IsWindowHovered(): split ImGuiHoveredFlags_FlattenChild into separate ChildWindows and RootWindow flags. Allowing more combination and a better symetry with IsWindowFocused() flags. (#1382)

Author: ocornut

imgui.cpp

@@ -221,7 +221,7 @@
  - 2017/11/18 (1.53) - Style: removed ImGuiCol_ComboBg in favor of combo boxes using ImGuiCol_PopupBg for consistency.
  - 2017/11/18 (1.53) - Style: renamed ImGuiCol_ChildWindowBg to ImGuiCol_ChildBg.
  - 2017/11/18 (1.53) - Style: renamed style.ChildWindowRounding to style.ChildRounding, ImGuiStyleVar_ChildWindowRounding to ImGuiStyleVar_ChildRounding.
- - 2017/11/02 (1.53) - marked IsRootWindowOrAnyChildHovered() as obsolete is favor of using IsWindowHovered(ImGuiHoveredFlags_FlattenChilds);
+ - 2017/11/02 (1.53) - marked IsRootWindowOrAnyChildHovered() as obsolete is favor of using IsWindowHovered(ImGuiHoveredFlags_RootWindow | ImGuiHoveredFlags_ChildWindows);
  - 2017/10/24 (1.52) - renamed IMGUI_DISABLE_WIN32_DEFAULT_CLIPBOARD_FUNCS/IMGUI_DISABLE_WIN32_DEFAULT_IME_FUNCS to IMGUI_DISABLE_WIN32_DEFAULT_CLIPBOARD_FUNCTIONS/IMGUI_DISABLE_WIN32_DEFAULT_IME_FUNCTIONS for consistency.
  - 2017/10/20 (1.52) - changed IsWindowHovered() default parameters behavior to return false if an item is active in another window (e.g. click-dragging item from another window to this window). You can use the newly introduced IsWindowHovered() flags to requests this specific behavior if you need it.
  - 2017/10/20 (1.52) - marked IsItemHoveredRect()/IsMouseHoveringWindow() as obsolete, in favor of using the newly introduced flags for IsItemHovered() and IsWindowHovered(). See https://github.com/ocornut/imgui/issues/1382 for details.
@@ -2032,7 +2032,7 @@ bool ImGui::IsItemHovered(ImGuiHoveredFlags flags)
     // Test for bounding box overlap, as updated as ItemAdd()
     if (!window->DC.LastItemRectHoveredRect)
         return false;
-    IM_ASSERT((flags & ImGuiHoveredFlags_FlattenChilds) == 0);   // Flags not supported by this function
+    IM_ASSERT((flags & (ImGuiHoveredFlags_RootWindow | ImGuiHoveredFlags_ChildWindows)) == 0);   // Flags not supported by this function
 
     // Test if we are hovering the right window (our window could be behind another window)
     // [2017/10/16] Reverted commit 344d48be3 and testing RootWindow instead. I believe it is correct to NOT test for RootWindow but this leaves us unable to use IsItemHovered() after EndChild() itself.
@@ -5440,20 +5440,43 @@ const char* ImGui::GetStyleColorName(ImGuiCol idx)
     return "Unknown";
 }
 
+bool ImGui::IsWindowChildOf(ImGuiWindow* window, ImGuiWindow* potential_parent)
+{
+    if (window->RootWindow == potential_parent)
+        return true;
+    while (window != NULL)
+    {
+        if (window == potential_parent)
+            return true;
+        window = window->ParentWindow;
+    }
+    return false;
+}
+
 bool ImGui::IsWindowHovered(ImGuiHoveredFlags flags)
 {
     IM_ASSERT((flags & ImGuiHoveredFlags_AllowWhenOverlapped) == 0);   // Flags not supported by this function
     ImGuiContext& g = *GImGui;
-    if (flags & ImGuiHoveredFlags_FlattenChilds)
+    switch (flags & (ImGuiHoveredFlags_RootWindow | ImGuiHoveredFlags_ChildWindows))
     {
+    case ImGuiHoveredFlags_RootWindow | ImGuiHoveredFlags_ChildWindows:
         if (g.HoveredRootWindow != g.CurrentWindow->RootWindow)
             return false;
-    }
-    else
-    {
+        break;
+    case ImGuiHoveredFlags_RootWindow:
+        if (g.HoveredWindow != g.CurrentWindow->RootWindow)
+            return false;
+        break;
+    case ImGuiHoveredFlags_ChildWindows:
+        if (g.HoveredWindow == NULL || !IsWindowChildOf(g.HoveredWindow, g.CurrentWindow))
+            return false;
+        break;
+    default:
         if (g.HoveredWindow != g.CurrentWindow)
             return false;
+        break;
     }
+
     if (!IsWindowContentHoverable(g.HoveredRootWindow, flags))
         return false;
     if (!(flags & ImGuiHoveredFlags_AllowWhenBlockedByActiveItem))

