OpenColorIO

Open Source Color Management

OpenColorIO v1.0.8 documentation

Python API

Description

A color configuration (Config) defines all the color spaces to be available at runtime.

(Config) is the main object for interacting with this library. It encapsulates all the information necessary to use customized PyOpenColorIO.ColorSpaceTransform and PyOpenColorIO.DisplayTransform operations.

See the User Guide for more information on selecting, creating, and working with custom color configurations.

For applications interested in using only one color configuration at a time (this is the vast majority of apps), their API would traditionally get the global configuration and use that, as opposed to creating a new one. This simplifies the use case for plugins and bindings, as it alleviates the need to pass around configuration handles.

An example of an application where this would not be sufficient would be a multi-threaded image proxy server (daemon) that wants to handle multiple show configurations concurrently in a single process. This app would need to keep multiple configurations alive, and manage them appropriately.

Roughly speaking, a novice user should select a default configuration that most closely approximates the use case (animation, visual effects, etc.), and set the OCIO environment variable to point at the root of that configuration.

Note

Initialization using environment variables is typically preferable in a multi-app ecosystem, as it allows all applications to be consistently configured.

Note

Paths to LUTs can be relative. The search paths are defined in Config.

See Usage Examples

Examples of Use

import PyOpenColorIO as OCIO

# Load an existing configuration from the environment.
# The resulting configuration is read-only. If $OCIO is set, it will use that.
# Otherwise it will use an internal default.
config = OCIO.GetCurrentConfig()

# What color spaces exist?
colorSpaceNames = [ cs.getName() for cs in config.getColorSpaces() ]

# Given a string, can we parse a color space name from it?
inputString = 'myname_linear.exr'
colorSpaceName = config.parseColorSpaceFromString(inputString)
if colorSpaceName:
    print 'Found color space', colorSpaceName
else:
    print 'Could not get color space from string', inputString

# What is the name of scene-linear in the configuration?
colorSpace = config.getColorSpace(OCIO.Constants.ROLE_SCENE_LINEAR)
if colorSpace:
    print colorSpace.getName()
else:
    print 'The role of scene-linear is not defined in the configuration'

# For examples of how to actually perform the color transform math,
# see 'Python: Processor' docs.

# Create a new, empty, editable configuration
config = OCIO.Config()

# Create a new color space, and add it
cs = OCIO.ColorSpace(...)
# (See ColorSpace for details)
config.addColorSpace(cs)

# For additional examples of config manipulation, see
# https://github.com/imageworks/OpenColorIO-Configs/blob/master/nuke-default/make.py

Exceptions

class PyOpenColorIO.Exception
class PyOpenColorIO.ExceptionMissingFile

Global

PyOpenColorIO.ClearAllCaches()
PyOpenColorIO.GetCurrentConfig()
PyOpenColorIO.GetLoggingLevel()
PyOpenColorIO.SetCurrentConfig()
PyOpenColorIO.SetLoggingLevel()

Config

class PyOpenColorIO.Config

Config

static CreateFromEnv()

CreateFromEnv()

Create a PyOpenColorIO.Config object using the environment variable.

Returns:Config object
static CreateFromFile()

CreateFromFile(filename)

Create a PyOpenColorIO.Config object using the information in a file.

Parameters:
  • filename (string) – name of file
Returns:

Config object

addColorSpace

addColorSpace(pyColorSpace)

Add a specified color space to PyOpenColorIO.Config.

Parameters:
  • pyColorSpace (object) – color space

Note

If another color space is already registered with the same name, this will overwrite it.

addDisplay

addDisplay(display, view, colorSpaceName[, looks])

NEEDS WORK

Parameters:
  • display (string) –
  • view (string) –
  • colorSpaceName (string) –
  • looks (string) – optional
addLook

addLook(pylook)

Adds a look to PyOpenColorIO.Config.

