Add TOC to Advanced Stamps How-To

docs/en/html/ADVANCED-STAMPS-HOWTO.html

@@ -23,10 +23,56 @@
         Copyright &copy; 2006-2021 by Albert Cahalan and others; see AUTHORS.<br>
         <a href="http://www.tuxpaint.org/">http://www.tuxpaint.org/</a>
       </p>
+
+      <p>
+        August 29, 2021      </p>
     </center>
 
+    <hr size="2"
+        noshade>
+
+    <table border="2"
+           cellspacing="0"
+           cellpadding="2"
+           summary="Table of Contents">
+      <tr>
+        <th>
+          Table of Contents        </th>
+      </tr>
+
+      <tr>
+        <td>
+          <ul>
+            <li>
+              <a href="#about">About this 'How-To'</a>
+            </li>
+            <li>
+              <a href="#choice">Image choice is crucial</a>
+            </li>
+            <li>
+              <a href="#prepare_mask">Prepare the mask</a>
+            </li>
+            <li>
+              <a href="#replace_fringe">Replace the fringe and junk pixels</a>
+            </li>
+            <li>
+              <a href="#save">Save the image for Tux Paint</a>
+            </li>
+          </ul>
+        </td>
+      </tr>
+    </table>
+
+    <hr size="2"
+        noshade>
+
+    <hr size="2"
+        noshade>
+
     <h2>
-      About this 'How-To'    </h2>
+      <a name="about" id="about">
+        About this 'How-To'      </a>
+    </h2>
 
     <blockquote>
       <p>
@@ -36,8 +82,13 @@
         This 'How-To' assumes you are dealing with normal opaque objects. Dealing with semi-transparent objects (fire, moving fan blade, kid's balloon) or light-giving objects (fire, lightbulb, sun) is best done with custom software. Images with perfect solid-color backgrounds are also best done with custom software, but are not troublesome to do as follows.      </p>
     </blockquote>
 
+    <hr size="2"
+        noshade>
+
     <h2>
-      Image choice is crucial    </h2>
+      <a name="choice" id="choice">
+        Image choice is crucial      </a>
+    </h2>
 
     <blockquote>
       <h3>
@@ -78,6 +129,9 @@
       </blockquote>
     </blockquote>
 
+    <hr size="2"
+        noshade>
+
     <h2>
       Prepare the image    </h2>
 
@@ -116,8 +170,13 @@
         <b>Warning:</b> once you have the mask, you may not rotate or scale the image normally. This would cause data loss. You will be given special scaling instructions later.      </p>
     </blockquote>
 
+    <hr size="2"
+        noshade>
+
     <h2>
-      Prepare the mask    </h2>
+      <a name="prepare_mask" id="prepare_mask">
+        Prepare the mask      </a>
+    </h2>
 
     <blockquote>
       <p>
@@ -151,8 +210,13 @@
         View and edit the mask. Select by color, choosing either black or white. Most likely you will see unselected specks that are not quite the expected color. Invert the selection, then paint these away using the pencil tool. Do this operation for both white and black.      </p>
     </blockquote>
 
+    <hr size="2"
+        noshade>
+
     <h2>
-      Replace the fringe and junk pixels    </h2>
+      <a name="replace_fringe" id="replace_fringe">
+        Replace the fringe and junk pixels      </a>
+    </h2>
 
     <blockquote>
       <p>
@@ -188,8 +252,13 @@
         Tux Paint can scale images down by a very large factor, so it is important to extend the edge of your object outward by a great deal. Right at the edge of your object, you should be very accurate about this. As you go outward away from the object, you can get a bit sloppy. It is reasonable to paint outward by a dozen pixels or more. The farther you go, the more Tux Paint can scale down without creating ugly color fringes. For areas that are more than a few pixels away from the object edge, you should use the pencil tool (or sloppy select with drag-and-drop color) to ensure that the result will compress well.      </p>
     </blockquote>
 
+    <hr size="2"
+        noshade>
+
     <h2>
-      Save the image for Tux Paint    </h2>
+      <a name="save" id="save">
+        Save the image for Tux Paint      </a>
+    </h2>
 
     <blockquote>
       <p>