NAME
Image::Leptonica::Func::pixafunc1
VERSION
version 0.04
pixafunc1.c
pixafunc1.c
Filters
PIX *pixSelectBySize()
PIXA *pixaSelectBySize()
NUMA *pixaMakeSizeIndicator()
PIX *pixSelectByPerimToAreaRatio()
PIXA *pixaSelectByPerimToAreaRatio()
PIX *pixSelectByPerimSizeRatio()
PIXA *pixaSelectByPerimSizeRatio()
PIX *pixSelectByAreaFraction()
PIXA *pixaSelectByAreaFraction()
PIX *pixSelectByWidthHeightRatio()
PIXA *pixaSelectByWidthHeightRatio()
PIXA *pixaSelectWithIndicator()
l_int32 pixRemoveWithIndicator()
l_int32 pixAddWithIndicator()
PIX *pixaRenderComponent()
Sort functions
PIXA *pixaSort()
PIXA *pixaBinSort()
PIXA *pixaSortByIndex()
PIXAA *pixaSort2dByIndex()
Pixa and Pixaa range selection
PIXA *pixaSelectRange()
PIXAA *pixaaSelectRange()
Pixa and Pixaa scaling
PIXAA *pixaaScaleToSize()
PIXAA *pixaaScaleToSizeVar()
PIXA *pixaScaleToSize()
Miscellaneous
PIXA *pixaAddBorderGeneral()
PIXA *pixaaFlattenToPixa()
l_int32 pixaaSizeRange()
l_int32 pixaSizeRange()
PIXA *pixaClipToPix()
l_int32 pixaAnyColormaps()
l_int32 pixaGetDepthInfo()
PIXA *pixaConvertToSameDepth()
l_int32 pixaEqual()FUNCTIONS
pixAddWithIndicator
l_int32 pixAddWithIndicator ( PIX *pixs, PIXA *pixa, NUMA *na )
pixAddWithIndicator()
Input: pixs (1 bpp pix from which components are added; in-place)
pixa (of connected components, some of which will be put
into pixs)
na (numa indicator: add components corresponding to 1s)
Return: 0 if OK, 1 on error
Notes:
(1) This complements pixRemoveWithIndicator(). Here, the selected
components are added to pixs.pixRemoveWithIndicator
l_int32 pixRemoveWithIndicator ( PIX *pixs, PIXA *pixa, NUMA *na )
pixRemoveWithIndicator()
Input: pixs (1 bpp pix from which components are removed; in-place)
pixa (of connected components in pixs)
na (numa indicator: remove components corresponding to 1s)
Return: 0 if OK, 1 on error
Notes:
(1) This complements pixAddWithIndicator(). Here, the selected
components are set subtracted from pixs.pixSelectByAreaFraction
PIX * pixSelectByAreaFraction ( PIX *pixs, l_float32 thresh, l_int32 connectivity, l_int32 type, l_int32 *pchanged )
pixSelectByAreaFraction()
Input: pixs (1 bpp)
thresh (threshold ratio of fg pixels to (w * h))
connectivity (4 or 8)
type (L_SELECT_IF_LT, L_SELECT_IF_GT,
L_SELECT_IF_LTE, L_SELECT_IF_GTE)
&changed (<optional return> 1 if changed; 0 if clone returned)
Return: pixd, or null on error
Notes:
(1) The args specify constraints on the amount of foreground
coverage of the components that are kept.
(2) If unchanged, returns a copy of pixs. Otherwise,
returns a new pix with the filtered components.
(3) This filters components based on the fraction of fg pixels
of the component in its bounding box.
(4) Use L_SELECT_IF_LT or L_SELECT_IF_LTE to save components
with less than the threshold fraction of foreground, and
L_SELECT_IF_GT or L_SELECT_IF_GTE to remove them.pixSelectByPerimSizeRatio
PIX * pixSelectByPerimSizeRatio ( PIX *pixs, l_float32 thresh, l_int32 connectivity, l_int32 type, l_int32 *pchanged )
pixSelectByPerimSizeRatio()
Input: pixs (1 bpp)
thresh (threshold ratio of fg boundary to fg pixels)
connectivity (4 or 8)
type (L_SELECT_IF_LT, L_SELECT_IF_GT,
L_SELECT_IF_LTE, L_SELECT_IF_GTE)
&changed (<optional return> 1 if changed; 0 if clone returned)
Return: pixd, or null on error
Notes:
(1) The args specify constraints on the size of the
components that are kept.
