Allow megaparsec 9.2 (#112)

Closes #106

ChangeLog.md

@@ -1,5 +1,13 @@
 # Changelog for dear-imgui
 
+## [1.2.2]
+
+- `imgui` updated to 1.85.
+
+## [1.2.1]
+
+- Added `DearImGui.Raw.IO` with attribute setters.
+
 ## [1.2.0]
 
 - Fixed `nullPtr` in place of default arguments.
@@ -36,3 +44,4 @@ Initial Hackage release based on 1.83.
 [1.0.2]: https://github.com/haskell-game/dear-imgui.hs/tree/v1.0.2
 [1.1.0]: https://github.com/haskell-game/dear-imgui.hs/tree/v1.1.0
 [1.2.0]: https://github.com/haskell-game/dear-imgui.hs/tree/v1.2.0
+[1.3.0]: https://github.com/haskell-game/dear-imgui.hs/tree/v1.3.0

Main.hs

@@ -7,6 +7,7 @@ module Main (main) where
 
 import Control.Monad
 import Data.IORef
+import qualified Data.Vector as Vector
 import DearImGui
 import DearImGui.OpenGL3
 import DearImGui.SDL
@@ -131,6 +132,21 @@ loop window checked color slider r pos size' selected tab1Ref tab2Ref = do
 
   endChild
 
+  text "ListClipper"
+  withChildOpen "##fixed" (ImVec2 0 200) True ImGuiWindowFlags_None do
+    let lotsOfItems = Vector.generate 50 (mappend "Item " . show)
+    withListClipper Nothing lotsOfItems text
+
+  text "ListClipper, Haskell-powered"
+  withChildOpen "##infinite" (ImVec2 0 200) True ImGuiWindowFlags_None do
+    let infiniteItems = map (mappend "Item " . show) [0 :: Int ..]
+    withListClipper Nothing infiniteItems text
+
+  text "Ethereal ListClipper"
+  withChildOpen "##ethereal" (ImVec2 0 200) True ImGuiWindowFlags_None do
+    withListClipper Nothing (ClipRange (0 :: Int) 1000) $
+      text . mappend "Item " . show
+
   plotHistogram "A histogram" [ 10, 10, 20, 30, 90 ]
 
   colorPicker3 "Test" color

README.md

@@ -54,38 +54,35 @@ main = do
 
   runManaged do
     -- Create a window using SDL. As we're using OpenGL, we need to enable OpenGL too.
-    w <- do
+    window <- do
       let title = "Hello, Dear ImGui!"
       let config = defaultWindow { windowGraphicsContext = OpenGLContext defaultOpenGL }
       managed $ bracket (createWindow title config) destroyWindow
 
     -- Create an OpenGL context
-    glContext <- managed $ bracket (glCreateContext w) glDeleteContext
+    glContext <- managed $ bracket (glCreateContext window) glDeleteContext
 
     -- Create an ImGui context
     _ <- managed $ bracket createContext destroyContext
 
     -- Initialize ImGui's SDL2 backend
-    _ <- managed_ $ bracket_ (sdl2InitForOpenGL w glContext) sdl2Shutdown
+    _ <- managed_ $ bracket_ (sdl2InitForOpenGL window glContext) sdl2Shutdown
 
     -- Initialize ImGui's OpenGL backend
     _ <- managed_ $ bracket_ openGL2Init openGL2Shutdown
 
-    liftIO $ mainLoop w
+    liftIO $ mainLoop window
 
 
 mainLoop :: Window -> IO ()
-mainLoop w = do
+mainLoop window = unlessQuit do
-  -- Process the event loop
-  untilNothingM pollEventWithImGui
-
   -- Tell ImGui we're starting a new frame
   openGL2NewFrame
   sdl2NewFrame
   newFrame
 
   -- Build the GUI
-  bracket_ (begin "Hello, ImGui!") end do
+  withWindowOpen "Hello, ImGui!" do
     -- Add a text widget
     text "Hello, ImGui!"
 
@@ -103,12 +100,25 @@ mainLoop w = do
   render
   openGL2RenderDrawData =<< getDrawData
 
