NAME
im_histplot - graph an image of one horizontal or vertical line
SYNOPSIS
#include <vips/vips.h>
int im_histplot(in, out)
IMAGE *in, *out;
DESCRIPTION
im_histplot(3) plots a graph of a horizontal or vertical image file
with one line. It is suitable for displaying the output of histogram
functions such as im_histgr(3) and for displaying line profiles.
Note that if you try to directly plot the result of im_histgr(3) you
will often get a very, very large image, since im_histplot(3) will draw
an image as high (or as wide) as the largest pixel value in the image
(potentially huge). Use im_histnorm(3) to normalise the histogram
maximum before plotting.
The input image should be either one horizontal line (Ysize=1) or one
vertical line (Xsize=1). If the image is FMTUCHAR, the graph is drawn
as 256 by line-length pixels. For all other unsigned integer types,
im_histplot(3) finds the image maximum, and draws the graph as max by
line-length pixels.
For signed integer types, im_histplot(3) finds minimum and maximum,
moves min up to zero, and draws the graph as min + max by line-lenth
pixels.
For float types, im_histplot(3) finds minimum and maximum, and scales
the image range so as to make the graph square.
RETURNED VALUE
The function returns 0 on success and -1 on error.
SEE ALSO
im_histgr(3), im_histnorm(3), im_extract(3).
COPYRIGHT
National Gallery and Birkbeck College, 1995
10 May 1991