(2) If unchanged, returns a copy of pixs. Otherwise,
returns a new pix with the filtered components.
(3) This filters components with smooth vs. dendritic shape, using
the ratio of the fg boundary pixels to the circumference of
the bounding box, and comparing it to a threshold value.
(4) Use L_SELECT_IF_LT or L_SELECT_IF_LTE to save the smooth
boundary components, and L_SELECT_IF_GT or L_SELECT_IF_GTE
to remove them.pixSelectByPerimToAreaRatio
PIX * pixSelectByPerimToAreaRatio ( PIX *pixs, l_float32 thresh, l_int32 connectivity, l_int32 type, l_int32 *pchanged )
pixSelectByPerimToAreaRatio()
Input: pixs (1 bpp)
thresh (threshold ratio of fg boundary to fg pixels)
connectivity (4 or 8)
type (L_SELECT_IF_LT, L_SELECT_IF_GT,
L_SELECT_IF_LTE, L_SELECT_IF_GTE)
&changed (<optional return> 1 if changed; 0 if clone returned)
Return: pixd, or null on error
Notes:
(1) The args specify constraints on the size of the
components that are kept.
(2) If unchanged, returns a copy of pixs. Otherwise,
returns a new pix with the filtered components.
(3) This filters "thick" components, where a thick component
is defined to have a ratio of boundary to interior pixels
that is smaller than a given threshold value.
(4) Use L_SELECT_IF_LT or L_SELECT_IF_LTE to save the thicker
components, and L_SELECT_IF_GT or L_SELECT_IF_GTE to remove them.pixSelectBySize
PIX * pixSelectBySize ( PIX *pixs, l_int32 width, l_int32 height, l_int32 connectivity, l_int32 type, l_int32 relation, l_int32 *pchanged )
pixSelectBySize()
Input: pixs (1 bpp)
width, height (threshold dimensions)
connectivity (4 or 8)
type (L_SELECT_WIDTH, L_SELECT_HEIGHT,
L_SELECT_IF_EITHER, L_SELECT_IF_BOTH)
relation (L_SELECT_IF_LT, L_SELECT_IF_GT,
L_SELECT_IF_LTE, L_SELECT_IF_GTE)
&changed (<optional return> 1 if changed; 0 otherwise)
Return: filtered pixd, or null on error
Notes:
(1) The args specify constraints on the size of the
components that are kept.
(2) If unchanged, returns a copy of pixs. Otherwise,
returns a new pix with the filtered components.
(3) If the selection type is L_SELECT_WIDTH, the input
height is ignored, and v.v.
(4) To keep small components, use relation = L_SELECT_IF_LT or
L_SELECT_IF_LTE.
To keep large components, use relation = L_SELECT_IF_GT or
L_SELECT_IF_GTE.pixSelectByWidthHeightRatio
PIX * pixSelectByWidthHeightRatio ( PIX *pixs, l_float32 thresh, l_int32 connectivity, l_int32 type, l_int32 *pchanged )
pixSelectByWidthHeightRatio()
Input: pixs (1 bpp)
thresh (threshold ratio of width/height)
connectivity (4 or 8)
type (L_SELECT_IF_LT, L_SELECT_IF_GT,
L_SELECT_IF_LTE, L_SELECT_IF_GTE)
&changed (<optional return> 1 if changed; 0 if clone returned)
Return: pixd, or null on error
Notes:
(1) The args specify constraints on the width-to-height ratio
for components that are kept.
(2) If unchanged, returns a copy of pixs. Otherwise,
returns a new pix with the filtered components.
(3) This filters components based on the width-to-height ratios.