-  glSwapWindow w
+  glSwapWindow window
 
-  mainLoop w
+  mainLoop window
 
   where
-    untilNothingM m = m >>= maybe (return ()) (\_ -> untilNothingM m)
+    -- Process the event loop
+    unlessQuit action = do
+      shouldQuit <- checkEvents
+      if shouldQuit then pure () else action
+
+    checkEvents = do
+      pollEventWithImGui >>= \case
+        Nothing ->
+          return False
+        Just event ->
+          (isQuit event ||) <$> checkEvents
+
+    isQuit event =
+      SDL.eventPayload event == SDL.QuitEvent
 ```
 
 # Hacking

dear-imgui.cabal

@@ -1,7 +1,7 @@
 cabal-version: 3.0
 
 name: dear-imgui
-version: 1.2.0
+version: 1.2.2
 author: Oliver Charles
 maintainer: ollie@ocharles.org.uk, aenor.realm@gmail.com
 license: BSD-3-Clause
@@ -24,10 +24,45 @@ extra-source-files:
   imgui/imconfig.h,
   imgui/LICENSE.txt
 
+common build-flags
+  if flag(debug)
+    if os(linux)
+      ghc-options: -Wall -g -rtsopts -dcore-lint -debug
+      cc-options: -g -O0 -fsanitize=address -fno-omit-frame-pointer
+      cxx-options: -g -O0 -fsanitize=address -fno-omit-frame-pointer -std=c++11
+    if os(darwin)
+      ghc-options: -Wall -g -rtsopts -dcore-lint -debug
+      cc-options: -g -O0 -fsanitize=address -fno-omit-frame-pointer
+      cxx-options: -g -O0 -fsanitize=address -fno-omit-frame-pointer -std=c++11
+    if os(windows)
+      ghc-options: -Wall -g -rtsopts -dcore-lint -debug
+      cc-options: -g -O0
+      cxx-options: -g -O0 -std=c++11
+  else
+    if os(linux)
+      ghc-options: -Wall -O2
+      cc-options: -O2
+      cxx-options: -std=c++11 -O2
+    if os(darwin)
+      ghc-options: -Wall -O2
+      cc-options: -O2
+    if os(windows)
+      ghc-options: -Wall -O2
+      cc-options: -O2
+
+
 source-repository head
   type: git
   location: https://github.com/haskell-game/dear-imgui.hs
 
+flag debug
+  description:
+    Enable debug mode.
+  default:
+    False
+  manual:
+    True
+
 flag opengl2
   description:
     Enable OpenGL 2 backend.
@@ -82,8 +117,6 @@ common common
         >= 4.12 && < 4.17
   default-language:
       Haskell2010
-  ghc-options:
-      -Wall
 
 library
   import: common
@@ -92,18 +125,20 @@ library
   exposed-modules:
     DearImGui
     DearImGui.Raw
+    DearImGui.Raw.DrawList
+    DearImGui.Raw.ListClipper
+    DearImGui.Raw.IO
   other-modules:
     DearImGui.Context
     DearImGui.Enums
     DearImGui.Structs
+  cxx-options: -std=c++11
   cxx-sources:
     imgui/imgui.cpp
     imgui/imgui_demo.cpp
     imgui/imgui_draw.cpp
     imgui/imgui_tables.cpp
     imgui/imgui_widgets.cpp
-  cxx-options:
-    -std=c++11
   extra-libraries:
     stdc++
   include-dirs:
@@ -116,6 +151,7 @@ library
     , inline-c-cpp
     , StateVar
     , unliftio
+    , vector
 
   if flag(opengl2)
     exposed-modules:
@@ -218,7 +254,7 @@ library dear-imgui-generator
     , inline-c
         >= 0.9.0.0 && < 0.10
     , megaparsec
-        >= 9.0 && < 9.1
+        >= 9.0 && < 9.3
     , parser-combinators
         >= 1.2.0 && < 1.4
     , scientific
@@ -233,27 +269,26 @@ library dear-imgui-generator
         >= 0.2.11 && < 0.2.15
 
 executable test
-  import: common
+  import: common, build-flags
   main-is: Main.hs
   default-language: Haskell2010
-  ghc-options: -Wall
   if (!flag(examples) || !flag(sdl) || !flag(opengl2))
     buildable: False
   else
-    build-depends: base, sdl2, gl, dear-imgui
+    build-depends: base, sdl2, gl, dear-imgui, vector
 
 executable glfw
+  import: common, build-flags
   main-is: Main.hs
   hs-source-dirs: examples/glfw
   default-language: Haskell2010
-  ghc-options: -Wall
   if (!flag(examples) || !flag(glfw) || !flag(opengl2))
     buildable: False
   else
     build-depends: base, GLFW-b, gl, dear-imgui, managed
 
 executable readme
-  import: common
+  import: common, build-flags
   main-is: Readme.hs
   hs-source-dirs: examples
   build-depends: sdl2, gl, dear-imgui, managed
@@ -261,7 +296,7 @@ executable readme
     buildable: False
 
 executable image
-  import: common
+  import: common, build-flags
   main-is: Image.hs
   hs-source-dirs: examples/sdl
   build-depends: sdl2, gl, dear-imgui, managed, vector
@@ -269,12 +304,11 @@ executable image
     buildable: False
 
 executable vulkan
-  import: common
+  import: common, build-flags
   main-is: Main.hs
   other-modules: Attachments, Backend, Input, Util
   hs-source-dirs: examples/vulkan
   default-language: Haskell2010
-  ghc-options: -Wall
   if (!flag(examples) || !flag(sdl) || !flag(vulkan))
     buildable: False
   else

default.nix

@@ -4,12 +4,12 @@ haskellNix ? (import (import ./nix/sources.nix)."haskell.nix" { })
 # haskell.nix provides access to the nixpkgs pins which are used by our CI,
 # hence you will be more likely to get cache hits when using these.
 # But you can also just use your own, e.g. '<nixpkgs>'.
-, nixpkgsSrc ? haskellNix.sources.nixpkgs-2009
+, nixpkgsSrc ? haskellNix.sources.nixpkgs-2105
 
   # haskell.nix provides some arguments to be passed to nixpkgs, including some
   # patches and also the haskell.nix functionality itself as an overlay.
 , nixpkgsArgs ? haskellNix.nixpkgsArgs
-, compiler-nix-name ? "ghc884"
+, compiler-nix-name ? "ghc8107"
 }:
 let
   pkgs = import nixpkgsSrc nixpkgsArgs;

examples/Readme.hs

@@ -45,10 +45,7 @@ main = do
 
 
 mainLoop :: Window -> IO ()
-mainLoop window = do
+mainLoop window = unlessQuit do
-  -- Process the event loop
-  untilNothingM pollEventWithImGui
-
   -- Tell ImGui we're starting a new frame
   openGL2NewFrame
   sdl2NewFrame
@@ -78,4 +75,17 @@ mainLoop window = do
   mainLoop window
 
   where
-    untilNothingM m = m >>= maybe (return ()) (\_ -> untilNothingM m)
+    -- Process the event loop
+    unlessQuit action = do
+      shouldQuit <- checkEvents
+      if shouldQuit then pure () else action
+
+    checkEvents = do
+      pollEventWithImGui >>= \case
+        Nothing ->
+          return False
+        Just event ->
+          (isQuit event ||) <$> checkEvents
+
+    isQuit event =
+      SDL.eventPayload event == SDL.QuitEvent

examples/sdl/Image.hs

@@ -14,6 +14,7 @@ import Control.Monad.IO.Class (MonadIO(..))
 import Control.Monad.Managed (managed, managed_, runManaged)
 import DearImGui
 import qualified DearImGui.Raw as Raw
+import qualified DearImGui.Raw.DrawList as DrawList
 import DearImGui.OpenGL3
 import DearImGui.SDL
 import DearImGui.SDL.OpenGL
