grokify/mogo

package imageutil

import (
    "bytes"
    "errors"
    "image"
    "image/jpeg"
    "image/png"
    "io"
    "net/http"
    "os"

    "github.com/grokify/mogo/net/http/httputilmore"
)

var (
    ErrImageNotSet  = errors.New("image not set")
    ErrWriterNotSet = errors.New("writer not set")
)

type Image struct {
    image.Image
}

func (im Image) BytesJPEG(opt *JPEGEncodeOptions) ([]byte, error) {
    return bytesJPEG(im.Image, opt)
}

func bytesJPEG(img image.Image, opt *JPEGEncodeOptions) ([]byte, error) {
    if img == nil {
        return []byte{}, ErrImageNotSet
    }
    buf := new(bytes.Buffer)
    err := writeJPEG(buf, img, opt)
    if err != nil {
        return []byte{}, err
    }
    return buf.Bytes(), nil
}

func (im Image) BytesPNG() ([]byte, error) {
    return bytesPNG(im.Image)
}

func bytesPNG(img image.Image) ([]byte, error) {
    if img == nil {
        return []byte{}, ErrImageNotSet
    }
    buf := new(bytes.Buffer)
    err := png.Encode(buf, img)
    if err != nil {
        return []byte{}, err
    }
    return buf.Bytes(), nil
}

func (im Image) WriteJPEG(w io.Writer, opt *JPEGEncodeOptions) error {
    return writeJPEG(w, im.Image, opt)
}

func writeJPEG(w io.Writer, img image.Image, opt *JPEGEncodeOptions) error {
    if w == nil {
        return ErrWriterNotSet
    } else if img == nil {
        return ErrImageNotSet
    }
    if opt != nil && len(opt.Exif) > 0 {
        if wexif, err := newWriterExif(w, opt.Exif); err != nil {
            return err
        } else {
            return jpeg.Encode(wexif, img, opt.Options)
        }
    }
    jopt := &jpeg.Options{}
    if opt != nil {
        jopt = opt.Options
    }
    return jpeg.Encode(w, img, jopt)
}

func (im Image) WriteJPEGFile(filename string, opt *JPEGEncodeOptions) error {
    return writeJPEGFile(filename, im.Image, opt)
}

func (im Image) WriteJPEGFileSimple(filename string, quality int) error {
    return writeJPEGFile(filename, im.Image, &JPEGEncodeOptions{
        Options: &jpeg.Options{
            Quality: quality,
        },
    })
}

func writeJPEGFile(filename string, img image.Image, opt *JPEGEncodeOptions) error {
    if img == nil {
        return ErrImageNotSet
    } else if w, err := os.OpenFile(filename, os.O_WRONLY|os.O_CREATE, 0600); err != nil {
        return err
    } else {
        defer w.Close()
        return writeJPEG(w, img, opt)
    }
}

func (im Image) WriteJPEGResponseWriter(w http.ResponseWriter, addContentTypeHeader bool, opt *JPEGEncodeOptions) error {
    return writeJPEGResponseWriter(w, addContentTypeHeader, im.Image, opt)
}

func writeJPEGResponseWriter(w http.ResponseWriter, addContentTypeHeader bool, img image.Image, opt *JPEGEncodeOptions) error {
    if img == nil {
        return ErrImageNotSet
    } else if b, err := bytesJPEG(img, opt); err != nil {
        return err
    } else {
        if addContentTypeHeader {
            w.Header().Set(httputilmore.HeaderContentType, httputilmore.ContentTypeImageJPEG)
        }
        _, err = w.Write(b)
        return err
    }
}

func (im Image) WritePNG(w io.Writer) error {
    return writePNG(w, im.Image)
}

func writePNG(w io.Writer, img image.Image) error {
    if img == nil {
        return ErrImageNotSet
    }
    return png.Encode(w, img)
}

func (im Image) WritePNGFile(filename string) error {
    return writePNGFile(filename, im.Image)
}

func writePNGFile(filename string, img image.Image) error {
    if img == nil {
        return ErrImageNotSet
    } else if w, err := os.OpenFile(filename, os.O_WRONLY|os.O_CREATE, 0600); err != nil {
        return err
    } else if err = png.Encode(w, img); err != nil {
        return err
    } else {
        return w.Close()
    }
}

func (im Image) WritePNGResponseWriter(w http.ResponseWriter, addContentTypeHeader bool) error {
    return writePNGResponseWriter(w, addContentTypeHeader, im.Image)
}

func writePNGResponseWriter(w http.ResponseWriter, addContentTypeHeader bool, img image.Image) error {
    if img == nil {
        return ErrImageNotSet
    } else if b, err := bytesPNG(img); err != nil {
        return err
    } else {
        if addContentTypeHeader {
            w.Header().Set(httputilmore.HeaderContentType, httputilmore.ContentTypeImagePNG)
        }
        _, err = w.Write(b)
        return err
    }
}