Add more detail to the doc and the README file

PackageInfo.g

@@ -55,8 +55,6 @@ ArchiveURL     := Concatenation(~.PackageWWWHome,
                                 ~.Version),
 ArchiveFormats := ".tar.gz",
 
-AbstractHTML := "TODO",
-
 PackageDoc := rec(
   BookName  := "graphviz",
   ArchiveURLSubset := ["doc"],
@@ -75,4 +73,30 @@ Dependencies := rec(
 
 AvailabilityTest := ReturnTrue,
 
-TestFile := "tst/testall.g"));
+TestFile := "tst/testall.g",
+
+AutoDoc := rec(
+    TitlePage := rec(
+        Copyright := """&copyright; by J. D. Mitchell and M. Pancer.<P/>
+        &GAPGraphviz; is free software; you can redistribute it and/or modify
+        it, under the terms of the GNU General Public License, version 3 of
+        the License, or (at your option) any later, version.""",
+        Abstract := """
+        This package facilitates the creation and rendering of graph
+        descriptions in the &DOT; language of the &Graphviz; graph drawing
+        software from &GAP;.
+        <P/>
+
+        Create a graphviz object, assemble the graph by adding nodes and edges,
+        and retrieve its &DOT; source code string. Save the source code to a file
+        and render it with the &Graphviz; installation of your system.
+        <P/>
+
+        Use the <Ref Func="Splash"/> function to directly inspect the resulting
+        graph.
+        <P/>
+
+        This package was inspired by the python package of the same name
+        &PyGraphviz;.""")),
+
+AbstractHTML := ~.AutoDoc.TitlePage.Abstract));

README.md

@@ -1,16 +1,126 @@
-# The GAP package graphviz
+## README
 
-TODO: add a description of your package; perhaps also instructions how how to
-install and use it, resp. where to find out more
+### Graphviz package for GAP
 
-## Contact
+#### Copyright (C) 2024 by J. D. Mitchell and M. Pancer
 
-TODO: add info on how to contact you and/or how to report issues with your
-package
+## Graphviz for GAP
+
+This package facilitates the creation and rendering of graph
+descriptions in the [DOT][] language of the [Graphviz][] graph drawing
+software from [GAP][].
+
+You can create a graphviz object, assemble the graph by adding nodes and
+edges, attributes, labels, colours, subgraphs, and clusters, and
+retrieve its [DOT][] source code string. Save the source code to a file
+and render it with the [Graphviz] installation on your system.
+
+You can use the [Splash] function to directly inspect the resulting
+graph.
+
+This package was inspired by the python package of the same name
+[Python Graphviz][].
 
 ## License
 
-TODO: Provide information on the license of your package. A license is
-important as it determines who has a right to distribute your package. The
-"default" license to consider is GNU General Public License v2 or later, as
-that is the license of GAP itself.
+This package is distributed under the GNU General Public License v2 or later.
+See the `LICENSE` file for more details.
+
+## Links
+
+- GitHub: [https://github.com/digraphs/graphviz](https://github.com/digraphs/graphviz)
+- Documentation: TODO
+- Changelog: TODO
+- Issue Tracker: [https://github.com/digraphs/graphviz/issues](https://github.com/digraphs/graphviz/issues)
+- Download: TODO
+
+## Installation
+
+This package requires [GAP][] version 4.11.0 or higher.  The most
+up-to-date version of GAP, and instructions on how to install it, can be
+obtained from the [main GAP webpage](https://www.gap-system.org). This
+package has no further dependencies!
+
+### From sources
+
+To get the latest version of the package, download the archive file
+`graphviz-x.x.x.tar.gz` from the [Graphviz package for GAP webpage][].
+Then, inside the `pkg` subdirectory of your GAP installation, unpack the
+archive `graphviz-x.x.x.tar.gz` in your `gap/pkg` directory, using
+
+    gunzip graphviz-x.x.x.tar.gz; tar xvf graphviz-x.x.x.tar
+
+for example.  This will create a subdirectory `graphviz-x.x.x`.
+
+### Using the [PackageManager][]
+
+Start GAP in the usual way, then type:
+
+    LoadPackage("PackageManager");
+    InstallPackage("graphviz");
+
+## Quickstart
+
+Create a graph object:
+
+    gap> LoadPackage("graphviz");
+    ───────────────────────────────────────────────────────────────────────────────────
+    Loading graphviz 0.0.0 (TODO)
+    by James D. Mitchell (https://jdbm.me) and
+       Matthew Pancer (mp322@st-andrews.ac.uk).
+    Homepage: https://digraphs.github.io/graphviz
+    Report issues at https://github.com/digraphs/graphviz/issues
+    ───────────────────────────────────────────────────────────────────────────────────
+    true
+    gap> dot := GraphvizDigraph("The Round Table");
+    <graphviz digraph "The Round Table" with 0 nodes and 0 edges>
+
+Add nodes and edges:
+
+    gap> GraphvizSetAttr(GraphvizAddNode(dot, "A"), "label", "King Arthur");
+    <graphviz node "A">
+    gap> GraphvizSetAttr(GraphvizAddNode(dot, "B"), "label", "Sir Bedevere the Wise");
+    <graphviz node "B">
+    gap> GraphvizSetAttr(GraphvizAddNode(dot, "L"), "label", "Sir Lancelot the Brave");
+    <graphviz node "L">
+    gap> GraphvizAddEdge(dot, "A", "B");
+    <graphviz edge (A, B)>
+    gap> GraphvizAddEdge(dot, "A", "L");
+    <graphviz edge (A, L)>
+    gap> GraphvizSetAttr(GraphvizAddEdge(dot, "B", "L"), "constraint", false);
+
+Check the generated source code:
+
+    gap> Print(AsString(dot));
+    //dot
+    digraph {
+        A [label="King Arthur"]
+        B [label="Sir Bedevere the Wise"]
+        L [label="Sir Lancelot the Brave"]
+        A -> B
+        A -> L
+        B -> L [constraint=false]
+    }
+
+Save the source code:
+
+    gap> FileString("round-table.gv", AsString(dot));
+    134
+
+Render and view the result:
+
+    gap> Splash(dot);
+
+![The Round Table](https://raw.github.com/digraphs/graphviz/main/docs/png/The_Round_Table.png)
+
+## Issues
+
+For questions, remarks, suggestions, and issues please use the
+[issue tracker](https://github.com/digraphs/graphviz/issues).
+
+[DOT]: https://www.graphviz.org/doc/info/lang.html
+[GAP]: https://www.gap-system.org
+[Graphviz]: https://www.graphviz.org
+[Graphviz webpage]: https://digraphs.github.io/Digraphs
+[PackageManager]: https://gap-packages.github.io/PackageManager
+[Python Graphviz]: https://pypi.org/project/graphviz/