writer.py

# -*- coding: utf-8 -*-

from __future__ import unicode_literals

import gzip
import os
import xml.dom

from barcode.version import version

try:
    import Image
    import ImageDraw
    import ImageFont
except ImportError:
    try:
        from PIL import Image, ImageDraw, ImageFont  # lint:ok
    except ImportError:
        import logging
        log = logging.getLogger('pyBarcode')
        log.info('PIL not found. Image output disabled')
        Image = ImageDraw = ImageFont = None  # lint:ok


def mm2px(mm, dpi=300):
    return (mm * dpi) / 25.4

def px2mm(px, dpi=300):
    return (px*25.4)/dpi

def pt2mm(pt):
    return pt * 0.352777778


def _set_attributes(element, **attributes):
    for key, value in attributes.items():
        element.setAttribute(key, value)


def create_svg_object():
    imp = xml.dom.getDOMImplementation()
    doctype = imp.createDocumentType(
        'svg',
        '-//W3C//DTD SVG 1.1//EN',
        'http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd'
    )
    document = imp.createDocument(None, 'svg', doctype)
    _set_attributes(document.documentElement, version='1.1',
                    xmlns='http://www.w3.org/2000/svg')
    return document


SIZE = '{0:.3f}mm'
COMMENT = 'Autogenerated with python-barcode {0}'.format(version)
PATH = os.path.dirname(os.path.abspath(__file__))
FONT = os.path.join(PATH, 'DejaVuSansMono.ttf')


class BaseWriter(object):
    """Baseclass for all writers.

    Initializes the basic writer options. Childclasses can add more
    attributes and can set them directly or using
    `self.set_options(option=value)`.

    :parameters:
        initialize : Function
            Callback for initializing the inheriting writer.
            Is called: `callback_initialize(raw_code)`
        paint_module : Function
            Callback for painting one barcode module.
            Is called: `callback_paint_module(xpos, ypos, width, color)`
        paint_text : Function
            Callback for painting the text under the barcode.
            Is called: `callback_paint_text(xpos, ypos)` using `self.text`
            as text.
        finish : Function
            Callback for doing something with the completely rendered
            output.
            Is called: `return callback_finish()` and must return the
            rendered output.
    """

    def __init__(self, initialize=None, paint_module=None, paint_text=None,
                 finish=None):
        self._callbacks = dict(
            initialize=initialize, paint_module=paint_module,
            paint_text=paint_text, finish=finish
        )
        self.module_width = 10
        self.module_height = 10
        self.font_size = 10
        self.quiet_zone = 6.5
        self.background = 'white'
        self.foreground = 'black'
        self.text = ''
        self.human = ''  # human readable text
        self.text_distance = 5
        self.center_text = True

    def calculate_size(self, modules_per_line, number_of_lines, dpi=300):
        """Calculates the size of the barcode in pixel.

        :parameters:
            modules_per_line : Integer
                Number of modules in one line.
            number_of_lines : Integer
                Number of lines of the barcode.
            dpi : Integer
                DPI to calculate.

        :returns: Width and height of the barcode in pixel.
        :rtype: Tuple
        """
        width = 2 * self.quiet_zone + modules_per_line * self.module_width
        height = 2.0 + self.module_height * number_of_lines
        if self.font_size and self.text:
            height += pt2mm(self.font_size) / 2 + self.text_distance
        return int(mm2px(width, dpi)), int(mm2px(height, dpi))

    def save(self, filename, output):
        """Saves the rendered output to `filename`.

        :parameters:
            filename : String
                Filename without extension.
            output : String
                The rendered output.

        :returns: The full filename with extension.
        :rtype: String
        """
        raise NotImplementedError

    def register_callback(self, action, callback):
        """Register one of the three callbacks if not given at instance
        creation.

        :parameters:
            action : String
                One of 'initialize', 'paint_module', 'paint_text', 'finish'.
            callback : Function
                The callback function for the given action.
        """
        self._callbacks[action] = callback

    def set_options(self, options):
        """Sets the given options as instance attributes (only
        if they are known).

        :parameters:
            options : Dict
                All known instance attributes and more if the childclass
                has defined them before this call.

        :rtype: None
        """
        for key, val in options.items():
            key = key.lstrip('_')
            if hasattr(self, key):
                setattr(self, key, val)

    def render(self, code):
        """Renders the barcode to whatever the inheriting writer provides,
        using the registered callbacks.

