[PyQt] QMacPasteboardMime

[Phil Thompson]

On 16 Jul 2018, at 5:58 pm, Michael Herrmann <michael at herrmann.io> wrote:
> 
> Hi all,
> 
> I'm trying to work around QTBUG-61562: On Mac, this bug prepends invisible Unicode characters to the clipboard when copy/pasting.
> 
> The class QMacPasteboardMime lets one customize copy/pasting on Mac. I created a subclass of it, which does get picked up by Qt. However, the crucial methods canConvert(...) and convertFromMime(...) aren't called. Only the more preliminary convertorName() and flavorFor(...) of my subclass are invoked.
> 
> Does anyone have experience with this? Here is my code, adapted from a solution posted in the discussion of QTBUG-61652:
> 
> from PyQt5.QtMacExtras import QMacPasteboardMime
> 
> class MyMime(QMacPasteboardMime):
>     def __init__(self):
>         super().__init__(QMacPasteboardMime.MIME_CLIP)
>     def convertorName(self):
>         return 'UnicodeTextUtf8Default'
>     def flavorFor(self, mime):
>         if mime == 'text/plain':
>             return 'public.utf8-plain-text'
>         i = mime.find('charset=')
>         if i >= 0:
>             charset = mime[i + len('charset='):]
>             charset = charset.split(';', 1)[0]
>             if charset == 'system':
>                 return 'public.utf8-plain-text'
>             if charset in ('iso-10646-ucs-2', 'ut16'):
>                 return 'public.utf16-plain-text'
>         return None
>     def canConvert(self, mime, flav):
>         return mime.startswith('text/plain') and \
>             flav in ('public.utf8-plain-text', 'public.utf16-plain-text')
>     def mimeFor(self, flavor):
>         if flavor == 'public.utf8-plain-text':
>             return 'text/plain'
>         if flavor == 'public.utf16-plain-text':
>             return 'text/plain;charset=utf16'
>         return None
>     def convertToMime(self, mimetype, data, flavor):
>         if len(data) > 1:
>             raise ValueError('Cannot handle multiple member data')
>         first, = data
>         if flavor == 'public.utf8-plain-text':
>             return first.decode('utf-8')
>         if flavor == 'public.utf16-plain-text':
>             return first.decode('utf-16')
>         raise ValueError('Unhandled MIME type: ' + mimetype)
>     def convertFromMime(self, mime, data, flavor):
>         string = data.toString()
>         if flavor == 'public.utf-8.plain-text':
>             return string.encode('utf-8')
>         if flavor == 'public.utf16-plain-text':
>             return string.encode('utf-16')
>         return b''
> 
> As I said, flavorFor(...) gets called with 'text/plain'. And convertorName() gets called. But not canConvert(...) and convertFromMime(...).

A small, complete example would help.

Phil