| .TH IM_HISTPLOT 3 "10 May 1991" |
| .SH NAME |
| im_histplot \- graph an image of one horizontal or vertical line |
| .SH SYNOPSIS |
| #include <vips/vips.h> |
| |
| int im_histplot(in, out) |
| .br |
| IMAGE *in, *out; |
| |
| .SH DESCRIPTION |
| .B 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 |
| .B im_histgr(3) |
| you will often get a very, very large image, since |
| .B im_histplot(3) |
| will draw an image as high (or as wide) as the largest pixel |
| value in the image (potentially huge). Use |
| .B 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, |
| .B im_histplot(3) |
| finds the image maximum, and draws the graph as max by line-length pixels. |
| |
| For signed integer types, |
| .B 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, |
| .B im_histplot(3) |
| finds minimum and maximum, and scales the image range so as to make the |
| graph square. |
| |
| .SH RETURNED VALUE |
| The function returns 0 on success and -1 on error. |
| .SH SEE ALSO |
| im_histgr(3), im_histnorm(3), im_extract(3). |
| .SH COPYRIGHT |
| National Gallery and Birkbeck College, 1995 |
