1 files changed, 23 insertions, 0 deletions
diff --git a/themagicpipe/imageconverter.go b/themagicpipe/imageconverter.go
new file mode 100644
index 0000000..5e5738e
--- /dev/null
+++ b/themagicpipe/imageconverter.go
@@ -0,0 +1,23 @@
+package themagicpipe
+import (
+	"os/exec"
+	"strings"
+	"errors"
+)
+
+// Where the magic happens, the base64 data url image is sent through Imagemagick
+// and converted to indexed colors 400x200 png
+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()
+	if err != nil {
+		return "", err
+	}
+	return "data:image/png;base64,"+string(output), nil
+}
+