1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
|
# coding=utf-8
#
# Copyright (C) 2010 Martin Owens
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110, USA.
#
"""
Base module for rendering barcodes for Inkscape.
"""
import itertools
import sys
from inkex import Group, TextElement, Rectangle
from inkex.localization import inkex_gettext as _
(TEXT_POS_BOTTOM, TEXT_POS_TOP) = range(2)
(WHITE_BAR, BLACK_BAR, TALL_BAR) = range(3)
TEXT_TEMPLATE = "font-size:%dpx;text-align:center;text-anchor:middle;"
try:
from typing import Optional
except ImportError:
pass
class Barcode(object):
"""Provide a base class for all barcode renderers"""
default_height = 30
font_size = 9
name = None # type: Optional[str]
def error(self, text, msg):
"""Cause an error to be reported"""
sys.stderr.write(
_("Error encoding '{}' as {} barcode: {}\n").format(text, self.name, msg)
)
return "ERROR"
def encode(self, text):
"""
Replace this with the encoding function, it should return
a string of ones and zeros
"""
raise NotImplementedError("You need to write an encode() function.")
def __init__(self, param):
param = param or {}
self.document = param.get("document", None)
self.known_ids = []
self._extra = []
self.pos_x = int(param.get("x", 0))
self.pos_y = int(param.get("y", 0))
self.text = param.get("text", None)
self.scale = param.get("scale", 1)
self.height = param.get("height", self.default_height)
self.pos_text = param.get("text_pos", TEXT_POS_BOTTOM)
if self.document:
self.known_ids = list(self.document.xpath("//@id"))
if not self.text:
raise ValueError(_("No string specified for barcode."))
def get_id(self, name="element"):
"""Get the next useful id (and claim it)"""
index = 0
while name in self.known_ids:
index += 1
name = "barcode{:d}".format(index)
self.known_ids.append(name)
return name
def add_extra_barcode(self, barcode, **kw):
"""Add an extra barcode along side this one, used for ean13 extras"""
from . import get_barcode
kw["height"] = self.height
kw["document"] = self.document
kw["scale"] = None
self._extra.append(get_barcode(barcode, **kw).generate())
def generate(self):
"""Generate the actual svg from the coding"""
string = self.encode(self.text)
if string == "ERROR":
return
name = self.get_id("barcode")
# use an svg group element to contain the barcode
barcode = Group()
barcode.set("id", name)
barcode.set("style", "fill: black;")
barcode.transform.add_translate(self.pos_x, self.pos_y)
if self.scale:
barcode.transform.add_scale(self.scale)
bar_id = 1
bar_offset = 0
tops = set()
for datum in self.graphical_array(string):
# Datum 0 tells us what style of bar is to come next
style = self.get_style(int(datum[0]))
# Datum 1 tells us what width in units,
# style tells us how wide a unit is
width = int(datum[1]) * int(style["width"])
if style["write"]:
tops.add(style["top"])
rect = Rectangle()
rect.set("x", str(bar_offset))
rect.set("y", str(style["top"]))
if self.pos_text == TEXT_POS_TOP:
rect.set("y", str(style["top"] + self.font_size))
rect.set("id", "{}_bar{:d}".format(name, bar_id))
rect.set("width", str(width))
rect.set("height", str(style["height"]))
barcode.append(rect)
bar_offset += width
bar_id += 1
for extra in self._extra:
if extra is not None:
barcode.append(extra)
bar_width = bar_offset
# Add text at the bottom of the barcode
text = TextElement()
text.set("x", str(int(bar_width / 2)))
text.set("y", str(min(tops) + self.font_size - 1))
if self.pos_text == TEXT_POS_BOTTOM:
text.set("y", str(self.height + max(tops) + self.font_size))
text.set("style", TEXT_TEMPLATE % self.font_size)
text.set("xml:space", "preserve")
text.set("id", "{}_text".format(name))
text.text = str(self.text)
barcode.append(text)
return barcode
def graphical_array(self, code):
"""Converts black and white markets into a space array"""
return [(x, len(list(y))) for x, y in itertools.groupby(code)]
def get_style(self, index):
"""Returns the styles that should be applied to each bar"""
result = {"width": 1, "top": 0, "write": True}
if index == BLACK_BAR:
result["height"] = int(self.height)
if index == TALL_BAR:
result["height"] = int(self.height) + int(self.font_size / 2)
if index == WHITE_BAR:
result["write"] = False
return result
|
