Provide some forward declarations for types used in this file, to keep
the LSP happy and avoid errors if the caller happens not to include the
required header.

Signed-off-by: Simon Glass <sjg@chromium.org>

It is useful to be able to edit text, e.g. to allow the user to edit the
environment or the command-line arguments for the OS.

Add the beginnings of an implementation. Future work is needed to finish
this: keypress handling and scrolling. For now it just displays the
text.

Signed-off-by: Simon Glass <sjg@chromium.org>

In some cases it is useful to obtain more than just two bounding boxes
from a menu, e.g. to line up all descriptions vertically.

Use an array to obtain bounding-box information and calculate it
separately for each item.

Signed-off-by: Simon Glass <sjg@chromium.org>

At present menu items are stored according to their sequence number in
the menu. In some cases we may want to have holes in that sequence, or
not use a sequence at all.

Add a new 'value' property for menu items. This will be used for
reading and writing, if present. If there is no 'value' property, then
the normal sequence number will be used instead.

Signed-off-by: Simon Glass <sjg@chromium.org>

At present a fixed position is used for menu items, 200 pixels to the
right of the left side of the labels. This means that a menu item with
a very long label may overlap the items.

It seems better to calculate the maximum label width and then place the
items to the right of all of them.

To implement this, add a new struct to containing arrangement
information. Calculate it before doing the actual arrangement. Add a
new style item which sets the amount of space from the right side of
the labels to left side of the items.

Signed-off-by: Simon Glass <sjg@chromium.org>

Provide an implementation for textlines in the scene code, so that they
are displayed correctly. Provide a way to have a border around the
textline, with the internal part being the same colour as the
background. This looks more natural.

Signed-off-by: Simon Glass <sjg@chromium.org>

This object needs special handling when it is opened, to set up the CLI
and the vidconsole context. Add special support for this.

Signed-off-by: Simon Glass <sjg@chromium.org>

So far only menus have a background. When other object types are
rendered, they may have a background too. Make this code more generic
so it will be usable by new object types.

Signed-off-by: Simon Glass <sjg@chromium.org>

We want to support this for any object, not just menus. Move the code
around to allow this.

Signed-off-by: Simon Glass <sjg@chromium.org>

This internal function could use a comment. Add one.

Also tidy up a few other comments.

Signed-off-by: Simon Glass <sjg@chromium.org>

fixup: comments