Merge pull request #105 from python-escpos/feature-disable-panel-buttons

FEATURE disable panel buttons

escpos/constants.py

@@ -54,6 +54,11 @@ _CUT_PAPER = lambda m: GS + b'V' + m
 PAPER_FULL_CUT = _CUT_PAPER(b'\x00')  # Full cut paper
 PAPER_PART_CUT = _CUT_PAPER(b'\x01')  # Partial cut paper
 
+# Panel buttons (e.g. the FEED button)
+_PANEL_BUTTON = lambda n: ESC + b'c5' + six.int2byte(n)
+PANEL_BUTTON_ON = _PANEL_BUTTON(0)  # enable all panel buttons
+PANEL_BUTTON_OFF = _PANEL_BUTTON(1)  # disable all panel buttons
+
 # Text format
 # TODO: Acquire the "ESC/POS Application Programming Guide for Paper Roll
 #       Printers" and tidy up this stuff too.

escpos/escpos.py

@@ -674,3 +674,26 @@ class Escpos(object):
             self._raw(CTL_HT)
         elif ctl.upper() == "VT":
             self._raw(CTL_VT)
+
+    def panel_buttons(self, enable=True):
+        """ Controls the panel buttons on the printer (e.g. FEED)
+
+        When enable is set to False the panel buttons on the printer will be disabled. Calling the method with
+        enable=True or without argument will enable the panel buttons.
+
+        If panel buttons are enabled, the function of the panel button, such as feeding, will be executed upon pressing
+        the button. If the panel buttons are disabled, pressing them will not have any effect.
+
+        This command is effective until the printer is initialized, reset or power-cycled. The default is enabled panel
+        buttons.
+
+        Some panel buttons will always work, especially when printer is opened. See for more information the manual
+        of your printer and the escpos-command-reference.
+
+        :param enable: controls the panel buttons
+        :rtype: None
+        """
+        if enable:
+            self._raw(PANEL_BUTTON_ON)
+        else:
+            self._raw(PANEL_BUTTON_OFF)

test/test_function_panel_button.py

@@ -0,0 +1,54 @@
+#!/usr/bin/python
+"""tests for panel button function
+
+:author: `Patrick Kanzler <patrick.kanzler@fablab.fau.de>`_
+:organization: `python-escpos <https://github.com/python-escpos>`_
+:copyright: Copyright (c) 2016 `python-escpos <https://github.com/python-escpos>`_
+:license: GNU GPL v3
+"""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
+from nose.tools import with_setup
+
+import escpos.printer as printer
+import os
+
+devfile = 'testfile'
+
+
+def setup_testfile():
+    """create a testfile as devfile"""
+    fhandle = open(devfile, 'a')
+    try:
+        os.utime(devfile, None)
+    finally:
+        fhandle.close()
+
+
+def teardown_testfile():
+    """destroy testfile again"""
+    os.remove(devfile)
+
+
+@with_setup(setup_testfile, teardown_testfile)
+def test_function_panel_button_on():
+    """test the panel button function (enabling) by comparing output"""
+    instance = printer.File(devfile=devfile)
+    instance.panel_buttons()
+    instance.flush()
+    with open(devfile, "rb") as f:
+        assert(f.read() == b'\x1B\x63\x35\x00')
+
+
+@with_setup(setup_testfile, teardown_testfile)
+def test_function_panel_button_off():
+    """test the panel button function (disabling) by comparing output"""
+    instance = printer.File(devfile=devfile)
+    instance.panel_buttons(False)
+    instance.flush()
+    with open(devfile, "rb") as f:
+        assert(f.read() == b'\x1B\x63\x35\x01')