Wrap ImGuiIO

Main.hs

@@ -5,6 +5,7 @@
 
 module Main (main) where
 
+import Data.StateVar
 import Data.IORef
 import DearImGui
 import DearImGui.OpenGL
@@ -23,6 +24,11 @@ main = do
     bracket createContext destroyContext \_imguiContext ->
     bracket_ (sdl2InitForOpenGL w glContext) sdl2Shutdown $
     bracket_ openGL2Init openGL2Shutdown do
+      iniFilename $= Just "imgui_state.ini"
+
+      putStr "State stored in: "
+      get iniFilename >>= print
+
       checkVersion
       styleColorsLight
 

dear-imgui.cabal

@@ -120,7 +120,7 @@ library
 executable test
   main-is: Main.hs
   default-language: Haskell2010
-  build-depends: base, sdl2, gl, dear-imgui
+  build-depends: base, sdl2, gl, dear-imgui, StateVar
   ghc-options: -Wall
 
 

src/DearImGui.hs

@@ -1,6 +1,7 @@
 {-# LANGUAGE BlockArguments #-}
 {-# LANGUAGE DuplicateRecordFields #-}
 {-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE NamedFieldPuns #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE PatternSynonyms #-}
@@ -27,6 +28,9 @@ module DearImGui
   , getDrawData
   , checkVersion
 
+    -- ** @ImGUIIO@
+  , iniFilename
+
     -- * Demo, Debug, Information
   , showDemoWindow
   , showMetricsWindow
@@ -126,7 +130,7 @@ import qualified Language.C.Inline.Cpp as Cpp
 
 -- StateVar
 import Data.StateVar
-  ( HasGetter(get), HasSetter, ($=!) )
+  ( HasGetter(get), HasSetter, StateVar(..), ($=!) )
 
 -- transformers
 import Control.Monad.IO.Class
@@ -196,6 +200,24 @@ checkVersion = liftIO do
   [C.exp| void { IMGUI_CHECKVERSION(); } |]
 
 
+-- | Path to @.ini@ file. Set to 'Nothing' to disable automatic .ini
+-- loading/saving, if e.g. you want to manually load/save from memory.
+iniFilename :: StateVar (Maybe String)
+iniFilename = StateVar getter setter
+  where
+    getter = do
+      cStr <- [C.exp| const char* { GetIO().IniFilename } |]
+      if cStr == nullPtr then return Nothing else Just <$> peekCString cStr
+
+    setter = \case
+      Nothing ->
+        [C.block| void { GetIO().IniFilename = $(char* nullPtr); } |]
+
+      Just str -> do
+        strPtr <- newCString str
+        [C.block| void { GetIO().IniFilename = $(char* strPtr); } |]
+
+
 -- | Create demo window. Demonstrate most ImGui features. Call this to learn
 -- about the library! Try to make it always available in your application!
 showDemoWindow :: MonadIO m => m ()