The graphics directory is a more suitable home for game assets.
Also, move card backs into their own subfolder in preparation for a
themes subfolder for card fronts.
Currently, the outside of the card highlight has rounded corners, but
the inside has square corners. It looks a bit more polished if they are
both rounded.
For example, in Solitaire, when dragging a card around, it's common for
other implementations to highlight the card underneath the dragged card
if that other card is a valid drop target. This implementation will draw
a rounded rectangle within the edges of the highlighted card, using a
rudimentary complementary color of the board background color.
We have a new, improved string type coming up in AK (OOM aware, no null
state), and while it's going to use UTF-8, the name UTF8String is a
mouthful - so let's free up the String name by renaming the existing
class.
Making the old one have an annoying name will hopefully also help with
quick adoption :^)
This was giving wonky results with images that do not fill the entire
card - and it's also unnecessary, since the Buggie image we have been
using, and the two I will be adding, are all small enough to not need
scaling anyway. :^)
`CardPainter::set_background_image_path()` immediately repaints the card
back and inverted card back bitmaps if they exist, so users just need
to `update()` that part of the screen. This is handled automatically by
`CardGame`, but other users will have to do this manually.
Instead of each card being responsible for painting its own bitmaps, we
now have a CardPainter which is responsible for this. It paints a given
card the first time it is requested, and then re-uses that bitmap when
requested in the future. This saves memory for duplicate cards (such as
in Spider where several sets of the same suit are used) or unused ones
(for example, the inverted cards which are only used by Hearts). It
also means we don't throw away bitmaps and then re-create identical
ones when starting a new game.
We get some nice memory savings from this:
| | Before | After | Before (Virtual) | After (Virtual) |
|:----------|---------:|---------:|-----------------:|----------------:|
| Hearts | 12.2 MiB | 9.3 MiB | 25.1 MiB | 22.2 MiB |
| Spider | 12.1 MiB | 10.1 MiB | 29.2 MiB | 22.9 MiB |
| Solitaire | 16.4 MiB | 9.0 MiB | 25.0 MiB | 21.9 MiB |
All these measurements taken from x86_64 build, from a fresh launch of
each game after the animation has finished, but without making any
moves. The Hearts value will go up once inverted cards start being
requested.
