Fix Surface.draw_texture (#1705)

[pushfoo]

Closes#1705

Changes

• arcade.gui.Surface.draw_texture now raises NotImplementedError when alpha != 255 or angle != 0.
• Added test

How to test

Run test suite as normal

Retained for context

I have the logic corrected, but there are two questions I need answered:

1. Is support for position implemented? One comment says it is, while another gives me the impression it isn't. Updated per comments
2. Is using the window fixture acceptable in tests/unit? If not, should I build out a new mock_window fixture to fully or partially mock the gl context + window? Implemented. I'd prefer to decouple this better, but it won't get us closer to 3.0.

[eruvanos]

@pushfoo
hi,

to 1.

Please remove the exception, it is implemented and we should support it.

TL;DR

I see the confusion :D
NinePatchTextures do support positioning. So in a general sense, we would be able to use it to render the NinePatchTexture in some specific place.

The big drawback is, that in the normal flow, a widgets sets the viewport and scissor box to its rect.
In combination, any other value then 0,0 for position would mostly move it out of the scissor box.

So in general speak, the Exception is wrong, NinePatch does support a position, but we had the exception, because we wanted to prevent devs to use it in the wrong way.

So I change my opinion:
we should support this feature of NinePatchTexture and remove the overprotective restriction.

[eruvanos]

Regarding 2.
Yes, window fixture is used in many places in unit test. You are good to go

[eruvanos]

Thanks