1<?xml version="1.0" encoding="UTF-8"?>
2<!DOCTYPE sect2 PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN"
3                       "http://www.docbook.org/xml/4.3/docbookx.dtd">
4<!-- section history:
5  2017-10-14 j.h: some updates
6-->
7<sect2 id="script-fu-tile-blur">
8  <title>Tileable Blur</title>
9
10  <indexterm>
11    <primary>Filters</primary>
12    <secondary>Blur</secondary>
13    <tertiary>Tileable Blur</tertiary>
14  </indexterm>
15  <indexterm>
16    <primary>Tileable Blur</primary>
17  </indexterm>
18
19  <sect3>
20    <title>Overview</title>
21    <figure>
22      <title>Example for the <quote>Tileable</quote> filter</title>
23      <mediaobject>
24        <imageobject>
25          <imagedata format="JPG"
26            fileref="images/filters/examples/taj_orig.jpg"/>
27        </imageobject>
28        <caption>
29          <para>Original</para>
30        </caption>
31      </mediaobject>
32      <mediaobject>
33        <imageobject>
34          <imagedata format="JPG"
35            fileref="images/filters/examples/blur-taj-tblur.jpg"/>
36        </imageobject>
37        <caption>
38          <para>Filter <quote>Tileable Blur</quote> applied</para>
39        </caption>
40      </mediaobject>
41    </figure>
42    <para>
43      This filter is a script-fu and not GEGL-based.
44    </para>
45    <para>
46      This filter is used to soften tile seams in images used in tiled
47      backgrounds. It does this by blending and blurring the boundary between
48      images that will be next to each other after tiling.
49    </para>
50    <tip>
51      <para>
52        If you want to treat only images borders, you can't apply filter
53        to the whole image. The solution to get the wanted effect is as
54        follows:
55      </para>
56      <procedure>
57        <step>
58          <para>
59            Duplicate layer
60            (<menuchoice>
61              <guimenu>Layer</guimenu>
62              <guimenuitem>Duplicate Layer</guimenuitem>
63            </menuchoice>)
64            and select it to work on it.
65          </para>
66        </step>
67        <step>
68          <para>
69            Apply <quote>Tileable Blur</quote> filter with a 20 pixels radius
70            to this layer.
71          </para>
72        </step>
73        <step>
74          <para>
75            Select all
76            (<keycombo><keycap>Ctrl</keycap><keycap>A</keycap></keycombo>) and
77            reduce selection
78            (<menuchoice>
79              <guimenu>Selection</guimenu>
80              <guimenuitem>Shrink</guimenuitem>
81            </menuchoice>)
82            to create a border with the wanted width.
83          </para>
84        </step>
85        <step>
86          <para>
87            Give a feathered border to the selection by using
88            <menuchoice>
89              <guimenu>Selection</guimenu>
90              <guimenuitem>Feather</guimenuitem>
91            </menuchoice>.
92          </para>
93        </step>
94        <step>
95          <para>
96            Delete selection with
97            <keycombo><keycap>Ctrl</keycap><keycap>K</keycap></keycombo>.
98          </para>
99        </step>
100        <step>
101          <para>
102            Merge layers with
103            <menuchoice>
104              <guimenu>Layer</guimenu>
105              <guimenuitem>Merge down</guimenuitem>
106            </menuchoice>.
107          </para>
108        </step>
109      </procedure>
110    </tip>
111  </sect3>
112
113  <sect3>
114    <title>Activate the filter</title>
115    <para>
116      You can find this filter in the image menu under
117      <menuchoice>
118        <guimenu>Filters</guimenu>
119        <guisubmenu>Blur</guisubmenu>
120        <guimenuitem>Tileable Blur…</guimenuitem>
121      </menuchoice>.
122    </para>
123  </sect3>
124
125  <sect3>
126    <title>Options</title>
127    <figure>
128      <title><quote>Tileable Blur</quote> filter options</title>
129      <mediaobject>
130        <imageobject>
131          <imagedata format="PNG"
132            fileref="images/filters/blur/tileable-options.png"/>
133        </imageobject>
134      </mediaobject>
135    </figure>
136    <variablelist>
137      <varlistentry>
138        <term><guilabel>Radius</guilabel></term>
139        <listitem>
140          <para>
141            The bigger the radius, the more marked is the blur. By selecting
142            <guilabel>Horizontal</guilabel> and <guilabel>Vertical</guilabel>,
143            you can make the horizontal and vertical borders tileable.
144          </para>
145        </listitem>
146      </varlistentry>
147      <varlistentry>
148        <term><guilabel>Blur vertically</guilabel></term>
149        <term><guilabel>Blur horizontally</guilabel></term>
150        <listitem>
151          <para>
152            These options are self-explanatory.
153          </para>
154        </listitem>
155      </varlistentry>
156      <varlistentry>
157        <term><guilabel>Blur type</guilabel></term>
158        <listitem>
159          <para>Choose the algorithm to be applied:</para>
160          <variablelist>
161            <varlistentry>
162              <term><guilabel>IIR</guilabel></term>
163              <listitem>
164                <para>for photographic or scanned images.</para>
165              </listitem>
166            </varlistentry>
167            <varlistentry>
168              <term><guilabel>RLE</guilabel></term>
169              <listitem>
170                <para>for computer-generated images.</para>
171              </listitem>
172            </varlistentry>
173          </variablelist>
174        </listitem>
175      </varlistentry>
176    </variablelist>
177  </sect3>
178</sect2>
179