brother_ql_web/brother_ql_web.py

#!/usr/bin/env python

"""
This is a web service to print labels on Brother QL label printers.
"""

import sys, logging, socket, os, subprocess, functools

from bottle import run, route, response, request
from PIL import Image, ImageDraw, ImageFont
import numpy as np
import markdown

from brother_ql.devicedependent import models
from brother_ql.raster import BrotherQLRaster
from brother_ql.backends import backend_factory, guess_backend

MODEL = None
BACKEND_CLASS = None
BACKEND_STRING_DESCR = None

logger = logging.getLogger(__name__)

# globals:
DEBUG = False

FONTS = None

DEFAULT_FONT = None

DEFAULT_FONTS = [
  {'family': 'Minion Pro',      'style': 'Semibold'},
  {'family': 'Linux Libertine', 'style': 'Regular'},
  {'family': 'DejaVu Serif',    'style': 'Book'},
]

@route('/')
def index():
    INDEX_MD = __doc__ + """
    Go to [/api/print/text/Your_Text](/api/print/text/)
    to print a label (replace `Your_Text` with your text).
    """
    return markdown.markdown(INDEX_MD)

def get_fonts(folder=None):
    """
    Scan a folder (or the system) for .ttf / .otf fonts and
    return a dictionary of the structure  family -> style -> file path
    """
    fonts = {}
    if folder:
        cmd = ['fc-scan', '--format', '"%{file}:%{family}:style=%{style}\n"', folder]
    else:
        cmd = ['fc-list', ':', 'file', 'family', 'style']
    for line in subprocess.check_output(cmd).decode('utf-8').split("\n"):
        logger.debug(line)
        line.strip()
        if not line: continue
        if 'otf' not in line and 'ttf' not in line: continue
        parts = line.split(':')
        path = parts[0]
        families = parts[1].strip().split(',')
        styles = parts[2].split('=')[1].split(',')
        if len(families) == 1 and len(styles) > 1:
            families = [families[0]] * len(styles)
        elif len(families) > 1 and len(styles) == 1:
            styles = [styles[0]] * len(families)
        if len(families) != len(styles):
            if DEBUG:
                print("Problem with this font:")
                print(line)
            continue
        for i in range(len(families)):
            try: fonts[families[i]]
            except: fonts[families[i]] = dict()
            fonts[families[i]][styles[i]] = path
            if DEBUG:
                print("Added this font:")
                print(families[i], styles[i], path)
    return fonts

@route('/api/print/text')
@route('/api/print/text/')
@route('/api/print/text/<content>')
def print_text(content=None):
    """
    API to print a label

    returns: JSON

    Ideas for additional URL parameters:
    - alignment
    """

    return_dict = {'success': False}

    if content is None:
        return_dict['error'] = 'Please provide the text for the label'
        return return_dict

    threshold = 170
    fontsize = int(request.query.get('font_size', 100))
    width = 720
    margin = 0
    height = 100 + 2*margin

    try:
        font_family = request.query.get('font_family')
        font_style  = request.query.get('font_style')
        if font_family is None:
            font_family = DEFAULT_FONT['family']
            font_style =  DEFAULT_FONT['style']
        if font_style is None:
            font_style =  'Regular'
        font_path = FONTS[font_family][font_style]
    except KeyError:
        return_dict['error'] = "Couln't find the font & style"
        return return_dict

    im = Image.new('L', (width, height), 'white')
    draw = ImageDraw.Draw(im)
    im_font = ImageFont.truetype(font_path, fontsize)
    textsize = draw.textsize(content, font=im_font)
    vertical_offset = (height - textsize[1])//2
    horizontal_offset = max((width - textsize[0])//2, 0)
    if 'ttf' in font_path: vertical_offset -= 10
    offset = horizontal_offset, vertical_offset
    if DEBUG: print("Offset: {}".format(offset))
    draw.text(offset, content, (0), font=im_font)
    if DEBUG: im.save('sample-out.png')
    arr = np.asarray(im, dtype=np.uint8)
    arr.flags.writeable = True
    white_idx = arr[:,:] <  threshold
    black_idx = arr[:,:] >= threshold
    arr[white_idx] = 1
    arr[black_idx] = 0

    qlr = BrotherQLRaster(MODEL)
    qlr.add_switch_mode()
    qlr.add_invalidate()
    qlr.add_initialize()
    qlr.add_status_information()
    qlr.mtype = 0x0A
    qlr.mwidth = 62
    qlr.mlength = 0
    qlr.add_media_and_quality(im.size[1])
    qlr.add_autocut(True)
    qlr.add_cut_every(1)
    qlr.dpi_600 = False
    qlr.cut_at_end = True
    qlr.add_expanded_mode()
    qlr.add_margins()
    qlr.add_compression(True)
    qlr.add_raster_data(arr)
    qlr.add_print()

    if not DEBUG:
        try:
            be = BACKEND_CLASS(BACKEND_STRING_DESCR)
            be.write(qlr.data)
            be.dispose()
            del be
        except Exception as e:
            return_dict['message'] = str(e)
            logger.warning('Exception happened: %s', e)
            response.status = 500
            return return_dict

    return_dict['success'] = True
    if DEBUG: return_dict['data'] = str(qlr.data)
    return return_dict

def main():
    global DEBUG, FONTS, DEFAULT_FONT, MODEL, BACKEND_CLASS, BACKEND_STRING_DESCR
    import argparse
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument('--port', default=8013)
    parser.add_argument('--loglevel', type=lambda x: getattr(logging, x.upper()), default='WARNING')
    parser.add_argument('--font-folder', help='folder for additional .ttf/.otf fonts')
    parser.add_argument('--model', default='QL-500', choices=models, help='The model of your printer (default: QL-500)')
    parser.add_argument('printer', help='String descriptor for the printer to use (like tcp://192.168.0.23:9100 or file:///dev/usb/lp0)')
    args = parser.parse_args()

    DEBUG = args.loglevel == logging.DEBUG
    logging.basicConfig(level=args.loglevel)

    try:
        selected_backend = guess_backend(args.printer)
    except:
        parser.error("Couln't guess the backend to use from the printer string descriptor")
    BACKEND_CLASS = backend_factory(selected_backend)['backend_class']
    BACKEND_STRING_DESCR = args.printer

    MODEL = args.model

    FONTS = get_fonts()
    if args.font_folder:
        FONTS.update(get_fonts(args.font_folder))

    for font in DEFAULT_FONTS:
        try:
            FONTS[font['family']][font['style']]
            DEFAULT_FONT = font
            logger.debug("Selected the following default font: {}".format(font))
            break
        except: pass
    if DEFAULT_FONT is None:
        sys.stderr.write('Could not find any of the default fonts')
        sys.exit()

    run(host='', port=args.port, debug=args.loglevel==logging.DEBUG)

if __name__ == "__main__":
    main()