(4) Use L_SELECT_IF_LT or L_SELECT_IF_LTE to save components
with less than the threshold ratio, and
L_SELECT_IF_GT or L_SELECT_IF_GTE to remove them.pixaAddBorderGeneral
PIXA * pixaAddBorderGeneral ( PIXA *pixad, PIXA *pixas, l_int32 left, l_int32 right, l_int32 top, l_int32 bot, l_uint32 val )
pixaAddBorderGeneral()
Input: pixad (can be null or equal to pixas)
pixas (containing pix of all depths; colormap ok)
left, right, top, bot (number of pixels added)
val (value of added border pixels)
Return: pixad (with border added to each pix), including on error
Notes:
(1) For binary images:
white: val = 0
black: val = 1
For grayscale images:
white: val = 2 ** d - 1
black: val = 0
For rgb color images:
white: val = 0xffffff00
black: val = 0
For colormapped images, use 'index' found this way:
white: pixcmapGetRankIntensity(cmap, 1.0, &index);
black: pixcmapGetRankIntensity(cmap, 0.0, &index);
(2) For in-place replacement of each pix with a bordered version,
use @pixad = @pixas. To make a new pixa, use @pixad = NULL.
(3) In both cases, the boxa has sides adjusted as if it were
expanded by the border.pixaAnyColormaps
l_int32 pixaAnyColormaps ( PIXA *pixa, l_int32 *phascmap )
pixaAnyColormaps()
Input: pixa
&hascmap (<return> 1 if any pix has a colormap; 0 otherwise)
Return: 0 if OK; 1 on errorpixaBinSort
PIXA * pixaBinSort ( PIXA *pixas, l_int32 sorttype, l_int32 sortorder, NUMA **pnaindex, l_int32 copyflag )
pixaBinSort()
Input: pixas
sorttype (L_SORT_BY_X, L_SORT_BY_Y, L_SORT_BY_WIDTH,
L_SORT_BY_HEIGHT, L_SORT_BY_PERIMETER)
sortorder (L_SORT_INCREASING, L_SORT_DECREASING)
&naindex (<optional return> index of sorted order into
original array)
copyflag (L_COPY, L_CLONE)
Return: pixad (sorted version of pixas), or null on error
Notes:
(1) This sorts based on the data in the boxa. If the boxa
count is not the same as the pixa count, this returns an error.
(2) The copyflag refers to the pix and box copies that are
inserted into the sorted pixa. These are either L_COPY
or L_CLONE.
(3) For a large number of boxes (say, greater than 1000), this
O(n) binsort is much faster than the O(nlogn) shellsort.
For 5000 components, this is over 20x faster than boxaSort().
(4) Consequently, pixaSort() calls this function if it will
likely go much faster.pixaClipToPix
PIXA * pixaClipToPix ( PIXA *pixas, PIX *pixs )
pixaClipToPix()
Input: pixas
pixs
Return: pixad, or null on error
Notes:
(1) This is intended for use in situations where pixas
was originally generated from the input pixs.
(2) Returns a pixad where each pix in pixas is ANDed
with its associated region of the input pixs. This
region is specified by the the box that is associated
with the pix.
(3) In a typical application of this function, pixas has
a set of region masks, so this generates a pixa of
the parts of pixs that correspond to each region
mask component, along with the bounding box for
the region.pixaConvertToSameDepth
PIXA * pixaConvertToSameDepth ( PIXA *pixas )
pixaConvertToSameDepth()
Input: pixas
Return: pixad, or null on error
Notes:
(1) If any pix has a colormap, they are all converted to rgb.
Otherwise, they are all converted to the maximum depth of
all the pix.
(2) This can be used to allow lossless rendering onto a single pix.pixaEqual
l_int32 pixaEqual ( PIXA *pixa1, PIXA *pixa2, l_int32 maxdist, NUMA **pnaindex, l_int32 *psame )
pixaEqual()
Input: pixa1
pixa2
maxdist
&naindex (<optional return> index array of correspondences
&same (<return> 1 if equal; 0 otherwise)
Return 0 if OK, 1 on error
Notes:
(1) The two pixa are the "same" if they contain the same
boxa and the same ordered set of pix. However, if they
have boxa, the pix in each pixa can differ in ordering
by an amount given by the parameter @maxdist. If they
don't have a boxa, the @maxdist parameter is ignored,
and the ordering must be identical.
(2) This applies only to boxa geometry, pixels and ordering;
other fields in the pix are ignored.
(3) naindex[i] gives the position of the box in pixa2 that
corresponds to box i in pixa1. It is only returned if the
pixa have boxa and the boxa are equal.
