This can perform arbitrary channel mixing between two images.
Alpha blend & maximum functions are demonstrated in the test.
However, it should make most of the usual photo editing blends
possible. (for dissolve, fill a mask bitmap with random values,
which may be expensive to do from circuitpython code; we can
specifically accelerate it if we need to)
The get, set and del item methods didn't correctly lookup the value
from the parent native instance because the functions took the type
from the instance.
Fixes#8758
morph9 is a form of morph which performs 9 different convolutions,
like a version of mix where each coefficient is a (2n+1)x(2n+1) matrix.
Most use cases are covered by morph-then-mix, but some advanced operations
may be more efficient to implement via morph9.
This allows operations between channels in an image. It can be used for
the following use cases:
* Conversion to B&W or sepia
* Adding color casts
* Mixing or swapping arbitrary channels
* Inverting or scaling arbitrary channels
bitmapfilter.morph is taken from openmv's imlib.
It is substantially faster than blur/sharpen implemented in ulab,
by up to 10x. It also avoids making many allocations.
This function in standard Python is a building block for custom REPLs:
```python
from codeop import compile_command
print("Repl in (Circuit-)Python")
ns = {}
PS1="<<< "
PS2=",,, "
command = ""
while True:
line = input(PS2 if command else PS1)
if command:
command = command + "\n" + line
else:
command = line
try:
if (code := compile_command(command)):
command = ""
exec(code, ns)
except Exception as e:
command = ""
print(e)
```
Previously, negative amplitudes were clamped to zero.
Now, they are allowed to range from -ALMOST_ONE to +ALMOST_ONE.
This is useful in certain circumstances, such as using synthio
to create CV-like outputs that can be positive or negative, by
using the amplitude property of the note.
