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IM_HISTPLOT

IM_HISTPLOT

Section: C Library Functions (3) Updated: 10 May 1991
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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


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURNED VALUE
SEE ALSO
COPYRIGHT

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Time: 21:48:20 GMT, April 16, 2011