(4) In situations where the ordering is very different, so that
a large @maxdist is required for "equality", this should be
implemented with a hash function for efficiency.pixaGetDepthInfo
l_int32 pixaGetDepthInfo ( PIXA *pixa, l_int32 *pmaxdepth, l_int32 *psame )
pixaGetDepthInfo()
Input: pixa
&maxdepth (<optional return> max pixel depth of pix in pixa)
&same (<optional return> true if all depths are equal)
Return: 0 if OK; 1 on errorpixaMakeSizeIndicator
NUMA * pixaMakeSizeIndicator ( PIXA *pixa, l_int32 width, l_int32 height, l_int32 type, l_int32 relation )
pixaMakeSizeIndicator()
Input: pixa
width, height (threshold dimensions)
type (L_SELECT_WIDTH, L_SELECT_HEIGHT,
L_SELECT_IF_EITHER, L_SELECT_IF_BOTH)
relation (L_SELECT_IF_LT, L_SELECT_IF_GT,
L_SELECT_IF_LTE, L_SELECT_IF_GTE)
Return: na (indicator array), or null on error
Notes:
(1) The args specify constraints on the size of the
components that are kept.
(2) If the selection type is L_SELECT_WIDTH, the input
height is ignored, and v.v.
(3) To keep small components, use relation = L_SELECT_IF_LT or
L_SELECT_IF_LTE.
To keep large components, use relation = L_SELECT_IF_GT or
L_SELECT_IF_GTE.pixaRenderComponent
PIX * pixaRenderComponent ( PIX *pixs, PIXA *pixa, l_int32 index )
pixaRenderComponent()
Input: pixs (<optional> 1 bpp pix)
pixa (of 1 bpp connected components, one of which will
be rendered in pixs, with its origin determined
by the associated box.)
index (of component to be rendered)
Return: pixd, or null on error
Notes:
(1) If pixs is null, this generates an empty pix of a size determined
by union of the component bounding boxes, and including the origin.
(2) The selected component is blitted into pixs.pixaScaleToSize
PIXA * pixaScaleToSize ( PIXA *pixas, l_int32 wd, l_int32 hd )
pixaScaleToSize()
Input: pixas
wd (target width; use 0 if using height as target)
hd (target height; use 0 if using width as target)
Return: pixad, or null on error
Notes:
(1) See pixaaScaleToSize()pixaSelectByAreaFraction
PIXA * pixaSelectByAreaFraction ( PIXA *pixas, l_float32 thresh, l_int32 type, l_int32 *pchanged )
pixaSelectByAreaFraction()
Input: pixas
thresh (threshold ratio of fg pixels to (w * h))
type (L_SELECT_IF_LT, L_SELECT_IF_GT,
L_SELECT_IF_LTE, L_SELECT_IF_GTE)
&changed (<optional return> 1 if changed; 0 if clone returned)
Return: pixad, or null on error
Notes:
(1) Returns a pixa clone if no components are removed.
(2) Uses pix and box clones in the new pixa.
(3) This filters components based on the fraction of fg pixels
of the component in its bounding box.
(4) Use L_SELECT_IF_LT or L_SELECT_IF_LTE to save components
with less than the threshold fraction of foreground, and
L_SELECT_IF_GT or L_SELECT_IF_GTE to remove them.pixaSelectByPerimSizeRatio
PIXA * pixaSelectByPerimSizeRatio ( PIXA *pixas, l_float32 thresh, l_int32 type, l_int32 *pchanged )
pixaSelectByPerimSizeRatio()
Input: pixas
thresh (threshold ratio of fg boundary to b.b. circumference)
type (L_SELECT_IF_LT, L_SELECT_IF_GT,
L_SELECT_IF_LTE, L_SELECT_IF_GTE)
&changed (<optional return> 1 if changed; 0 if clone returned)
Return: pixad, or null on error
Notes:
(1) Returns a pixa clone if no components are removed.
(2) Uses pix and box clones in the new pixa.
(3) See pixSelectByPerimSizeRatio().pixaSelectByPerimToAreaRatio
PIXA * pixaSelectByPerimToAreaRatio ( PIXA *pixas, l_float32 thresh, l_int32 type, l_int32 *pchanged )
pixaSelectByPerimToAreaRatio()
Input: pixas
thresh (threshold ratio of fg boundary to fg pixels)
type (L_SELECT_IF_LT, L_SELECT_IF_GT,
L_SELECT_IF_LTE, L_SELECT_IF_GTE)
&changed (<optional return> 1 if changed; 0 if clone returned)
Return: pixad, or null on error
Notes:
(1) Returns a pixa clone if no components are removed.
