Use 'ALPHA' instead 'ALPHA_PREMULT'.

And take advantage of using 2D coordinates instead of 3D.

See D16030 for details.

* AMTH_NODE_OT_show_active_node_image in Node Editor
* AMTH_VIEW3D_OT_render_border_camera in 3D Viewport

"Add/Remove nested from selection" was inverting the selection for the
branch instead of adding or removing.  This fixes it to behave similarly
to toggling nested RTOs.

Bring back the auto-generated block delimiters
Also: sort unregister() in reverse order to register()

Revert part of rBAad1966474ed2 in nw_check() which was giving no benefit
afaict (and instead tried to access space.node_tree for Spaces other
than the Node Editor, spamming the console with errors).

Differential Revision: https://developer.blender.org/D15770

glTF exporter: do not bake selected skinned meshes, as glTF transforms must be ignored on skinned meshes

A variety of operators were missing appropriate bl_options for correct
undo support.

This results in either crashes (auto loft, bi-rail) or other odd
behaviors around returning the scene to the correct previous state
(sometimes having to hit ctrl-z twice to undo once, sometimes undo skips
steps, etc.)

Differential Revision: https://developer.blender.org/D13283

Add guards to the functions triggered by checkbox updates
in the preferences.  This prevents them from being called
multiple times, such as when the mouse is hovered over
the checkbox and the backspace key is repeatedly pressed.

glTF exporter: performance: cache parent/children data to avoid bad .children performance when used a lot
Thanks rotoglup!

Ref D15432

Currently, the nodes in the Switch menu (Shift+S) are generated from Node
Wrangler's own long static list of categories and nodes, which often goes
out of sync when Blender changes.

This changes to using the node_categories_iter utility which uses the correct
list of available nodes from nodeitems_builtins.py.

The submenu classes are now procedurally generated and registered in the same
fashion as the add menu, but just with a different operator in their draw
function.

Removing the static lists required a couple changes outside of the Switch menu.
Mostly having to compare types using the verbose node.rna_type.identifier.

Includes improvements on the original patch by Benni Merz.

No need to subtract scroll bar widths as they are hidden by default in 2.80+.

The Operator is internally called "Swap Links" and the manual also calls it
"Swap Links" as it can swap inputs and outputs.

Differential Revision: https://developer.blender.org/D10031

Add utility function to check for the first output that is actually enabled
rather than always using the first output of a node.

The previous behavior would lead to confusing situations, where a mix/math
node was added but didn't seem to be connected, when the first output was
currently disabled.

Differential Revision: https://developer.blender.org/D14251

* The added nodes are now top aligned with the nodes they belong to. This looks
  nicer and works independent of screen DPI.
* There is a vertical offset based on the socket the added nodes are connected
  to. This prevents nodes from overlapping too much, when executing the texture
  setup several times in a row.
* Ignore disabled sockets, which would create nodes seemingly connected to
  nothing.

Differential Revision: https://developer.blender.org/D15031

Both the "Libraries" panel and the "Current Blend's Folder" button are
meant for the File Browser editor, not the Asset Browser.

Fixes T94212

The regular Save operator does not automatically save changes in images,
users become aware of this when quitting Blender or changing files.

This became a problem for the Save/Reload operator since you'd lose work
without noticing it. This commit adds a check and let the user now in the
terminal which image files have not been saved.

Fixes T73905

Related to T98252

The code was looking for background images in the 3D Viewport, which have
been moved to Camera objects in 2.8.

Fixes T98252

Based on suggestion from D13223, but applied a different fix.

Feature removed in rBAb56a6acb9f4f.