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| author | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2011-03-03 00:55:32 +0000 |
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| committer | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2011-03-03 00:55:32 +0000 |
| commit | 69d5437a1393def7eb6db6bb467fd2fef0246ca8 (patch) | |
| tree | f8df0ece21a0ae5b104db3012567caa6de1bc172 | |
| parent | d36e60dce9a7c75066f867f238262b9921a08fe5 (diff) | |
| download | netpbm-mirror-69d5437a1393def7eb6db6bb467fd2fef0246ca8.tar.gz netpbm-mirror-69d5437a1393def7eb6db6bb467fd2fef0246ca8.tar.xz netpbm-mirror-69d5437a1393def7eb6db6bb467fd2fef0246ca8.zip | |
miscellaneous update
git-svn-id: http://svn.code.sf.net/p/netpbm/code/userguide@1413 9d0c8265-081b-0410-96cb-a4ca84ce46f8
| -rw-r--r-- | directory.html | 3 | ||||
| -rw-r--r-- | pamrubber.html | 162 |
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diff --git a/directory.html b/directory.html index 4a84f493..d3a4aad7 100644 --- a/directory.html +++ b/directory.html @@ -720,6 +720,9 @@ All of these generate Netpbm format output. <DT><B><a href=pamenlarge.html>pamenlarge</a> </B> <DD>enlarge an image N times +<DT><B><a href=pamrubber.html>pamrubber</a> </B> +<DD>Rubber sheet deforming, distortion, stretching of an image + <DT><B><a href=pamperspective.html>pamperspective</a> </B> <DD>Change perspective distortion in an image diff --git a/pamrubber.html b/pamrubber.html new file mode 100644 index 00000000..8475bc6b --- /dev/null +++ b/pamrubber.html @@ -0,0 +1,162 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> +<html> +<head> +<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1"> +<title>PamRubber User Manual</title> +</head> +<body> +<h1>pamrubber</h1> +Updated: February 2011 +<br> +<a href="#index">Table Of Contents</a> +<p><br></p> + +<h2>NAME</h2> +pamrubber - a rubber-sheeting utility that stretches an image +based on control points + +<h2 id="synopsis">SYNOPSIS</h2> +<b>pamrubber</b> +{<b>-tri | -quad</b>} +[<b>-linear</b>] +[<b>-frame</b>] +[<b>-verbose</b>] +<i>cp1x cp1y</i> [<i>cp2x cp2y</i> [<i>cp3x cp3y</i> [<i>cp4x cp4y</i>]]] +<i>cp1x cp1y</i> [<i>cp2x cp2y</i> [<i>cp3x cp3y</i> [<i>cp4x cp4y</i>]]] +[<i>filename</i>] + +<p>Minimum unique abbreviation of options is acceptable. You may use double +hyphens instead of single hyphen to denote options.</p> + +<h2 id="description">DESCRIPTION</h2> + +<p>This program is part +of <a href="http://netpbm.sourceforge.net/doc/index.html">Netpbm</a>.</p> + +<p>The <b>pamrubber</b> utility converts a pam image into a new image with the +contents moved around. The transformation is often called "rubber +sheeting": you identify control points (CP) on the source image and +specify new positions for those points in the new image. <b>pamrubber</b> +moves all the pixels around, stretching and compressing as necessary, as +if the original image were on a sheet of rubber and you pulled on the sheet +to make the control points move to their new locations. + +<p>The new image has the same dimensions and format as the original. + +<p>The transformation can happen in two very different ways, called +"quad" and "tri." With the former, you must specify four +control points (for both source and target). These are the corners of two +quadrilaterals that will act as the coordinate system for both source and +target images. Consider them as non-orthogonal (0,0), (0,1), (1,0) and (1,1) +points. This transformation comes close to the one <b>pamperspective</b> +does, however that program does other corrections as well.</p> + +<p>When you specify less than four control points, the program adds control +points in the following way. With three control points, <b>pamrubber</b> +chooses the fourth one such that the four points form a parallelogram. With +two points, <b>pamrubber</b> considers them the opposite corners of a +rectangle. When you specify only one control point, <b>pamrubber</b> uses a +rectangle from the top left corner of the image to the single control +point.