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

examples/morphology_linear.hs

@@ -0,0 +1,60 @@
+#!/usr/bin/env stack
+-- stack runghc --package reanimate
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE ParallelListComp  #-}
+module Main(main) where
+
+import           Codec.Picture
+import           Codec.Picture.Types
+import           Graphics.SvgTree         (LineJoin (..))
+import           Reanimate
+import           Reanimate.Morph.Common
+import           Reanimate.Morph.Linear
+
+bgColor :: PixelRGBA8
+bgColor = PixelRGBA8 252 252 252 0xFF
+
+main :: IO ()
+main = reanimate $
+  addStatic (mkBackgroundPixel bgColor) $
+  mapA (withStrokeWidth defaultStrokeWidth) $
+  mapA (withStrokeColor "black") $
+  mapA (withStrokeLineJoin JoinRound) $
+  mapA (withFillOpacity 1) $
+    sceneAnimation $
+      showPair (stages ++ take 1 stages)
+  where
+    showPair (from:to:rest) =
+      waitOn $ do
+        toS <- newSpriteSVG $
+          translate (4) 0 to
+        spriteE toS $ overBeginning 0.2 fadeInE
+        spriteE toS $ overEnding 0.2 fadeOutE
+        m <- fork $ newSpriteA $ animate (morph linear from to)
+          # signalA (curveS 4)
+          # mapA (translate (-4) 0)
+        wait 4
+        destroySprite m
+        destroySprite toS
+        showPair (to:rest)
+        return ()
+    showPair _ = return ()
+
+    stages = map (lowerTransformations . scale 8 . pathify . center) $ colorize
+      [ latex "X"
+      , latex "$\\aleph$"
+      , latex "Y"
+      , latex "$\\infty$"
+      , latex "I"
+      , latex "$\\pi$"
+      , latex "1"
+      , latex "S"
+      , mkRect 0.5 0.5
+      ]
+
+colorize :: [SVG] -> [SVG]
+colorize lst =
+  [ withFillColorPixel (promotePixel $ parula (n/fromIntegral (length lst-1))) elt
+  | elt <- lst
+  | n <- [0..]
+  ]