Last two weeks evenings I spent programming in python. No, let’s start from the beginning: some weeks ago I conducted some tests with an oscilloscope, and we have a lovely old app to copy and annotate screenshots. But this app has some annoying bugs, and some functions simply don’t work.<\/p>\n\n\n\n
So, the last two weeks evenings I spent programming in python. Writing new, better, feature-rich, app. And fixing the most annoying bugs.<\/p>\n\n\n\n
On this way, I learned some new things, and want to document these learnings.<\/p>\n\n\n\n\n\n\n\n
I started cleaning up my zoo from different and outdated python versions and packets, installing fresh Visual Studio Code and python 3.11.1, and installing fresh packets. One of the reasons – the old pyinstaller generated .exe with a size >300Mb. So, after updated everything, the resulting .exe was only 25Mb.<\/p>\n\n\n\n
I quickly programmed a simple flask server to mock the oscilloscope features, it helped a lot to debug features.<\/p>\n\n\n\n
After many hundreds of lines of code, I was ready to test first prototype on the lab PC. And first fail – “no DLL, fatal error, …” A lot of googling, some misleading links, and the root of the problem – python 3.11 doesn’t run on Windows 7. Installation of python 3.7.9 solved the problem.<\/p>\n\n\n\n
And I learned a bit about virtual environments, I should’ve done it a long time ago!<\/p>\n\n\n\n
One of the problems for each widget, for any event you can bind only one command. <\/p>\n\n\n\n
For example, I wanted for Button <Enter> event to display the tooltip and highlight the corresponding entry fields.<\/p>\n\n\n\n
Of course, if you need two commands, you can use bind one function, which calls two others. I wanted a more elegant solution.<\/p>\n\n\n\n
class Events():\n '''events.bind(widget, event, command) #repeat as much as you need'''\n def __init__(self):\n self._events = {}\n def bind(self, widget, event, command):\n if not widget in self._events:\n self._events[widget] = {}\n if not event in self._events[widget]:\n self._events[widget][event] = {command}\n else:\n self._events[widget][event].add(command)\n \n widget.bind(event, lambda *args: self.run(widget, event, *args))\n def run(self, widget, event, *args):\n for cmd in self._events[widget][event]:\n cmd(*args)\n\nevents = Events()\n\n#########################\n\n# instead of:\nwidget.bind('<Event>', command)\n# use:\nevents.bind(widget, '<Event>', command1)\nevents.bind(widget, '<Event>', command2)<\/pre>\n\n\n\nThis class creates dict of a widget, with dicts of a assigned events, with sets of a assigned commands; and binds a lambda for function, to iterate through the commands. Simple and elegant.<\/p>\n\n\n\n
And I found an amazing ascii-text generator:<\/p>\n\n\n\n
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