crop_image_handler.go

package uadmin

import (
	"image"
	"image/draw"
	"image/gif"
	"image/jpeg"
	"image/png"
	"net/http"
	"os"
	"strconv"
	"strings"
)

func cropImageHandler(w http.ResponseWriter, r *http.Request, session *Session) {
	img := "." + r.FormValue("img")
	top, _ := strconv.ParseFloat(r.FormValue("top"), 32)
	left, _ := strconv.ParseFloat(r.FormValue("left"), 32)
	bottom, _ := strconv.ParseFloat(r.FormValue("bottom"), 32)
	right, _ := strconv.ParseFloat(r.FormValue("right"), 32)
	fType := strings.Split(img, ".")

	// check if the user has edit permission for the model
	modelNameParts := strings.Split(img, "/")
	if len(modelNameParts) < 2 {
		ReturnJSON(w, r, map[string]string{"status": "error", "err_msg": "The image path is too short"})
		return
	}
	modelName := modelNameParts[len(modelNameParts)-2]
	modelName = strings.Split(modelName, "_")[0]
	if !session.User.GetAccess(modelName).Edit {
		ReturnJSON(w, r, map[string]string{"status": "error", "err_msg": "You don't have permission to edit this model"})
		return
	}

	// Open the file
	imageFile, err := os.Open(img)
	if err != nil {
		ReturnJSON(w, r, map[string]string{"status": "error", "err_msg": "Unable to open image. Check logs for details"})
		return
	}
	defer imageFile.Close()
	var myImage image.Image
	if strings.ToLower(fType[len(fType)-1]) == "jpg" || strings.ToLower(fType[len(fType)-1]) == "jpeg" {
		myImage, err = jpeg.Decode(imageFile)
		if err != nil {
			ReturnJSON(w, r, map[string]string{"status": "error", "err_msg": "Unable to decode JPEG image. Check logs for details"})
			return
		}
	}
	if strings.ToLower(fType[len(fType)-1]) == "png" {
		myImage, err = png.Decode(imageFile)
		if err != nil {
			ReturnJSON(w, r, map[string]string{"status": "error", "err_msg": "Unable to decode PNG image. Check logs for details"})
			return
		}
	}

	if strings.ToLower(fType[len(fType)-1]) == "gif" {
		myImage, err = gif.Decode(imageFile)
		if err != nil {
			ReturnJSON(w, r, map[string]string{"status": "error", "err_msg": "Unable to decode GIF image. Check logs for details"})
			return
		}
	}

	rect := image.Rect(int(left), int(top), int(right), int(bottom))

	mySubImage := image.NewRGBA(rect)
	draw.Draw(mySubImage, rect, myImage, image.Point{int(top), int(left)}, draw.Src)

	f, err := os.Create(strings.Replace(img, "_raw", "", -1))
	if err != nil {
		ReturnJSON(w, r, map[string]string{"status": "error", "err_msg": "Unable to create image. Check logs for details"})
		return
	}
	defer f.Close()

	if strings.ToLower(fType[len(fType)-1]) == cJPG || strings.ToLower(fType[len(fType)-1]) == cJPEG {
		err = jpeg.Encode(f, mySubImage, nil)
		if err != nil {
			ReturnJSON(w, r, map[string]string{"status": "error", "err_msg": "Unable to encode JPEG image. Check logs for details"})
			return
		}
	}
	if strings.ToLower(fType[len(fType)-1]) == cPNG {
		err = png.Encode(f, mySubImage)
		if err != nil {
			ReturnJSON(w, r, map[string]string{"status": "error", "err_msg": "Unable to encode PNG image. Check logs for details"})
			return
		}
	}

	if strings.ToLower(fType[len(fType)-1]) == cGIF {
		o := gif.Options{}
		err = gif.Encode(f, mySubImage, &o)
		if err != nil {
			ReturnJSON(w, r, map[string]string{"status": "error", "err_msg": "Unable to encode GIF image. Check logs for details"})
			return
		}
	}
	ReturnJSON(w, r, map[string]string{"status": "ok"})
}