Add goo filter example.

README.md

@@ -24,6 +24,7 @@ Live coding playground: https://lemmih.github.io/reanimate/
 The example gifs are displayed at 25 fps. The source code for many of these examples are available
 on the live coding playground.
 
+![Goo](gifs/goo.gif)
 ![Drawing LaTeX equations](gifs/latex_draw.gif)
 ![Bounding boxes](gifs/bbox.gif)
 ![Colorful LaTeX](gifs/latex_color.gif)

src/Reanimate/Examples.hs

@@ -751,3 +751,55 @@ drawSunflower = mkAnimation 10 $ do
     sunflower n = frame 4 $ position $ take n $ zip mkCoords florets
       where
         florets = [ floret (sqrt (fromIntegral i)) | i <- [1 ..]]
+
+mkFilter :: String -> [FilterElement] -> Filter
+mkFilter ident fe = defaultSvg & filterChildren .~ fe & attrId .~ Just ident
+
+gooEffect :: Animation
+gooEffect = mkAnimation 5 $ do
+  s <- oscillate $ signal 0 3
+  emit $ mkBackground "black"
+  emit $ FilterTree $ mkFilter "blur"
+    [FEGaussianBlur $ defaultSvg
+      & gaussianBlurStdDeviationX .~ Num dev
+      & filterResult .~ Just "blur"
+    ] & filterWidth .~ pure (Percent 3)
+      & filterX .~ pure (Percent (-1))
+      & filterHeight .~ pure (Percent 3)
+      & filterY .~ pure (Percent (-1))
+  emit $ FilterTree $ mkFilter "goo"
+    [FEGaussianBlur $ defaultSvg
+      & gaussianBlurStdDeviationX .~ Num dev
+      & filterResult .~ Just "blur"
+    ,FEColorMatrix $ defaultSvg
+      & colorMatrixType .~ Matrix
+      & colorMatrixValues .~ "1 0 0 0 0 \
+                             \0 1 0 0 0 \
+                             \0 0 1 0 0 \
+                             \0 0 0 " ++ show (sharpness*2) ++ " -" ++ show sharpness
+      & filterResult .~ pure "goo"
+    ,FEComposite $ defaultSvg
+      & compositeIn .~ pure SourceGraphic
+      & compositeIn2 .~ pure (SourceRef "goo")
+      & compositeOperator .~ CompositeAtop
+    ] & filterHeight .~ pure (Percent 3)
+      & filterY .~ pure (Percent (-1))
+  emit $ translate 0 (-radius*2) $ withFillColor "red" $ mkGroup
+    [ translate (s*(-radius)) 0 circ
+    , translate (s*radius) 0 circ
+    ]
+  emit $ withFillColor "red" $ mkGroup
+    [ translate (s*(-radius)) 0 circ
+    , translate (s*radius) 0 circ
+    ]
+    & filterRef .~ pure (Ref "blur")
+  emit $ translate 0 (radius*2) $ withFillColor "red" $ set filterRef (pure $ Ref "goo")
+    $ mkGroup [ translate (s*(-radius)) 0 circ
+              , translate (s*radius) 0 circ ]
+  where
+    sharpness = 60
+    dev = 10
+    radius = 25
+    circ = CircleTree $ defaultSvg
+      & circleCenter .~ (Num 0, Num 0)
+      & circleRadius .~ Num radius