make a working API

main.go

@@ -1,12 +1,9 @@
 package karaoke
 
 import (
-	"fmt"
+	"bytes"
 	"image"
 	"image/png"
-	"io/ioutil"
-	"log"
-	"os"
 )
 
 const (
@@ -71,7 +68,7 @@ func ScreenshotAtTime(cdgBytes []byte, timeInSec int) []byte {
 /** @Return raw PNG buffer **/
 func snap() []byte {
 	buf := new(bytes.Buffer)
-	png.Encode(out_file, internal_rgba_context)
+	png.Encode(buf, internal_rgba_context)
 	return buf.Bytes()
 }
 

test/main.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"io/ioutil"
+	"log"
+	"os"
+	".."
+)
+
+func main() {
+	//load data
+	cdg_file_data, err := ioutil.ReadFile("../cdg/SC-SBI-REMIX - Billy Idol - Rebel Yell.cdg")
+	if err != nil {
+		log.Fatal("Couldn't read .cdg file")
+	}
+
+	png := karaoke.ScreenshotAtTime(cdg_file_data, 3)
+
+    file, err := os.OpenFile(
+		"screenshot.png",
+		os.O_WRONLY|os.O_TRUNC|os.O_CREATE,
+		0666,
+    )
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer file.Close()
+
+	bytesWritten, err := file.Write(png)
+	if err != nil {
+	  log.Fatal(err)
+	}
+
+	log.Printf("Wrote %d bytes to %s\n", bytesWritten, "screenshot.png")
+}