Select Instances by region

[DanBThom]

Thank you for KFactory, the fill_tiled function is quick and useful. I would like to fill_tiled a polygon, and then use another polygon (which is a subset of the original polygon) or region to select the portion of tiled instances that fall within this polygon. The purpose of such is to change the pointer/instance to a different cell, so that the grid is constant across the larger polygon, but the geometry can change. This would have an application of augmented reality waveguides.

[sebastian-goeldi]

Hello,

Let me think a bit on how to do this. It is definitely possible, but might needs to have some pieces exposed.

But first let me ask a few guestions:

• Are you trying to fill a user generated polygon or are you trying to fill an extracted area?
• Is the polygon very complex or rather simple (think rectangle vs patches of random polygons to fill)

If it's rather a simple polygon and is user generated, you should probably directly use kf.kdb.Region.fill_region or kf.kdb.Region.fill_region_multi.

Otherwise, let me know and I might be able to expose the right parameter to enable user setting (it will most likely be the origin, but we need to check that multi is disabled)

[DanBThom]

Hi Sebastian, thanks for your response.

1. User generated polygons. So that a designer can modify the polygon for a different design.
2. Complex polygon.
   Effectively there would be a large polygon (complex) that would be subdivided into smaller polygon areas (also complex). Each subdivided area would point to a unique cell to have the fill ratio be the same in the subdivided area. The reason to change an instance is that the pitch over the large polygon needs to remain constant. Otherwise I would fill each subdivided area with the fill; but because of the constant pitch requirement I envision it would be difficult to line up the fills of each subdivided polygon to be on the same pitch.

[sebastian-goeldi]

I see. So, the global pitch should already be maintained in the case of multi=False (it might not fill all the cases it should as it seems I forgot to actually use that case, though I am not 100% it's necessary). But therefore, it should not be necessary to have a larger polygon, it's just a set origin. If you were to fill multiple cells and have a certain instantiation against each other, it would be a bit more complex.

It can currently not be globally configured but I can very easily expose it.

I will confirm tomorrow morning and patch it in. The necessary parameter to be set is origin in the FillTiledOperator class in utils/fill.py

[DanBThom]

Thanks for looking into this: here is example code with comments in capitals in the section in question:
import kfactory as kf
from kfactory.utils.fill import fill_tiled

if name == "main":
#create two polygon sets of points. One is a subset of the other.
points = [(-14899.999999999996, -13000.000000000002),
(-14699.999999999996, -16500.0),
(-15999.999999999996, -19200.000000000004),
(-18499.999999999996, -21200.0),
(-20999.999999999996, -21700.000000000004),
(-23500.0, -21000.000000000007),
(-25799.999999999996, -19000.000000000004),
(-35399.99999999999, 2000.0000000000005),
(-30199.999999999996, 5300.000000000001),
(-14899.999999999996, -13000.000000000002)]
points_sub_polygon = [(-14899.999999999996, -13000.000000000002),
(-14699.999999999996, -16500.0),
(-15999.999999999996, -19200.000000000004),
(-18499.999999999996, -21200.0),
(-20999.999999999996, -21700.000000000004)]
#allow for grid to be on an angle, user defined.
angle = 25

#create cells to fill
c = kf.KCell()
c_outer1 = kf.KCell()
c_outer2 = kf.KCell()

'''
Create instances
'''
c_inst_rotate = c_outer1.create_inst(c)
c_inst_top = c_outer2.create_inst(c_outer1)
'''
rotate the instance prior to tiling
'''
c_inst_rotate.drotate(angle)
'''
create shapes to receive tiling and put them in the lowest level cell "c"
points_sub_polygon is a subset of points of points
'''
poly1  = c.shapes(kf.kcl.layer(1, 0)).insert(
    kf.kdb.DPolygon(points)
)
poly2 = c.shapes(kf.kcl.layer(1, 1)).insert(
    kf.kdb.DPolygon(points_sub_polygon)
)
#create cell to fill with.  Couple of ellipses.  1 to populate, the other to replace.
fc1 = kf.KCell()
fc2 = kf.KCell()
fc1.shapes(fc1.kcl.layer(2, 0)).insert(kf.kdb.DPolygon.ellipse(kf.kdb.DBox(20, 40),10))
fc2.shapes(fc2.kcl.layer(2, 0)).insert(kf.kdb.DPolygon.ellipse(kf.kdb.DBox(30, 30),10))

#copied Sebastien's code on the gdsfactory Geometry page
fill_tiled(
    c_outer1,
    fc1,
    [(kf.kdb.LayerInfo(1, 0), 0)],
    exclude_layers=[
        (kf.kdb.LayerInfo(10, 0), 100),
        (kf.kdb.LayerInfo(2, 0), 0),
        (kf.kdb.LayerInfo(3, 0), 0),
    ],
    x_space=5,
    y_space=5,
)
'''
DO SOMETHING TO REPLACE THE INSTANCES OF THE fc1 SHAPES WITH fc2 SHAPESIN THE 
'''
#Rotate the intance back, so that the grid itself is at an angle    
angle  = -angle
c_inst_top.drotate(angle)


#output to gds
gdspath = "mylayout.gds"