From 58c7c33fe946bd3b5a25eba0866b0e8947e7e121 Mon Sep 17 00:00:00 2001
From: Dean Rispin <drispin@marinepartssupply.com>
Date: Mon, 29 Feb 2016 10:04:00 -0800
Subject: [PATCH] Add inverted printing to set method

---
 doc/user/methods.rst | 5 +++--
 escpos/constants.py  | 2 ++
 escpos/escpos.py     | 7 ++++++-
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/doc/user/methods.rst b/doc/user/methods.rst
index 976bde6..10f4fb8 100644
--- a/doc/user/methods.rst
+++ b/doc/user/methods.rst
@@ -65,8 +65,8 @@ text("text")
 
 Prints raw text. Raises ``TextError`` exception.
 
-set("align", "font", "type", width, height)
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+set("align", "font", "type", width, height, invert)
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 Set text properties.
 * ``align`` set horizontal position for text, the possible values are:
@@ -79,6 +79,7 @@ Set text properties.
 * ``type`` type could be ``B`` (Bold), ``U`` (Underline) or ``normal``. *Default:* normal
 * ``width`` is a numeric value, 1 is for regular size, and 2 is twice the standard size. *Default*: 1
 * ``height`` is a numeric value, 1 is for regular size and 2 is twice the standard size. *Default*: 1
+* ``invert`` is a boolean value, True enables white on black printing. *Default*: False
 
 cut("mode")
 ^^^^^^^^^^^
diff --git a/escpos/constants.py b/escpos/constants.py
index c7e5309..59a8853 100644
--- a/escpos/constants.py
+++ b/escpos/constants.py
@@ -64,6 +64,8 @@ TXT_FONT_B     = ESC + '\x4d\x01'  # Font type B
 TXT_ALIGN_LT   = ESC + '\x61\x00'  # Left justification
 TXT_ALIGN_CT   = ESC + '\x61\x01'  # Centering
 TXT_ALIGN_RT   = ESC + '\x61\x02'  # Right justification
+TXT_INVERT_ON  = GS  + '\x42\x01'  # Inverse Printing ON
+TXT_INVERT_OFF = GS  + '\x42\x00'  # Inverse Printing OFF
 
 # Char code table
 CHARCODE_PC437  = ESC + '\x74\x00'  # USA: Standard Europe
diff --git a/escpos/escpos.py b/escpos/escpos.py
index b8b8342..f082b4b 100644
--- a/escpos/escpos.py
+++ b/escpos/escpos.py
@@ -451,7 +451,7 @@ class Escpos(object):
         colCount = self.columns if columns is None else columns
         self.text(textwrap.fill(txt, colCount))
 
-    def set(self, align='left', font='a', text_type='normal', width=1, height=1, density=9):
+    def set(self, align='left', font='a', text_type='normal', width=1, height=1, density=9, invert=False):
         """ Set text properties by sending them to the printer
 
         :param align: horizontal position for text, possible values are:
@@ -541,6 +541,11 @@ class Escpos(object):
             self._raw(PD_P50)
         else:  # DEFAULT: DOES NOTHING
             pass
+        # Invert Printing
+        if invert == True:
+            self._raw(TXT_INVERT_ON)
+        else:
+            self._raw(TXT_INVERT_OFF)
 
     def cut(self, mode=''):
         """ Cut paper.