use corner spinner on item page, and fix delay bug

Fading the whole preview to a black overlay for the loading state was feeling aggressive, especially since loading delay wasn't working correctly!

In this change, I fix loading delay, and I add a nice subtle "corner" variant for outfit preview spinners :)

src/app/HomePage.js

@@ -40,7 +40,7 @@ function HomePage() {
           colorId={previewState?.colorId}
           pose={previewState?.pose}
           wornItemIds={[]}
-          loadingDelay="1.5s"
+          loadingDelayMs={1500}
           placeholder={
             <Box
               as="img"

src/app/ItemPage.js

@@ -383,6 +383,8 @@ function ItemPageOutfitPreview({ itemId }) {
           colorId="8"
           pose="HAPPY_FEM"
           wornItemIds={[itemId]}
+          spinnerVariant="corner"
+          loadingDelayMs={2000}
         />
       </Box>
     </AspectRatio>

src/app/components/HangerSpinner.js

@@ -86,12 +86,7 @@ function HangerSpinner({ size = "md", ...props }) {
         `}
         {...props}
       >
-        <HangerIcon
-          boxSize={boxSize}
-          color={color}
-          transition="color 0.2s"
-          {...props}
-        />
+        <HangerIcon boxSize={boxSize} color={color} transition="color 0.2s" />
       </Box>
     </>
   );

src/app/components/OutfitPreview.js

@@ -1,7 +1,7 @@
 import React from "react";
 import { css, cx } from "emotion";
 import { CSSTransition, TransitionGroup } from "react-transition-group";
-import { Box, Flex, DarkMode, Text } from "@chakra-ui/core";
+import { Box, DarkMode, Flex, Text } from "@chakra-ui/core";
 import { WarningIcon } from "@chakra-ui/icons";
 
 import HangerSpinner from "./HangerSpinner";
@@ -25,10 +25,11 @@ function OutfitPreview({
   speciesId,
   colorId,
   pose,
-  appearanceId = null,
   wornItemIds,
+  appearanceId = null,
   placeholder,
-  loadingDelay,
+  loadingDelayMs,
+  spinnerVariant,
 }) {
   const { loading, error, visibleLayers } = useOutfitAppearance({
     speciesId,
@@ -55,15 +56,14 @@ function OutfitPreview({
   }
 
   return (
-    <DarkMode>
     <OutfitLayers
       loading={loading || loading2}
       visibleLayers={loadedLayers}
       placeholder={placeholder}
-        loadingDelay={loadingDelay}
+      loadingDelayMs={loadingDelayMs}
+      spinnerVariant={spinnerVariant}
       doAnimations
     />
-    </DarkMode>
   );
 }
 
@@ -75,13 +75,18 @@ export function OutfitLayers({
   loading,
   visibleLayers,
   placeholder,
-  loadingDelay = "0.5s",
+  loadingDelayMs = 500,
+  spinnerVariant = "overlay",
   doAnimations = false,
 }) {
-  const [isMounted, setIsMounted] = React.useState(false);
-  React.useLayoutEffect(() => {
-    setIsMounted(true);
-  }, []);
+  const [loadingDelayHasPassed, setLoadingDelayHasPassed] = React.useState(
+    false
+  );
+
+  React.useEffect(() => {
+    const t = setTimeout(() => setLoadingDelayHasPassed(true), loadingDelayMs);
+    return () => clearTimeout(t);
+  }, [loadingDelayMs]);
 
   return (
     <Box
@@ -164,14 +169,14 @@ export function OutfitLayers({
         zIndex="9000"
         // This is similar to our Delay util component, but Delay disappears
         // immediately on load, whereas we want this to fade out smoothly. We
-        // also delay the fade-in by 0.5s, but don't delay the fade-out at all.
-        //
-        // We also use `isMounted` here to make sure it actually _fades_ in!
-        // (This starts the opacity at 0, then fires an immediate callback to
-        // set it to 1, triggering the transition.)
-        opacity={isMounted && loading ? 1 : 0}
-        transition={`opacity 0.2s ${loading ? loadingDelay : "0s"}`}
+        // also use a timeout to delay the fade-in by 0.5s, but don't delay the
+        // fade-out at all. (The timeout was an awkward choice, it was hard to
+        // find a good CSS way to specify this delay well!)
+        opacity={loading && loadingDelayHasPassed ? 1 : 0}
+        transition="opacity 0.2s"
       >
+        {spinnerVariant === "overlay" && (
+          <>
             <Box
               position="absolute"
               top="0"
@@ -181,7 +186,15 @@ export function OutfitLayers({
               backgroundColor="gray.900"
               opacity="0.7"
             />
+            {/* Against the dark overlay, use the Dark Mode spinner. */}
+            <DarkMode>
               <HangerSpinner />
+            </DarkMode>
+          </>
+        )}
+        {spinnerVariant === "corner" && (
+          <HangerSpinner size="sm" position="absolute" bottom="2" right="2" />
+        )}
       </FullScreenCenter>
     </Box>
   );