Description
Describe the bug
As title explain, ProgressBar widget on Windows doesn't support alpha color and raise an exception when set to transparent. To avoid this, the widget class should declare _background_supports_alpha = False
Steps to reproduce
Simply create a Progress bar with TRANSPARENT background.
Expected behavior
Should not raise an exception.
Screenshots
No response
Environment
- Operating System: Windows
- Python version: 3.10
- Software versions:
- Briefcase: NA
- Toga: 0.4.2
- ...
Logs
self._applicator.set_background_color(value)
File "c:\Users\vmtest\Documents\minarca-agent\.venv\lib\site-packages\toga\style\applicator.py", line 51, in set_background_color
self.widget._impl.set_background_color(color)
File "c:\Users\vmtest\Documents\minarca-agent\.venv\lib\site-packages\toga_winforms\widgets\base.py", line 132, in set_background_color
self.native.BackColor = win_color
System.ArgumentException: Control does not support transparent background colors.
at System.Windows.Forms.Control.set_BackColor(Color value)
Additional context
No response