feat: add QIcon backed by iconify

[tlambert03]

Iconify is a pretty great API unifying pretty much all of the major font-icon libraries into a single API from which you can request standardized SVGs. I wrapped the API in library pyconify that makes it easier to work with in python, and caches all svgs locally for faster/offline usage (after first using online once). This PR makes a simple QIcon wrapper:

from qtpy.QtCore import QSize
from qtpy.QtWidgets import QApplication, QPushButton

from superqt import QIconifyIcon

app = QApplication([])

btn = QPushButton()
# search https://icon-sets.iconify.design for available icon keys
btn.setIcon(QIconifyIcon("fa:smile-o", color="blue"))
btn.setIconSize(QSize(60, 60))
btn.show()

app.exec()

A downside of using this is that it's SVG based, which makes it a bit harder than font libraries to change colors simply using style sheets (like napari does for its themes... though even that may be possible). A big upside is that you no longer need to include the whole font-family file just to grab a couple icons, and you can pick and choose from all of the libraries without having to bring in a new plugin for each one. Also, for reasons beyond just color changing, SVGs are preferable in many cases to fonts (animations are possible, for example)

[codecov]

Codecov Report

All modified lines are covered by tests ✅

Comparison is base (65a4a6e) 87.38% compared to head (3426f3d) 87.42%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #209      +/-   ##
==========================================
+ Coverage   87.38%   87.42%   +0.03%     
==========================================
  Files          45       46       +1     
  Lines        3346     3356      +10     
==========================================
+ Hits         2924     2934      +10     
  Misses        422      422              

Files	Coverage Δ
src/superqt/__init__.py	91.30% <100.00%> (+0.39%)	⬆️
src/superqt/fonticon/__init__.py	88.88% <ø> (ø)
src/superqt/iconify/__init__.py	100.00% <100.00%> (ø)

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[Czaki]

It looks ok. Few minor remarks.

Did you plan to ship pyconify to conda?|

Why not allow to cache icons svg between sessions?

[tlambert03]

Why not allow to cache icons svg between sessions?

They are cached between sessions:
https://github.com/pyapp-kit/pyconify#cache

The main difference between temp_svg and svg is that temp_svg returns a file path and svg returns bytes. But they both use the same persistent cache

yes I’ll put it on conda

[Czaki]

Hm. Did you try to play with QIconEngine? Qt documentation suggest that it could be used to render svg without need to load it from drive.

[tlambert03]

Did you try to play with QIconEngine? Qt documentation suggest that it could be used to render svg without need to load it from drive.

Yep, I did quite a bit. I originally started with a similar strategy to what i did in napari: https://github.com/napari/napari/blob/main/napari/_qt/qt_resources/_svg.py

However, after looking into more in this round, I'm less of a fan of that approach. If you look into the c++ code of the builtin QIconEngine, you'll find that it actually does quite a bit more than a naive approach might, it handles caching of pixmaps for various sizes, and better handles rendering svgs for different states (enabled/disabled, active/inactive). So, after a fair amount of experimentation, I decided that simply writing a file to disk and letting the builtin QIconEngine handle it is well worth the cost. It still all loads in about 10µs (after the original caching from the API), so it's hardly a performance limitation. And there's a large amount of code that no longer needs to be maintained. So that's why I went with this approach.

I will, however, update pyconify to be able to give you the path to the actual cached file in the pyconify cache (rather than this current approach, which costs one additional local file copy from the pyconify cache to the tempdir)

[tlambert03]

@Czaki, will likely merge this soon. Would welcome your thoughts on QIconEngine, specifically, I'm curious what specifically you expect/hope would be gained by using it. with the current implementation, there is only one disk read (from the pyconify) cache (which is also significantly faster than the time to fetch from the pyconify API on the first retrieval). So I expect it will be both performant and take advantage of all of the extra goodies provided by the default QIconEngine (not to mention it's less code to maintain)

[Czaki]

As far as I check the svg_path is improperly uses cache. I have created PR to fix this: pyapp-kit/pyconify#5

I have two small remarks (one typo, and one for test). But general image is good.

[tlambert03]

thanks @Czaki!

merged your PR, and bumped the dependency here.