Merge pull request #335 from lizhaoxian/expose-background-drawlist

Expose background drawlist

src/lib.rs

@@ -544,6 +544,11 @@ impl<'ui> Ui<'ui> {
     pub fn get_window_draw_list(&'ui self) -> WindowDrawList<'ui> {
         WindowDrawList::new(self)
     }
+
+    #[must_use]
+    pub fn get_background_draw_list(&'ui self) -> WindowDrawList<'ui> {
+        WindowDrawList::new(self).background()
+    }
 }
 
 /// Condition for applying a setting

src/window_draw_list.rs

@@ -82,6 +82,13 @@ impl<'ui> WindowDrawList<'ui> {
         }
     }
 
+    pub(crate) fn background(self) -> Self {
+        Self {
+            draw_list: unsafe { sys::igGetBackgroundDrawList() },
+            _phantom: PhantomData,
+        }
+    }
+
     /// Split into *channels_count* drawing channels.
     /// At the end of the closure, the channels are merged. The objects
     /// are then drawn in the increasing order of their channel number, and not