Save/Load file as byte buffer

Question

So I have a line of code like this:

func TestImage(){
    img, _ := imgio.Open(`input.jpg`)
    inverted := effect.Invert(img)
    f, _ := os.Create("output.jpg")
    defer f.Close()
    Encoder := imgio.JPEGEncoder(80)
    Encoder(f, inverted)
}

All it does is just invert an image, which is simple enough. However, it can only do so to local file. So, say, if I have an image on site A that needs to be download, modify and upload back, I would have to

Download the image to a local storage
Load it
Modify using that function
Save it to the local storage
Load it again to a POST function for uploading or something

I was wondering if there is anyway to achieve such task with out reading to save it and load it from a local storage? Like save the image as a "fake" file, which is a byte buffer or something.

You're not showing the function signatures for `imgio.*`, `effect.*`, and `Encoder`. If they take `io.Reader` and `io.Writer` interfaces (which they should), they can take a byte buffer. But we can't tell. — Marc, Jul 29 '20 at 07:42

score 1 · Accepted Answer · answered Jul 29 '20 at 08:33

Package imgio provides basic image file input/output.

If you don't want to read from and write to files, don't use this package. Use the image package in the standard library directly.

package main

import (
    "bytes"
    "image"
    "image/jpeg"

    "github.com/anthonynsimon/bild/imgio"
)

func TestImage() {
    input := new(bytes.Buffer)
    img, err := image.Decode(input)
    // TODO: handle error

    output := new(bytes.Buffer)
    err = jpeg.Encode(output, img, &jpeg.Options{Quality: 80})
}

Save/Load file as byte buffer

1 Answers1