From 93dc416dd3a2cc56e99586e8c45112fef4a2c0b6 Mon Sep 17 00:00:00 2001
From: Thomas Rehn <thomas.rehn@initos.com>
Date: Thu, 9 Oct 2014 18:05:09 +0200
Subject: [PATCH] only use alpha channel if it exists

---
 addons/hw_escpos/escpos/escpos.py | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/addons/hw_escpos/escpos/escpos.py b/addons/hw_escpos/escpos/escpos.py
index 13ea11af7a6..d35da17412f 100644
--- a/addons/hw_escpos/escpos/escpos.py
+++ b/addons/hw_escpos/escpos/escpos.py
@@ -438,7 +438,12 @@ class Escpos:
             f.seek(0)
             img_rgba = Image.open(f)
             img = Image.new('RGB', img_rgba.size, (255,255,255))
-            img.paste(img_rgba, mask=img_rgba.split()[3]) 
+            channels = img_rgba.split()
+            kwargs = {}
+            if len(channels) > 1:
+                # use alpha channel as mask
+                kwargs['mask'] = img_rgba.split()[3]
+            img.paste(img_rgba, **kwargs)
 
             print 'convert image'