From 81e22becffcccf98e89a2c7ec5d33c4d12f8e9ed Mon Sep 17 00:00:00 2001
From: Christian Hesse <mail@eworm.de>
Date: Tue, 4 Jun 2013 18:47:44 +0200
Subject: add comments abount defines

---
 cqrlogo.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/cqrlogo.c b/cqrlogo.c
index f1ef1ae..5ed5a4c 100644
--- a/cqrlogo.c
+++ b/cqrlogo.c
@@ -13,7 +13,14 @@
 #include <gdk-pixbuf/gdk-pixbuf.h>
 #include <qrencode.h>
 
+/* pixels are scaled up by this factor */
 #define QRCODE_SCALE	2
+/* error correction level used for QR code
+ * possible values: QR_ECLEVEL_L (lowest, about 7% error can be corrected)
+ *                  QR_ECLEVEL_M (about 15%)
+ *                  QR_ECLEVEL_Q (about 25%)
+ *                  QR_ECLEVEL_H (highest, about 30%)
+ * image size raises with higher levels */
 #define QRCODE_LEVEL	QR_ECLEVEL_L
 
 GdkPixbuf * encode_qrcode (char *text) {
-- 
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