@@ -134,18 +135,18 @@ mainLoop window textures flag = unlessQuit do
   sdl2NewFrame
   newFrame
 
+  let texture = if flag then fst textures else snd textures
+  -- Drawing images require some backend-specific code.
+  -- Meanwhile, we have to deal with raw bindings.
+  let openGLtextureID = intPtrToPtr $ fromIntegral $ textureID texture
+
   -- Build the GUI
   clicked <- withWindow "Image example" \open ->
     if open then do
       text "That's an image, click it"
       newLine
 
-      let texture = if flag then fst textures else snd textures
+      -- Using imageButton
-
-      -- Drawing images require some backend-specific code.
-      -- Meanwhile, we have to deal with raw binding.
-      let openGLtextureID = intPtrToPtr $ fromIntegral $ textureID texture
-
       Foreign.with (textureSize texture) \sizePtr ->
         Foreign.with (ImVec2 0 0) \uv0Ptr ->
           Foreign.with (ImVec2 1 1) \uv1Ptr ->
@@ -155,6 +156,19 @@ mainLoop window textures flag = unlessQuit do
     else
       pure False
 
+  -- Using DrawList
+  bg <- getBackgroundDrawList
+  Foreign.with (ImVec2 100 100) \pMin ->
+    Foreign.with (ImVec2 200 200) \pMax ->
+      Foreign.with (ImVec2 0.25 0.25) \uvMin ->
+        Foreign.with (ImVec2 0.75 0.75) \uvMax ->
+          DrawList.addImageRounded
+            bg
+            openGLtextureID
+            pMin pMax uvMin uvMax
+            (Raw.imCol32 0 255 0 0xFF) -- Extract green channel
+            32 ImDrawFlags_RoundCornersBottom
+
   -- Render
   glClear GL_COLOR_BUFFER_BIT
 

src/DearImGui.hs

@@ -3,6 +3,7 @@
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE NamedFieldPuns #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE PatternSynonyms #-}
@@ -54,6 +55,7 @@ module DearImGui
 
     -- ** Utilities
 
+  , Raw.getWindowDrawList
   , Raw.getWindowPos
   , Raw.getWindowSize
   , Raw.getWindowWidth
@@ -172,11 +174,11 @@ module DearImGui
   , inputTextMultiline
   , inputTextWithHint
 
-    -- * Color Editor/Picker
+    -- ** Color Editor/Picker
   , colorPicker3
   , colorButton
 
-    -- * Trees
+    -- ** Trees
   , treeNode
   , treePush
   , Raw.treePop
@@ -187,7 +189,7 @@ module DearImGui
     -- ** List Boxes
   , listBox
 
-    -- * Data Plotting
+    -- ** Data Plotting
   , plotHistogram
 
     -- ** Menus
@@ -221,7 +223,7 @@ module DearImGui
   , tabItemButton
   , setTabItemClosed
 
-    -- * Tooltips
+    -- ** Tooltips
   , withTooltip
   , Raw.beginTooltip
   , Raw.endTooltip
@@ -252,6 +254,18 @@ module DearImGui
   , Raw.buildFontAtlas
   , Raw.clearFontAtlas
 
+    -- * Utilities
+
+    -- ** ListClipper
+  , withListClipper
+  , ClipItems(..)
+  , ClipRange(..)
+
+    -- ** Miscellaneous
+  , Raw.getBackgroundDrawList
+  , Raw.getForegroundDrawList
+  , Raw.imCol32
+
     -- * Types
   , module DearImGui.Enums
   , module DearImGui.Structs
@@ -290,7 +304,12 @@ import UnliftIO (MonadUnliftIO)
 import UnliftIO.Exception (bracket, bracket_)
 
 import qualified DearImGui.Raw as Raw
+import qualified DearImGui.Raw.ListClipper as Raw.ListClipper
 
+-- vector
+import qualified Data.Vector as V
+import qualified Data.Vector.Storable as VS
+import qualified Data.Vector.Unboxed as VU
 
 -- | Get the compiled version string e.g. "1.80 WIP" (essentially the value for
 -- @IMGUI_VERSION@ from the compiled version of @imgui.cpp@).
@@ -1690,3 +1709,86 @@ addFontFromFileTTF font size = liftIO do
     if castPtr ptr == nullPtr
       then Nothing
       else Just res
+
+-- | Clips a large list of items
+--
+-- The requirements on @a@ are that they are all of the same height.
+withListClipper :: (ClipItems t a, MonadUnliftIO m) => Maybe Float -> t a -> (a -> m ()) -> m ()
+withListClipper itemHeight items action =
+  bracket
+    (liftIO $ throwIfNull "withListClipper: ListClipper allocation failed" Raw.ListClipper.new)
+    Raw.ListClipper.delete
+    step
+  where
+    itemHeight' = maybe (-1.0) CFloat itemHeight
+    itemCount' = maybe maxBound fromIntegral (itemCount items)
+
+    step clipper = do
+      Raw.ListClipper.begin clipper itemCount' itemHeight'
+      go clipper
+
+    go clipper = do
+      doStep <- Raw.ListClipper.step clipper
+      when doStep do
+        let
+          startIndex = fromIntegral $ Raw.ListClipper.displayStart clipper
+          endIndex   = fromIntegral $ Raw.ListClipper.displayEnd clipper
+        stepItems action $
+          clipItems startIndex endIndex items
+
+        go clipper
+
+-- | Containers usable with 'ListClipper'.
+class ClipItems t a where
+  itemCount :: t a -> Maybe Int
+  clipItems :: Int -> Int -> t a -> t a
+  stepItems :: Monad m => (a -> m ()) -> t a -> m ()
+
+-- | Unbounded stream of items.
+instance ClipItems [] a where
+  itemCount = const Nothing
+
+  clipItems displayStart displayEnd =
+    take (displayEnd - displayStart) . drop displayStart
+
+  stepItems = mapM_
+
+instance ClipItems V.Vector a where
+  itemCount = Just . V.length
+
+  clipItems displayStart displayEnd =
+    V.slice displayStart (displayEnd - displayStart)
+
+  stepItems = V.mapM_
+
+instance Storable a => ClipItems VS.Vector a where
+  itemCount = Just . VS.length
+
+  clipItems displayStart displayEnd =
+    VS.slice displayStart (displayEnd - displayStart)
+
+  stepItems = VS.mapM_
+
+instance VU.Unbox a => ClipItems VU.Vector a where
+  itemCount = Just . VU.length
+
+  clipItems displayStart displayEnd =
+    VU.slice displayStart (displayEnd - displayStart)
+
+  stepItems = VU.mapM_
+
+-- | ClipList helper for arbitrary unmaterialized ranges.
+data ClipRange a = ClipRange a a
+  deriving (Eq, Ord, Show)
+
+instance (Ord a, Enum a, Num a) => ClipItems ClipRange a where
+  itemCount (ClipRange _begin end) =
+    Just $ fromEnum end
+
+  clipItems clipBegin clipEnd (ClipRange oldBegin oldEnd) =
+    ClipRange
+      (toEnum $ max clipBegin $ fromEnum oldBegin)
+      (toEnum $ min clipEnd $ fromEnum oldEnd)
+
+  stepItems action (ClipRange start end) =
+    mapM_ action [start .. end - 1]

src/DearImGui/Context.hs

@@ -33,7 +33,10 @@ imguiContext = mempty
       [ ( TypeName "ImVec2", [t| ImVec2 |] )
       , ( TypeName "ImVec3", [t| ImVec3 |] )
       , ( TypeName "ImVec4", [t| ImVec4 |] )
+      , ( TypeName "ImU32", [t| ImU32 |] )
+      , ( TypeName "ImDrawList", [t| ImDrawList |] )
       , ( TypeName "ImGuiContext", [t| ImGuiContext |] )
       , ( TypeName "ImFont", [t| ImFont |] )
