diff --git a/CHANGELOG b/CHANGELOG
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,8 @@
+0.8.3
+
+* Add `defaultArgs` and `generateJsonData` for using eventlog2html as a library
+* Update to hvega-0.11
+
 0.8.2, release 2020-12-17
 
 * Fix initialisation of fancyTable (#137)
diff --git a/eventlog2html.cabal b/eventlog2html.cabal
--- a/eventlog2html.cabal
+++ b/eventlog2html.cabal
@@ -1,6 +1,6 @@
 cabal-version:       2.4
 Name:                eventlog2html
-Version:             0.8.2
+Version:             0.8.3
 Synopsis:            Visualise an eventlog
 Description:         eventlog2html is a library for visualising eventlogs.
                      At the moment, the intended use is to visualise eventlogs
@@ -34,8 +34,7 @@
 
 Library
   Build-depends:
-    cpu,
-    aeson                >= 1.4.3 && < 1.5,
+    aeson                >= 1.4.3 && < 1.6,
     attoparsec           >= 0.13.2 && < 0.14,
     array                >= 0.5.3 && < 0.6,
     base                 >= 4 && < 5,
@@ -46,7 +45,7 @@
     filepath             >= 1.4.2 && < 1.5,
     ghc-events           >= 0.13.0 && < 0.14,
     hashtables           >= 1.2.3 && < 1.3,
-    hvega                >= 0.6.0 && < 0.7,
+    hvega                >= 0.11.0 && < 0.12,
     mtl                  >= 2.2.2 && < 2.3,
     optparse-applicative >= 0.14.3 && < 0.16,
     semigroups           >= 0.18 && < 0.20,
@@ -55,9 +54,7 @@
     vector               >= 0.11,
     trie-simple          >= 0.4,
     hashable             >= 1.0,
-    directory,
-    strict,
-    statistics-linreg,
+    statistics-linreg    >= 0.3,
     ghc-heap
 
   GHC-options:         -Wall
@@ -89,7 +86,7 @@
   build-depends:
       base >= 4 && < 5,
       eventlog2html,
-      aeson                >= 1.4.3 && < 1.5,
+      aeson                >= 1.4.3 && < 1.6,
       text                 >= 1.2.3 && < 1.3,
       filepath             >= 1.4.2 && < 1.5
 
diff --git a/src/Eventlog/Args.hs b/src/Eventlog/Args.hs
--- a/src/Eventlog/Args.hs
+++ b/src/Eventlog/Args.hs
@@ -7,6 +7,7 @@
   , argsInfo
   , Args(..)
   , Sort(..)
+  , defaultArgs
   ) where
 
 import Options.Applicative
@@ -117,6 +118,11 @@
 
 args :: IO Args
 args = execParser argsInfo
+
+
+defaultArgs :: FilePath -> IO Args
+defaultArgs fp = handleParseResult (execParserPure defaultPrefs argsInfo [fp])
+
 
 argsInfo :: ParserInfo Args
 argsInfo = opts
diff --git a/src/Eventlog/Data.hs b/src/Eventlog/Data.hs
--- a/src/Eventlog/Data.hs
+++ b/src/Eventlog/Data.hs
@@ -1,5 +1,5 @@
 {-# LANGUAGE OverloadedStrings #-}
-module Eventlog.Data (generateJson, generateJsonValidate ) where
+module Eventlog.Data (generateJson, generateJsonValidate, generateJsonData ) where
 
 import Prelude hiding (readFile)
 import Data.Aeson (Value(..), (.=), object)
@@ -18,11 +18,8 @@
 import Eventlog.Detailed
 import Text.Blaze.Html
 
-generateJsonValidate :: (ProfData -> IO ()) -> FilePath -> Args -> IO (Header, Value, Maybe Value, Maybe Html)
-generateJsonValidate validate file a = do
-  let chunk = if heapProfile a then H.chunk else E.chunk a
-  dat@(ProfData h binfo ccMap fs traces _ipes) <- chunk file
-  validate dat
+generateJsonData :: Args -> ProfData -> IO (Header, Value, Maybe Value, Maybe Html)
+generateJsonData a (ProfData h binfo ccMap fs traces _ipes) = do
   let keeps = pruneBands a binfo
       bs = bands h (Map.map fst keeps) fs
       combinedJson = object [
@@ -49,4 +46,12 @@
 
 generateJson :: FilePath -> Args -> IO (Header, Value, Maybe Value, Maybe Html)
 generateJson = generateJsonValidate (const (return ()))
+
+generateJsonValidate :: (ProfData -> IO ()) -> FilePath
+                     -> Args -> IO (Header, Value, Maybe Value, Maybe Html)
+generateJsonValidate validate file a = do
+  let chunk = if heapProfile a then H.chunk else E.chunk a
+  dat <- chunk file
+  validate dat
+  generateJsonData a dat
 
diff --git a/src/Eventlog/VegaTemplate.hs b/src/Eventlog/VegaTemplate.hs
--- a/src/Eventlog/VegaTemplate.hs
+++ b/src/Eventlog/VegaTemplate.hs
@@ -104,7 +104,7 @@
             , MSort [ByFieldOp "k" Max, Descending]
             , MLegend [LNoTitle]]
     . position X [PName "x", PmType Quantitative, PAxis [AxTitle ""]
-                 ,PScale [SDomain (DSelection "brush")]]
+                 ,PScale [SDomainOpt (DSelection "brush")]]
     . position Y [PName "norm_y", PmType Quantitative, PAxis [AxTitle "Allocation", AxFormat ".1f"]]
 
 transformLineLayer :: [TransformSpec] -> (VLProperty, VLSpec)
@@ -185,7 +185,7 @@
         , [TName "c", TmType Nominal, TTitle "Type"]
         ]
     . position X [PName "x", PmType Quantitative, PAxis [AxTitle ""]
-                 , PScale [SDomain (DSelection "brush")]]
+                 , PScale [SDomainOpt (DSelection "brush")]]
     . position Y ([PName "y"
                  , PmType Quantitative
                  , PAxis $ case ct of
@@ -225,7 +225,7 @@
   encoding
     . color [MString "grey"]
     . position X [PmType Quantitative, PAxis [], PName "tx"
-                 , PScale [SDomain (DSelection "brush")] ]
+                 , PScale [SDomainOpt (DSelection "brush")] ]
     . VL.size [MNumber 2]
     . tooltip [TName "desc", TmType Nominal]