From 70370611e5c3694e9ef9ba0ecf0679442fdbd077 Mon Sep 17 00:00:00 2001
From: Joonas Javanainen <joonas.javanainen@gmail.com>
Date: Sun, 3 Jun 2018 11:21:13 +0300
Subject: [PATCH 1/2] Renderers take DrawData, not DrawList

---
 imgui-gfx-renderer/src/lib.rs   |  7 ++-
 imgui-glium-renderer/src/lib.rs |  7 ++-
 src/lib.rs                      | 77 ++++++++++++++++++++++++++++-----
 3 files changed, 77 insertions(+), 14 deletions(-)

diff --git a/imgui-gfx-renderer/src/lib.rs b/imgui-gfx-renderer/src/lib.rs
index be792bd..ccd32fd 100644
--- a/imgui-gfx-renderer/src/lib.rs
+++ b/imgui-gfx-renderer/src/lib.rs
@@ -180,8 +180,11 @@ impl<R: Resources> Renderer<R> {
             [-1.0, 1.0, 0.0, 1.0],
         ];
 
-        ui.render(|ui, draw_list| {
-            self.render_draw_list(ui, factory, encoder, &draw_list)
+        ui.render(|ui, draw_data| {
+            for draw_list in &draw_data {
+                self.render_draw_list(ui, factory, encoder, &draw_list)?;
+            }
+            Ok(())
         })
     }
     fn render_draw_list<'a, F: Factory<R>, C: CommandBuffer<R>>(
diff --git a/imgui-glium-renderer/src/lib.rs b/imgui-glium-renderer/src/lib.rs
index b24af57..4a70fba 100644
--- a/imgui-glium-renderer/src/lib.rs
+++ b/imgui-glium-renderer/src/lib.rs
@@ -73,8 +73,11 @@ impl Renderer {
 
     pub fn render<'a, S: Surface>(&mut self, surface: &mut S, ui: Ui<'a>) -> RendererResult<()> {
         let _ = self.ctx.insert_debug_marker("imgui-rs: starting rendering");
-        let result = ui.render(|ui, draw_list| {
-            self.render_draw_list(surface, ui, &draw_list)
+        let result = ui.render(|ui, draw_data| {
+            for draw_list in draw_data.into_iter() {
+                self.render_draw_list(surface, ui, &draw_list)?;
+            }
+            Ok(())
         });
         let _ = self.ctx.insert_debug_marker("imgui-rs: rendering finished");
         result
diff --git a/src/lib.rs b/src/lib.rs
index 737868a..8e22bc9 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -396,6 +396,68 @@ impl Drop for ImGui {
 
 static mut CURRENT_UI: Option<Ui<'static>> = None;
 
+pub struct DrawData<'a> {
+    raw: &'a mut sys::ImDrawData,
+}
+
+impl<'a> DrawData<'a> {
+    pub fn is_valid(&self) -> bool {
+        self.raw.valid
+    }
+    pub fn draw_list_count(&self) -> usize {
+        self.raw.cmd_lists_count as usize
+    }
+    pub fn total_vtx_count(&self) -> usize {
+        self.raw.total_vtx_count as usize
+    }
+    pub fn total_idx_count(&self) -> usize {
+        self.raw.total_idx_count as usize
+    }
+    pub fn deindex_all_buffers(&mut self) {
+        unsafe {
+            sys::ImDrawData_DeIndexAllBuffers(self.raw);
+        }
+    }
+    pub fn scale_clip_rects<S: Into<ImVec2>>(&mut self, sc: S) {
+        unsafe {
+            sys::ImDrawData_ScaleClipRects(self.raw, sc.into());
+        }
+    }
+}
+
+impl<'a> IntoIterator for &'a DrawData<'a> {
+    type Item = DrawList<'a>;
+    type IntoIter = DrawListIterator<'a>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        unsafe {
+            DrawListIterator {
+                iter: self.raw.cmd_lists().iter(),
+            }
+        }
+    }
+}
+
+pub struct DrawListIterator<'a> {
+    iter: std::slice::Iter<'a, *const sys::ImDrawList>,
+}
+
+impl<'a> Iterator for DrawListIterator<'a> {
+    type Item = DrawList<'a>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.iter.next().map(|&ptr| {
+            unsafe {
+                DrawList {
+                    cmd_buffer: (*ptr).cmd_buffer.as_slice(),
+                    idx_buffer: (*ptr).idx_buffer.as_slice(),
+                    vtx_buffer: (*ptr).vtx_buffer.as_slice(),
+                }
+            }
+        })
+    }
+}
+
 pub struct DrawList<'a> {
     pub cmd_buffer: &'a [sys::ImDrawCmd],
     pub idx_buffer: &'a [sys::ImDrawIdx],
@@ -442,20 +504,15 @@ impl<'ui> Ui<'ui> {
     }
     pub fn render<F, E>(self, mut f: F) -> Result<(), E>
     where
-        F: FnMut(&Ui, DrawList) -> Result<(), E>,
+        F: FnMut(&Ui, DrawData) -> Result<(), E>,
     {
         unsafe {
             sys::igRender();
 
-            let draw_data = sys::igGetDrawData();
-            for &cmd_list in (*draw_data).cmd_lists() {
-                let draw_list = DrawList {
-                    cmd_buffer: (*cmd_list).cmd_buffer.as_slice(),
-                    idx_buffer: (*cmd_list).idx_buffer.as_slice(),
-                    vtx_buffer: (*cmd_list).vtx_buffer.as_slice(),
-                };
-                try!(f(&self, draw_list));
-            }
+            let draw_data = DrawData {
+                raw: &mut *sys::igGetDrawData(),
+            };
+            f(&self, draw_data)?;
             CURRENT_UI = None;
         }
         Ok(())

From 9537fd83b3c2ef9812c816db0b8133388bbdd33e Mon Sep 17 00:00:00 2001
From: Joonas Javanainen <joonas.javanainen@gmail.com>
Date: Sun, 3 Jun 2018 11:27:10 +0300
Subject: [PATCH 2/2] Render callback should be FnOnce

The callback is no longer called multiple times
---
 src/lib.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 8e22bc9..87c0190 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -502,9 +502,9 @@ impl<'ui> Ui<'ui> {
         let io = self.imgui.io();
         io.metrics_active_windows
     }
-    pub fn render<F, E>(self, mut f: F) -> Result<(), E>
+    pub fn render<F, E>(self, f: F) -> Result<(), E>
     where
-        F: FnMut(&Ui, DrawData) -> Result<(), E>,
+        F: FnOnce(&Ui, DrawData) -> Result<(), E>,
     {
         unsafe {
             sys::igRender();