NAME

pixel_iterator - Pixel iterator pattern support functions


SYNOPSIS

MagickPassFail PixelIterateDualModify( PixelIteratorDualModifyCallback call_back, const char *description, void *user_data, const unsigned long columns, const unsigned long rows, const Image *source_image, const long source_x, const long source_y, Image *update_image, const long update_x, const long update_y, ExceptionInfo *exception );

MagickPassFail PixelIterateDualRead( PixelIteratorDualReadCallback call_back, const char *description, void *user_data, const unsigned long columns, const unsigned long rows, const Image *first_image, const long first_x, const long first_y, const Image *second_image, const long second_x, const long second_y, ExceptionInfo *exception );;

MagickPassFail PixelIterateMonoModify( PixelIteratorMonoModifyCallback call_back, const char *description, void *user_data, const long x, const long y, const unsigned long columns, const unsigned long rows, Image *image, ExceptionInfo *exception );

MagickPassFail PixelIterateMonoRead( PixelIteratorMonoReadCallback call_back, const char *description, void *user_data, const long x, const long y, const unsigned long columns, const unsigned long rows, const Image *image, ExceptionInfo *exception );


FUNCTION DESCRIPTIONS

PixelIterateMonoRead

PixelIterateMonoRead() iterates through a region of an image and invokes a user-provided callback function ( of type PixelIteratorMonoReadCallback ) for each pixel. This is useful to support simple operations such as statistics computation.

The format of the PixelIterateMonoRead method is:

MagickPassFail PixelIterateMonoRead ( PixelIteratorMonoReadCallback call_back, const char *description, void *user_data, const long x, const long y, const unsigned long columns, const unsigned long rows, const Image *image, ExceptionInfo *exception );

A description of each parameter follows:

call_back:

A user-provided C callback function which is passed the address of a pixel from each image.

description:

textual description of operation being performed.

user_data:

User-provided context data.

x:

The horizontal ordinate of the top left corner of the region.

y:

The vertical ordinate of the top left corner of the region.

columns:

Width of pixel region

rows:

Height of pixel region

image:

The address of the Image.

exception:

If an error is reported, this argument is updated with the reason.

PixelIterateMonoModify

PixelIterateMonoModify() iterates through a region of an image and invokes a user-provided callback function ( of type PixelIteratorMonoReadCallback ) for each pixel. This is useful to support simple operations such as level shifting, colorspace translation, or thresholding.

The format of the PixelIterateMonoModify method is:

MagickPassFail PixelIterateMonoModify ( PixelIteratorMonoModifyCallback call_back, const char *description, void *user_data, const long x, const long y, const unsigned long columns, const unsigned long rows, Image *image, ExceptionInfo *exception );

A description of each parameter follows:

call_back:

A user-provided C callback function which is passed the address of a pixel from each image.

description:

textual description of operation being performed.

user_data:

User-provided context data.

x:

The horizontal ordinate of the top left corner of the region.

y:

The vertical ordinate of the top left corner of the region.

columns:

Width of pixel region

rows:

Height of pixel region

image:

The address of the Image.

exception:

If an error is reported, this argument is updated with the reason.

PixelIterateDualRead

PixelIterateDualRead() iterates through pixel regions of two images and invokes a user-provided callback function ( of type PixelIteratorDualReadCallback ) for each pixel. This is useful to support operations such as image comparison.

The format of the PixelIterateDualModify method is:

MagickPassFail PixelIterateDualRead ( PixelIteratorDualReadCallback call_back, const char *description, void *user_data, const unsigned long columns, const unsigned long rows, const Image *first_image, const long first_x, const long first_y, const Image *second_image, const long second_x, const long second_y, ExceptionInfo *exception );;

A description of each parameter follows:

call_back:

A user-provided C callback function which is passed the address of a pixel from each image.

description:

textual description of operation being performed.

user_data:

User-provided context data.

columns:

Width of pixel region

rows:

Height of pixel region

first_image:

The address of the first Image.

first_x:

The horizontal ordinate of the top left corner of the first region.

first_y:

The vertical ordinate of the top left corner of the first region.

second_image:

The address of the second Image.

second_x:

The horizontal ordinate of the top left corner of the second region.

second_y:

The vertical ordinate of the top left corner of the second region.

exception:

If an error is reported, this argument is updated with the reason.

PixelIterateDualModify

PixelIterateDualModify() iterates through pixel regions of two images and invokes a user-provided callback function ( of type PixelIteratorDualModifyCallback ) for each pixel. This is useful to support operations such as composition.

The format of the PixelIterateDualModify method is:

MagickPassFail PixelIterateDualModify ( PixelIteratorDualModifyCallback call_back, const char *description, void *user_data, const unsigned long columns, const unsigned long rows, const Image *source_image, const long source_x, const long source_y, Image *update_image, const long update_x, const long update_y, ExceptionInfo *exception );

A description of each parameter follows:

call_back:

A user-provided C callback function which reads from a source pixel and updates a destination pixel.

description:

textual description of operation being performed.

user_data:

User-provided context data.

columns:

Width of pixel region

rows:

Height of pixel region

source_image:

The address of the constant source Image.

source_x:

The horizontal ordinate of the top left corner of the source region.

source_y:

The vertical ordinate of the top left corner of the source region.

update_image:

The address of the update Image.

update_x:

The horizontal ordinate of the top left corner of the update region.

update_y:

The vertical ordinate of the top left corner of the update region.

exception:

If an error is reported, this argument is updated with the reason.