Add IsEditorHovered

- This should help ensure that node editor interactions don't happen
  when the mouse is outside the canvas, or the canvas is blocked by
  another window.

Author: Nelarius

example/color_node_editor.cpp

@@ -691,10 +691,11 @@ class ColorNodeEditor
             imnodes::Link(iter->first, iter->second.from, iter->second.to);
         }
 
-        imnodes::EndNodeEditor();
-
         const bool open_popup =
-            ImGui::IsMouseClicked(1) || ImGui::IsKeyReleased(SDL_SCANCODE_A);
+            ImGui::IsWindowFocused(ImGuiFocusedFlags_RootAndChildWindows) &&
+            imnodes::IsEditorHovered() && ImGui::IsKeyReleased(SDL_SCANCODE_A);
+
+        imnodes::EndNodeEditor();
 
         ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(8.f, 8.f));
         if (!ImGui::IsAnyItemHovered() && open_popup)

example/multi_editor.cpp

@@ -71,6 +71,14 @@ void show_editor(const char* editor_name, Editor& editor)
         imnodes::Link(link.id, link.start_attr, link.end_attr);
     }
 
+    if (ImGui::IsWindowFocused(ImGuiFocusedFlags_RootAndChildWindows) &&
+        imnodes::IsEditorHovered() && ImGui::IsKeyReleased(SDL_SCANCODE_A))
+    {
+        const int node_id = ++editor.current_id;
+        imnodes::SetNodeScreenSpacePos(node_id, ImGui::GetMousePos());
+        editor.nodes.push_back(Node(node_id, 0.f));
+    }
+
     imnodes::EndNodeEditor();
 
     {
@@ -97,14 +105,6 @@ void show_editor(const char* editor_name, Editor& editor)
         }
     }
 
-    if (ImGui::IsKeyReleased(SDL_SCANCODE_A) &&
-        ImGui::IsWindowFocused(ImGuiFocusedFlags_RootAndChildWindows))
-    {
-        const int node_id = ++editor.current_id;
-        imnodes::SetNodeScreenSpacePos(node_id, ImGui::GetMousePos());
-        editor.nodes.push_back(Node(node_id, 0.f));
-    }
-
     ImGui::End();
 }
 

imnodes.cpp

@@ -1858,6 +1858,12 @@ void SetNodeDraggable(int node_id, const bool draggable)
     node.draggable = draggable;
 }
 
+bool IsEditorHovered()
+{
+    return g.canvas_rect_screen_space.Contains(ImGui::GetMousePos()) &&
+           ImGui::IsWindowHovered();
+}
+
 bool IsNodeHovered(int* const node_id)
 {
     assert(g.current_scope == Scope_None);

imnodes.h

@@ -187,6 +187,9 @@ void SetNodeGridSpacePos(int node_id, const ImVec2& grid_pos);
 // Enable or disable the ability to click and drag a specific node.
 void SetNodeDraggable(int node_id, const bool draggable);
 
+// Returns true if the current node editor canvas is being hovered over by the
+// mouse, and is not blocked by any other windows.
+bool IsEditorHovered();
 // The following functions return true if a UI element is being hovered over by
 // the mouse cursor. Assigns the id of the UI element being hovered over to the
 // function argument. Use these functions after EndNodeEditor() has been called.