(2) Uses pix and box clones in the new pixa.
(3) See pixSelectByPerimToAreaRatio().pixaSelectBySize
PIXA * pixaSelectBySize ( PIXA *pixas, l_int32 width, l_int32 height, l_int32 type, l_int32 relation, l_int32 *pchanged )
pixaSelectBySize()
Input: pixas
width, height (threshold dimensions)
type (L_SELECT_WIDTH, L_SELECT_HEIGHT,
L_SELECT_IF_EITHER, L_SELECT_IF_BOTH)
relation (L_SELECT_IF_LT, L_SELECT_IF_GT,
L_SELECT_IF_LTE, L_SELECT_IF_GTE)
&changed (<optional return> 1 if changed; 0 otherwise)
Return: pixad, or null on error
Notes:
(1) The args specify constraints on the size of the
components that are kept.
(2) Uses pix and box clones in the new pixa.
(3) If the selection type is L_SELECT_WIDTH, the input
height is ignored, and v.v.
(4) To keep small components, use relation = L_SELECT_IF_LT or
L_SELECT_IF_LTE.
To keep large components, use relation = L_SELECT_IF_GT or
L_SELECT_IF_GTE.pixaSelectByWidthHeightRatio
PIXA * pixaSelectByWidthHeightRatio ( PIXA *pixas, l_float32 thresh, l_int32 type, l_int32 *pchanged )
pixaSelectByWidthHeightRatio()
Input: pixas
thresh (threshold ratio of width/height)
type (L_SELECT_IF_LT, L_SELECT_IF_GT,
L_SELECT_IF_LTE, L_SELECT_IF_GTE)
&changed (<optional return> 1 if changed; 0 if clone returned)
Return: pixad, or null on error
Notes:
(1) Returns a pixa clone if no components are removed.
(2) Uses pix and box clones in the new pixa.
(3) This filters components based on the width-to-height ratio
of each pix.
(4) Use L_SELECT_IF_LT or L_SELECT_IF_LTE to save components
with less than the threshold ratio, and
L_SELECT_IF_GT or L_SELECT_IF_GTE to remove them.pixaSelectRange
PIXA * pixaSelectRange ( PIXA *pixas, l_int32 first, l_int32 last, l_int32 copyflag )
pixaSelectRange()
Input: pixas
first (use 0 to select from the beginning)
last (use 0 to select to the end)
copyflag (L_COPY, L_CLONE)
Return: pixad, or null on error
Notes:
(1) The copyflag specifies what we do with each pix from pixas.
Specifically, L_CLONE inserts a clone into pixad of each
selected pix from pixas.pixaSelectWithIndicator
PIXA * pixaSelectWithIndicator ( PIXA *pixas, NUMA *na, l_int32 *pchanged )
pixaSelectWithIndicator()
Input: pixas
na (indicator numa)
&changed (<optional return> 1 if changed; 0 if clone returned)
Return: pixad, or null on error
Notes:
(1) Returns a pixa clone if no components are removed.
(2) Uses pix and box clones in the new pixa.
(3) The indicator numa has values 0 (ignore) and 1 (accept).
(4) If the source boxa is not fully populated, it is left
empty in the dest pixa.pixaSizeRange
l_int32 pixaSizeRange ( PIXA *pixa, l_int32 *pminw, l_int32 *pminh, l_int32 *pmaxw, l_int32 *pmaxh )
pixaSizeRange()
Input: pixa
&minw, &minh, &maxw, &maxh (<optional return> range of
dimensions of pix in the array)
Return: 0 if OK, 1 on errorpixaSort
PIXA * pixaSort ( PIXA *pixas, l_int32 sorttype, l_int32 sortorder, NUMA **pnaindex, l_int32 copyflag )
pixaSort()
Input: pixas
sorttype (L_SORT_BY_X, L_SORT_BY_Y, L_SORT_BY_WIDTH,
L_SORT_BY_HEIGHT, L_SORT_BY_MIN_DIMENSION,
L_SORT_BY_MAX_DIMENSION, L_SORT_BY_PERIMETER,
L_SORT_BY_AREA, L_SORT_BY_ASPECT_RATIO)
sortorder (L_SORT_INCREASING, L_SORT_DECREASING)
&naindex (<optional return> index of sorted order into
original array)
copyflag (L_COPY, L_CLONE)
Return: pixad (sorted version of pixas), or null on error
Notes:
(1) This sorts based on the data in the boxa. If the boxa
count is not the same as the pixa count, this returns an error.
