Read grid from PDK

[bradley-w-snyder]

I added code to read the grid size from the PDK.

I also added some fixes here and there for snapping to the grid. These issues are more apparent when using grid sizes > 1 nm, For instance, when defining a rectangular grating coupler with 5 nm grid, if you have a 15 nm trench from x = 0 to x = 15, the midpoint was previously calculated as 7.5 nm, and then snapped to the grid at x = 5 or x = 10, and then the whole trench was shifted.

There are also some random defaults fixes.

I had some commits to also snap the ports, but this actually makes less sense since they are not physical on the mask. So for a waveguide of 15 nm wide with the port in the middle at 7.5, this should not be snapped since the connecting waveguide will still have mask points at 0 and 15. Therefore, I did not include these changes.

All changes are cherry-picked from my master.

[sourcery-ai]

Sourcery Code Quality Report

❌  Merging this PR will decrease code quality in the affected files by 0.01%.

Quality metrics	Before	After	Change
Complexity	9.84 🙂	9.86 🙂	0.02 👎
Method Length	90.56 🙂	90.64 🙂	0.08 👎
Working memory	12.68 😞	12.66 😞	-0.02 👍
Quality	58.03% 🙂	58.02% 🙂	-0.01% 👎

Other metrics	Before	After	Change
Lines	6714	6745	31

Changed files	Quality Before	Quality After	Quality Change
gdsfactory/component.py	68.58% 🙂	68.45% 🙂	-0.13% 👎
gdsfactory/cross_section.py	49.47% 😞	49.47% 😞	0.00%
gdsfactory/path.py	37.70% 😞	38.37% 😞	0.67% 👍
gdsfactory/port.py	61.65% 🙂	61.66% 🙂	0.01% 👍
gdsfactory/snap.py	84.46% ⭐	82.81% ⭐	-1.65% 👎
gdsfactory/types.py	63.32% 🙂	63.32% 🙂	0.00%
gdsfactory/components/init.py	30.74% 😞	30.68% 😞	-0.06% 👎
gdsfactory/components/bend_circular.py	55.35% 🙂	55.35% 🙂	0.00%
gdsfactory/components/grating_coupler_elliptical.py	41.85% 😞	42.42% 😞	0.57% 👍
gdsfactory/components/grating_coupler_rectangular_arbitrary.py	40.25% 😞	40.57% 😞	0.32% 👍
gdsfactory/components/taper_cross_section.py	75.69% ⭐	73.00% 🙂	-2.69% 👎
gdsfactory/geometry/boolean.py	40.15% 😞	39.60% 😞	-0.55% 👎
gdsfactory/geometry/functions.py	70.42% 🙂	70.42% 🙂	0.00%
gdsfactory/read/from_picwriter.py	64.89% 🙂	64.22% 🙂	-0.67% 👎
gdsfactory/routing/get_route_from_steps.py	61.32% 🙂	61.32% 🙂	0.00%

Here are some functions in these files that still need a tune-up:

File	Function	Complexity	Length	Working Memory	Quality	Recommendation
gdsfactory/path.py	extrude	89 ⛔	1028 ⛔	28 ⛔	1.52% ⛔	Refactor to reduce nesting. Try splitting into smaller methods. Extract out complex expressions
gdsfactory/path.py	transition	28 😞	360 ⛔	20 ⛔	16.55% ⛔	Refactor to reduce nesting. Try splitting into smaller methods. Extract out complex expressions
gdsfactory/geometry/boolean.py	boolean	32 😞	354 ⛔	16 ⛔	18.00% ⛔	Refactor to reduce nesting. Try splitting into smaller methods. Extract out complex expressions
gdsfactory/cross_section.py	pn	7 ⭐	484 ⛔	43 ⛔	27.12% 😞	Try splitting into smaller methods. Extract out complex expressions
gdsfactory/cross_section.py	pn_ge_detector_si_contacts	7 ⭐	463 ⛔	45 ⛔	27.23% 😞	Try splitting into smaller methods. Extract out complex expressions

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• ⛔ very poor

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[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
2.3% Duplication

[joamatab]

Looks great, thank you Brad, releasing 5.34.0 with your improvements