blitting - rotated ? subtractive ?

[MichaelJPCT]

i wish blitting can be 90 degree rotated and can be subtractive in color.
rotated blitting can be used to mimic the rotation of screen without setting it from Android , and without using different textures.
subtractive color is easier to achieve dark text on light color background, without using different textures. ( i currently use textures with white text on black background and no alpha, additive makes the text look good on dark background)
are these possible?

[AeroShark333]

I think both are achievable using some workarounds.
The 90° rotated texture could be done using 3 ways:
1st: load the texture's bitmap 90° rotated
2nd: use Overlay to rotate the texture layer
3rd: use a blitting shader to draw your texture 90° rotated

For the subtractive color, I believe you'd need to use a blitting shader too

I'm not sure if a RenderTexture is needed for a blitting shader to work