+      , ( TypeName "ImGuiListClipper", [t| ImGuiListClipper |] )
       ]
   }

src/DearImGui/Raw.hs

@@ -49,6 +49,7 @@ module DearImGui.Raw
 
     -- ** Utilities
 
+  , getWindowDrawList
   , getWindowPos
   , getWindowSize
   , getWindowWidth
@@ -89,6 +90,7 @@ module DearImGui.Raw
   , beginGroup
   , endGroup
   , setCursorPos
+  , getCursorScreenPos
   , alignTextToFramePadding
 
     -- * Widgets
@@ -217,6 +219,13 @@ module DearImGui.Raw
   , buildFontAtlas
   , clearFontAtlas
 
+    -- * Utilities
+
+    -- ** Miscellaneous
+  , getBackgroundDrawList
+  , getForegroundDrawList
+  , imCol32
+
     -- * Types
   , module DearImGui.Enums
   , module DearImGui.Structs
@@ -228,12 +237,15 @@ import Control.Monad.IO.Class
   ( MonadIO, liftIO )
 import Foreign
 import Foreign.C
+import System.IO.Unsafe
+  ( unsafePerformIO )
 
 -- dear-imgui
 import DearImGui.Context
   ( imguiContext )
 import DearImGui.Enums
 import DearImGui.Structs
+import DearImGui.Raw.DrawList (DrawList(..))
 
 -- inline-c
 import qualified Language.C.Inline as C
@@ -1264,6 +1276,19 @@ isItemHovered :: (MonadIO m) => m Bool
 isItemHovered = liftIO do
   (0 /=) <$> [C.exp| bool { IsItemHovered() } |]
 
+
+-- | Get draw list associated to the current window.
+getWindowDrawList :: (MonadIO m) => m DrawList
+getWindowDrawList = liftIO do
+  DrawList <$> [C.exp|
+    ImDrawList* {
+      GetWindowDrawList()
+    }
+  |]
+
+-- | Get current window position in screen space.
+--
+-- Useful if you want to do your own drawing via the "DrawList" API.
 getWindowPos :: (MonadIO m) => m ImVec2
 getWindowPos = liftIO do
   C.withPtr_ \ptr ->
@@ -1445,6 +1470,21 @@ setCursorPos :: (MonadIO m) => Ptr ImVec2 -> m ()
 setCursorPos posPtr = liftIO do
   [C.exp| void { SetCursorPos(*$(ImVec2* posPtr)) } |]
 
+-- | Cursor position in absolute coordinates.
+--
+-- Useful to work with 'DrawList' API.
+--
+-- Generally top-left == @GetMainViewport()->Pos == (0,0)@ in single viewport mode,
+-- and bottom-right == @GetMainViewport()->Pos+Size == io.DisplaySize@ in single-viewport mode.
+getCursorScreenPos :: (MonadIO m) => m ImVec2
+getCursorScreenPos = liftIO do
+  C.withPtr_ \ptr ->
+    [C.block|
+      void {
+        *$(ImVec2 * ptr) = GetCursorScreenPos();
+      }
+    |]
+
 
 -- | Modify a style color by pushing to the shared stack. always use this if you modify the style after `newFrame`
 --
@@ -1573,3 +1613,42 @@ clearFontAtlas = liftIO do
       GetIO().Fonts->Clear();
     }
   |]
+
+
+-- | This draw list will be the first rendering one.
+--
+-- Useful to quickly draw shapes/text behind dear imgui contents.
+getBackgroundDrawList :: (MonadIO m) => m DrawList
+getBackgroundDrawList = liftIO do
+  DrawList <$> [C.exp|
+    ImDrawList* {
+      GetBackgroundDrawList()
+    }
+  |]
+
+--  | This draw list will be the last rendered one.
+--
+-- Useful to quickly draw shapes/text over dear imgui contents.
+getForegroundDrawList :: (MonadIO m) => m DrawList
+getForegroundDrawList = liftIO do
+  DrawList <$> [C.exp|
+    ImDrawList* {
+      GetForegroundDrawList()
+    }
+  |]
+
+-- | Generate 32-bit encoded colors using DearImgui macros.
+--
+-- Follows @IMGUI_USE_BGRA_PACKED_COLOR@ define to put bytes in appropriate positions.
+imCol32 :: CUChar -> CUChar -> CUChar -> CUChar -> ImU32
+imCol32 r g b a = unsafePerformIO
+  [C.exp|
+    ImU32 {
+      IM_COL32(
+        $(unsigned char r),
+        $(unsigned char g),
+        $(unsigned char b),
+        $(unsigned char a)
+      )
+    }
+  |]

src/DearImGui/Raw/DrawList.hs

@@ -0,0 +1,742 @@
+{-# LANGUAGE BlockArguments #-}
+{-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE PatternSynonyms #-}
+{-# LANGUAGE QuasiQuotes #-}
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE ViewPatterns #-}
+
+{-| Draw command list
+
+This is the low-level list of polygons that ImGui functions are filling.
+
+At the end of the frame, all command lists are passed to your @ImGuiIO::RenderDrawListFn@ function for rendering.
+
+Each dear imgui window contains its own ImDrawList.
+
+You can use 'getWindowDrawList' to access the current window draw list and draw custom primitives.
+
+You can interleave normal ImGui calls and adding primitives to the current draw list.
+
+In single viewport mode, top-left is == @GetMainViewport()->Pos@ (generally @0,0@),
+bottom-right is == @GetMainViewport()->Pos+Size@ (generally io.DisplaySize).
+
+You are totally free to apply whatever transformation matrix to want to the data
+(depending on the use of the transformation you may want to apply it to ClipRect as well!).
+
+__Important__: Primitives are always added to the list and not culled (culling is done at higher-level by ImGui functions),
+if you use this API a lot consider coarse culling your drawn objects.
+-}
+
+module DearImGui.Raw.DrawList
+  ( DrawList(..)
+  , new
+  , destroy
+
+    -- * Primitives
+
+    -- $primitives
+  , addLine
+
+  , addRect
+  , addRectFilled
+  , addRectFilledMultiColor
+
+  , addQuad
+  , addQuadFilled
+
+  , addTriangle
+  , addTriangleFilled
+
+  , addCircle
+  , addCircleFilled
+
+  , addNgon
+  , addNgonFilled
+
+  , addText_
+  , addText
+
+  , addPolyLine
+  , addConvexPolyFilled
+
+  , addBezierCubic
+  , addBezierQuadratic
+
+    -- ** Image primitives
+
+    -- $image
+  , addImage
+  , addImageQuad
+  , addImageRounded
+
+    -- * Stateful path API
+
+    -- $stateful
+  , pathClear
+  , pathLineTo
+  , pathLineToMergeDuplicate
+  , pathFillConvex
+  , pathStroke
+
+  , pathArcTo
+  , pathArcToFast
+
+  , pathBezierCubicCurveTo
+  , pathBezierQuadraticCurveTo
+
+  , pathRect
+
+    -- * Advanced
+
+  -- , addCallback
+  , addDrawCmd
+  , cloneOutput
+
+    -- * Internal state
+
+  , pushClipRect
+  , pushClipRectFullScreen
+  , popClipRect
+  , getClipRectMin
+  , getClipRectMax
+
+  , pushTextureID
+  , popTextureID
+  )
+  where
+
+import Control.Monad.IO.Class
+  ( MonadIO, liftIO )
+import Foreign hiding (new)
+import Foreign.C
+
+-- dear-imgui
+import DearImGui.Context
+  ( imguiContext )
+import DearImGui.Enums
+import DearImGui.Structs
+
+-- inline-c
+import qualified Language.C.Inline as C
+
+-- inline-c-cpp
+import qualified Language.C.Inline.Cpp as Cpp
+
+C.context (Cpp.cppCtx <> C.bsCtx <> imguiContext)
+C.include "imgui.h"
+Cpp.using "namespace ImGui"
+
+-- | A single draw command list.
