Previously we only had `Point::end_point_for_square_aspect_ratio`,
which was convenient for PixelPaint but assumed the aspect ratio
was always fixed at 1. This patch replaces it with a new mthod that
takes in an arbitrary aspect ratio and computes the end point based
off that.
There's some explicit casting going on in `Point.cpp` to ensure that
the types line up, since we're templating Point based on `T`.`
This singleton simplifies many aspects that we struggled with before:
1. There's no need to make derived classes of Device expose the
constructor as public anymore. The singleton is a friend of them, so he
can call the constructor. This solves the issue with try_create_device
helper neatly, hopefully for good.
2. Getting a reference of the NullDevice is now being done from this
singleton, which means that NullDevice no longer needs to use its own
singleton, and we can apply the try_create_device helper on it too :)
3. We can now defer registration completely after the Device constructor
which means the Device constructor is merely assigning the major and
minor numbers of the Device, and the try_create_device helper ensures it
calls the after_inserting method immediately after construction. This
creates a great opportunity to make registration more OOM-safe.
Previously, attempting to call sys$waitid on non-child processes
returned ECHILD.
That prevented debugging non-child processes by attaching to them during
runtime (as opposed to forking and debugging the child, which is what
was previously supported).
We now allow calling sys$waitid on a any process that is being traced
by us, even if it's not our child.
See #10042 for details. In short: qemu doesn't seem to implement that
feature, therefore the test correctly fails. However, that does not help
us, so we skip that test.
In some cases, we were infinite-looping when asked to paint something
with a thickness of '0', so now every Painter method that takes a
thickness, does a check for a thickness <= 0 and bails early. After all,
you can't draw something that's 0px wide. :^)
In the spec, `fill` and `stroke` are supposed to be a shorthands for
various properties. But since the spec is still a working draft, and
neither Firefox or Chrome support the `fill-color` or `stroke-color`
properties, we'll stick with `fill` and `stroke` as simple colors for
now.
Also, note that SVG expects things in "user units", and we are assuming
that 1px = 1 user unit for now.
