MaskSpec¶

class photonforge.MaskSpec(operand1=None, operand2=None, operation='+', dilation=0)¶

Mask specification.

This class is mainly used when creating an ExtrusionSpec for a Technology.

Parameters:

operand1 – Layer tuple, mask specification, or iterable of those. If an iterable is used, the effective operand is the union of all the items.
operand2 – Layer tuple, mask specification, or iterable of those. If an iterable is used, the effective operand is the union of all the items.
operation – One of "+" (union), "*" (intersection), "-" (difference), or "^" (symmetric difference).
dilation – Dilation (erosion, if negative) applied to the mask.

Examples

Masks specifications can be combined using arithmetic operations:

>>> layer_1_0 = MaskSpec((1, 0))
>>> layer_2_0 = MaskSpec((2, 0), dilation=0.1)
>>> difference = layer_1_0 - layer_2_0
>>> eroded_diff = difference ** -0.1
>>> eroded_diff
MaskSpec(operand0=[MaskSpec((1, 0))], operand1=[MaskSpec((2, 0), dilation=0.1)], operation='-', dilation=-0.1)

Note

An empty list of operands indicates the full component bounds. The inversion of a layer is indicated by subtracting it from the component bounds.

Methods

`copy`([deep])	Create a copy of this mask specification.
`format`([layer_names, technology])	Create a string expression for this mask using names instead of layers.
`from_json`(json_str)	Create a mask specification object from a json string.
`parse`(expression[, technology])	Parse a string expression into a mask specification.

Attributes

`dilation`	Mask dilation.
`json`	Json representation of this Mask specification.
`layer`	Mask layer (read only).
`operand1`	First operand for this mask.
`operand2`	Second operand for this mask.
`operation`	Mask generation operation.

copy(deep=False)¶

Create a copy of this mask specification.

Returns:: New copy.

dilation¶: Mask dilation.

format(layer_names=None, technology=None)¶

Create a string expression for this mask using names instead of layers.

Parameters:

layer_names – Dictionary mapping layer tuples to names, that will replace the layer tuples in the resulting expression. If not set, the technology layer names are used instead.
technology – Technology whose layers will be used to extract the layer names. Not used if layer_names is defined. If not specified, the current default technology is used.

Returns:

Mask specification string.

Example

>>> mask = MaskSpec.parse("(0, 0) * (1, 0)")
>>> mask.format({(0, 0): "A", (1, 0): "B"})
"('A' * 'B')"

static from_json(json_str)¶

Create a mask specification object from a json string.

Parameters:: json_str – Strig containing the json data.
Returns:: MaskSpec instance.

json¶: Json representation of this Mask specification.

layer¶: Mask layer (read only).

operand1¶: First operand for this mask.

operand2¶: Second operand for this mask.

operation¶: Mask generation operation.

static parse(expression, technology=None)¶

Parse a string expression into a mask specification.

Parameters:

expression – String expression to parse.
technology – Technology to be used for layer names in the expression.

Returns:

MaskSpec object.

Example

Invert layer (0, 0) and intersect the result with layer (10, 0):

>>> MaskSpec.parse("-(0, 0) * (10, 0)")
MaskSpec(operand0=[MaskSpec(operand0=[MaskSpec(operand0=[], operand1=[], operation='+')], operand1=[MaskSpec((0, 0))], operation='-')], operand1=[MaskSpec((10, 0))], operation='*')

Difference between layers ‘SLAB’ and ‘WG_CORE’ intersected with (9, 10):

>>> MaskSpec.parse("('SLAB' - 'WG_CORE') * (9, 10)")
MaskSpec(operand0=[MaskSpec(operand0=[MaskSpec((3, 0))], operand1=[MaskSpec((2, 0))], operation='-')], operand1=[MaskSpec((9, 10))], operation='*')

Union of ‘WG_CORE’ and ‘WG_CLAD’ eroded by 100 nm:

>>> MaskSpec.parse("('WG_CORE' + 'WG_CLAD') ** -0.1")
MaskSpec(operand0=[MaskSpec((2, 0)), MaskSpec((1, 0))], operand1=[], operation='+', dilation=-0.1)