Classical condition boxes are now drawn as bullets in text drawer

[TharrmashasthaPV]

Summary

Fixes #6290 .

Details and comments

In this PR, the classical condition boxes are replaced with open and close bullets when cregbundle=False. This ensures that the text drawer drawings of classical conditioned gates are consistent with that of the latex and mpl drawers.

For instance, the example circuit given in #6290 is now drawn as

Update:
As it was suggested in the comment, the conditional value is also drawn along with the circuit. It looks like the following

     ┌───┐
q_0: ┤ H ├
     └─╥─┘
q_1: ──╫──
       ║  
c_0: ══o══
       ║  
c_1: ══■══
       =2 

Also the existing tests have been modified and new tests have been added.

[1ucian0]

This is great! Can we still keep the hex representation of the condition?

     ┌───┐
q_0: ┤ H ├
     └─╥─┘
q_1: ──╫──
       ║  
c_0: ──o──
       ║  
c_1: ──■──
      0x2

Like MPL:

[TharrmashasthaPV]

This is great! Can we still keep the hex representation of the condition?

     ┌───┐
q_0: ┤ H ├
     └─╥─┘
q_1: ──╫──
       ║  
c_0: ──o──
       ║  
c_1: ──■──
      0x2

Like MPL:

Hey @1ucian0 . I was actually unable to give the condition value as '0x2' as that would require a significant amount of code change. However, in the new circuit diagram the condition values are given as '=2'. I suppose that is fine.

[enavarro51]

@TharrmashasthaPV #5938 fixes a problem with condition bits not reordering when reverse_bits is set. This was not addressed for the text drawer, because it wasn't showing the condition bits. Now that your PR fixes that, the reverse_bits issue should be addressed, either here or in a new issue. The fix is fairly simple

• In circuit_visualization.py, pass reverse_bits to the text drawer.
• In the text drawer __init__ add self._reverse_bits = reverse_bits
• In set_cond_bullets, your current line 1474 could change to

vlist = list(val) if self._reverse_bits else list(val[::-1])

[1ucian0]

Dont forget the reno!

[TharrmashasthaPV]

@TharrmashasthaPV #5938 fixes a problem with condition bits not reordering when reverse_bits is set. This was not addressed for the text drawer, because it wasn't showing the condition bits. Now that your PR fixes that, the reverse_bits issue should be addressed, either here or in a new issue. The fix is fairly simple

• In circuit_visualization.py, pass reverse_bits to the text drawer.
• In the text drawer __init__ add self._reverse_bits = reverse_bits
• In set_cond_bullets, your current line 1474 could change to

vlist = list(val) if self._reverse_bits else list(val[::-1])

Sorry @enavarro51 . I missed your comment somehow. Sure, I will fix that. Just to keep things a bit simple, I will push that as a different PR. Thanks a lot for pointing this out!!!

[1ucian0]

Let me know when you add the @enavarro51 fix . Once done, I think it will be ready to go.

[TharrmashasthaPV]

Hi @1ucian0 . I have added the fix for the reverse_bits as suggested by @enavarro51 . I have also added two tests. I think it is now ready to go.

[1ucian0]

Thanks Tharrma!

[TharrmashasthaPV]

I had to push a new commit since there were some conflicts with main. I have resolved the conflicts. The changes were minor. I guess this PR needs a re-review. Sorry for the inconvenience.

[javabster]

This LGTM 🚀 @1ucian0 thoughts?

[1ucian0]

Thanks!