labelmaker/labelmaker/main.py

import json
import math
import os
import subprocess
import time

import cairocffi as cairo
import flask
import img2pdf
import pangocffi as pango
import pangocairocffi as pangocairo
import requests

class App(flask.Flask):
    def __init__(self, *args, **kwargs):
        super(App, self).__init__(*args, **kwargs)
        self.last = 0

app = App(__name__)

class Renderer(object):
    INCH_PER_MM = 0.039
    DPI = 300
    def __init__(self, size=(36, 89)):
        width, height = [int(s * self.INCH_PER_MM * self.DPI) for s in size]
        surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, width, height)
        context = cairo.Context(surface)

        context.rectangle(0, 0, width, height)
        context.set_source_rgb(1, 1, 1)
        context.fill()

        context.translate(width, 0)
        context.rotate(math.pi/2)

        self.width, self.height = height, width
        self.font = pango.FontDescription()

        self.context = context
        self.surface = surface

    def export_png(self, name):
        with open(name, 'wb') as f:
            self.surface.write_to_png(f)

    def render_text(self, text, fontname, x, y, html=False):
        print("Fontname:", fontname)
        self.context.save()
        if y != -1:
            self.context.translate(x, y)
        self.context.set_antialias(cairo.ANTIALIAS_SUBPIXEL)
        layout = pangocairo.create_layout(self.context)
        layout._set_width(pango.units_from_double(self.width))
        layout._set_alignment(pango.Alignment.CENTER)
        if html:
            # Absolutely horrifying hack to fix broken text wrapping
            layout.apply_markup('<span font_desc="%s">%s</span>' % (fontname, text))
        else:
            self.font.family = fontname.split()[0]
            self.font.size = pango.units_from_double(int(fontname.split()[1]))

            layout.font_description = self.font
            layout.text = text
        if y == -1:
            self.context.translate(0, (self.height - pango.units_to_double(layout.get_size()[1]))/2)

        self.context.set_source_rgb(0, 0, 0)
        pangocairo.update_layout(self.context, layout)
        pangocairo.show_layout(self.context, layout)

        self.context.restore()

@app.route('/')
def index():
    return flask.render_template('index.html')

@app.route('/api/preview/<int:size>/')
def stuff_preview(size):
    text = flask.request.args.get('text')
    html = flask.request.args.get('html') == '1'
    renderer = Renderer()
    renderer.render_text(text, 'Sans {}'.format(size), 0, -1, html)

    preview = renderer.surface.write_to_png()
    return flask.Response(preview, mimetype='image/png')

DELAY = 5
@app.route('/api/print/<int:size>/', methods=['POST'])
def stuff_print(size):
    last = app.last
    print(last, time.time() - last)
    if time.time() - last < DELAY:
        return 'Please wait {} more seconds before next print.'.format(int(DELAY - (time.time() - last)))
    text = flask.request.args.get('text')
    html = flask.request.args.get('html') == '1'
    renderer = Renderer()
    renderer.render_text(text, 'Sans {}'.format(size), 0, -1, html)

    data = renderer.surface.write_to_png()
    payload = {'printer': 'dymo_labelwriter450', 'copies': 1, 'body': data}
    r = requests.post(os.environ.get('PRINTSERVANT_HOST') + '/print', params=payload)
    print('Printing job response', r.text)

    app.last = time.time()
    return 'ok'

def main():
    app.run(host="0.0.0.0", port=5000, debug=True)

if __name__ == '__main__':
    main()