splitting revisitor to new file and updating docs

image_revisitor.go

@@ -0,0 +1,65 @@
+package gorevisit
+
+import (
+	"bytes"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"image"
+	"image/gif"
+	"image/jpeg"
+	"image/png"
+)
+
+// ImageRevisitor, given a RevisitMsg and an image transformation function, runs the
+// image data through the transformation and returns a new RevisitMsg with the
+// transformed image
+func ImageRevisitor(m *RevisitMsg, t func(src image.Image, dst image.RGBA) error) (*RevisitMsg, error) {
+	reader := m.Content.ByteReader()
+	srcImg, _, err := image.Decode(reader)
+	if err != nil {
+		return m, err
+	}
+
+	dstImg := image.NewRGBA(srcImg.Bounds())
+	err = t(srcImg, *dstImg)
+
+	dstImgBuf := bytes.NewBuffer(nil)
+
+	format := m.ImageType()
+	log.Infof("Processing image in format: %s", format)
+
+	switch format {
+	case "image/jpeg":
+		err = jpeg.Encode(dstImgBuf, dstImg, nil)
+		if err != nil {
+			return m, err
+		}
+	case "image/jpg":
+		err = jpeg.Encode(dstImgBuf, dstImg, nil)
+		if err != nil {
+			return m, err
+		}
+
+	case "image/png":
+		err = png.Encode(dstImgBuf, dstImg)
+		if err != nil {
+			return m, err
+		}
+	case "image/gif":
+		err = gif.Encode(dstImgBuf, dstImg, nil)
+		if err != nil {
+			return m, err
+		}
+	default:
+		return m, errors.New(fmt.Sprintf("%s is not a supported image format", format))
+	}
+
+	dstImgBase64 := base64.StdEncoding.EncodeToString(dstImgBuf.Bytes())
+
+	return &RevisitMsg{
+		Content: ImageData{
+			Data: fmt.Sprintf("data:image/%s;base64,%s", format, dstImgBase64),
+		},
+	}, nil
+}

revisit_msg.go

@@ -1,14 +1,9 @@
 package gorevisit
 
 import (
-	"bytes"
 	"encoding/base64"
 	"errors"
 	"fmt"
-	"image"
-	"image/gif"
-	"image/jpeg"
-	"image/png"
 	"io"
 	"io/ioutil"
 	"strings"
@@ -53,59 +48,6 @@ func (r *RevisitMsg) ImageType() string {
 	return strings.Split(subheader, ";")[0]
 }
 
-// ImageRevisitor, given a RevisitMsg and an image transformation function, runs the
-// image data through the transformation and returns a new RevisitMsg with the
-// transformed image
-func ImageRevisitor(m *RevisitMsg, t func(src image.Image, dst image.RGBA) error) (*RevisitMsg, error) {
-	reader := m.Content.ByteReader()
-	srcImg, _, err := image.Decode(reader)
-	if err != nil {
-		return m, err
-	}
-
-	dstImg := image.NewRGBA(srcImg.Bounds())
-	err = t(srcImg, *dstImg)
-
-	dstImgBuf := bytes.NewBuffer(nil)
-
-	format := m.ImageType()
-	log.Infof("Processing image in format: %s", format)
-
-	switch format {
-	case "image/jpeg":
-		err = jpeg.Encode(dstImgBuf, dstImg, nil)
-		if err != nil {
-			return m, err
-		}
-	case "image/jpg":
-		err = jpeg.Encode(dstImgBuf, dstImg, nil)
-		if err != nil {
-			return m, err
-		}
-
-	case "image/png":
-		err = png.Encode(dstImgBuf, dstImg)
-		if err != nil {
-			return m, err
-		}
-	case "image/gif":
-		err = gif.Encode(dstImgBuf, dstImg, nil)
-		if err != nil {
-			return m, err
-		}
-	default:
-		return m, errors.New(fmt.Sprintf("%s is not a supported image format", format))
-	}
-
-	dstImgBase64 := base64.StdEncoding.EncodeToString(dstImgBuf.Bytes())
-
-	return &RevisitMsg{
-		Content: ImageData{
-			Data: fmt.Sprintf("data:image/%s;base64,%s", format, dstImgBase64),
-		},
-	}, nil
-}
-
 // BytesToDataURI, given a byte array and a content type,
 // creates a Data URI of the content
 func BytesToDataURI(data []byte, contentType string) string {