+-- Generally one per window, conceptually you may see this as a dynamic "mesh" builder.
+newtype DrawList = DrawList (Ptr ImDrawList)
+
+new :: MonadIO m => m DrawList
+new = liftIO do
+  DrawList <$> [C.block|
+    ImDrawList* {
+      return IM_NEW(ImDrawList(GetDrawListSharedData()));
+    }
+  |]
+
+destroy :: MonadIO m => DrawList -> m ()
+destroy (DrawList drawList) = liftIO do
+  [C.block|
+    void {
+      IM_DELETE($(ImDrawList* drawList));
+    }
+  |]
+
+
+pushClipRect :: MonadIO m => DrawList -> Ptr ImVec2 -> Ptr ImVec2 -> CBool -> m ()
+pushClipRect (DrawList drawList) clip_rect_min clip_rect_max intersect_with_current_clip_rect = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->PushClipRect(
+        *$(ImVec2* clip_rect_min),
+        *$(ImVec2* clip_rect_max),
+        $(bool intersect_with_current_clip_rect)
+      );
+    }
+  |]
+
+pushClipRectFullScreen :: MonadIO m => DrawList -> m ()
+pushClipRectFullScreen (DrawList drawList) = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->PushClipRectFullScreen();
+    }
+  |]
+
+popClipRect :: MonadIO m => DrawList -> m ()
+popClipRect (DrawList drawList) = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->PopClipRect();
+    }
+  |]
+
+
+getClipRectMin :: MonadIO m => DrawList -> m ImVec2
+getClipRectMin (DrawList drawList) = liftIO do
+  C.withPtr_ \ptr ->
+    [C.block|
+      void {
+        *$(ImVec2 * ptr) = $(ImDrawList* drawList)->GetClipRectMin();
+      }
+    |]
+
+getClipRectMax :: MonadIO m => DrawList -> m ImVec2
+getClipRectMax (DrawList drawList) = liftIO do
+  C.withPtr_ \ptr ->
+    [C.block|
+      void {
+        *$(ImVec2 * ptr) = $(ImDrawList* drawList)->GetClipRectMax();
+      }
+    |]
+
+
+pushTextureID :: MonadIO m => DrawList -> Ptr () -> m ()
+pushTextureID (DrawList drawList) userTextureIDPtr = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->PushTextureID(
+        $(void* userTextureIDPtr)
+      );
+    }
+  |]
+
+popTextureID :: MonadIO m => DrawList -> m ()
+popTextureID (DrawList drawList) = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->PopTextureID();
+    }
+  |]
+
+
+{- $primitives
+- For rectangular primitives, @p_min@ and @p_max@ represent the upper-left and lower-right corners.
+- For circle primitives, use @num_segments == 0@ to automatically calculate tessellation (preferred).
+  In older versions (until Dear ImGui 1.77) the 'addCircle' functions defaulted to num_segments == 12.
+  In future versions we will use textures to provide cheaper and higher-quality circles.
+  Use 'addNgon' and 'addNgonFilled' functions if you need to guaranteed a specific number of sides.
+-}
+
+addLine :: MonadIO m => DrawList -> Ptr ImVec2 -> Ptr ImVec2 -> ImU32 -> CFloat -> m ()
+addLine (DrawList drawList) p1 p2 col thickness = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddLine(
+        *$(ImVec2* p1),
+        *$(ImVec2* p2),
+        $(ImU32 col),
+        $(float thickness)
+      );
+    }
+  |]
+
+
+addRect :: MonadIO m => DrawList -> Ptr ImVec2 -> Ptr ImVec2 -> ImU32 -> CFloat -> ImDrawFlags -> CFloat -> m ()
+addRect (DrawList drawList) p_min p_max col rounding flags thickness = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddRect(
+        *$(ImVec2* p_min),
+        *$(ImVec2* p_max),
+        $(ImU32 col),
+        $(float rounding),
+        $(ImDrawFlags flags),
+        $(float thickness)
+      );
+    }
+  |]
+
+addRectFilled :: MonadIO m => DrawList -> Ptr ImVec2 -> Ptr ImVec2 -> ImU32 -> CFloat -> ImDrawFlags -> m ()
+addRectFilled (DrawList drawList) p_min p_max col rounding flags = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddRectFilled(
+        *$(ImVec2* p_min),
+        *$(ImVec2* p_max),
+        $(ImU32 col),
+        $(float rounding),
+        $(ImDrawFlags flags)
+      );
+    }
+  |]
+
+addRectFilledMultiColor :: MonadIO m => DrawList -> Ptr ImVec2 -> Ptr ImVec2 -> ImU32 -> ImU32 -> ImU32 -> ImU32 -> m ()
+addRectFilledMultiColor (DrawList drawList) p_min p_max col_upr_left col_upr_right col_bot_right col_bot_left = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddRectFilledMultiColor(
+        *$(ImVec2* p_min),
+        *$(ImVec2* p_max),
+        $(ImU32 col_upr_left),
+        $(ImU32 col_upr_right),
+        $(ImU32 col_bot_right),
+        $(ImU32 col_bot_left)
+      );
+    }
+  |]
+
+
+addQuad :: MonadIO m => DrawList -> Ptr ImVec2 -> Ptr ImVec2 -> Ptr ImVec2 -> Ptr ImVec2 -> ImU32 -> CFloat -> m ()
+addQuad (DrawList drawList) p1 p2 p3 p4 col thickness = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddQuad(
+        *$(ImVec2* p1),
+        *$(ImVec2* p2),
+        *$(ImVec2* p3),
+        *$(ImVec2* p4),
+        $(ImU32 col),
+        $(float thickness)
+      );
+    }
+  |]
+
+addQuadFilled :: MonadIO m => DrawList -> Ptr ImVec2 -> Ptr ImVec2 -> Ptr ImVec2 -> Ptr ImVec2 -> ImU32 -> m ()
+addQuadFilled (DrawList drawList) p1 p2 p3 p4 col = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddQuadFilled(
+        *$(ImVec2* p1),
+        *$(ImVec2* p2),
+        *$(ImVec2* p3),
+        *$(ImVec2* p4),
+        $(ImU32 col)
+      );
+    }
+  |]
+
+
+addTriangle :: MonadIO m => DrawList -> Ptr ImVec2 -> Ptr ImVec2 -> Ptr ImVec2 -> ImU32 -> CFloat -> m ()
+addTriangle (DrawList drawList) p1 p2 p3 col thickness = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddTriangle(
+        *$(ImVec2* p1),
+        *$(ImVec2* p2),
+        *$(ImVec2* p3),
+        $(ImU32 col),
+        $(float thickness)
+      );
+    }
+  |]
+
+addTriangleFilled :: MonadIO m => DrawList -> Ptr ImVec2 -> Ptr ImVec2 -> Ptr ImVec2 -> ImU32 -> m ()
+addTriangleFilled (DrawList drawList) p1 p2 p3 col = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddTriangleFilled(
+        *$(ImVec2* p1),
+        *$(ImVec2* p2),
+        *$(ImVec2* p3),
+        $(ImU32 col)
+      );
+    }
+  |]
+
+
+addCircle :: MonadIO m => DrawList -> Ptr ImVec2 -> CFloat -> ImU32 -> CInt -> CFloat -> m ()
+addCircle (DrawList drawList) center radius col num_segments thickness = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddCircle(
+        *$(ImVec2* center),
+        $(float radius),
+        $(ImU32 col),
+        $(int num_segments),
+        $(float thickness)
+      );
+    }
+  |]
+
+addCircleFilled :: MonadIO m => DrawList -> Ptr ImVec2 -> CFloat -> ImU32 -> CInt -> m ()
