receipts/printer.py

from escpos.printer import CupsPrinter
from itertools import zip_longest


class CallbackContext:
    def __init__(self, enter=None, exit=None):
        self.enter = enter
        self.exit = exit

    def __enter__(self):
        if self.enter:
            return self.enter()

    def __exit__(self, *_):
        if self.exit:
            self.exit()


class Split2Context:
    def __init__(
        self, printer, num_cols=2, widths=None, align="<", aligns=None, columns=48
    ):
        self.printer = printer

        self.num_cols = num_cols or len(widths)
        self.widths = widths or [columns // self.num_cols] * self.num_cols

        self.aligns = aligns or [align] * self.num_cols

        self.col_length = columns // 2

        self.columns = [[] for i in range(self.num_cols)]

    def col(self, num, text):
        self.columns[num].append(f"{text:{self.aligns[num]}{self.widths[num]}}")

    def left(self, text):
        self.col(0, text)

    def right(self, text):
        self.col(-1, text)

    def __enter__(self):
        return self

    def __exit__(self, *_):
        lines = map("".join, zip_longest(*self.columns, fillvalue=" " * self.num_cols))
        for line in lines:
            self.printer.textln(line)


class ReceiptPrinter(CupsPrinter):
    def __init__(self, *args, autocut=True, **kwargs):
        self.autocut = autocut
        super().__init__(*args, **kwargs)

    def __enter__(self):
        self.open()
        return self

    def __exit__(self, _type, _value, _traceback):
        if self.autocut:
            self.cut()
        self.close()

    def set(self, *args, **kwargs):
        super().set(*args, **kwargs)
        return CallbackContext(exit=super().set_with_default)

    def set_with_default(self, *args, **kwargs):
        super().set_with_default(*args, **kwargs)
        return CallbackContext(exit=super().set_with_default)

    def split(self, left, right, cols=48):
        self.textln(f"{left:<{cols//2}}{right:<{cols//2}}")

    def vsplit(self, *args, **kwargs):
        return Split2Context(self, *args, **kwargs)

    def invert(self, text):
        with self.set(invert=True):
            self.text(text)

    def invertln(self, text):
        self.invert(text)
        self.ln()

    def bold(self, text):
        with self.set(bold=True):
            self.text(text)

    def boldln(self, text):
        self.bold(text)
        self.ln()

    def title(self, text, size=6, width=None, height=None):
        width = width or size
        height = height or size
        with self.set(align="center", bold=True, invert=True, smooth=True, custom_size=True, width=width, height=height):
            self.textln(text)
            self.ln()

    def subtitle(self, text):
        with self.set(align="center", double_height=True, double_width=True):
            p.textln(text)

#p = ReceiptPrinter("EPSON-TM-m30", profile="default")
p = ReceiptPrinter("EPSON-TM-m30-remote", profile="default")