Stubbing out ImGui::ColorButton() and ImVec4

src/DearImGui/Context.hs

@@ -0,0 +1,40 @@
+{-# language NamedFieldPuns #-}
+{-# language OverloadedStrings #-}
+{-# language TemplateHaskell #-}
+
+module DearImGui.Context where
+
+import Language.C.Types
+import Language.C.Inline.Context
+import qualified Data.Map.Strict as Map
+import Foreign
+
+
+data ImVec4 = ImVec4 { x, y, z, w :: {-# unpack #-} Float }
+
+
+instance Storable ImVec4 where
+  sizeOf ~ImVec4{x, y, z, w} = sizeOf x + sizeOf y + sizeOf z + sizeOf w
+
+  alignment _ = 0
+
+  poke ptr ImVec4{ x, y, z, w } = do
+    poke (castPtr ptr `plusPtr` (sizeOf x * 0)) x
+    poke (castPtr ptr `plusPtr` (sizeOf x * 1)) y
+    poke (castPtr ptr `plusPtr` (sizeOf x * 2)) z
+    poke (castPtr ptr `plusPtr` (sizeOf x * 3)) w
+
+  peek ptr = do
+    x <- peek (castPtr ptr `plusPtr`               )
+    y <- peek (castPtr ptr `plusPtr` (sizeOf x * 1))
+    z <- peek (castPtr ptr `plusPtr` (sizeOf x * 2))
+    w <- peek (castPtr ptr `plusPtr` (sizeOf x * 3))
+    return ImVec4{ x, y, z, w }
+
+
+imguiContext :: Context
+imguiContext = mempty
+  { ctxTypesTable = Map.fromList
+      [ ( TypeName "ImVec4", [t| ImVec4 |] )
+      ]
+    }