Before this, the spacers were handled as just another child widget, and
as such could take away space from real widgets when growing.
This also fixes the problem of effectively 0 sized spacers, that doubled
the spacing between the widgets they were placed between.
Previously, the layout algorithm preferred to give every item an equally
sized slice of the remaining space. This meant that not the entire area
was used when the remaining size did not divide evenly by the number of
items. This caused, for example, the ResizeCorner in HexEditor to be a
couple of pixels left of the actual corner for some sizes of the window.
Now, the remaining pixels are distributed on a first come, first served
basis. However, only one pixel is distributed at a time. This means
items towards the left might me a pixel larger than their siblings
towards the right.
This also moves Widget::load_from_json into Core::Object as a virtual
function in order to allow loading non-widget objects in GML (e.g.
BoxLayout).
Co-authored-by: Gunnar Beutner <gbeutner@serenityos.org>
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
While space distribution along the primary axis of a BoxLayout is
pretty sophisticated, the secondary axis is very simple: we simply
center the widget.
However, this doesn't always look very nice if we don't take margins
into account, so make sure we subtract them from the rect we do all
the centering within.