Parameters:
  • pylook (look object) – look
clearColorSpaces

clearColorSpaces()

Clear the color spaces in PyOpenColorIO.Config.

clearDisplays

clearDisplays()

clearLook

clearLooks()

Clear looks in PyOpenColorIO.Config.

clearLooks

clearLooks()

Clear looks in PyOpenColorIO.Config.

createEditableCopy

createEditableCopy()

Returns an editable copy of PyOpenColorIO.Config.

Returns:editable copy of PyOpenColorIO.Config
Return type:Config object
getActiveDisplays

getActiveDisplays()

Returns the active displays in PyOpenColorIO.Config.

Returns:active displays
Return type:string
getActiveViews

getActiveViews()

Returns the active views in PyOpenColorIO.Config.

Returns:active views
Return type:string
getCacheID

getCacheID([, pycontext])

This will produce a hash of the all colorspace definitions, etc.

All external references, such as files used in FileTransforms, etc., will be incorporated into the cacheID. While the contents of the files are not read, the file system is queried for relavent information (mtime, inode) so that the PyOpenColorIO.Config‘s cacheID will change when the underlying luts are updated.

If a context is not provided, the current Context will be used. If a null context is provided, file references will not be taken into account (this is essentially a hash of :py:method:`PyOpenColorIO.Config.serialize`).

Parameters:
  • pycontext (object) – optional
Returns:

hash of PyOpenColorIO.Config

Return type:

string

getColorSpace

getColorSpace(name)

Returns the data for the specified color space in Config.

This will return null if the specified name is not found.

Parameters:
  • name (string) – name of color space
Returns:

data for specified color space

Return type:

pyColorSpace object

getColorSpaces

getColorSpaces()

Returns all the ColorSpaces defined in Config.

Returns:ColorSpaces in PyOpenColorIO.Config
Return type:tuple
getCurrentContext

getCurrentContext()

Return the current context, which is essentially a record of all the environment variables that are available for use in file path lookups.

Returns:context
Return type:pycontext
getDefaultDisplay

getDefaultDisplay()

Returns the default display set in PyOpenColorIO.Config.

Returns:default display
Return type:string
getDefaultLumaCoefs

getDefaultLumaCoefs()

Returns the default luma coefficients in PyOpenColorIO.Config.

Returns:luma coefficients
Return type:list of floats
getDefaultView

getDefaultView(display)

Returns the default view of PyOpenColorIO.Config.

Parameters:
  • display (string) – default view
Returns:

view

Return type:

string

getDescription

getDescription()

Returns the stored description of PyOpenColorIO.Config.

Returns:stored description of PyOpenColorIO.Config
Return type:string
getDisplayColorSpaceName

getDisplayColorSpaceName(display, view)

Returns the ColorSpace name corresponding to the display and view combination in PyOpenColorIO.Config.

Parameters:
  • display (string) – display
  • view (string) – view
Returns:

display color space name

Return type:

string

getDisplayLooks

getDisplayLooks(display, view)

Returns the looks corresponding to the display and view combination in PyOpenColorIO.Config.

Parameters:
  • display (string) – display
  • view (string) – view
Returns:

looks

Return type:

string

getDisplays

getDisplays()

Returns all the displays defined in PyOpenColorIO.Config.

Returns:displays in Config
Return type:list of strings
getLook

getLook(str)

Returns the information of a specified look in PyOpenColorIO.Config.

Parameters:
  • str (string) – look
Returns:

specified look

Return type:

look object

getLooks

getLooks()

Returns a list of all the looks defined in PyOpenColorIO.Config.

Returns:looks
Return type:tuple of look objects
getProcessor

getProcessor(arg1[, arg2[, direction[, context]])

Returns a processor for a specified transform.

Although this is not often needed, it allows for the reuse of atomic OCIO functionality, such as applying an individual LUT file.

There are two canonical ways of creating a PyOpenColorIO.Processor:

  1. Pass a transform into arg1, in which case arg2 will be ignored.
  2. Set arg1 as the source and arg2 as the destination. These can be ColorSpace names, objects, or roles.

Both arguments, direction (of transform) and context, are optional and respected for both methods of PyOpenColorIO.Processor creation.

