opngtrans.h File Reference

OPNGTRANS is a PNG Transformer. More...

#include "opngcore.h"

Go to the source code of this file.

Typedefs
typedef struct opng_transformer	opng_transformer_t
	The transformer type.

Functions
opng_transformer_t *	opng_create_transformer (void)
	Creates a transformer object.
void	opng_set_transformer (opng_optimizer_t *optimizer, opng_transformer_t *transformer)
	Sets the transformer in an optimizer object.
int	opng_transform_set_object (opng_transformer_t *transformer, const char *object_name_eq_value, size_t *err_objname_offset_ptr, size_t *err_objname_length_ptr, const char **err_message_ptr)
	Specifies an object to be set to a given value by the given transformer.
int	opng_transform_reset_objects (opng_transformer_t *transformer, const char *object_names, size_t *err_objname_offset_ptr, size_t *err_objname_length_ptr, const char **err_message_ptr)
	Specifies a list of objects to be reset by the given transformer.
int	opng_transform_strip_objects (opng_transformer_t *transformer, const char *object_names, size_t *err_objname_offset_ptr, size_t *err_objname_length_ptr, const char **err_message_ptr)
	Specifies a list of objects to be stripped by the given transformer.
int	opng_transform_protect_objects (opng_transformer_t *transformer, const char *object_names, size_t *err_objname_offset_ptr, size_t *err_objname_length_ptr, const char **err_message_ptr)
	Specifies a list of objects to be protected (i.e.
const opng_transformer_t *	opng_seal_transformer (opng_transformer_t *transformer)
	Seals a transformer object.
void	opng_destroy_transformer (opng_transformer_t *transformer)
	Destroys a transformer object.

Detailed Description

OPNGTRANS is a PNG Transformer.

Copyright (C) 2001-2011 Cosmin Truta.

This software is distributed under the zlib license. Please see the accompanying LICENSE file, or visit http://www.opensource.org/licenses/zlib-license.php

Typedef Documentation

typedef struct opng_transformer opng_transformer_t

The transformer type.

A transformer object can be used to apply transformations to the image properties or to the image contents.

Currently-supported transformations are: erasing channels (alpha channel only) and stripping metadata.

Other transformations, hopefully to be implemented in some future, are: erasing other channels (e.g. chroma), altering the sample precision (e.g. 16-to-8 bits for all channels, any-to-1 bit for the alpha channel), etc.

Function Documentation

opng_transformer_t* opng_create_transformer

(

void

)

Creates a transformer object.

Returns

the transformer created, or NULL on failure.

void opng_destroy_transformer

(

opng_transformer_t *

transformer

)

Destroys a transformer object.

Parameters

transformer

the transformer object to be destroyed.

const opng_transformer_t* opng_seal_transformer

(

opng_transformer_t *

transformer

)

Seals a transformer object.

Parameters

transformer

the transformer object to be sealed.

Returns

the sealed transformer.

void opng_set_transformer	(	opng_optimizer_t *	optimizer,
		opng_transformer_t *	transformer
	)

Sets the transformer in an optimizer object.

Parameters

optimizer	the optimizer object whose transformer is changed. By default, the optimizer has a NULL transformer.
transformer	the transformer to be changed. It can be NULL, which means that the optimized images are not altered.

int opng_transform_protect_objects	(	opng_transformer_t *	transformer,
		const char *	object_names,
		size_t *	err_objname_offset_ptr,
		size_t *	err_objname_length_ptr,
		const char **	err_message_ptr
	)

Specifies a list of objects to be protected (i.e.

not stripped) by the given transformer. For example, it is possible to strip all metadata, but protect sRGB and iCCP. These objects will be added to (not replace) any previously-specified list of objects. Only metadata objects can be protected.

Parameters

transformer	the transformer object.
object_names	a comma- or semicolon-separated enumeration of object names.
err_objname_offset_ptr	in case of failure, shall point to the erroneous object within object_names.
err_objname_length_ptr	in case of failure, shall store the length of the erroneous object.
err_message_ptr	in case of failure, may point to an error message.

Returns

0 on success, or -1 on failure.

int opng_transform_reset_objects	(	opng_transformer_t *	transformer,
		const char *	object_names,
		size_t *	err_objname_offset_ptr,
		size_t *	err_objname_length_ptr,
		const char **	err_message_ptr
	)

Specifies a list of objects to be reset by the given transformer.

This list of objects will be added to (not replace) any previously-specified list of objects. Only image data objects can be reset.

Parameters

transformer	the transformer object.
object_names	a comma- or semicolon-separated enumeration of object names.
err_objname_offset_ptr	in case of failure, shall point to the erroneous object within object_names.
err_objname_length_ptr	in case of failure, shall store the length of the erroneous object.
err_message_ptr	in case of failure, may point to an error message.

Returns

0 on success, or -1 on failure.

int opng_transform_set_object	(	opng_transformer_t *	transformer,
		const char *	object_name_eq_value,
		size_t *	err_objname_offset_ptr,
		size_t *	err_objname_length_ptr,
		const char **	err_message_ptr
	)

Specifies an object to be set to a given value by the given transformer.

Only image data objects can be reset.

Parameters

transformer	the transformer object.
object_name_eq_value	an expression in the form "name=value".
err_objname_offset_ptr	in case of failure, shall point to the erroneous object within object_name_eq_value.
err_objname_length_ptr	in case of failure, shall store the length of the erroneous object.
err_message_ptr	in case of failure, may point to an error message.

Returns

0 on success, or -1 on failure.

int opng_transform_strip_objects	(	opng_transformer_t *	transformer,
		const char *	object_names,
		size_t *	err_objname_offset_ptr,
		size_t *	err_objname_length_ptr,
		const char **	err_message_ptr
	)

Specifies a list of objects to be stripped by the given transformer.

These objects will be added to (not replace) any previously-specified list of objects. Only metadata objects can be stripped.

Parameters

transformer	the transformer object.
object_names	a comma- or semicolon-separated enumeration of object names.
err_objname_offset_ptr	in case of failure, shall point to the erroneous object within object_names.
err_objname_length_ptr	in case of failure, shall store the length of the erroneous object.
err_message_ptr	in case of failure, may point to an error message.

Returns

0 on success, or -1 on failure.