imgui.h

@@ -607,7 +607,8 @@ enum ImGuiHoveredFlags_
     //ImGuiHoveredFlags_AllowWhenBlockedByModal     = 1 << 1,   // Return true even if a modal popup window is normally blocking access to this item/window. FIXME-TODO: Unavailable yet.
     ImGuiHoveredFlags_AllowWhenBlockedByActiveItem  = 1 << 2,   // Return true even if an active item is blocking access to this item/window
     ImGuiHoveredFlags_AllowWhenOverlapped           = 1 << 3,   // Return true even if the position is overlapped by another window
-    ImGuiHoveredFlags_FlattenChilds                 = 1 << 4,   // Treat all child windows as the same window (for IsWindowHovered())
+    ImGuiHoveredFlags_ChildWindows                  = 1 << 4,   // IsWindowHovered() only: Return true if any children of the window is hovered
+    ImGuiHoveredFlags_RootWindow                    = 1 << 5,   // IsWindowHovered() only: Test from root window (top most parent of the current hierarchy)
     ImGuiHoveredFlags_RectOnly                      = ImGuiHoveredFlags_AllowWhenBlockedByPopup | ImGuiHoveredFlags_AllowWhenBlockedByActiveItem | ImGuiHoveredFlags_AllowWhenOverlapped
 };
 
@@ -937,8 +938,8 @@ struct ImGuiIO
 #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
 namespace ImGui
 {
-    static inline void      SetNextWindowContentWidth(float width) { ImGui::SetNextWindowContentSize(ImVec2(width, 0.0f)); } // OBSOLETE 1.53+ (nb: original version preserved last Y value set by SetNextWindowContentSize())
-    static inline bool      IsRootWindowOrAnyChildHovered(ImGuiHoveredFlags flags = 0) { return IsItemHovered(flags | ImGuiHoveredFlags_FlattenChilds); } // OBSOLETE 1.53+ use flags directly
+    static inline void      SetNextWindowContentWidth(float width) { SetNextWindowContentSize(ImVec2(width, 0.0f)); } // OBSOLETE 1.53+ (nb: original version preserved last Y value set by SetNextWindowContentSize())
+    static inline bool      IsRootWindowOrAnyChildHovered(ImGuiHoveredFlags flags = 0) { return IsItemHovered(flags | ImGuiHoveredFlags_RootWindow | ImGuiHoveredFlags_ChildWindows); } // OBSOLETE 1.53+ use flags directly
     bool                    Begin(const char* name, bool* p_open, const ImVec2& size_on_first_use, float bg_alpha_override = -1.0f, ImGuiWindowFlags flags = 0); // OBSOLETE 1.52+. use SetNextWindowSize() instead if you want to set a window size.
     static inline void      AlignFirstTextHeightToWidgets() { AlignTextToFramePadding(); }     // OBSOLETE 1.52+
     static inline void      SetNextWindowPosCenter(ImGuiCond cond = 0) { SetNextWindowPos(ImVec2(GetIO().DisplaySize.x * 0.5f, GetIO().DisplaySize.y * 0.5f), cond, ImVec2(0.5f, 0.5f)); } // OBSOLETE 1.52+

imgui_demo.cpp

@@ -1788,11 +1788,15 @@ void ImGui::ShowTestWindow(bool* p_open)
                 "IsWindowHovered() = %d\n"
                 "IsWindowHovered(_AllowWhenBlockedByPopup) = %d\n"
                 "IsWindowHovered(_AllowWhenBlockedByActiveItem) = %d\n"
-                "IsWindowHovered(_FlattenChilds) = %d\n",
+                "IsWindowHovered(_ChildWindows) = %d\n"
+                "IsWindowHovered(_ChildWindows|_RootWindow) = %d\n"
+                "IsWindowHovered(_RootWindow) = %d\n",
                 ImGui::IsWindowHovered(),
                 ImGui::IsWindowHovered(ImGuiHoveredFlags_AllowWhenBlockedByPopup),
                 ImGui::IsWindowHovered(ImGuiHoveredFlags_AllowWhenBlockedByActiveItem),
-                ImGui::IsWindowHovered(ImGuiHoveredFlags_FlattenChilds));
+                ImGui::IsWindowHovered(ImGuiHoveredFlags_ChildWindows),
+                ImGui::IsWindowHovered(ImGuiHoveredFlags_ChildWindows | ImGuiHoveredFlags_RootWindow),
+                ImGui::IsWindowHovered(ImGuiHoveredFlags_RootWindow));
 
             // Testing IsItemHovered() function (because BulletText is an item itself and that would affect the output of IsItemHovered, we pass all lines in a single items to shorten the code)
             ImGui::Button("ITEM");
@@ -1808,6 +1812,10 @@ void ImGui::ShowTestWindow(bool* p_open)
                 ImGui::IsItemHovered(ImGuiHoveredFlags_AllowWhenOverlapped),
                 ImGui::IsItemHovered(ImGuiHoveredFlags_RectOnly));
 
+            ImGui::BeginChild("child", ImVec2(0,50), true);
+            ImGui::Text("This is a child window for testing IsWindowHovered() flags.");
+            ImGui::EndChild();
+
             ImGui::TreePop();
         }
 

imgui_internal.h

@@ -804,6 +804,7 @@ namespace ImGui
     IMGUI_API void          FocusWindow(ImGuiWindow* window);
     IMGUI_API void          BringWindowToFront(ImGuiWindow* window);
     IMGUI_API void          BringWindowToBack(ImGuiWindow* window);
+    IMGUI_API bool          IsWindowChildOf(ImGuiWindow* window, ImGuiWindow* potential_parent);
 
     IMGUI_API void          Initialize();