+addCircleFilled (DrawList drawList) center radius col num_segments = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddCircleFilled(
+        *$(ImVec2* center),
+        $(float radius),
+        $(ImU32 col),
+        $(int num_segments)
+      );
+    }
+  |]
+
+
+addNgon :: MonadIO m => DrawList -> Ptr ImVec2 -> CFloat -> ImU32 -> CInt -> CFloat -> m ()
+addNgon (DrawList drawList) center radius col num_segments thickness = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddNgon(
+        *$(ImVec2* center),
+        $(float radius),
+        $(ImU32 col),
+        $(int num_segments),
+        $(float thickness)
+      );
+    }
+  |]
+
+addNgonFilled :: MonadIO m => DrawList -> Ptr ImVec2 -> CFloat -> ImU32 -> CInt -> m ()
+addNgonFilled (DrawList drawList) center radius col num_segments = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddNgonFilled(
+        *$(ImVec2* center),
+        $(float radius),
+        $(ImU32 col),
+        $(int num_segments)
+      );
+    }
+  |]
+
+
+addText_ :: MonadIO m => DrawList -> Ptr ImVec2 -> ImU32 -> CString -> CString -> m ()
+addText_ (DrawList drawList) pos col text_begin text_end = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddText(
+        *$(ImVec2* pos),
+        $(ImU32 col),
+        $(char* text_begin),
+        $(char* text_end)
+      );
+    }
+  |]
+
+addText :: MonadIO m => DrawList -> Ptr ImFont -> CFloat -> Ptr ImVec2 -> ImU32 -> CString -> CString -> CFloat -> Ptr ImVec4 -> m ()
+addText (DrawList drawList) fontPtr font_size pos col text_begin text_end wrap_width cpu_fine_clip_rect = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddText(
+        $(ImFont* fontPtr),
+        $(float font_size),
+        *$(ImVec2* pos),
+        $(ImU32 col),
+        $(char* text_begin),
+        $(char* text_end),
+        $(float wrap_width),
+        $(ImVec4* cpu_fine_clip_rect)
+      );
+    }
+  |]
+
+
+addPolyLine :: MonadIO m => DrawList -> Ptr ImVec2 -> CInt -> ImU32 -> ImDrawFlags -> CFloat -> m ()
+addPolyLine (DrawList drawList) points num_points col flags thickness = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddPolyline(
+        $(ImVec2* points),
+        $(int num_points),
+        $(ImU32 col),
+        $(ImDrawFlags flags),
+        $(float thickness)
+      );
+    }
+  |]
+
+addConvexPolyFilled :: MonadIO m => DrawList -> Ptr ImVec2 -> CInt -> ImU32 -> m ()
+addConvexPolyFilled (DrawList drawList) points num_points col = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddConvexPolyFilled(
+        $(ImVec2* points),
+        $(int num_points),
+        $(ImU32 col)
+      );
+    }
+  |]
+
+
+addBezierCubic
+  :: MonadIO m
+  => DrawList
+  -> Ptr ImVec2 -> Ptr ImVec2 -> Ptr ImVec2 -> Ptr ImVec2 -- Positions (control points)
+  -> ImU32
+  -> CFloat
+  -> CInt
+  -> m ()
+addBezierCubic (DrawList drawList) p1 p2 p3 p4 col thickness numSegments = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddBezierCubic(
+        *$(ImVec2* p1),
+        *$(ImVec2* p2),
+        *$(ImVec2* p3),
+        *$(ImVec2* p4),
+        $(ImU32 col),
+        $(float thickness),
+        $(int numSegments)
+      );
+    }
+  |]
+
+addBezierQuadratic
+  :: MonadIO m
+  => DrawList
+  -> Ptr ImVec2 -> Ptr ImVec2 -> Ptr ImVec2 -- Positions (control points)
+  -> ImU32
+  -> CFloat
+  -> CInt
+  -> m ()
+addBezierQuadratic (DrawList drawList) p1 p2 p3 col thickness numSegments = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddBezierQuadratic(
+        *$(ImVec2* p1),
+        *$(ImVec2* p2),
+        *$(ImVec2* p3),
+        $(ImU32 col),
+        $(float thickness),
+        $(int numSegments)
+      );
+    }
+  |]
+
+
+{- $image
+* Read FAQ to understand what @ImTextureID@ is.
+* @p_min@ and @p_max@ represent the upper-left and lower-right corners of the rectangle.
+* @uv_min@ and @uv_max@ represent the normalized texture coordinates to use for those corners.
+  Using @(0,0)->(1,1)@ texture coordinates will generally display the entire texture.
+-}
+
+addImage
+  :: MonadIO m
+  => DrawList
+  -> Ptr ()
+  -> Ptr ImVec2 -> Ptr ImVec2 -- Positions
+  -> Ptr ImVec2 -> Ptr ImVec2 -- UVs
+  -> ImU32
+  -> m ()
+addImage (DrawList drawList) userTextureIDPtr p_min p_max uv_min uv_max col = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddImage(
+        $(void* userTextureIDPtr),
+        *$(ImVec2* p_min),
+        *$(ImVec2* p_max),
+        *$(ImVec2* uv_min),
+        *$(ImVec2* uv_max),
+        $(ImU32 col)
+      );
+    }
+  |]
+
+addImageQuad
+  :: MonadIO m
+  => DrawList
+  -> Ptr ()
+  -> Ptr ImVec2 -> Ptr ImVec2 -> Ptr ImVec2 -> Ptr ImVec2 -- Positions
+  -> Ptr ImVec2 -> Ptr ImVec2 -> Ptr ImVec2 -> Ptr ImVec2 -- UVs
+  -> ImU32
+  -> m ()
+addImageQuad (DrawList drawList) userTextureIDPtr p1 p2 p3 p4 uv1 uv2 uv3 uv4 col = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddImageQuad(
+        $(void* userTextureIDPtr),
+        *$(ImVec2* p1),
+        *$(ImVec2* p2),
+        *$(ImVec2* p3),
+        *$(ImVec2* p4),
+        *$(ImVec2* uv1),
+        *$(ImVec2* uv2),
+        *$(ImVec2* uv3),
+        *$(ImVec2* uv4),
+        $(ImU32 col)
+      );
+    }
+  |]
+
+addImageRounded
+  :: MonadIO m
+  => DrawList
+  -> Ptr ()
+  -> Ptr ImVec2 -> Ptr ImVec2 -- Positions
+  -> Ptr ImVec2 -> Ptr ImVec2 -- UVs
+  -> ImU32
+  -> CFloat
+  -> ImDrawFlags
+  -> m ()
+addImageRounded (DrawList drawList) userTextureIDPtr p_min p_max uv_min uv_max col rounding flags = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddImageRounded(
+        $(void* userTextureIDPtr),
+        *$(ImVec2* p_min),
+        *$(ImVec2* p_max),
+        *$(ImVec2* uv_min),
+        *$(ImVec2* uv_max),
+        $(ImU32 col),
+        $(float rounding),
+        $(ImDrawFlags flags)
+      );
+    }
+  |]
+
+{- $stateful
+Add points then finish with 'pathFillConvex' or 'pathStroke'.
+-}
+
+pathClear :: MonadIO m => DrawList -> m ()
+pathClear (DrawList drawList) = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->PathClear();
+    }
+  |]
+
+pathLineTo :: MonadIO m => DrawList -> Ptr ImVec2 -> m ()
+pathLineTo (DrawList drawList) pos = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->PathLineTo(
+        *$(ImVec2* pos)
+      );
+    }
+  |]
+
+pathLineToMergeDuplicate :: MonadIO m => DrawList -> Ptr ImVec2 -> m ()
+pathLineToMergeDuplicate (DrawList drawList) pos = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->PathLineToMergeDuplicate(
