This example provides a core color management example module that acts as an interface to the open source LittleCMS color management library. More...

Files
file	cmm_littlecms.h
	CMM Interface to the LittleCMS module.

file	cmm_littlecms.c
	CMM Implementation of the interface to the LittleCMS library.

file	cmm_littlecmspriv.h
	Header for linking the custom color space module with the Hybrid module.

Functions
sw_cmm_api *	lcms_getInstance (void)
	Return the singleton instance of a sw_cmm_api object containing details specific to the LittleCMS CMM example module. More...

static sw_cmm_result	lcms_construct (sw_cmm_instance *instance)
	Construct an instance of the sw_cmm_api interface. More...

sw_cmm_result	lcms_open_profile (sw_cmm_instance instance, sw_blob_instance ICC_profile, sw_cmm_profile *handle)
	Create an internal profile structure for ICC profile data stored in memory. Required for use by lcms_open_transform(). More...

void	lcms_close_profile (sw_cmm_instance *instance, sw_cmm_profile profile)
	Close a profile with a handle previously created with lcms_open_profile(). More...

sw_cmm_result	lcms_open_transform (sw_cmm_instance instance, sw_cmm_profile profiles[], uint32 num_profiles, int32 intents[], HqBool black_point_compensations[], uint32 num_input_channels, uint32 num_output_channels, sw_cmm_transform handle)
	Create a transform structure. More...

void	lcms_close_transform (sw_cmm_instance *instance, sw_cmm_transform transform)
	Close a transform previously opened with lcms_open_transform(). More...

sw_cmm_result	lcms_invoke_transform (sw_cmm_instance instance, sw_cmm_transform transform, float input_data, float *output_data, uint32 num_pixels)
	Use the specified transform to adjust color data. More...

Detailed Description

This example provides a core color management example module that acts as an interface to the open source LittleCMS color management library.

To configure the RIP to use this color management module, use this fragment in the configuration PostScript:

(CMM_LittleCMS) setalternatecmm

With this configuration, color transforms involving ICC profiles will be directed to this module, which in turn will use the LittleCMS API. Further details in the Extensions Manual.

This example module is registered by calling SwRegisterCMM() with the singleton API instance returned by lcms_getInstance(). The module implements the CMM API methods lcms_construct(), lcms_open_profile(), lcms_close_profile(), lcms_open_transform(), lcms_close_transform() and lcms_invoke_transform().

Function Documentation

◆ lcms_close_profile()

void lcms_close_profile	(	sw_cmm_instance *	instance,
		sw_cmm_profile	profile
	)

Close a profile with a handle previously created with lcms_open_profile().

Parameters

[in]	instance	The alternate CMM instance owning the profile.
[in]	profile	A profile handle previous opened by an `open_profile()` or open_custom_colorspace() calls on the same alternate CMM instance. The alternate CMM implementation should discard any resources associated with the profile.

See also: lcms_open_profile()

◆ lcms_close_transform()

void lcms_close_transform	(	sw_cmm_instance *	instance,
		sw_cmm_transform	transform
	)

Close a transform previously opened with lcms_open_transform().

Parameters

[in]	instance	The alternate CMM instance owning the color transform.
[in]	transform	A valid transform handle created by an `open_transform()` or open_transform2() call on the same alternate CMM instance. The alternate CMM implementation should discard any resources associated with the transform.

See also: lcms_open_transform()

◆ lcms_construct()

static sw_cmm_result lcms_construct ( sw_cmm_instance * instance )

static

Construct an instance of the sw_cmm_api interface.

The RIP constructs an instance for each CMM module after booting the interpreter. RIP fills in the implementation pointer, and pointers to the memory API and blob API instances. The module is expected to fill in the remaining fields, which contains flags defining of the implementation capabilities of the module. Some of the information returned will be used by the RIP to determine whether a particular profile or transform can be handled by this module, and in other cases the RIP will use this information to divert color conversions through its built-in CMM if appropriate.

Parameters

[in,out] instance An incomplete instance of the sw_cmm_instance structure to complete. The RIP will allocate a structure of the size presented in the implementation's sw_cmm_api::info.instance_size field, fill in the implementation and callback API instance pointers, and then pass it to this routine. The construct() method is expected to fill in the remaining fields. The implementation may sub-class the instance to allocate private workspace by initialising the implementation's sw_cmm_api::info.instance_size larger than the size of the sw_cmm_instance structure, then downcasting the instance pointer in method calls.

Returns: SW_CMM_SUCCESS if the instance is fully constructed, otherwise one of the SW_CMM_RESULT error codes.

◆ lcms_getInstance()

sw_cmm_api* lcms_getInstance ( void )

Return the singleton instance of a sw_cmm_api object containing details specific to the LittleCMS CMM example module.

Returns: A single instance of the CMM.

See also: SwRegisterCMM()

If compiled normally, the "clrip" application layer registers this module during RIP startup. CMM module examples may be excluded from "clrip" by building with NO_CMMEG defined.

◆ lcms_invoke_transform()

sw_cmm_result lcms_invoke_transform	(	sw_cmm_instance *	instance,
		sw_cmm_transform	transform,
		float *	input_data,
		float *	output_data,
		uint32	num_pixels
	)

Use the specified transform to adjust color data.

