Restore the 'valentine' example.

Former-commit-id: 1bfd8ed5fcef2e54f0033f5ac5b3a667bc74f913

web/src/Presets.jsx

@@ -151,8 +151,48 @@ animation = mkAnimation 1 $ do
       withSubglyphs [4] (withFillColor "darkslategrey") $
       svg
   where
-    svg = scale 10 $ center $ latex "\\\\LaTeX"`
+    svg = scale 10 $ center $ latex "\\\\LaTeX"`;
 
+const valentine =
+`animation :: Animation
+animation =
+    all_red \`before\`
+    ( background \`sim\`
+      (backgroundDelay \`before\`
+       foldr1 sim [ pause p \`before\` fallingLove x | (p, x) <- falling ]
+     ) \`sim\`
+      (heart_ani \`before\` heart_disappear) \`sim\`
+      (pause 5 \`before\` message ai)
+    )
+  where
+    falling = [(6.4, 0.09), (4.9, 0.12), (4.5, 0.88), (0.3, 0.43), (5.3, 0.93)
+              ,(0.1, 0.80), (1.1, 0.39), (2.3, 0.21), (2.9, 0.77), (3.4, 0.46)
+              ,(6.2, 0.19), (5.9, 0.53), (3.2, 0.14), (7.7, 0.99) ]
+    ai = center $ xelatex "爱"
+    all_red = mkAnimation 1 $ emit $ mkBackground "red"
+    background = mkAnimation 2 $ do
+      n <- round <$> signal 0 0xFF
+      emit $ mkBackgroundPixel $ PixelRGBA8 0xFF n n 0xFF
+    backgroundDelay = pause (duration background-1)
+    heart_ani = repeatAnimation 10 $ mkAnimation 1 $ do
+      n <- oscillate $ signalSCurve 2 0.9 1.1
+      mapF (scale n) $ drawHeart
+    heart_disappear = mkAnimation 3 $ do
+      n  <- signal 0.9 10
+      mapF (scale n) drawHeart
+    fallingLove xPos = mkAnimation 2 $ do
+      n <- signal (-100) 100
+      o <- oscillate $ signal (-1) 1
+      emit $ scale 2 $ withFillColor "red" $
+        translate ((xPos*2-1)*60) n $ rotate (45*o) ai
+    message txt = mkAnimation 1 $ do
+      o <- oscillate $ signal 0 1
+      n <- oscillate $ signalSCurve 2 0.9 1.1
+      emit $ scale n $ scale 2 $ withFillColor "white" $ withFillOpacity o txt
+
+    drawHeart = emit $ withFillColor "red" $ heartShape
+    hex n = if n < 0x10 then "0" ++ showHex (round n) ""
+            else showHex (round n) ""`;
 
 export default [
   { name: "Examples"
@@ -165,6 +205,7 @@ export default [
     , {name: "Morphwave", code: morph_wave }
     , {name: "Morphwave Circle", code: morph_wave_circle }
     , {name: "Progress meters", code: progressMeters }
+    , {name: "Valentine", code: valentine }
     // , {name: "Highlight", code: highlight }
     ]
   },