Feature morph (#62)

* Disable windows CI (because of hmatrix)
* Implement ear-clip triangulation.
* Implement common framework for polygon morphing.
* Draft implementations of compatible triangulation and mesh smoothing.
* Implement least-work morphing.
* Implement as-rigid-as-possible morphing.
* Implement SSSP.
* Draft article about polygon morphing.

Former-commit-id: f6f19f58b9dd58c655bcca0ed2d65f72726f0a06

docs/index.md

@@ -1,3 +1,10 @@
+
+# Reanimate is:
+ * **An animation library** - a system for turning code into movies, similar to [3b1b's manim](https://github.com/3b1b/manim) of [YouTube fame](https://www.youtube.com/channel/UCYO_jab_esuFRV4b17AJtAw).
+ * **User friendly** - extensively documented with example animations covering the [entire API](http://hackage.haskell.org/package/reanimate/docs/Reanimate.html).
+ * **Cross-platform** - works on Linux, Mac and Windows.
+
+
 # Getting started
 
 ## Viewing a basic animation
@@ -6,19 +13,87 @@
 $ git clone https://github.com/Lemmih/reanimate.git
 $ cd reanimate/
 $ stack build
-$ stack ./examples/raster.hs
+$ stack ./examples/doc_andThen.hs
 ```
 
+Running the above code should open a browser window containing this animation:
+
+<details>
+  <summary>Toggle doc_andThen.hs source code.</summary>
+  <pre><code class="haskell">
+  {!examples/doc_andThen.hs!}
+  </code></pre>
+</details>
+<br/>
+<video width="640" height="360" muted autoplay loop>
+  <source src="https://i.imgur.com/bvLqalX.mp4">
+</video>
+
+
 ## Checking dependencies
 
-Reanimate includes a run-time for optional dependencies.
+If something doesn't work, you can run a check for run-time dependencies like
+this:
 
 ```console
-$ stack ./examples/raster.hs check
+$ stack ./examples/doc_andThen.hs check
+reanimate checks:
+  Has ffmpeg:                        4.1.3-0ubuntu1
+  Has dvisvgm:                       /usr/bin/dvisvgm
+  Has povray:                        /usr/bin/povray
+  Has blender:                       2.82
+  Has rsvg-convert:                  2.44.10
+  Has inkscape:                      0.92.4
+  Has convert:                       6.9.10-14
+  Has LaTeX:                         /usr/bin/latex
+  Has LaTeX package 'babel':         OK
+  Has LaTeX package 'preview':       OK
+  Has LaTeX package 'amsmath':       OK
+  Has XeLaTeX:                       /usr/bin/xelatex
+  Has XeLaTeX package 'ctex':        OK
 ```
 
-## Rendering movies
+None of these dependencies are vital but the functionality of **reanimate**
+will be reduced if they are missing. For example, without 'ffmpeg', you won't
+be able to generate stand-alone video files (but can still view animations
+in a browser window). Without 'LaTeX' and 'dvisvgm', you won't be able use
+LaTeX for typesetting.
+
+## Rendering animations
+
+**reanimate** has builtin support for rendering animations to video files and
+gifs. To render an animation with default options, use the 'render' command:
 
 ```console
-$ stack ./examples/raster.hs render
+$ stack ./examples/doc_andThen.hs render
 ```
+
+For computationally intense animations, use the `--compile` flag to compile
+your animation script and run it using all available cores:
+
+```console
+$ stack ./examples/doc_andThen.hs render --compile
+```
+
+If the defaults are too aggressive for you tastes, change them directly or use
+a different preset:
+
+```console
+$ stack ./examples/doc_andThen.hs render --preset high --fps 10
+```
+
+Rendering to gifs automatically does two passes and uses a color palette to
+improve the quality and size of the gif. GIFs are, by default, rendered at
+24 fps with a resolution of 320x180:
+
+```console
+$ stack ./examples/doc_andThen.hs render --format gif
+```
+
+# Learning resources
+
+* [API documentation](http://hackage.haskell.org/package/reanimate/docs/Reanimate.html)
+* [Core concepts](introduction)
+* [Gallery](gallery)
+* [Examples](https://github.com/Lemmih/reanimate/tree/master/examples)
+* [Design overview](glue_tut)