</p> + +<p>In "tri" mode, <b>pamrubber</b> conceptually cuts up the source +and target image into triangles. It Transforms within each corresponding pair +of triangles in a stretching fashion. It's like pulling on the three corners +of the triangle. In this mode, each pixel in the source image gets mapped to +a position in the target image. No pixels are lost.</b> + +<p>When, in "tri" mode, you specify only a single control point in +the source and target image, <b>pamrubber</b> creates four triangles from this +point to the four corners of the image. With two points, the program creates +six triangles from the two endpoints of the line connecting the two points, +again to the four corners of the image. Three control points is in a way the +core of this utility in "tri" mode. Between the three edges of the +central triangle and the four edges of the image, <b>pamrubber</b> constructs +another seven triangles. Four control points define two central connected +triangles. In total this results in cutting the source and target image up +into ten triangles.</p> + +<p>In this case clearly a picture says more than a thousand words. There is a +graphical illustration of these various modes at +<a href="http://www.schaik.com/netpbm/rubber"> +www.schaik.com/netpbm/rubber</a>. An example of how to use this type of +rubber sheeting in cartography is in the article +<a href="http://www.isprs.org/proceedings/XXXVI/5-W1/papers/21.pdf"> +Visualizing the Landscape of Old-Time Tokyo</a>.</p> + + +<h2 id="parameters">PARAMETERS</h2> + +<p>The parameters are control points (<i>cp</i>) in pairs of <i>x</i> +and <i>y</i>. The source and target image must have the same number of +control points. The minimum number of values specified here is 4 for a single +control point in the source and target image. The maximum is 16 for four +control points in each image. +</p> + +<p><i>filename</i> is the name of the input file. If you don't specify +this, <b>pamrubber</b> reads the image from Standard Input.</p> + + +<h2 id="options">OPTIONS</h2> +<dl compact="compact"> + +<dt><b>-tri</b> | <b>-quad</b></dt> +<dd> +<p>This selects the type of rubber sheeting done. +You must specify exactly one of these options. +</dd> + +<dt><b>-linear</b></dt> +<dd> +<p>This determines whether <b>pamrubber</b> uses nearest neighbor +interpolation or bilinear interpolation of four source pixels. +</p> +</dd> + +<dt><b>-frame</b></dt> +<dd> +<p>This option causes <b>pamrubber</b> to overlay the target image with the +edges of the quadrilaterals, respectively the triangles used for the rubber +sheeting. To get the same overlay for the source image, use a <b>pamrubber</b> +transformation with identical control points for source and target. +</dd> + +<dt><b>-verbose</b></dt> +<dd> +<p>This option causes <b>pamrubber</b> to print some information about the +source image. +</dd> +</dl> + + +<h2 id="seealso">SEE ALSO</h2> +<b><a href="http://netpbm.sourceforge.net/doc/pam.html">pam</a></b> and +<b><a href="http://netpbm.sourceforge.net/doc/pamperspective.html">pamperspective</a></b> + + +<h2 id="history">HISTORY</h2> +<p><b>pamrubber</b> was new in Netpbm 10.54 (March 2011).</p> + + +<h2 id="authors">AUTHORS</h2> + +<p><a href="mailto:willem@schaik.com">Willem van Schaik</a> wrote this program +in February 2011 and contributed it to Netpbm.</p> + +<br> +<hr> + +<h2 id="index">Table Of Contents</h2> +<ul> +<li><a href="#synopsis">SYNOPSIS</a> +</li><li><a href="#description">DESCRIPTION</a> +</li><li><a href="#parameters">PARAMETERS</a> +</li><li><a href="#options">OPTIONS</a> +</li><li><a href="#seealso">SEE ALSO</a> +</li><li><a href="#authors">AUTHORS</a> +</li> +</ul> +</body> +</html> + |