public distro 2.1.0

pmsco/igor.py

@@ -0,0 +1,143 @@
+"""
+@package pmsco.igor
+data exchange with wavemetrics igor pro.
+
+this module provides functions for loading/saving pmsco data in igor pro.
+
+@author Matthias Muntwiler
+
+@copyright (c) 2019 by Paul Scherrer Institut @n
+Licensed under the Apache License, Version 2.0 (the "License"); @n
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+  http://www.apache.org/licenses/LICENSE-2.0
+"""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import numpy as np
+
+from pmsco.compat import open
+
+
+def _escape_igor_string(s):
+    s = s.replace('\\', '\\\\')
+    s = s.replace('"', '\\"')
+    return s
+
+
+def namefix_double(name):
+    """
+    fix 1-character wave name by doubling
+
+    replaces length-1 string by a doubled version.
+
+    @param name: (str) proposed wave name
+
+    @return: corrected name
+    """
+    return name*2 if len(name) == 1 else name
+
+
+def namefix_etpais(name):
+    """
+    fix 1-character wave name according to ETPAIS scheme
+
+    replaces 'e' by 'en' etc.
+
+    @param name: (str) proposed wave name
+
+    @return: corrected name
+    """
+    name_map = {'e': 'en', 't': 'th', 'p': 'ph', 'i': 'in', 'm': 'mo', 's': 'si'}
+    try:
+        return name_map[name]
+    except KeyError:
+        return name
+
+
+class IgorExport(object):
+    """
+    class exports pmsco data to an Igor text (ITX) file.
+
+    usage:
+    1) create an object instance.
+    2) set @ref data.
+    3) set optional attributes: @ref prefix and @ref namefix.
+    4) call @ref export.
+    """
+
+    def __init__(self):
+        super(IgorExport, self).__init__()
+        self.data = None
+        self.prefix = ""
+        self.namefix = namefix_double
+
+    def set_data(self, data):
+        """
+        set the data array to export.
+
+        this must (currently) be a one-dimensional structured array.
+        the column names will become wave names.
+
+        @param data: numpy.ndarray
+        @return:
+        """
+        self.data = data
+
+    def export(self, filename):
+        """
+        write to igor file.
+        """
+        with open(filename, 'w') as f:
+            self._write_header(f)
+            self._write_data(f)
+
+    def _fix_name(self, name):
+        """
+        fix a wave name.
+
+        this function first applies @ref namefix and @ref prefix to the proposed wave name.
+
+        @param name: (str) proposed wave name
+
+        @return: corrected name
+        """
+        if self.namefix is not None:
+            name = self.namefix(name)
+        return self.prefix + name
+
+    def _write_header(self, f):
+        """
+        write the header of the igor text file
+
+        @param f: open file or stream
+
+        @return: None
+        """
+        f.write('IGOR' + '\n')
+        f.write('X // pmsco data export\n')
+
+    def _write_data(self, f):
+        """
+        write a data section to the igor text file.
+
+        @param f: open file or stream
+
+        @return: None
+        """
+        assert isinstance(self.data, np.ndarray)
+        assert len(self.data.shape) == 1
+        assert len(self.data.dtype.names[0]) >= 1
+
+        arr = self.data
+        shape = ",".join(map(str, arr.shape))
+        names = (self._fix_name(name) for name in arr.dtype.names)
+        names = ", ".join(names)
+
+        f.write('Waves/O/D/N=({shape}) {names}\n'.format(shape=shape, names=names))
+        f.write('BEGIN\n')
+        np.savetxt(f, arr, fmt='%g')
+        f.write('END\n')