IsWindowHovered: Added support for ImGuiHoveredFlags_Stationary.

docs/CHANGELOG.txt

@@ -63,6 +63,7 @@ Other changes:
     isn't covered as much. (Match offset for drag and drop tooltips)
   - IsItemHovered: Tweaked default value of style.HoverDelayNormal from 0.30 to 0.40,
     Tweaked default value of style.HoverDelayShort from 0.10 to 0.15. (#1485)
+- IsWindowHovered: Added support for ImGuiHoveredFlags_Stationary.
 - Tables: Fixed a regression in 1.89.6 leading to the first column of tables with either
   ScrollX or ScrollY flags from being impossible to resize. (#6503)
 - Clipper: Rework inner logic to allow functioning with a zero-clear constructor.

imgui.cpp

@@ -3933,6 +3933,16 @@ bool ImGui::IsWindowContentHoverable(ImGuiWindow* window, ImGuiHoveredFlags flag
     return true;
 }
 
+static inline float CalcDelayFromHoveredFlags(ImGuiHoveredFlags flags)
+{
+    ImGuiContext& g = *GImGui;
+    if (flags & ImGuiHoveredFlags_DelayShort)
+        return g.Style.HoverDelayShort;
+    if (flags & ImGuiHoveredFlags_DelayNormal)
+        return g.Style.HoverDelayNormal;
+    return 0.0f;
+}
+
 // This is roughly matching the behavior of internal-facing ItemHoverable()
 // - we allow hovering to be true when ActiveId==window->MoveID, so that clicking on non-interactive items such as a Text() item still returns true with IsItemHovered()
 // - this should work even for non-interactive items that have no ID, so we cannot use LastItemId
@@ -3995,13 +4005,7 @@ bool ImGui::IsItemHovered(ImGuiHoveredFlags flags)
 
     // Handle hover delay
     // (some ideas: https://www.nngroup.com/articles/timing-exposing-content)
-    float delay;
+    const float delay = CalcDelayFromHoveredFlags(flags);
-    if (flags & ImGuiHoveredFlags_DelayShort)
-        delay = g.Style.HoverDelayShort;
-    else if (flags & ImGuiHoveredFlags_DelayNormal)
-        delay = g.Style.HoverDelayNormal;
-    else
-        delay = 0.0f;
     if (delay > 0.0f || (flags & ImGuiHoveredFlags_Stationary))
     {
         ImGuiID hover_delay_id = (g.LastItemData.ID != 0) ? g.LastItemData.ID : window->GetIDFromRectangle(g.LastItemData.Rect);
@@ -4567,6 +4571,10 @@ void ImGui::NewFrame()
         g.HoverItemUnlockedStationaryId = g.HoverItemDelayId;
     else if (g.HoverItemDelayId == 0)
         g.HoverItemUnlockedStationaryId = 0;
+    if (g.HoveredWindow != NULL && g.MouseStationaryTimer >= g.Style.HoverStationaryDelay)
+        g.HoverWindowUnlockedStationaryId = g.HoveredWindow->ID;
+    else if (g.HoveredWindow == NULL)
+        g.HoverWindowUnlockedStationaryId = 0;
 
     // Update hover delay for IsItemHovered() with delays and tooltips
     g.HoverItemDelayIdPreviousFrame = g.HoverItemDelayId;
@@ -7274,6 +7282,16 @@ bool ImGui::IsWindowHovered(ImGuiHoveredFlags flags)
         if (g.ActiveId != 0 && !g.ActiveIdAllowOverlap && g.ActiveId != ref_window->MoveId)
             return false;
 
+    // When changing hovered window we requires a bit of stationary delay before activating hover timer.
+    // FIXME: We don't support delay other than stationary one for now, other delay would need a way
+    // to fullfill the possibility that multiple IsWindowHovered() with varying flag could return true
+    // for different windows of the hierarchy. Possibly need a Hash(Current+Flags) ==> (Timer) cache.
+    // We can implement this for _Stationary because the data is linked to HoveredWindow rather than CurrentWindow.
+    if (flags & ImGuiHoveredFlags_ForTooltip)
+        flags |= g.Style.HoverFlagsForTooltipMouse;
+    if ((flags & ImGuiHoveredFlags_Stationary) != 0 && g.HoverWindowUnlockedStationaryId != ref_window->ID)
+        return false;
+
     return true;
 }
 

imgui.h

@@ -1297,13 +1297,13 @@ enum ImGuiHoveredFlags_
     // - this is a shortcut to pull flags from 'style.HoverFlagsForTooltipMouse' or 'style.HoverFlagsForTooltipNav' where you can reconfigure desired behavior.
     //   e.g. 'TooltipHoveredFlagsForMouse' defaults to 'ImGuiHoveredFlags_Stationary | ImGuiHoveredFlags_DelayShort'.
     // - for frequently actioned or hovered items providing a tooltip, you want may to use ImGuiHoveredFlags_ForTooltip (stationary + delay) so the tooltip doesn't show too often.
-    // - for items which main purpose is to be hovered, or items with low affordance, or less consistent app, prefer no delay or shorter delay.
+    // - for items which main purpose is to be hovered, or items with low affordance, or in less consistent apps, prefer no delay or shorter delay.
     ImGuiHoveredFlags_ForTooltip                    = 1 << 11,  // Shortcut for standard flags when using IsItemHovered() + SetTooltip() sequence.
 
