Momento

Please add an option that makes slice/all slices document size.
I usually work with a lot of layers that have to be exported to HitFilm for animation
When slices are created; i have to resize each one of them to fit the document size (fullHD)
They cant all be selected to type the transformation, so i have to do the one by one (100+ layers)

@Ushur,
You can do at least the first three already using the move tool after making your selection.
To set the rotation point, turn on the "Enable Transform Origin" button on the context toolbar, then drag it to where you want the rotation to anchor.  To use that same point to scale around, hold down the command key (on Mac - if you are using the other platform check the status bar for what key to use) while dragging one of the handles.
Depending on what you mean by distortion, if your selection is not an entire layer try Layer -> Duplicate Layer to make it into one, then try either the Mesh Warp Tool or the Perspective Tool; one of those might do what you want?

From Wikipedia:
"In July 2017, Adobe announced[15] that it would end support for Flash Player at the end of 2020, and continued to encourage the use of open HTML5 standards in place of Flash.[16][17] The announcement was coordinated with Apple,[18] Facebook,[19] Google,[20] Microsoft,[21] and Mozilla.[22]"

Hi Miguel-2011,
Welcome to Affinity Forums :)
Currently it's not possible to create a selection from its center in Affinity Photo. A way to work around this is to draw a rectangular shape pressing ⌘ (cmd) to create it from its center, then press ⌘ (cmd) + ↵ (Enter) to convert it to Curves, change to the Pen Tool and click the Selection button in the context toolbar to convert it to a selection.

Hi Miguel-2011
 
Welcome to the forums
 
Currently we do not have this functionality for the pixel selection tools but it is a great feature to have. Therefore im moving this post to the feature requests section to be considered
 
Cheers