Crash was caused by deferred invocation of a lambda on the SpinBox's
TextEditor widget's on_change. The lambda referenced the SpinBox ptr,
but in GML Playground the SpinBox was free'd before the deferred
lambda could run, causing a use-after-free error. Fixed by using
a weak ptr to detect if the SpinBox was free'd.
This is a helpful option to prevent unwanted side effects, distinguish
between user and programmatic input, etc. Sliders and SpinBoxes were
implementing it idiosyncratically, so let's generalize the API and
give Buttons and TextEditors the same ability.
These suffered the same visual defect as scrollbars when styled
as normal buttons: against backgrounds with the same color as
their highlighting, aspect was lost.
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 *
Prevents discrete values from being skipped when using the mouse
wheel on SpinBoxes and proportional Sliders. Wheel delta can be
accelerated by holding Ctrl.
(...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED)
Since all of these checks are done in release builds as well,
let's rename them to VERIFY to prevent confusion, as everyone is
used to assertions being compiled out in release.
We can introduce a new ASSERT macro that is specifically for debug
checks, but I'm doing this wholesale conversion first since we've
accumulated thousands of these already, and it's not immediately
obvious which ones are suitable for ASSERT.
