[solang/help] Added a page about histograms

[Florent Thévenet <fthevenet src gnome org>]

commit b8a320733ccefac7ea718edecc018d6987fb7cd4
Author: Florent Thévenet <feuloren free fr>
Date:   Tue Mar 9 12:08:21 2010 +0100

    Added a page about histograms
    
    the page is not complete yet and some image are protected by a copyright :-(

 help/C/figures/grid.png               |  Bin 0 -> 456 bytes
 help/C/figures/histogram_bar.gif      |  Bin 0 -> 1546 bytes
 help/C/figures/histogram_original.gif |  Bin 0 -> 1068 bytes
 help/C/figures/histogram_original.jpg |  Bin 0 -> 60068 bytes
 help/C/figures/stack.png              |  Bin 0 -> 581 bytes
 help/C/histogram.page                 |   64 +++++++++++++++++++++++++++++++++
 help/C/index.page                     |    3 +-
 help/Makefile.am                      |    3 +-
 8 files changed, 68 insertions(+), 2 deletions(-)
---
diff --git a/help/C/figures/grid.png b/help/C/figures/grid.png
new file mode 100644
index 0000000..8a6eae8
Binary files /dev/null and b/help/C/figures/grid.png differ
diff --git a/help/C/figures/histogram_bar.gif b/help/C/figures/histogram_bar.gif
new file mode 100644
index 0000000..5cf8271
Binary files /dev/null and b/help/C/figures/histogram_bar.gif differ
diff --git a/help/C/figures/histogram_original.gif b/help/C/figures/histogram_original.gif
new file mode 100644
index 0000000..2991761
Binary files /dev/null and b/help/C/figures/histogram_original.gif differ
diff --git a/help/C/figures/histogram_original.jpg b/help/C/figures/histogram_original.jpg
new file mode 100644
index 0000000..c645041
Binary files /dev/null and b/help/C/figures/histogram_original.jpg differ
diff --git a/help/C/figures/stack.png b/help/C/figures/stack.png
new file mode 100644
index 0000000..189971c
Binary files /dev/null and b/help/C/figures/stack.png differ
diff --git a/help/C/histogram.page b/help/C/histogram.page
new file mode 100644
index 0000000..1fa9f25
--- /dev/null
+++ b/help/C/histogram.page
@@ -0,0 +1,64 @@
+<page xmlns="http://projectmallard.org/1.0/";
+      type="topic"
+      id="histogram">
+<info>
+	<link type="guide" xref="index_tips"/>
+	<desc>
+	It's not just beautiful.
+	</desc>
+	<credit type="author">
+		<name>Florent Thévenet</name>
+		<email>feuloren free fr</email>
+	</credit>
+	<include href="legal.xml" xmlns="http://www.w3.org/2001/XInclude"/>
+</info>
+<title>What is an histogram ?</title>
+
+<section>
+	<title>What's that ?</title>
+	<p>Take the following mosaic and imagine one order the squares by color and them stack them up in piles. It will give us the color distribution of the mosaic.</p>
+
+  <figure>
+    <title>The mosaic</title>
+    <media type="image" src="figures/grid.png" mime="image/png" style="right">
+      <p>The mosaic</p>
+    </media>
+  </figure>
+  <figure>
+    <title>Its color distribution</title>
+    <media type="image" src="figures/stack.png" mime="image/png" style="right">
+      <p>Its color distribution.</p>
+    </media>
+  </figure>
+
+	<p>You know that a digital photography is composed of millions of colored dots called pixels. If instead of ordering the pixels by color, one order them by brightness, from the darker to the lighter, it gives us the histogram of that photo. <app>Solang</app> automatically create an histogram with 256 levels of brightness, the height of each stack indicate us the number of pixel of that brightness in the image.</p>
+
+  <figure>
+    <title>The original image</title>
+    <media type="image" src="figures/histogram_original.jpg" mime="image/jpg" style="right">
+      <p>An image of sea and beach.</p>
+    </media>
+  </figure>
+  <figure>
+    <title>Its histogram</title>
+    <desc>In a real histogram there is no white spaces between each stack; here the histogram is in shade of Grey to allow you to distinguish each stack and the three tones: the shadows - near from black (0) -, the midtones and the highlights - near from white (255) -.</desc>
+    <media type="image" src="figures/histogram_bar.gif" mime="image/gif" style="right">
+      <p>The histogram associated to that image</p>
+    </media>
+  </figure>
+  <figure>
+    <title>Its histogram</title>
+    <media type="image" src="figures/histogram_original.gif" mime="image/gif" style="right">
+      <p>The histogram associated to that image</p>
+    </media>
+  </figure>
+
+</section>
+
+<section>
+<title>How to use these histograms</title>
+<p>Histograms are useful because they let you see if your images are correctly exposed. Take the following examples.</p>
+
+</section>
+
+</page>
diff --git a/help/C/index.page b/help/C/index.page
index 638541f..b22bab0 100644
--- a/help/C/index.page
+++ b/help/C/index.page
@@ -43,10 +43,11 @@
 		</info>
 	</section>
 
-	<section id="index_tips" style="2colum">
+	<section id="index_tips" style="2column">
 		<title>Tips and Tricks</title>
 		<info>
 			<link type="topic" xref="keys"/>
+			<link type="topic" xref="histogram"/>
 		</info>
 	</section>
 
diff --git a/help/Makefile.am b/help/Makefile.am
index 5e5e68e..36661c0 100644
--- a/help/Makefile.am
+++ b/help/Makefile.am
@@ -15,7 +15,8 @@ DOC_PAGES = \
 	tags_intro.page \
 	howto_search.page \
 	keys.page \
-	tags_manage.page
+	tags_manage.page \
+	histogram.page
 
 DOC_LINGUAS = de