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#!/usr/bin/env python3
#
# Electron Cash - lightweight Bitcoin client
# Copyright (C) 2019 Axel Gembe <derago@gmail.com>
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation files
# (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
import ctypes
from typing import List, Tuple
from abc import ABC, abstractmethod
QrCodePoint = Tuple[int, int]
QrCodePointList = List[QrCodePoint]
class QrCodeResult():
"""
A detected QR code.
"""
def __init__(self, data: str, center: QrCodePoint, points: QrCodePointList):
self.data: str = data
self.center: QrCodePoint = center
self.points: QrCodePointList = points
def __str__(self) -> str:
return 'data: {} center: {} points: {}'.format(self.data, self.center, self.points)
def __hash__(self):
return hash(self.data)
def __eq__(self, other):
return self.data == other.data
def __ne__(self, other):
return not self == other
class AbstractQrCodeReader(ABC):
"""
Abstract base class for QR code readers.
"""
def interval(self) -> float:
''' Reimplement to specify a time (in seconds) that the implementation
recommends elapse between subsequent calls to read_qr_code.
Implementations that have very expensive and/or slow detection code
may want to rate-limit read_qr_code calls by overriding this function.
e.g.: to make detection happen every 200ms, you would return 0.2 here.
Defaults to 0.0'''
return 0.0
@abstractmethod
def read_qr_code(self, buffer: ctypes.c_void_p,
buffer_size: int, # overall image size in bytes
rowlen_bytes: int, # the scan line length in bytes. (many libs, such as OSX, expect this value to properly grok image data)
width: int, height: int, frame_id: int = -1) -> List[QrCodeResult]:
"""
Reads a QR code from an image buffer in Y800 / GREY format.
Returns a list of detected QR codes which includes their data and positions.
"""