        :parameters:
            code : List
                List of strings matching the writer spec
                (only contain 0 or 1).
        """
        if self._callbacks['initialize'] is not None:
            self._callbacks['initialize'](code)
        ypos = 1.0
        for cc, line in enumerate(code):
            """
            Pack line to list give better gfx result, otherwise in can
            result in aliasing gaps
            '11010111' -> [2, -1, 1, -1, 3]
            """
            line += ' '
            c = 1
            mlist = []
            for i in range(0, len(line) - 1):
                if line[i] == line[i+1]:
                    c += 1
                else:
                    if line[i] == "1":
                        mlist.append(c)
                    else:
                        mlist.append(-c)
                    c = 1
            # Left quiet zone is x startposition
            xpos = self.quiet_zone
            bxs = xpos  # x start of barcode
            for mod in mlist:
                if mod < 1:
                    color = self.background
                else:
                    color = self.foreground
                # remove painting for background colored tiles?
                self._callbacks['paint_module'](
                    xpos, ypos, self.module_width * abs(mod), color
                )
                xpos += self.module_width * abs(mod)
            bxe = xpos
            # Add right quiet zone to every line, except last line,
            # quiet zone already provided with background,
            # should it be removed complety?
            if (cc + 1) != len(code):
                self._callbacks['paint_module'](
                    xpos, ypos, self.quiet_zone, self.background
                )
            ypos += self.module_height
        if self.text and self._callbacks['paint_text'] is not None:
            ypos += self.text_distance
            if self.center_text:
                # better center position for text
                xpos = bxs + ((bxe - bxs) / 2.0)
            else:
                font = ImageFont.truetype(FONT, self.font_size * 2)
                width, height = font.getsize(self.text)
                xpos = bxs + px2mm(width // 2)
            self._callbacks['paint_text'](xpos, ypos)
        return self._callbacks['finish']()


class SVGWriter(BaseWriter):

    def __init__(self):
        BaseWriter.__init__(self, self._init, self._create_module,
                            self._create_text, self._finish)
        self.compress = False
        self.dpi = 25.4
        self._document = None
        self._root = None
        self._group = None

    def _init(self, code):
        width, height = self.calculate_size(len(code[0]), len(code), self.dpi)
        self._document = create_svg_object()
        self._root = self._document.documentElement
        attributes = dict(width=SIZE.format(width), height=SIZE.format(height))
        _set_attributes(self._root, **attributes)
        self._root.appendChild(self._document.createComment(COMMENT))
        # create group for easier handling in 3rd party software
        # like corel draw, inkscape, ...
        group = self._document.createElement('g')
        attributes = dict(id='barcode_group')
        _set_attributes(group, **attributes)
        self._group = self._root.appendChild(group)
        background = self._document.createElement('rect')
        attributes = dict(width='100%', height='100%',
                          style='fill:{0}'.format(self.background))
        _set_attributes(background, **attributes)
        self._group.appendChild(background)

    def _create_module(self, xpos, ypos, width, color):
        element = self._document.createElement('rect')
        attributes = dict(x=SIZE.format(xpos), y=SIZE.format(ypos),
                          width=SIZE.format(width),
                          height=SIZE.format(self.module_height),
                          style='fill:{0};'.format(color))
        _set_attributes(element, **attributes)
        self._group.appendChild(element)

    def _create_text(self, xpos, ypos):
        element = self._document.createElement('text')
        attributes = dict(x=SIZE.format(xpos), y=SIZE.format(ypos),
                          style='fill:{0};font-size:{1}pt;text-anchor:'
                                'middle;'.format(self.foreground,
                                                 self.font_size))
        _set_attributes(element, **attributes)
        # check option to override self.text with self.human (barcode as
        # human readable data, can be used to print own formats)
        if self.human != '':
            barcodetext = self.human
        else:
            barcodetext = self.text
        text_element = self._document.createTextNode(barcodetext)
        element.appendChild(text_element)
        self._group.appendChild(element)

    def _finish(self):
        if self.compress:
            return self._document.toxml(encoding='UTF-8')
        else:
            return self._document.toprettyxml(indent=4 * ' ', newl=os.linesep,
                                              encoding='UTF-8')

    def save(self, filename, output):
        if self.compress:
            _filename = '{0}.svgz'.format(filename)
            f = gzip.open(_filename, 'wb')
            f.write(output)
            f.close()
        else:
            _filename = '{0}.svg'.format(filename)
            with open(_filename, 'wb') as f:
                f.write(output)
        return _filename


if Image is None:
    ImageWriter = None
else:
    class ImageWriter(BaseWriter):

        def __init__(self):
            BaseWriter.__init__(self, self._init, self._paint_module,
                                self._paint_text, self._finish)
            self.format = 'PNG'
            self.dpi = 300
            self._image = None
            self._draw = None

        def _init(self, code):
            size = self.calculate_size(len(code[0]), len(code), self.dpi)
            self._image = Image.new('RGB', size, self.background)
            self._draw = ImageDraw.Draw(self._image)

        def _paint_module(self, xpos, ypos, width, color):
            size = [(mm2px(xpos, self.dpi), mm2px(ypos, self.dpi)),
                    (mm2px(xpos + width, self.dpi),
                     mm2px(ypos + self.module_height, self.dpi))]
            self._draw.rectangle(size, outline=color, fill=color)

        def _paint_text(self, xpos, ypos):
            font = ImageFont.truetype(FONT, self.font_size * 2)
            width, height = font.getsize(self.text)
            pos = (mm2px(xpos, self.dpi) - width // 2,
                   mm2px(ypos, self.dpi) - height // 4)
            self._draw.text(pos, self.text, font=font, fill=self.foreground)

        def _finish(self):
            return self._image

        def save(self, filename, output):
            filename = '{0}.{1}'.format(filename, self.format.lower())
            output.save(filename, self.format.upper())
            return filename