the new image. Example:
//
// cropped := Crop()
func Crop(src image.Image, x, y, w, h int) image.Image {
dst := image.NewRGBA(image.Rect(0, 0, w, h))
srcrect := image.Rect(x, y, x+w, y+h)
draw.Copy(dst, image.ZP, src, srcrect, draw.Over, nil)
return dst
}
// ReCrop an image, loading the original image from disk. Returns the newly created filename.
func ReCrop(filename string, x, y, w, h int) (string, error) {
var (
ext = filepath.Ext(filename)
cropFilename = NewFilename(ext)
)
fh, err := os.Open(DiskPath(filename))
if err != nil {
return "", err
}
// Decode the image.
var img image.Image
switch ext {
case ".jpg":
img, err = jpeg.Decode(fh)
if err != nil {
return "", err
}
case ".png":
img, err = png.Decode(fh)
if err != nil {
return "", err
}
default:
return "", errors.New("unsupported file type")
}
// Crop it.
croppedImg := Crop(img, x, y, w, h)
// Write it.
err = ToDisk(cropFilename, ext, croppedImg)
return cropFilename, err
}
// ParseCropCoords splits a string of x,y,w,h values into proper crop coordinates, or nil.
func ParseCropCoords(coords string) []int {
// Parse and validate crop coordinates.
var crop []int
if len(coords) > 0 {
aints := strings.Split(coords, ",")
if len(aints) >= 4 {
crop = []int{}
for i, aint := range aints {
if number, err := strconv.Atoi(strings.TrimSpace(aint)); err == nil {
crop = append(crop, number)
} else {
log.Error("Failure to parse crop coordinates ('%s') at number %d: %s", coords, i, err)
}
}
}
}
return crop
}
// ToDisk commits a photo image to disk in the right file format.
//
// Filename is like NewFilename() and it goes to e.g. "./web/static/photos/"
func ToDisk(filename string, extension string, img image.Image) error {
if path, err := EnsurePath(filename); err == nil {
fh, err := os.Create(path)
if err != nil {
return err
}
defer fh.Close()
switch extension {
case ".jpg":
jpeg.Encode(fh, img, &jpeg.Options{
Quality: config.JpegQuality,
})
case ".png":
png.Encode(fh, img)
}
} else {
return fmt.Errorf("couldn't EnsurePath: %s", err)
}
return nil
}
// Delete a photo from disk.
func Delete(filename string) error {
if len(filename) > 0 {
return os.Remove(DiskPath(filename))
}
return errors.New("filename is required")
}