status-im/status-go

package images

import (
    "bytes"
    "errors"
    "image"
    "io/ioutil"
    "os"
)

const (
    maxChatMessageImageSize = 400000
    resizeTargetImageSize   = 350000
    idealTargetImageSize    = 50000
)

var DefaultBounds = FileSizeLimits{Ideal: idealTargetImageSize, Max: resizeTargetImageSize}

func OpenAndAdjustImage(inputImage CroppedImage, crop bool) ([]byte, error) {
    file, err := os.Open(inputImage.ImagePath)
    if err != nil {
        return nil, err
    }
    defer file.Close()

    payload, err := ioutil.ReadAll(file)
    if err != nil {
        return nil, err
    }

    img, err := Decode(inputImage.ImagePath)
    if err != nil {
        return nil, err
    }

    if crop {
        cropRect := image.Rectangle{
            Min: image.Point{X: inputImage.X, Y: inputImage.Y},
            Max: image.Point{X: inputImage.X + inputImage.Width, Y: inputImage.Y + inputImage.Height},
        }
        img, err = Crop(img, cropRect)
        if err != nil {
            return nil, err
        }
    }

    bb := bytes.NewBuffer([]byte{})
    err = CompressToFileLimits(bb, img, DefaultBounds)
    if err != nil {
        return nil, err
    }

    // We keep the smallest one
    if len(payload) > len(bb.Bytes()) {
        payload = bb.Bytes()
    }

    if len(payload) > maxChatMessageImageSize {
        return nil, errors.New("image too large")
    }

    return payload, nil
}