+        *$(ImVec2* pos)
+      );
+    }
+  |]
+
+-- | Note: Anti-aliased filling requires points to be in clockwise order.
+pathFillConvex :: MonadIO m => DrawList -> ImU32 -> m ()
+pathFillConvex (DrawList drawList) col = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->PathFillConvex(
+        $(ImU32 col)
+      );
+    }
+  |]
+
+pathStroke :: MonadIO m => DrawList -> ImU32 -> ImDrawFlags -> CFloat -> m ()
+pathStroke (DrawList drawList) col flags thickness = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->PathStroke(
+        $(ImU32 col),
+        $(ImDrawFlags flags),
+        $(float thickness)
+      );
+    }
+  |]
+
+
+pathArcTo :: MonadIO m => DrawList -> Ptr ImVec2 -> CFloat -> CFloat -> CFloat -> CInt -> m ()
+pathArcTo (DrawList drawList) center radius a_min a_max num_segments = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->PathArcTo(
+        *$(ImVec2* center),
+        $(float radius),
+        $(float a_min),
+        $(float a_max),
+        $(int num_segments)
+      );
+    }
+  |]
+
+-- | Use precomputed angles for a 12 steps circle.
+pathArcToFast :: MonadIO m => DrawList -> Ptr ImVec2 -> CFloat -> CInt -> CInt -> m ()
+pathArcToFast (DrawList drawList) center radius a_min_of_12 a_max_of_12 = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->PathArcToFast(
+        *$(ImVec2* center),
+        $(float radius),
+        $(int a_min_of_12),
+        $(int a_max_of_12)
+      );
+    }
+  |]
+
+
+pathBezierCubicCurveTo
+  :: MonadIO m
+  => DrawList
+  -> Ptr ImVec2
+  -> Ptr ImVec2
+  -> Ptr ImVec2
+  -> CInt
+  -> m ()
+pathBezierCubicCurveTo (DrawList drawList) p1 p2 p3 num_segments = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->PathBezierCubicCurveTo(
+        *$(ImVec2* p1),
+        *$(ImVec2* p2),
+        *$(ImVec2* p3),
+        $(int num_segments)
+      );
+    }
+  |]
+
+pathBezierQuadraticCurveTo
+  :: MonadIO m
+  => DrawList
+  -> Ptr ImVec2
+  -> Ptr ImVec2
+  -> CInt
+  -> m ()
+pathBezierQuadraticCurveTo (DrawList drawList) p1 p2 num_segments = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->PathBezierQuadraticCurveTo(
+        *$(ImVec2* p1),
+        *$(ImVec2* p2),
+        $(int num_segments)
+      );
+    }
+  |]
+
+
+pathRect :: MonadIO m => DrawList -> Ptr ImVec2 -> Ptr ImVec2 -> CFloat -> ImDrawFlags -> m ()
+pathRect (DrawList drawList) rect_min rect_max rounding flags = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->PathRect(
+        *$(ImVec2* rect_min),
+        *$(ImVec2* rect_max),
+        $(float rounding),
+        $(ImDrawFlags flags)
+      );
+    }
+  |]
+
+
+-- | This is useful if you need to forcefully create a new draw call (to allow for dependent rendering / blending).
+-- Otherwise primitives are merged into the same draw-call as much as possible.
+addDrawCmd :: MonadIO m => DrawList -> m ()
+addDrawCmd (DrawList drawList) = liftIO do
+  [C.block|
+    void {
+      $(ImDrawList* drawList)->AddDrawCmd();
+    }
+  |]
+
+-- | Create a clone of the CmdBuffer/IdxBuffer/VtxBuffer.
+cloneOutput :: MonadIO m => DrawList -> m DrawList
+cloneOutput (DrawList drawList) = liftIO do
+  DrawList <$> [C.block|
+    ImDrawList* {
+      return $(ImDrawList* drawList)->CloneOutput();
+    }
+  |]

src/DearImGui/Raw/IO.hs

@@ -0,0 +1,137 @@
+{-# LANGUAGE BlockArguments #-}
+{-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE PatternSynonyms #-}
+{-# LANGUAGE QuasiQuotes #-}
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE ViewPatterns #-}
+
+{-| Main configuration and I/O between your application and ImGui
+
+-}
+
+module DearImGui.Raw.IO
+  ( setIniFilename
+  , setLogFilename
+
+  , setMouseDoubleClickMaxDist
+  , setMouseDoubleClickTime
+  , setMouseDragThreshold
+
+  , setKeyRepeatDelay
+  , setKeyRepeatRate
+
+  , setUserData
+  ) where
+
+-- TODO: add exports
+
+import Control.Monad.IO.Class
+  ( MonadIO, liftIO )
+import Foreign
+  ( Ptr )
+import Foreign.C
+  ( CFloat(..)
+  , CString
+  )
+
+-- dear-imgui
+import DearImGui.Context
+  ( imguiContext )
+-- import DearImGui.Enums
+-- import DearImGui.Structs
+
+-- inline-c
+import qualified Language.C.Inline as C
+
+-- inline-c-cpp
+import qualified Language.C.Inline.Cpp as Cpp
+
+C.context (Cpp.cppCtx <> C.bsCtx <> imguiContext)
+C.include "imgui.h"
+Cpp.using "namespace ImGui"
+
+setIniFilename :: MonadIO m => CString -> m ()
+setIniFilename ptr = liftIO do
+  [C.block|
+    void {
+      GetIO().IniFilename = $(char * ptr);
+    }
+  |]
+
+setLogFilename :: MonadIO m => CString -> m ()
+setLogFilename ptr = liftIO do
+  [C.block|
+    void {
+      GetIO().LogFilename = $(char * ptr);
+    }
+  |]
+
+setMouseDoubleClickTime :: MonadIO m => CFloat -> m ()
+setMouseDoubleClickTime seconds = liftIO do
+  [C.block|
+    void {
+      GetIO().MouseDoubleClickTime = $(float seconds);
+    }
+  |]
+
+setMouseDoubleClickMaxDist :: MonadIO m => CFloat -> m ()
+setMouseDoubleClickMaxDist pixels = liftIO do
+  [C.block|
+    void {
+      GetIO().MouseDoubleClickMaxDist = $(float pixels);
+    }
+  |]
+
+setMouseDragThreshold :: MonadIO m => CFloat -> m ()
+setMouseDragThreshold pixels = liftIO do
+  [C.block|
+    void {
+      GetIO().MouseDragThreshold = $(float pixels);
+    }
+  |]
+
+setKeyRepeatDelay :: MonadIO m => CFloat -> m ()
+setKeyRepeatDelay seconds = liftIO do
+  [C.block|
+    void {
+      GetIO().KeyRepeatDelay = $(float seconds);
+    }
+  |]
+
+setKeyRepeatRate :: MonadIO m => CFloat -> m ()
+setKeyRepeatRate pixels = liftIO do
+  [C.block|
+    void {
+      GetIO().KeyRepeatRate = $(float pixels);
+    }
+  |]
+
+setUserData :: MonadIO m => Ptr () -> m ()
+setUserData ptr = liftIO do
+  [C.block|
+    void {
+      GetIO().UserData = $(void* ptr);
+    }
+  |]
+
+{- TODO:
+
+bool   WantCaptureMouse;         // Set when Dear ImGui will use mouse inputs, in this case do not dispatch them to your main game/application (either way, always pass on mouse inputs to imgui). (e.g. unclicked mouse is hovering over an imgui window, widget is active, mouse was clicked over an imgui window, etc.).
+bool   WantCaptureKeyboard;      // Set when Dear ImGui will use keyboard inputs, in this case do not dispatch them to your main game/application (either way, always pass keyboard inputs to imgui). (e.g. InputText active, or an imgui window is focused and navigation is enabled, etc.).
