From 5a1f5c78ecb213b596acdb80224444179f2f5e67 Mon Sep 17 00:00:00 2001
From: Ollie Charles <ollie@ocharles.org.uk>
Date: Sun, 24 Jan 2021 16:03:18 +0000
Subject: [PATCH] Wrap ImGui::ProgressBar()

---
 Main.hs          |  2 ++
 src/DearImGui.hs | 14 ++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/Main.hs b/Main.hs
index 305adb0..a610669 100644
--- a/Main.hs
+++ b/Main.hs
@@ -58,6 +58,8 @@ loop w checked = do
     True  -> readIORef checked >>= print
     False -> return ()
 
+  progressBar 0.314 (Just "Pi")
+
   end
 
   render
diff --git a/src/DearImGui.hs b/src/DearImGui.hs
index bbc9e6a..4045860 100644
--- a/src/DearImGui.hs
+++ b/src/DearImGui.hs
@@ -57,6 +57,7 @@ module DearImGui
   , smallButton
   , arrowButton
   , checkbox
+  , progressBar
   , bullet
 
     -- * Types
@@ -316,6 +317,14 @@ checkbox label ref = do
     return changed
 
 
+progressBar :: Float -> Maybe String -> IO ()
+progressBar progress overlay = withCStringOrNull overlay \overlayPtr ->
+  [C.exp| void { ProgressBar($(float c'progress), ImVec2(-FLT_MIN, 0), $(char* overlayPtr)) } |]
+  where
+    c'progress :: CFloat
+    c'progress = realToFrac progress
+
+
 -- | Draw a small circle + keep the cursor on the same line. Advance cursor x
 -- position by 'getTreeNodeToLabelSpacing', same distance that 'treeNode' uses.
 bullet :: IO ()
@@ -331,3 +340,8 @@ pattern ImGuiDirLeft  = ImGuiDir 0
 pattern ImGuiDirRight = ImGuiDir 1
 pattern ImGuiDirUp    = ImGuiDir 2
 pattern ImGuiDirDown  = ImGuiDir 3
+
+
+withCStringOrNull :: Maybe String -> (Ptr CChar -> IO a) -> IO a
+withCStringOrNull Nothing k  = k nullPtr
+withCStringOrNull (Just s) k = withCString s k