149 lines
4.1 KiB
Python
149 lines
4.1 KiB
Python
''' Kivy Widget that accepts data and displays qrcode
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'''
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from threading import Thread
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from functools import partial
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import qrcode
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from kivy.uix.floatlayout import FloatLayout
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from kivy.graphics.texture import Texture
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from kivy.properties import StringProperty
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from kivy.properties import ObjectProperty, StringProperty, ListProperty,\
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BooleanProperty
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from kivy.lang import Builder
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from kivy.clock import Clock
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Builder.load_string('''
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<QRCodeWidget>
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canvas.before:
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# Draw white Rectangle
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Color:
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rgba: root.background_color
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Rectangle:
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size: self.size
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pos: self.pos
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canvas.after:
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Color:
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rgba: root.foreground_color
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Rectangle:
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size: self.size
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pos: self.pos
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Image
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id: qrimage
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pos_hint: {'center_x': .5, 'center_y': .5}
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allow_stretch: True
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size_hint: None, None
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size: root.width * .9, root.height * .9
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''')
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class QRCodeWidget(FloatLayout):
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data = StringProperty(None, allow_none=True)
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background_color = ListProperty((1, 1, 1, 1))
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foreground_color = ListProperty((0, 0, 0, 0))
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#loading_image = StringProperty('gui/kivy/theming/loading.gif')
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def __init__(self, **kwargs):
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super(QRCodeWidget, self).__init__(**kwargs)
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self.data = None
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self.qr = None
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self._qrtexture = None
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def on_data(self, instance, value):
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print "on data", value
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if not (self.canvas or value):
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return
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img = self.ids.get('qrimage', None)
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if not img:
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# if texture hasn't yet been created delay the texture updation
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Clock.schedule_once(lambda dt: self.on_data(instance, value))
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return
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#Thread(target=partial(self.update_qr, )).start()
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self.update_qr()
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def set_data(self, data):
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print "set data", data
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if self.data == data:
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return
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MinSize = 210 if len(data) < 128 else 500
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self.setMinimumSize((MinSize, MinSize))
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self.data = data
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self.qr = None
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def update_qr(self):
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if not self.data and self.qr:
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return
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L = qrcode.constants.ERROR_CORRECT_L
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data = self.data
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self.qr = qr = qrcode.QRCode(
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version=None,
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error_correction=L,
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box_size=10,
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border=0,
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)
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qr.add_data(data)
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qr.make(fit=True)
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self.update_texture()
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def setMinimumSize(self, size):
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# currently unused, do we need this?
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self._texture_size = size
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def _create_texture(self, k, dt):
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self._qrtexture = texture = Texture.create(size=(k,k), colorfmt='rgb')
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# don't interpolate texture
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texture.min_filter = 'nearest'
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texture.mag_filter = 'nearest'
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def update_texture(self):
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if not self.qr:
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return
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matrix = self.qr.get_matrix()
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k = len(matrix)
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# create the texture in main UI thread otherwise
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# this will lead to memory corruption
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Clock.schedule_once(partial(self._create_texture, k), -1)
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buff = []
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bext = buff.extend
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cr, cg, cb, ca = self.background_color[:]
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cr, cg, cb = cr*255, cg*255, cb*255
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for r in range(k):
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for c in range(k):
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bext([0, 0, 0] if matrix[r][c] else [cr, cg, cb])
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# then blit the buffer
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buff = ''.join(map(chr, buff))
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# update texture in UI thread.
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Clock.schedule_once(lambda dt: self._upd_texture(buff), .1)
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def _upd_texture(self, buff):
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texture = self._qrtexture
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if not texture:
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# if texture hasn't yet been created delay the texture updation
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Clock.schedule_once(lambda dt: self._upd_texture(buff), .1)
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return
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texture.blit_buffer(buff, colorfmt='rgb', bufferfmt='ubyte')
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img =self.ids.qrimage
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img.anim_delay = -1
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img.texture = texture
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img.canvas.ask_update()
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if __name__ == '__main__':
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from kivy.app import runTouchApp
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import sys
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data = str(sys.argv[1:])
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runTouchApp(QRCodeWidget(data=data))
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