58 lines
1.7 KiB
Groff
58 lines
1.7 KiB
Groff
.TH LINES 3 "14 May 1991"
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.SH NAME
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im_cntlines, im_profile \- calculate transitions between black and white pels horizontally or vertically
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.SH SYNOPSIS
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.B #include <vips/vips.h>
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.B int im_profile(in, out, dir)
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.br
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.B IMAGE *in, *out;
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.br
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.B int dir;
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.B int im_cntlines(in, nolines, dir)
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.br
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.B IMAGE *in;
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.br
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.B double *nolines;
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.br
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.B int dir;
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.SH DESCRIPTION
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.B im_profile(3)
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searches inward from the edge of the image and finds the first non-zero pixel.
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It outputs an image containing a list of the offsets for each row or column.
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If
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.B dir
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==0, then
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.B im_profile(3)
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searches down from the top edge, writing an image as wide as the input
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image, but only 1 pixel high, containing the number of pixels down to the
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first non-zero pixel for each column of input pixels.
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If
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.B dir
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==1, then
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.B im_profile(3)
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searches across from the left edge, writing an image as high as the input
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image, but only 1 pixel wide, containing the number of pixels across to the
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first non-zero pixel for each row of input pixels.
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.B im_cntlines(3)
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calculates the number of transitions between black and white pixels of
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an image. If dir is 1 then all transitions across the
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vertical direction are calculated for all Xsize lines of the image. If dir
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is 0 then all transitions along the horizontal direction for all Ysize
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lines are calculated. The function returns the number of transitions
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divided by twice the number of the corresponding Xsize of Ysize lines.
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The program is primarily used to calculate the number of unbroken horizontal
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(dir=0) or vertical lines (dir=1) that exist within an image.
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Input image in can have only one channel.
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.SH RETURN VALUE
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All functions returns 0 on success and -1 on error.
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.SH SEE ALSO
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im_erode(3), im_dilate(3).
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