While stretching camera bounds, changing width adds black offset while changing height stretches image.

How can I achieve opposite behavior and match the bounds to the width instead of height ?

![Stretching width][1]
![Original square][3]
![Stretching height][2]

[1]: https://i.sstatic.net/k39DMm.png
[2]: https://i.sstatic.net/N8HiLm.png
[3]: https://i.sstatic.net/gy0Oqm.png