LINES(3) LINES(3)
NAME
im_cntlines, im_profile - calculate transitions between black and white
pels horizontally or vertically
SYNOPSIS
#include <vips/vips.h>
int im_profile(in, out, dir)
IMAGE *in, *out;
int dir;
int im_cntlines(in, nolines, dir)
IMAGE *in;
double *nolines;
int dir;
DESCRIPTION
im_profile(3) searches inward from the edge of the image and finds the
first non-zero pixel. It outputs an image containing a list of the
offsets for each row or column.
If dir ==0, then im_profile(3) searches down from the top edge, writing
an image as wide as the input image, but only 1 pixel high, containing
the number of pixels down to the first non-zero pixel for each column
of input pixels.
If dir ==1, then im_profile(3) searches across from the left edge,
writing an image as high as the input image, but only 1 pixel wide,
containing the number of pixels across to the first non-zero pixel for
each row of input pixels.
im_cntlines(3) calculates the number of transitions between black and
white pixels of an image. If dir is 1 then all transitions across the
vertical direction are calculated for all Xsize lines of the image. If
dir is 0 then all transitions along the horizontal direction for all
Ysize lines are calculated. The function returns the number of transi-
tions divided by twice the number of the corresponding Xsize of Ysize
lines. The program is primarily used to calculate the number of unbro-
ken horizontal (dir=0) or vertical lines (dir=1) that exist within an
image. Input image in can have only one channel.
RETURN VALUE
All functions returns 0 on success and -1 on error.
SEE ALSO
im_erode(3), im_dilate(3).
14 May 1991 LINES(3)
im_cntlines 7.14.5 - Generated Sat Sep 6 08:05:35 CDT 2008