Parameters

[in]	instance	The alternate CMM instance owning the color transform.
[in]	transform	A valid transform handle created by an open_transform() call on the same alternate CMM instance.
[in]	input_data	An array of num_pixels sets of pixel-interleaved color values to transform. Colors are interleaved in the order specified by the input space of the first profile in the transform.
[out]	output_data	An array in which to store num_pixels sets of pixel-interleaved color values. Colors are interleaved in the order specified by the output space of the last profile in the transform.
	num_pixels	The number of sets of input pixel colorvalues to convert from the input space to the output space of the transform.

Returns: SW_CMM_SUCCESS if the invocation succeeded, one of the SW_CMM_RESULT error codes otherwise.

In all cases, both the input and output data should be pixel interleaved with each color value contained in a 32-bit IEEE floating value. The interleaving of the input data is in the same order as that expected by the first profile in a transform and the interleaving of the output data should be in the same order as produced by the last profile in the transform. It is the responsibility of the alternate CMM to marshal the data into and out of the format required for its internal use. As an example, if five pixels of RGB data were to be converted to CMYK, the RIP will arrange the input data as follows:

RGBRGBRGBRGBRGB

and invoke_transform() will produce this arrangement of output data:

CMYKCMYKCMYKCMYKCMYK

The number of channels for each pixel is derived from the first and last profiles in the transform as returned by open_transform().

The memory referenced by input_data and output_data is managed by the RIP and can be assumed to contain valid memory for the appropriate amount of data. The size, in bytes, allocated by the RIP to each is:

input_data: num_pixels * num_input_channels * sizeof(float)
output_data: num_pixels * num_output_channels * sizeof(float)

LCMS and the RIP store pixel data in different formats so this code uses convertFloatToWORDArray() and convertWORDToFloatArray() to convert the data to the appropriate format.

See also: lcms_open_transform()

◆ lcms_open_profile()

sw_cmm_result lcms_open_profile	(	sw_cmm_instance *	instance,
		sw_blob_instance *	ICC_profile,
		sw_cmm_profile *	handle
	)

Create an internal profile structure for ICC profile data stored in memory. Required for use by lcms_open_transform().

Parameters

[in]	instance	The alternate CMM implementation instance owning the ICC profile.
[in]	ICC_profile	A blob data source, giving access to the raw ICC profile data through the blob's sw_blob_api implementation methods. This blob will have been opened for non-exclusive read access. If the alternate CMM wishes to use the data source after the open_profile() method returns, it must create a new blob reference using the sw_blob_api::open_blob() method, and use that reference for all access after open_profile() terminates. If a new blob reference is created, the alternate CMM implementation must close that reference when it has finished accessing to it.
[out]	handle	A pointer in which a CMM profile handle is stored. This handle will be used to refer to the profile by close_profile(), open_transform(), and open_transform2().

Returns: SW_CMM_SUCCESS if the profile was successfully opened, in which case a non-NULL profile pointer should have been stored in handle. If the profile could not be opened, one of the SW_CMM_RESULT error codes is returned.

If a valid profile handle is returned, the close_profile() method will be called to destroy the profile later.

See also: lcms_close_profile(), lcms_open_transform()

◆ lcms_open_transform()

sw_cmm_result lcms_open_transform	(	sw_cmm_instance *	instance,
		sw_cmm_profile	profiles[],
		uint32	num_profiles,
		int32	intents[],
		HqBool	black_point_compensations[],
		uint32 *	num_input_channels,
		uint32 *	num_output_channels,
		sw_cmm_transform *	handle
	)

Create a transform structure.

Prior to creating a transform the RIP will ensure compatibility with the capabilities of this CMM as indicated by its optional capabilities. If the transform isn't compatible then color conversion will be attempted using the RIP's built-in CMM instead.

The RIP will have previously opened the profiles that are passed in as arguments.

Note: This example code supports a limited number of input/output color spaces. For more info see isSupportedColorSpace().

Parameters

[in]	instance	The alternate CMM instance owning the profiles.
[in]	profiles	An array of num_profiles profile handles, returned by calls to open_profile() or open_custom_colorspace().
	num_profiles	The number of profiles in the transform chain.
[in]	intents	An array of length num_profiles-1 specifying the rendering intents use for color conversions between adjacent profiles in the profiles parameter.
[in]	black_point_compensations	An array of length num_profiles-1 containing boolean flags, indicating if black point compensation is performed when converting colors between adjacent profiles in the profiles parameter.
[out]	num_input_channels	A location for the alternate CMM to fill in the number of color channels in the input space of the first profile in the transform.
[out]	num_output_channels	A location for the alternate CMM to fill in the number of color channels in the output space of the last profile in the transform.
[out]	handle	A pointer in which a CMM transform handle is stored by the alternate CMM implementation. This handle will be used to refer to the transform by close_transform() and invoke_transform() methods.

Returns: SW_CMM_SUCCESS if the transform was successfully opened, in which case a non-NULL transform pointer should have been stored in handle. If the profile could not be opened, one of the SW_CMM_RESULT error codes is returned.

If a valid transform handle is returned, the close_transform() method will be called to destroy the transform later.

See also: lcms_close_transform(), lcms_invoke_transform()

Files

Functions

Detailed Description

Function Documentation

◆ lcms_close_profile()

◆ lcms_close_transform()

◆ lcms_construct()

◆ lcms_getInstance()

◆ lcms_invoke_transform()

◆ lcms_open_profile()

◆ lcms_open_transform()