Merge pull request #1 from shrapnelnet/master

Inline ImageMagick logic

1 files changed, 53 insertions, 8 deletions

diff --git a/themagicpipe/imageconverter.go b/themagicpipe/imageconverter.go
index 5e5738e..07ce826 100644
--- a/themagicpipe/imageconverter.go
+++ b/themagicpipe/imageconverter.go
@@ -1,8 +1,10 @@
 package themagicpipe
+
 import (
-	"os/exec"
-	"strings"
+	"encoding/base64"
 	"errors"
+	"gopkg.in/gographics/imagick.v3/imagick"
+	"strings"
 )
 
 // Where the magic happens, the base64 data url image is sent through Imagemagick
@@ -11,13 +13,56 @@ func DataURLConverter(dataURL string) (string, error) {
 	if !strings.HasPrefix(dataURL, "data:image/png;base64,") {
 		return "", errors.New("invalid dataURL")
 	}
-	cmd := "base64 -d | convert - -background white -flatten -resize 400x200! -colors 4 PNG8:- | base64 -w0"
-   converter := exec.Command("sh","-c",cmd)
-	converter.Stdin = strings.NewReader(strings.TrimPrefix(dataURL, "data:image/png;base64,"))
-	output, err := converter.Output()
+	imageBase64 := strings.TrimPrefix(dataURL, "data:image/png;base64,")
+	imageRaw, err := base64.StdEncoding.DecodeString(imageBase64)
+	if err != nil {
+		return "", err
+	}
+	// doing conversion inline soothes the soul
+	imagick.Initialize()
+	defer imagick.Terminate()
+	magick := imagick.NewMagickWand()
+	defer magick.Destroy()
+	// read in from base64
+	err = magick.ReadImageBlob(imageRaw)
+	if err != nil {
+		return "", err
+	}
+	// swap all transparent pixels with white
+	transparent := imagick.NewPixelWand()
+	defer transparent.Destroy()
+	transparent.SetColor("none")
+	whiteFill := imagick.NewPixelWand()
+	defer whiteFill.Destroy()
+	whiteFill.SetColor("#ffffff")
+	err = magick.OpaquePaintImage(transparent, whiteFill, 5, false)
+	if err != nil {
+		return "", err
+	}
+	err = magick.ResizeImage(400, 200, imagick.FILTER_POINT)
+	if err != nil {
+		return "", err
+	}
+	err = magick.SetCompression(imagick.COMPRESSION_LZMA)
+	if err != nil {
+		return "", err
+	}
+	err = magick.StripImage()
+	if err != nil {
+		return "", err
+	}
+	err = magick.SetDepth(8)
 	if err != nil {
 		return "", err
 	}
-	return "data:image/png;base64,"+string(output), nil
+	err = magick.QuantizeImage(4, imagick.COLORSPACE_UNDEFINED, 0, imagick.DITHER_METHOD_RIEMERSMA, false)
+	if err != nil {
+		return "", err
+	}
+	imageBytesProcessed, err := magick.GetImageBlob()
+	if err != nil {
+		return "", err
+	}
+	imageBase64Processed := base64.StdEncoding.EncodeToString(imageBytesProcessed)
+	return "data:image/png;base64," + imageBase64Processed, nil
 }
-