This will fail if either the source or destination color space is null.

See Python: Processor for more details.

Note

This may provide higher fidelity than anticipated due to internal optimizations. For example, if inputColorSpace and outputColorSpace are members of the same family, no conversion will be applied, even though, strictly speaking, quantization should be added.

If you wish to test these calls for quantization characteristics, apply in two steps; the image must contain RGB triples (though arbitrary numbers of additional channels can be optionally supported using the pixelStrideBytes arg). ???

Parameters:
  • arg1 (object) –
  • arg2 (object) – ignored if arg1 is a transform
  • direction (string) – optional
  • context (object) – optional
getSearchPath

getSearchPath()

Returns the search path.

Returns:search path
Return type:string
getViews

getViews(display)

Returns all the views defined in PyOpenColorIO.Config.

Parameters:
  • display (string) – views in Config
Returns:

views in Config.

Return type:

list of strings

getWorkingDir

getWorkingDir()

Returns the working directory.

Returns:the working directory
Rtype path:string
isEditable

isEditable()

Returns whether Config is editable.

The configurations returned from :py:function:`PyOpenColorIO.GetCurrentConfig` are not editable, and if you want to edit them you can use :py:method:`PyOpenColorIO.Config.createEditableCopy`.

If you attempt to call any of the set functions on a noneditable Config, an exception will be thrown.

Returns:state of PyOpenColorIO.Config‘s editability
Return type:bool
parseColorSpaceFromString

parseColorSpaceFromString(str)

Parses out the color space from a string.

Given the specified string, gets the longest, right-most color space substring. * If strict parsing is enabled, and no color space is found, return an empty string. * If strict parsing is disabled, return the default role, if defined. * If the default role is not defined, return an empty string.

Parameters:
  • str (string) – ColorSpace data
Returns:

parsed data

Return type:

string

sanityCheck

sanityCheck()

This will throw an exception if PyOpenColorIO.Config is malformed. The most common error occurs when references are made to colorspaces that do not exist.

serialize

serialize()

Returns the string representation of PyOpenColorIO.Config in YAML text form. This is typically stored on disk in a file with the .ocio extension.

Returns:PyOpenColorIO.Config in YAML text form
Return type:string
setActiveDisplays

setActiveDisplays(displays)

Sets the active displays in PyOpenColorIO.Config.

Parameters:
  • displays (string) – active displays
setActiveViews

setActiveViews(views)

Sets the active views in PyOpenColorIO.Config.

Parameters:
  • views (string) – active views
setDefaultLumaCoefs

setDefaultLumaCoefs(pyCoef)

Sets the default luma coefficients in PyOpenColorIO.Config.

Parameters:
  • pyCoef (object) – luma coefficients
setDescription

setDescription(desc)

Sets the description of PyOpenColorIO.Config.

Parameters:
setRole

setRole(role, csname)

Set a role’s ColorSpace.

Setting the colorSpaceName name to a null string unsets it.

Parameters:
  • role (string) – role whose ColorSpace will be set
  • csname (string) – name of ColorSpace
setSearchPath

setSearchPath(path)

Sets the search path.

Parameters:
  • path (string) – the search path
setWorkingDir

setWorkingDir(path)

Sets the working directory.

Parameters:
  • path (string) – the working directory

ColorSpace

class PyOpenColorIO.ColorSpace

A color space is the state of an image in terms of colorimetry and color encoding. I.e., it defines how an image’s color information needs to be interpreted.

Transforming images between different color spaces is the primary motivation for the OCIO library.

While a complete discussion of color spaces is beyond the scope of this documentation, traditional uses would be to have color spaces describing image capture devices, such as cameras and scanners, and internal ‘convenience’ spaces, such as scene-linear and logarithmic.

