前几天，我估摸着做一个能生成QR Code小程序，并能用wxPython在屏幕上显示出来。当然，我想用纯Python实现，观望了一会后，我找到了三个候选：
github 上的 python-qrcode
sourceforge上的 pyqrcode
Goolge code 上的 pyqrnative
我尝试了python-qrcode以及pyqrnative，因为它们能够运行在Windows/Mac/Linux。也不需要依赖额外的其他库除了Python图像库。pyqrcode项目需要其他一些先决条件，并且不能在Windows上运行，所以我不想与之纠缠了。我最后使用了一些以前写过的一个Photo Viewer程序的代码，然后稍微地修改了一下，就成了QRCode的查看器了。
开始
正如我上面提到的，你只需要Python图像库，GUI部分我们将使用wxPython。python-qrcode相比pyqrnative生成图片更快，并包含了你见过的大多数QR码类型。
生成 QR Codes
当你准备好所有需要的以后，你可以运行以下代码，看看Python做了些啥：
import os
import wx
try:
import qrcode
except ImportError:
qrcode = None
try:
import PyQRNative
except ImportError:
PyQRNative = None
########################################################################
class QRPanel(wx.Panel):
""""""
#----------------------------------------------------------------------
def __init__(self, parent):
"""Constructor"""
wx.Panel.__init__(self, parent=parent)
self.photo_max_size = 240
sp = wx.StandardPaths.Get()
self.defaultLocation = sp.GetDocumentsDir()
img = wx.EmptyImage(240,240)
self.imageCtrl = wx.StaticBitmap(self, wx.ID_ANY,
wx.BitmapFromImage(img))
qrDataLbl = wx.StaticText(self, label="Text to turn into QR Code:")
self.qrDataTxt = wx.TextCtrl(self, value="http://www.mousevspython.com", size=(200,-1))
instructions = "Name QR image file"
instructLbl = wx.StaticText(self, label=instructions)
self.qrPhotoTxt = wx.TextCtrl(self, size=(200,-1))
browseBtn = wx.Button(self, label='Change Save Location')
browseBtn.Bind(wx.EVT_BUTTON, self.onBrowse)
defLbl = "Default save location: " + self.defaultLocation
self.defaultLocationLbl = wx.StaticText(self, label=defLbl)
qrcodeBtn = wx.Button(self, label="Create QR with qrcode")
qrcodeBtn.Bind(wx.EVT_BUTTON, self.onUseQrcode)
pyQRNativeBtn = wx.Button(self, label="Create QR with PyQRNative")
pyQRNativeBtn.Bind(wx.EVT_BUTTON, self.onUsePyQR)
# Create sizer
self.mainSizer = wx.BoxSizer(wx.VERTICAL)
qrDataSizer = wx.BoxSizer(wx.HORIZONTAL)
locationSizer = wx.BoxSizer(wx.HORIZONTAL)
qrBtnSizer = wx.BoxSizer(wx.VERTICAL)
qrDataSizer.Add(qrDataLbl, 0, wx.ALL, 5)
qrDataSizer.Add(self.qrDataTxt, 1, wx.ALL|wx.EXPAND, 5)
self.mainSizer.Add(wx.StaticLine(self, wx.ID_ANY),
0, wx.ALL|wx.EXPAND, 5)
self.mainSizer.Add(qrDataSizer, 0, wx.EXPAND)
self.mainSizer.Add(self.imageCtrl, 0, wx.ALL, 5)
locationSizer.Add(instructLbl, 0, wx.ALL, 5)
locationSizer.Add(self.qrPhotoTxt, 0, wx.ALL, 5)
locationSizer.Add(browseBtn, 0, wx.ALL, 5)
self.mainSizer.Add(locationSizer, 0, wx.ALL, 5)
self.mainSizer.Add(self.defaultLocationLbl, 0, wx.ALL, 5)
qrBtnSizer.Add(qrcodeBtn, 0, wx.ALL, 5)
qrBtnSizer.Add(pyQRNativeBtn, 0, wx.ALL, 5)
self.mainSizer.Add(qrBtnSizer, 0, wx.ALL|wx.CENTER, 10)
self.SetSizer(self.mainSizer)
self.Layout()
#----------------------------------------------------------------------
def onBrowse(self, event):
""""""
dlg = wx.DirDialog(self, "Choose a directory:",
style=wx.DD_DEFAULT_STYLE)
if dlg.ShowModal() == wx.ID_OK:
path = dlg.GetPath()
self.defaultLocation = path
self.defaultLocationLbl.SetLabel("Save location: %s" % path)
dlg.Destroy()
#----------------------------------------------------------------------
def onUseQrcode(self, event):
"""
https://github.com/lincolnloop/python-qrcode
"""
qr = qrcode.QRCode(version=1, box_size=10, border=4)
qr.add_data(self.qrDataTxt.GetValue())
qr.make(fit=True)
x = qr.make_image()
qr_file = os.path.join(self.defaultLocation, self.qrPhotoTxt.GetValue() + ".jpg")
img_file = open(qr_file, 'wb')
x.save(img_file, 'JPEG')
img_file.close()
self.showQRCode(qr_file)
#----------------------------------------------------------------------
def onUsePyQR(self, event):
"""
http://code.google.com/p/pyqrnative/
"""
qr = PyQRNative.QRCode(20, PyQRNative.QRErrorCorrectLevel.L)
qr.addData(self.qrDataTxt.GetValue())
qr.make()
im = qr.makeImage()
qr_file = os.path.join(self.defaultLocation, self.qrPhotoTxt.GetValue() + ".jpg")
img_file = open(qr_file, 'wb')
im.save(img_file, 'JPEG')
img_file.close()
self.showQRCode(qr_file)
#----------------------------------------------------------------------
def showQRCode(self, filepath):
""""""
img = wx.Image(filepath, wx.BITMAP_TYPE_ANY)
# scale the image, preserving the aspect ratio
W = img.GetWidth()
H = img.GetHeight()
if W > H:
NewW = self.photo_max_size
NewH = self.photo_max_size * H / W
else:
NewH = self.photo_max_size
NewW = self.photo_max_size * W / H
img = img.Scale(NewW,NewH)
self.imageCtrl.SetBitmap(wx.BitmapFromImage(img))
self.Refresh()
########################################################################
class QRFrame(wx.Frame):
""""""
#----------------------------------------------------------------------
def __init__(self):
"""Constructor"""
wx.Frame.__init__(self, None, title="QR Code Viewer", size=(550,500))
panel = QRPanel(self)
if __name__ == "__main__":
app = wx.App(False)
frame = QRFrame()
frame.Show()
app.MainLoop()
python-qrcode生成效果图：
PyQRNative生成效果图：
