Encode blurhashes in the app

src/Logic.purs

@@ -2,7 +2,7 @@ module Aviary.Logic where
 
 import Prelude
 import AviaryFormat.Format (Format(..), Image, Index, parseIndex) as Format
-import Aviary.FFI (arrayBufferToBlob, nonce)
+import Aviary.FFI (arrayBufferToBlob, nonce, decodeBlurhash32)
 import Aviary.Model (formatToMime, GalleryError(..), Image, ImageData(..), ImageError(..), Model(..))
 
 import Control.Monad.Error.Class (try)
@@ -60,10 +60,11 @@ convertImageFromProtobuf protoimage = let protoimage' = unwrap protoimage in do
     thumbUrl <- note (IndexMissingField "images[].thumb_url") protoimage'.thumb_url
     blurhash <- note (IndexMissingField "images[].blurhash") protoimage'.blurhash
     format <- note (IndexMissingField "images[].format") protoimage'.format
+    let blurhashUrl = decodeBlurhash32 blurhash
     let key = hush <$> (importKey =<< liftEffect (databuffToBuffer $ unwrap rawKey))
     let thumb = Unloaded thumbUrl
     let full = Unloaded fullUrl
-    pure { key, blurhash, format, thumb, full }
+    pure { key, blurhashUrl, format, thumb, full }
 
 convertIndexFromProtobuf :: Format.Index -> Model
 convertIndexFromProtobuf protoindex =

src/Model.purs

@@ -5,7 +5,7 @@ import Prelude
 import AviaryFormat.Format (Format(..)) as Format
 
 import Crypto.Subtle.Key.Types (CryptoKey)
-import Data.Maybe (Maybe)
+import Data.Maybe (Maybe(..))
 import Effect.Aff (Aff)
 
 data GalleryError
@@ -41,7 +41,7 @@ instance showImageData :: Show ImageData where
 
 type Image =
     { key :: Aff (Maybe CryptoKey)
-    , blurhash :: String
+    , blurhashUrl :: Maybe String
     , format :: Format.Format
     , thumb :: ImageData
     , full :: ImageData
@@ -58,6 +58,17 @@ data Model
     = GError GalleryError
     | GLoaded LoadedGallery
 
+imgOrBlurhash :: (Image -> ImageData) -> Image -> Maybe String
+imgOrBlurhash idealData image = case idealData image of
+    ILoaded url -> Just url
+    _ -> image.blurhashUrl
+
+thumbOrBlurhash :: Image -> Maybe String
+thumbOrBlurhash = imgOrBlurhash _.thumb
+
+fullOrBlurhash :: Image -> Maybe String
+fullOrBlurhash = imgOrBlurhash _.full
+
 instance showGalleryError :: Show GalleryError where
     show (UnexpectedError message) =
         "Something that should be impossible just happened!  Please open up a new issue "

src/UI.purs

@@ -3,7 +3,13 @@ module Aviary.UI where
 import Prelude
 
 import Aviary.Logic (fetchFull, fetchThumb)
-import Aviary.Model (GalleryError(..), Image, ImageData(..), Model(..))
+import Aviary.Model ( fullOrBlurhash
+                    , GalleryError(..)
+                    , Image
+                    , ImageData(..)
+                    , Model(..)
+                    , thumbOrBlurhash
+                    )
 
 import Control.Parallel (parSequence_)
 import Data.Array (index, mapWithIndex, modifyAt)
@@ -27,9 +33,6 @@ component initialState = H.mkComponent
     , eval: H.mkEval $ H.defaultEval { handleAction = update, initialize = Just LoadThumbs }
     }
 
-placeholderBlurhash :: forall r i. String -> HH.IProp r i
-placeholderBlurhash = HH.attr (HH.AttrName "data-blurhash")
-
 renderThumbnail :: forall m. Int -> Image -> H.ComponentHTML Event () m
 renderThumbnail pos image =
     HH.div
@@ -37,13 +40,9 @@ renderThumbnail pos image =
         , HE.onClick \_ -> Focus pos
         ]
         ( [ HH.img
-            ( [ placeholderBlurhash image.blurhash
-                , HP.width 400
-                , HP.height 400
-            ] <> case image.thumb of
-                ILoaded url -> [HP.src url]
-                _ -> []
-            )
+            ( [ HP.width 400
+              , HP.height 400
+            ] <> maybe [] (HP.src >>> pure) (thumbOrBlurhash image))
         ] <> case image.thumb of
             Unloaded _ -> [HH.p_ [HH.text "Loading..."]]
             IError e -> [HH.p_ [HH.text $ "Error!  " <> (show e)]]
@@ -51,18 +50,14 @@ renderThumbnail pos image =
         )
 
 renderFocused :: forall m. Image -> H.ComponentHTML Event () m
-renderFocused {blurhash, full} =
+renderFocused image =
     HH.div
         [ HP.class_ $ ClassName "focused-panel"
         , HP.class_ $ ClassName "visible"
         ]
-        ( [ HH.img
-            ( [ placeholderBlurhash blurhash ]
-            <> case full of
-                ILoaded url -> [HP.src url]
-                _ -> []
-            )
-        ] <> case full of
+        ( [ HH.img $
+            maybe [] (HP.src >>> pure) (fullOrBlurhash image)
+        ] <> case image.full of
             Unloaded _ -> [HH.p_ [HH.text "Loading..."]]
             IError e -> [HH.p_ [HH.text $ "Error!  " <> (show e)]]
             _ -> []

src/ffi.js

@@ -5,3 +5,19 @@ export function arrayBufferToBlob(mime) {
 }
 
 export const nonce = new Uint8Array([0xd0, 0xc3, 0x75, 0x56, 0x58, 0xc1, 0x7e, 0x5f, 0xd6, 0xcc, 0xb6, 0x76]).buffer
+
+export function decodeBlurhashImpl(just) {
+	return function(nothing) {
+		return function(x) {
+			return function(y) {
+				return function(blurhash) {
+					try {
+						return just(BlurHash.toDataURL(blurhash, x, y))
+					} catch(_) {
+						return nothing
+					}
+				}
+			}
+		}
+	}
+}

src/ffi.purs

@@ -1,6 +1,7 @@
 module Aviary.FFI where
 
 import Data.ArrayBuffer.Types (ArrayBuffer)
+import Data.Maybe (Maybe(..))
 import Web.File.Blob (Blob)
 
 -- mimeType :: String
@@ -8,3 +9,9 @@ import Web.File.Blob (Blob)
 foreign import arrayBufferToBlob :: String -> ArrayBuffer -> Blob
 
 foreign import nonce :: ArrayBuffer
+
+foreign import decodeBlurhashImpl :: (forall x. x -> Maybe x) -> (forall x. Maybe x) -> Int -> Int -> String -> Maybe String
+decodeBlurhash :: Int -> Int -> String -> Maybe String
+decodeBlurhash = decodeBlurhashImpl Just Nothing
+decodeBlurhash32 :: String -> Maybe String
+decodeBlurhash32 = decodeBlurhash 32 32