+bool   WantTextInput;            // Mobile/console: when set, you may display an on-screen keyboard. This is set by Dear ImGui when it wants textual keyboard input to happen (e.g. when a InputText widget is active).
+bool   WantSetMousePos;          // MousePos has been altered, backend should reposition mouse on next frame. Rarely used! Set only when ImGuiConfigFlags_NavEnableSetMousePos flag is enabled.
+bool   WantSaveIniSettings;      // When manual .ini load/save is active (io.IniFilename == NULL), this will be set to notify your application that you can call SaveIniSettingsToMemory() and save yourself. Important: clear io.WantSaveIniSettings yourself after saving!
+bool   NavActive;                // Keyboard/Gamepad navigation is currently allowed (will handle ImGuiKey_NavXXX events) = a window is focused and it doesn't use the ImGuiWindowFlags_NoNavInputs flag.
+bool   NavVisible;               // Keyboard/Gamepad navigation is visible and allowed (will handle ImGuiKey_NavXXX events).
+float  Framerate;                // Rough estimate of application framerate, in frame per second. Solely for convenience. Rolling average estimation based on io.DeltaTime over 120 frames.
+int    MetricsRenderVertices;    // Vertices output during last call to Render()
+int    MetricsRenderIndices;     // Indices output during last call to Render() = number of triangles * 3
+int    MetricsRenderWindows;     // Number of visible windows
+int    MetricsActiveWindows;     // Number of active windows
+int    MetricsActiveAllocations; // Number of active allocations, updated by MemAlloc/MemFree based on current context. May be off if you have multiple imgui contexts.
+ImVec2 MouseDelta;
+-}

src/DearImGui/Raw/ListClipper.hs

@@ -0,0 +1,149 @@
+{-# LANGUAGE BlockArguments #-}
+{-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE PatternSynonyms #-}
+{-# LANGUAGE QuasiQuotes #-}
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE ViewPatterns #-}
+
+{-| Helper: Manually clip large list of items.
+
+If you are submitting lots of evenly spaced items and you have a random access to the list,
+you can perform coarse clipping based on visibility to save yourself from processing those items at all.
+
+The clipper calculates the range of visible items and advance the cursor to compensate for the non-visible items we have skipped.
+
+Dear ImGui already clips items based on their bounds but it needs to measure text size to do so,
+whereas manual coarse clipping before submission makes this cost and your own data fetching/submission cost almost null.
+
+Usage:
+
+@
+clipper <- ListClipper.new
+ListClipper.begin clipper 1000 -- We have 1000 elements, evenly spaced.
+whileTrue (ListClipper.step clipper) $
+  start <- ListClipper.displayStart clipper
+  end <- ListClipper.displayEnd clipper
+  for_ [start .. end] \ix ->
+    ImGui.text $ "line number " <> show ix
+@
+
+Generally what happens is:
+
+* Clipper lets you process the first element (DisplayStart = 0, DisplayEnd = 1) regardless of it being visible or not.
+* User code submit one element.
+* Clipper can measure the height of the first element
+* Clipper calculate the actual range of elements to display based on the current clipping rectangle,
+  position the cursor before the first visible element.
+* User code submit visible elements.
+-}
+
+module DearImGui.Raw.ListClipper
+  ( ListClipper
+  , new
+  , delete
+  , begin
+  , displayStart
+  , displayEnd
+  , step
+  )
+  where
+
+import Control.Monad.IO.Class
+  ( MonadIO, liftIO )
+import Foreign hiding (new)
+import Foreign.C
+import System.IO.Unsafe (unsafePerformIO)
+
+-- dear-imgui
+import DearImGui.Context
+  ( imguiContext )
+import DearImGui.Structs
+  ( ImGuiListClipper )
+
+-- inline-c
+import qualified Language.C.Inline as C
+
+-- inline-c-cpp
+import qualified Language.C.Inline.Cpp as Cpp
+
+C.context (Cpp.cppCtx <> C.bsCtx <> imguiContext)
+C.include "imgui.h"
+Cpp.using "namespace ImGui"
+
+
+-- | @ImGuiListClipper@ object handle.
+type ListClipper = Ptr ImGuiListClipper
+
+
+-- | Create a new 'ListClipper' instance.
+new :: (MonadIO m) => m ListClipper
+new = liftIO do
+  [C.block|
+    ImGuiListClipper* {
+      return IM_NEW(ImGuiListClipper);
+    }
+  |]
+
+-- | Destroy 'ListClipper' instance.
+delete :: (MonadIO m) => ListClipper -> m ()
+delete clipper = liftIO do
+  [C.block|
+    void {
+      IM_DELETE($(ImGuiListClipper* clipper));
+    }
+  |]
+
+
+-- | ListClipper setup
+--
+-- @items_count@: Use 'maxBound' if you don't know how many items you have
+-- (in which case the cursor won't be advanced in the final step).
+--
+-- @items_height@: Use -1.0f to be calculated automatically on first step.
+-- Otherwise pass in the distance between your items, typically
+-- 'getTextLineHeightWithSpacing' or 'getFrameHeightWithSpacing'.
+--
+-- Wraps @ListClipper::Begin()@.
+begin :: (MonadIO m) => ListClipper -> CInt -> CFloat -> m ()
+begin clipper items_count items_height = liftIO do
+  [C.block|
+    void {
+      $(ImGuiListClipper* clipper)->Begin($(int items_count), $(float items_height));
+    }
+  |]
+
+-- | An accessor for @ListClipper::Begin@
+displayStart :: ListClipper -> CInt
+displayStart clipper = unsafePerformIO do
+  [C.exp|
+    int {
+      $(ImGuiListClipper* clipper)->DisplayStart
+    }
+  |]
+
+-- | An accessor for @ListClipper::DisplayStart@
+displayEnd :: ListClipper -> CInt
+displayEnd clipper = unsafePerformIO
+  [C.exp|
+    int {
+      $(ImGuiListClipper* clipper)->DisplayEnd
+    }
+  |]
+
+
+-- | Call until it returns 'False'.
+--
+-- The 'displayStart'/'displayEnd' fields will be set and you can process/draw those items.
+--
+-- Wraps @ListClipper::Step()@.
+step :: (MonadIO m) => ListClipper -> m Bool
+step clipper = liftIO do
+  (0 /=) <$> [C.block|
+    bool {
+      return $(ImGuiListClipper* clipper)->Step();
+    }
+  |]

src/DearImGui/Structs.hs

@@ -4,6 +4,8 @@
 module DearImGui.Structs where
 
 -- base
+import Data.Word
+  ( Word32 )
 import Foreign
   ( Storable(..), castPtr, plusPtr )
 
@@ -77,3 +79,12 @@ data ImGuiContext
 
 -- | Individual font handle.
 data ImFont
+
+-- | Opaque DrawList handle.
+data ImDrawList
+
+-- | 'DearImGui.Raw.ListClipper.ListClipper' pointer tag.
+data ImGuiListClipper
+
+-- | 32-bit unsigned integer (often used to store packed colors).
+type ImU32 = Word32