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#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright 2014 Hamilton Kibbe <ham@hamiltonkib.be>
# Licensed under the Apache License, Version 2.0 (the "License");
# 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
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
gerber.utils
============
**Gerber and Excellon file handling utilities**
This module provides utility functions for working with Gerber and Excellon
files.
"""
# Author: Hamilton Kibbe <ham@hamiltonkib.be>
# License:
MILLIMETERS_PER_INCH = 25.4
def parse_gerber_value(value, format=(2, 5), zero_suppression='trailing'):
""" Convert gerber/excellon formatted string to floating-point number
.. note::
Format and zero suppression are configurable. Note that the Excellon
and Gerber formats use opposite terminology with respect to leading
and trailing zeros. The Gerber format specifies which zeros are
suppressed, while the Excellon format specifies which zeros are
included. This function uses the Gerber-file convention, so an
Excellon file in LZ (leading zeros) mode would use
`zero_suppression='trailing'`
Parameters
----------
value : string
A Gerber/Excellon-formatted string representing a numerical value.
format : tuple (int,int)
Gerber/Excellon precision format expressed as a tuple containing:
(number of integer-part digits, number of decimal-part digits)
zero_suppression : string
Zero-suppression mode. May be 'leading' or 'trailing'
Returns
-------
value : float
The specified value as a floating-point number.
"""
# Handle excellon edge case with explicit decimal. "That was easy!"
if '.' in value:
return float(value)
# Format precision
integer_digits, decimal_digits = format
MAX_DIGITS = integer_digits + decimal_digits
# Absolute maximum number of digits supported. This will handle up to
# 6:7 format, which is somewhat supported, even though the gerber spec
# only allows up to 6:6
if MAX_DIGITS > 13 or integer_digits > 6 or decimal_digits > 7:
raise ValueError('Parser only supports precision up to 6:7 format')
# Remove extraneous information
#value = value.strip()
value = value.lstrip('+')
negative = '-' in value
if negative:
value = value.lstrip('-')
digits = list('0' * MAX_DIGITS)
offset = 0 if zero_suppression == 'trailing' else (MAX_DIGITS - len(value))
for i, digit in enumerate(value):
digits[i + offset] = digit
result = float(''.join(digits[:integer_digits] + ['.'] + digits[integer_digits:]))
return -result if negative else result
def write_gerber_value(value, format=(2, 5), zero_suppression='trailing'):
""" Convert a floating point number to a Gerber/Excellon-formatted string.
.. note::
Format and zero suppression are configurable. Note that the Excellon
and Gerber formats use opposite terminology with respect to leading
and trailing zeros. The Gerber format specifies which zeros are
suppressed, while the Excellon format specifies which zeros are
included. This function uses the Gerber-file convention, so an
Excellon file in LZ (leading zeros) mode would use
`zero_suppression='trailing'`
Parameters
----------
value : float
A floating point value.
format : tuple (n=2)
Gerber/Excellon precision format expressed as a tuple containing:
(number of integer-part digits, number of decimal-part digits)
zero_suppression : string
Zero-suppression mode. May be 'leading' or 'trailing'
Returns
-------
value : string
The specified value as a Gerber/Excellon-formatted string.
"""
# Format precision
integer_digits, decimal_digits = format
MAX_DIGITS = integer_digits + decimal_digits
if MAX_DIGITS > 13 or integer_digits > 6 or decimal_digits > 7:
raise ValueError('Parser only supports precision up to 6:7 format')
# Edge case... (per Gerber spec we should return 0 in all cases, see page 77)
if value == 0:
return '0'
# negative sign affects padding, so deal with it at the end...
negative = value < 0.0
if negative:
value = -1.0 * value
# Format string for padding out in both directions
fmtstring = '%%0%d.0%df' % (MAX_DIGITS + 1, decimal_digits)
digits = [val for val in fmtstring % value if val != '.']
# If all the digits are 0, return '0'.
digit_sum = reduce(lambda x,y:x+int(y), digits, 0)
if digit_sum == 0:
return '0'
# Suppression...
if zero_suppression == 'trailing':
while digits and digits[-1] == '0':
digits.pop()
else:
while digits and digits[0] == '0':
digits.pop(0)
if not digits:
return '0'
return ''.join(digits) if not negative else ''.join(['-'] + digits)
def decimal_string(value, precision=6, padding=False):
""" Convert float to string with limited precision
Parameters
----------
value : float
A floating point value.
precision :
Maximum number of decimal places to print
Returns
-------
value : string
The specified value as a string.
"""
floatstr = '%0.10g' % value
integer = None
decimal = None
if '.' in floatstr:
integer, decimal = floatstr.split('.')
elif ',' in floatstr:
integer, decimal = floatstr.split(',')
else:
integer, decimal = floatstr, "0"
if len(decimal) > precision:
decimal = decimal[:precision]
elif padding:
decimal = decimal + (precision - len(decimal)) * '0'
if integer or decimal:
return ''.join([integer, '.', decimal])
else:
return int(floatstr)
def detect_file_format(filename):
""" Determine format of a file
Parameters
----------
filename : string
Filename of the file to read.
Returns
-------
format : string
File format. either 'excellon' or 'rs274x'
"""
# Read the first 20 lines (if possible)
lines = []
with open(filename, 'r') as f:
try:
for i in range(20):
lines.append(f.readline())
except StopIteration:
pass
# Look for
for line in lines:
if 'M48' in line:
return 'excellon'
elif '%FS' in line:
return'rs274x'
return 'unknown'
def validate_coordinates(position):
if position is not None:
if len(position) != 2:
raise TypeError('Position must be a tuple (n=2) of coordinates')
else:
for coord in position:
if not (isinstance(coord, int) or isinstance(coord, float)):
raise TypeError('Coordinates must be integers or floats')
def metric(value):
return value * MILLIMETERS_PER_INCH
def inch(value):
return value / MILLIMETERS_PER_INCH
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