     // (Advanced) Mouse Hovering delays.
     // - generally you can use ImGuiHoveredFlags_ForTooltip to use application-standardized flags.
     // - use those if you need specific overrides.
-    ImGuiHoveredFlags_Stationary                    = 1 << 12,  // IsItemHovered() only: Require mouse to be stationary for style.HoverStationaryDelay (~0.15 sec) _at least one time_. After this, can move on same item.
+    ImGuiHoveredFlags_Stationary                    = 1 << 12,  // Require mouse to be stationary for style.HoverStationaryDelay (~0.15 sec) _at least one time_. After this, can move on same item/window. Using the stationary test tends to reduces the need for a long delay.
     ImGuiHoveredFlags_DelayNone                     = 1 << 13,  // IsItemHovered() only: Return true immediately (default). As this is the default you generally ignore this.
     ImGuiHoveredFlags_DelayShort                    = 1 << 14,  // IsItemHovered() only: Return true after style.HoverDelayShort elapsed (~0.15 sec) (shared between items) + requires mouse to be stationary for style.HoverStationaryDelay (once per item).
     ImGuiHoveredFlags_DelayNormal                   = 1 << 15,  // IsItemHovered() only: Return true after style.HoverDelayNormal elapsed (~0.40 sec) (shared between items) + requires mouse to be stationary for style.HoverStationaryDelay (once per item).

imgui_demo.cpp

@@ -2523,7 +2523,8 @@ static void ShowDemoWindowWidgets()
             "IsWindowHovered(_RootWindow) = %d\n"
             "IsWindowHovered(_RootWindow|_NoPopupHierarchy) = %d\n"
             "IsWindowHovered(_ChildWindows|_AllowWhenBlockedByPopup) = %d\n"
-            "IsWindowHovered(_AnyWindow) = %d\n",
+            "IsWindowHovered(_AnyWindow) = %d\n"
+            "IsWindowHovered(_Stationary) = %d\n",
             ImGui::IsWindowHovered(),
             ImGui::IsWindowHovered(ImGuiHoveredFlags_AllowWhenBlockedByPopup),
             ImGui::IsWindowHovered(ImGuiHoveredFlags_AllowWhenBlockedByActiveItem),
@@ -2534,7 +2535,8 @@ static void ShowDemoWindowWidgets()
             ImGui::IsWindowHovered(ImGuiHoveredFlags_RootWindow),
             ImGui::IsWindowHovered(ImGuiHoveredFlags_RootWindow | ImGuiHoveredFlags_NoPopupHierarchy),
             ImGui::IsWindowHovered(ImGuiHoveredFlags_ChildWindows | ImGuiHoveredFlags_AllowWhenBlockedByPopup),
-            ImGui::IsWindowHovered(ImGuiHoveredFlags_AnyWindow));
+            ImGui::IsWindowHovered(ImGuiHoveredFlags_AnyWindow),
+            ImGui::IsWindowHovered(ImGuiHoveredFlags_Stationary));
 
         ImGui::BeginChild("child", ImVec2(0, 50), true);
         ImGui::Text("This is another child window for testing the _ChildWindows flag.");

imgui_internal.h

@@ -1963,12 +1963,13 @@ struct ImGuiContext
     ImGuiID                 HoverItemDelayIdPreviousFrame;
     float                   HoverItemDelayTimer;                // Currently used by IsItemHovered()
     float                   HoverItemDelayClearTimer;           // Currently used by IsItemHovered(): grace time before g.TooltipHoverTimer gets cleared.
-    ImGuiID                 HoverItemUnlockedStationaryId;
+    ImGuiID                 HoverItemUnlockedStationaryId;      // Mouse has once been stationary on this item. Only reset after departing the item.
+    ImGuiID                 HoverWindowUnlockedStationaryId;    // Mouse has once been stationary on this window. Only reset after departing the window.
 
     // Mouse state
     ImGuiMouseCursor        MouseCursor;
     int                     MouseMovingFrames;
-    float                   MouseStationaryTimer;
+    float                   MouseStationaryTimer;               // Time the mouse has been stationary (with some loose heuristic)
     ImVec2                  MouseLastValidPos;
 
     // Widget state
@@ -2167,7 +2168,7 @@ struct ImGuiContext
         TablesTempDataStacked = 0;
         CurrentTabBar = NULL;
 
-        HoverItemDelayId = HoverItemDelayIdPreviousFrame = HoverItemUnlockedStationaryId = 0;
+        HoverItemDelayId = HoverItemDelayIdPreviousFrame = HoverItemUnlockedStationaryId = HoverWindowUnlockedStationaryId = 0;
         HoverItemDelayTimer = HoverItemDelayClearTimer = 0.0f;
 
         MouseCursor = ImGuiMouseCursor_Arrow;