Colour 0.4.5 - Alpha Milestone

Features

Dependencies

• Support for Numpy 2.0 was implemented. (#1279)
• pygraphviz was replaced with pydot so that installation is easier: pygraphviz needs to be built , which is not trivial, whereas pydot is a pure Python package.

Development Environment

Astral's uv

• We switched from Poetry to uv and hatch for managing the development environment and build our wheels. (#1300)

  • uv is faster at resolving the environment and the team at astral.sh has been doing wonders for the Python ecosystem, we have been using ruff for a while now.
  • It is so good that it literally only requires uv run --with colour-science my_script.py to run a script using Colour.
  • Thanks a ton to @charliermarsh et al.!

• Improve static typing checks using multi-threading thanks to @erictraut suggestion.

Environment

It is now possible to create a ~/.colour-science/colour-science.jenv JSON file from which Colour will load environment variables from: (#1239, @KelSolaar)

{
  "COLOUR_SCIENCE__COLOUR__SHOW_WARNINGS_WITH_TRACEBACK": 1
}

The following new environment variables are now supported:

• COLOUR_SCIENCE__FILTER_RUNTIME_WARNINGS: Filter Colour runtime warnings.
• COLOUR_SCIENCE__FILTER_USAGE_WARNINGS: Filter Colour usage warnings.
• COLOUR_SCIENCE__FILTER_COLOUR_WARNINGS: Filter Colour warnings, this also filters Colour usage and runtime warnings.
• COLOUR_SCIENCE__FILTER_PYTHON_WARNINGS: Filter Python warnings.

Input and Output

• Definitions reading from and writing to files now support the pathlib.Path type. (ff4fe99, @KelSolaar)

colour.adaptation

• Implement support for vK20 chromatic adaptation transform with colour.adaptation.matrix_chromatic_adaptation_vk20 and colour.adaptation.chromatic_adaptation_vK20 definitions. (#1131, @KelSolaar)

colour.characterisation

• Add the ColorChecker SG chromaticity coordinates with the colour.CCS_COLOURCHECKERS["ColorCheckerSG - Before November 2014"] and colour.CCS_COLOURCHECKERS["ColorCheckerSG - After November 2014"] attribute keys.

colour.colorimetry

• Use shape if passed, to also reshape the colour.continuous.AbstractContinuousSignal sub-classes in colour.colorimetry.sd_to_XYZ_integration definition. (#1250, @KelSolaar)

colour.models

• Programmatically add polar conversions to the following definitions: (#1183, #1272, @KelSolaar)

• colour.Lab_to_LCHab *

• colour.LCHab_to_Lab *

• colour.Luv_to_LCHuv *

• colour.LCHuv_to_Luv *

• colour.hdr_CIELab_to_hdr_CIELCHab

• colour.hdr_CIELCHab_to_hdr_CIELab

• colour.Hunter_Lab_to_Hunter_LCHab

• colour.Hunter_LCHab_to_Hunter_Lab

• colour.Hunter_Rdab_to_Hunter_RdCHab

• colour.Hunter_RdCHab_to_Hunter_Rdab

• colour.ICaCb_to_ICHab

• colour.ICHab_to_ICaCb

• colour.ICtCp_to_ICHtp

• colour.ICHtp_to_ICtCp

• colour.IgPgTg_to_IgCHpt

• colour.IgCHpt_to_IgPgTg

• colour.IPT_to_ICH

• colour.ICH_to_IPT

• colour.Izazbz_to_IzCHab

• colour.IzCHab_to_Izazbz

• colour.Jzazbz_to_JzCHab

• colour.JzCHab_to_Jzazbz

• colour.hdr_IPT_to_hdr_ICH

• colour.hdr_ICH_to_hdr_IPT

• colour.Oklab_to_Oklch

• colour.Oklch_to_Oklab

• colour.ProLab_to_ProLCHab

• colour.ProLCHab_to_ProLab

• colour.IPT_Ragoo2021_to_ICH_Ragoo2021

• colour.ICH_Ragoo2021_to_IPT_Ragoo2021

* Now programmatically defined

colour.utilities

Port-Based Nodes and Graphs (#1277, @KelSolaar)

6 new classes were introduced to support for a port-based node-graph:

• colour.utilities.Port
• colour.utilities.PortNode
• colour.utilities.PortGraph
• colour.utilities.For
• colour.utilities.ParallelForThread
• colour.utilities.ParallelForMultiProcess

They enable the construction of processing graphs:

class NodeAdd(PortNode):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        self.description = "Perform the addition of the two input port values."

        self.add_input_port("a")
        self.add_input_port("b")
        self.add_output_port("output")

    def process(self):
        a = self.get_input("a")
        b = self.get_input("b")

        if a is None or b is None:
            return

        self._output_ports["output"].value = a + b

        self.dirty = False

class NodeMultiply(PortNode):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        self.description = (
            "Perform the multiplication of the two input port values."
        )

        self.add_input_port("a")
        self.add_input_port("b")
        self.add_output_port("output")

    def process(self):
        a = self.get_input("a")
        b = self.get_input("b")

        if a is None or b is None:
            return

        self._output_ports["output"].value = a * b

        self.dirty = False

node_add = NodeAdd()
node_add.set_input("a", 1)
node_add.set_input("b", 1)
node_multiply = NodeMultiply()
node_multiply.set_input("b", 2)

graph = PortGraph()

graph.add_node(node_add)
graph.add_node(node_multiply)

graph.connect(node_add, "output", node_multiply, "a")

graph.process()

print(node_multiply.get_output("output"))
graph.to_graphviz().draw("Graph.png", prog="dot")

colour-hdri uses the new classes to implement a multi-processed HDRI merging graph: https://github.com/colour-science/colour-hdri/blob/develop/colour_hdri/examples/examples_advanced_processing_with_an_input_device_transform.ipynb

Fixes

colour.colorimetry

• Fix issue where colour.colorimetry.sds_and_msds_to_msds definition did not always copy the converted spectral distributions and was causing seemingly random unit tests failure. (891d364, @KelSolaar)
• Fix issue when passing a colour.MultiSpectralDistributions to colour.sd_to_XYZ definition using the ASTM E308 method. (20fb963, @KelSolaar, @gul916)

colour.io

• Ensure that colour.io.process_image_OpenColorIO definition handles non-contiguous arrays. (387c9e5, @nick-shaw, @KelSolaar)

colour.models

• Change Canon Cinema Gamut whitepoint to D55. (c25934e, @MrLixm, @KelSolaar)

colour.notation

• Reduce various thresholds in Munsell Renotation computations to allow sRGB colours to be converted. (#1173, 4b0c38d, @KelSolaar)

colour.utilities

• Ensure that caches are systematically cleared when changing dtype: It was causing seemingly random unit tests failure. (8faeb09, @KelSolaar)

Changes

colour.algebra

colour.plotting

colour.utilities

• ~colour.utilities.is_string: (@KelSolaar)
  • Remove