Extended font & glyph support (#114)

* Separate font utils, add glyph support (#113)
* Implement font glyph ranges builder
* Implement raw font config binds
* Implement font atlas module
* Rewrite font altas rebuilder in Managed

examples/fonts/Main.hs

@@ -0,0 +1,150 @@
+{-# language BlockArguments #-}
+{-# language LambdaCase #-}
+{-# language OverloadedStrings #-}
+{-# language RecordWildCards #-}
+{-# language NamedFieldPuns #-}
+{-# language DeriveTraversable #-}
+
+{- | Font usage example.
+
+Loads two non-standard fonts
+
+This example uses NotoSansJP-Regular.otf from Google Fonts
+Licensed under the SIL Open Font License, Version 1.1
+https://fonts.google.com/noto/specimen/Noto+Sans+JP
+-}
+
+module Main ( main ) where
+
+import Control.Exception
+import Control.Monad
+import Control.Monad.IO.Class
+import Control.Monad.Managed
+import Data.IORef
+import DearImGui
+import qualified DearImGui.FontAtlas as FontAtlas
+import DearImGui.OpenGL2
+import DearImGui.SDL
+import DearImGui.SDL.OpenGL
+import Graphics.GL
+import SDL
+
+-- Rebuild syntax enables us to keep fonts in any
+-- traversable type, so let's make our life a little easier.
+-- But feel free to use lists or maps.
+data FontSet a = FontSet
+  { droidFont :: a
+  , defaultFont :: a
+  , notoFont :: a
+  }
+  deriving (Functor, Foldable, Traversable)
+
+main :: IO ()
+main = do
+  -- Window initialization is similar to another examples.
+  initializeAll
+  runManaged do
+    window <- do
+      let title = "Hello, Dear ImGui!"
+      let config = defaultWindow { windowGraphicsContext = OpenGLContext defaultOpenGL }
+      managed $ bracket (createWindow title config) destroyWindow
+    glContext <- managed $ bracket (glCreateContext window) glDeleteContext
+    _ <- managed $ bracket createContext destroyContext
+    _ <- managed_ $ bracket_ (sdl2InitForOpenGL window glContext) sdl2Shutdown
+    _ <- managed_ $ bracket_ openGL2Init openGL2Shutdown
+
+    -- We use high-level syntax to build font atlas and
+    -- get handles to use in the main loop.
+    fontSet <- FontAtlas.rebuild FontSet
+      { -- The first mentioned font is loaded first
+        -- and set as a global default.
+        droidFont =
+          FontAtlas.FromTTF
+            "./imgui/misc/fonts/DroidSans.ttf"
+            15
+            Nothing
+            FontAtlas.Cyrillic
+
+        -- You also may use a default hardcoded font for
+        -- some purposes (i.e. as fallback)
+      , defaultFont =
+          FontAtlas.DefaultFont
+
+        -- To optimize atlas size, use ranges builder and
+        -- provide source localization data.
+      , notoFont =
+          FontAtlas.FromTTF
+            "./examples/fonts/NotoSansJP-Regular.otf"
+            20
+            Nothing
+            ( FontAtlas.RangesBuilder $ mconcat
+                [ FontAtlas.addRanges FontAtlas.Latin
+                , FontAtlas.addText "私をクリックしてください"
+                , FontAtlas.addText "こんにちは"
+                ]
+            )
+      }
+
+    liftIO $ do
+      fontFlag <- newIORef False
+      mainLoop window do
+        let FontSet{..} = fontSet
+        withWindowOpen "Hello, ImGui!" do
+          -- To use a font for widget text, you may either put it
+          -- into a 'withFont' block:
+          withFont defaultFont do
+            text "Hello, ImGui!"
+
+          text "Привет, ImGui!"
+
+          -- ...or you can explicitly push and pop a font.
+          -- Though it's not recommended.
+          toggled <- readIORef fontFlag
+
+          when toggled $
+            pushFont notoFont
+
+          -- Some of those are only present in Noto font range
+          -- and will render as `?`s.
+          text "こんにちは, ImGui!"
+
+          let buttonText = if toggled then "私をクリックしてください" else "Click Me!"
+          button buttonText >>= \clicked ->
+            when clicked $
+              modifyIORef' fontFlag not
+
+          when toggled
+            popFont
+
+        showDemoWindow
+
+mainLoop :: Window -> IO () -> IO ()
+mainLoop window frameAction = loop
+  where
+  loop = unlessQuit do
+    openGL2NewFrame
+    sdl2NewFrame
+    newFrame
+
+    frameAction
+
+    glClear GL_COLOR_BUFFER_BIT
+    render
+    openGL2RenderDrawData =<< getDrawData
+    glSwapWindow window
+
+    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/vulkan/Main.hs

@@ -134,12 +134,6 @@ app = do
     ImGui.createContext
     ImGui.destroyContext
 
-  logDebug "Adding fonts"
-  ImGui.clearFontAtlas
-  _default <- ImGui.addFontDefault
-  _custom <- ImGui.addFontFromFileTTF "imgui/misc/fonts/ProggyTiny.ttf" 10
-  ImGui.buildFontAtlas
-
   let
     preferredFormat :: Vulkan.SurfaceFormatKHR
     preferredFormat =