(2) The copyflag refers to the pix and box copies that are
inserted into the sorted pixa. These are either L_COPY
or L_CLONE.pixaSort2dByIndex
PIXAA * pixaSort2dByIndex ( PIXA *pixas, NUMAA *naa, l_int32 copyflag )
pixaSort2dByIndex()
Input: pixas
naa (numaa that maps from the new pixaa to the input pixas)
copyflag (L_CLONE or L_COPY)
Return: paa (sorted), or null on errorpixaSortByIndex
PIXA * pixaSortByIndex ( PIXA *pixas, NUMA *naindex, l_int32 copyflag )
pixaSortByIndex()
Input: pixas
naindex (na that maps from the new pixa to the input pixa)
copyflag (L_COPY, L_CLONE)
Return: pixad (sorted), or null on errorpixaaFlattenToPixa
PIXA * pixaaFlattenToPixa ( PIXAA *paa, NUMA **pnaindex, l_int32 copyflag )
pixaaFlattenToPixa()
Input: paa
&naindex (<optional return> the pixa index in the pixaa)
copyflag (L_COPY or L_CLONE)
Return: pixa, or null on error
Notes:
(1) This 'flattens' the pixaa to a pixa, taking the pix in
order in the first pixa, then the second, etc.
(2) If &naindex is defined, we generate a Numa that gives, for
each pix in the pixaa, the index of the pixa to which it belongs.pixaaScaleToSize
PIXAA * pixaaScaleToSize ( PIXAA *paas, l_int32 wd, l_int32 hd )
pixaaScaleToSize()
Input: paas
wd (target width; use 0 if using height as target)
hd (target height; use 0 if using width as target)
Return: paad, or null on error
Notes:
(1) This guarantees that each output scaled image has the
dimension(s) you specify.
- To specify the width with isotropic scaling, set @hd = 0.
- To specify the height with isotropic scaling, set @wd = 0.
- If both @wd and @hd are specified, the image is scaled
(in general, anisotropically) to that size.
- It is an error to set both @wd and @hd to 0.pixaaScaleToSizeVar
PIXAA * pixaaScaleToSizeVar ( PIXAA *paas, NUMA *nawd, NUMA *nahd )
pixaaScaleToSizeVar()
Input: paas
nawd (<optional> target widths; use NULL if using height)
nahd (<optional> target height; use NULL if using width)
Return: paad, or null on error
Notes:
(1) This guarantees that the scaled images in each pixa have the
dimension(s) you specify in the numas.
- To specify the width with isotropic scaling, set @nahd = NULL.
- To specify the height with isotropic scaling, set @nawd = NULL.
- If both @nawd and @nahd are specified, the image is scaled
(in general, anisotropically) to that size.
- It is an error to set both @nawd and @nahd to NULL.
(2) If either nawd and/or nahd is defined, it must have the same
count as the number of pixa in paas.pixaaSelectRange
PIXAA * pixaaSelectRange ( PIXAA *paas, l_int32 first, l_int32 last, l_int32 copyflag )
pixaaSelectRange()
Input: paas
first (use 0 to select from the beginning)
last (use 0 to select to the end)
copyflag (L_COPY, L_CLONE)
Return: paad, or null on error
Notes:
(1) The copyflag specifies what we do with each pixa from paas.
Specifically, L_CLONE inserts a clone into paad of each
selected pixa from paas.pixaaSizeRange
l_int32 pixaaSizeRange ( PIXAA *paa, l_int32 *pminw, l_int32 *pminh, l_int32 *pmaxw, l_int32 *pmaxh )
pixaaSizeRange()
Input: paa
&minw, &minh, &maxw, &maxh (<optional return> range of
dimensions of all boxes)
Return: 0 if OK, 1 on errorAUTHOR
Zakariyya Mughal <zmughal@cpan.org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2014 by Zakariyya Mughal.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.