Color spaces are specific to a particular image precision (float32, uint8, etc.). The set of color spaces that provide equivalent mappings (at different precisions) are referred to as a ‘family’.

import PyOpenColorIO as OCIO
config = OCIO.Config()
createEditableCopy
getAllocation

If this colorspace needs to be transferred to a limited dynamic range coding space (such as during display with a GPU path), use this allocation to maximize bit efficiency.

getAllocationVars
getBitDepth
getDescription
getEqualityGroup
getFamily
getName
getTransform
isData

ColorSpaces that are data are treated a bit special. Basically, any colorspace transforms you try to apply to them are ignored. (Think of applying a gamut mapping transform to an ID pass). Also, the PyOpenColorIO.DisplayTransform process obeys special ‘data min’ and ‘data max’ args.

This is traditionally used for pixel data that represents non-color pixel data, such as normals, point positions, ID information, etc.

isEditable
setAllocation
setAllocationVars
setBitDepth
setDescription
setEqualityGroup
setFamily
setIsData
setName
setTransform

Look

class PyOpenColorIO.Look

The Look is an ‘artistic’ image modification, in a specified image state.

The processSpace defines the ColorSpace the image is required to be in, for the math to apply correctly.

createEditableCopy
getName
getProcessSpace
getTransform
isEditable
setName
setProcessSpace
setTransform

Processor

class PyOpenColorIO.Processor

Processor is the baked representation of a particular color transform. Once you have a process for a particular transform created, you can hang onto it to efficiently transform pixels.

Processors can only be created from the PyOpenColorIO.Config getProcessor(...) call.

applyRGB

applyRGB(pixeldata)

Apply the RGB part of the transform represented by PyOpenColorIO.Processor to an image.

Parameters:
  • pixeldata (object) – rgbrgb... array (length % 3 == 0)
Returns:

color converted pixeldata

Return type:

list

applyRGBA

applyRGBA(pixeldata)

Apply the RGB and alpha part of the transform represented by PyOpenColorIO.Processor to an image.

Parameters:
  • pixeldata (object) – rgbargba... array (length % 4 == 0)
Returns:

color converted pixeldata

Return type:

list

getCpuCacheID

getCpuCacheID()

Returns the cache ID of the CPU that PyOpenColorIO.Processor will run on.

Returns:CPU cache ID
Return type:string
getGpuLut3D

getGpuLut3D(shaderDesc)

Returns the GPU LUT 3D.

Parameters:
  • shaderDesc (dict) – define ‘language’,’functionName’,’lut3DEdgeLen’
Returns:

GPU LUT 3D

Return type:

list

getGpuLut3DCacheID

getGpuLut3DCacheID(shaderDesc)

Returns the GPU 3D LUT cache ID.

Parameters:
  • shaderDesc (dict) – two params
Returns:

GPU 3D LUT cache ID

Return type:

string

getGpuShaderText

getGpuShaderText(shaderDesc)

Returns the GPU shader text.

Parameters:
  • shaderDesc (dict) – define ‘language’,’functionName’,’lut3DEdgeLen’
Returns:

GPU shader text

Return type:

string

getGpuShaderTextCacheID

getGpuShaderTextCacheID(shaderDesc)

Returns the GPU shader text cache ID.

Parameters:
  • shaderDesc (dict) – define ‘language’,’functionName’,’lut3DEdgeLen’
Returns:

GPU shader text cache ID

Return type:

string

getMetadata

getMetadata()

Returns information about the process that generated this processor.

Returns:processor metadata
Return type:PyOpenColorIO.ProcessorMetadata
hasChannelCrosstalk

hasChannelCrosstalk()

Returns whether the transformation of PyOpenColorIO.Processor introduces crosstalk between the image channels.

Returns:whether there’s crosstalk between channels
Return type:bool
isNoOp

isNoOp()

Returns whether the actual transformation represented by PyOpenColorIO.Processor is a no-op.

Returns:whether transform is a no-op
Return type:bool

Context

class PyOpenColorIO.Context

Context

createEditableCopy
getCacheID
getSearchPath
getStringVar
getWorkingDir
isEditable
loadEnvironment
resolveFileLocation
resolveStringVar
setSearchPath
setStringVar
setWorkingDir