Internals: Popup: Moved popup/menu/tooltip positioning code (viewport branch needs it organized in a different manner, so we are pushing the bulk of it here to minimize differences).

imgui.cpp

@@ -5241,15 +5241,18 @@ enum ImGuiPopupPositionPolicy
     ImGuiPopupPositionPolicy_ComboBox
 };
 
-static ImVec2 FindBestWindowPosForPopup(const ImVec2& ref_pos, const ImVec2& size, ImGuiDir* last_dir, const ImRect& r_avoid, ImGuiPopupPositionPolicy policy = ImGuiPopupPositionPolicy_Default)
+static ImRect FindScreenRectForWindow(ImGuiWindow* window)
+{
+    ImVec2 padding = GImGui->Style.DisplaySafeAreaPadding;
+    ImRect r_screen = GetViewportRect();
+    r_screen.Expand(ImVec2((window->Size.x - r_screen.GetWidth() > padding.x * 2) ? -padding.x : 0.0f, (window->Size.y - r_screen.GetHeight() > padding.y * 2) ? -padding.y : 0.0f));
+    return r_screen;
+}
+    
+// r_avoid = the rectangle to avoid (e.g. for tooltip it is a rectangle around the mouse cursor which we want to avoid. for popups it's a small point around the cursor.)
+// r_outer = the visible area rectangle, minus safe area padding. If our popup size won't fit because of safe area padding we ignore it.
+static ImVec2 FindBestWindowPosForPopupEx(const ImVec2& ref_pos, const ImVec2& size, ImGuiDir* last_dir, const ImRect& r_outer, const ImRect& r_avoid, ImGuiPopupPositionPolicy policy = ImGuiPopupPositionPolicy_Default)
 {
-    const ImGuiStyle& style = GImGui->Style;
-
-    // r_avoid = the rectangle to avoid (e.g. for tooltip it is a rectangle around the mouse cursor which we want to avoid. for popups it's a small point around the cursor.)
-    // r_outer = the visible area rectangle, minus safe area padding. If our popup size won't fit because of safe area padding we ignore it.
-    ImVec2 safe_padding = style.DisplaySafeAreaPadding;
-    ImRect r_outer(GetViewportRect());
-    r_outer.Expand(ImVec2((size.x - r_outer.GetWidth() > safe_padding.x*2) ? -safe_padding.x : 0.0f, (size.y - r_outer.GetHeight() > safe_padding.y*2) ? -safe_padding.y : 0.0f));
     ImVec2 base_pos_clamped = ImClamp(ref_pos, r_outer.Min, r_outer.Max - size);
     //GImGui->OverlayDrawList.AddRect(r_avoid.Min, r_avoid.Max, IM_COL32(255,0,0,255));
     //GImGui->OverlayDrawList.AddRect(r_outer.Min, r_outer.Max, IM_COL32(0,255,0,255));
@@ -5301,6 +5304,49 @@ static ImVec2 FindBestWindowPosForPopup(const ImVec2& ref_pos, const ImVec2& siz
     return pos;
 }
 
+static ImVec2 FindBestWindowPosForPopup(ImGuiWindow* window)
+{
+    ImGuiContext& g = *GImGui;
+
+    ImRect r_screen = FindScreenRectForWindow(window);
+    if (window->Flags & ImGuiWindowFlags_ChildMenu)
+    {
+        // Child menus typically request _any_ position within the parent menu item, and then our FindBestPopupWindowPos() function will move the new menu outside the parent bounds.
+        // This is how we end up with child menus appearing (most-commonly) on the right of the parent menu.
+        IM_ASSERT(g.CurrentWindow == window);
+        ImGuiWindow* parent_menu = g.CurrentWindowStack[g.CurrentWindowStack.Size - 2];
+        float horizontal_overlap = g.Style.ItemSpacing.x;       // We want some overlap to convey the relative depth of each menu (currently the amount of overlap is hard-coded to style.ItemSpacing.x).
+        ImRect r_avoid;
+        if (parent_menu->DC.MenuBarAppending)
+            r_avoid = ImRect(-FLT_MAX, parent_menu->Pos.y + parent_menu->TitleBarHeight(), FLT_MAX, parent_menu->Pos.y + parent_menu->TitleBarHeight() + parent_menu->MenuBarHeight());
+        else
+            r_avoid = ImRect(parent_menu->Pos.x + horizontal_overlap, -FLT_MAX, parent_menu->Pos.x + parent_menu->Size.x - horizontal_overlap - parent_menu->ScrollbarSizes.x, FLT_MAX);
+        return FindBestWindowPosForPopupEx(window->PosFloat, window->Size, &window->AutoPosLastDirection, r_screen, r_avoid);
+    }
+    if (window->Flags & ImGuiWindowFlags_Popup)
+    {
+        ImRect r_avoid(window->PosFloat.x - 1, window->PosFloat.y - 1, window->PosFloat.x + 1, window->PosFloat.y + 1);
+        return FindBestWindowPosForPopupEx(window->PosFloat, window->Size, &window->AutoPosLastDirection, r_screen, r_avoid);
+    }
+    if (window->Flags & ImGuiWindowFlags_Tooltip)
+    {
+        // Position tooltip (always follows mouse)
+        float sc = g.Style.MouseCursorScale;
+        ImVec2 ref_pos = (!g.NavDisableHighlight && g.NavDisableMouseHover) ? NavCalcPreferredMousePos() : g.IO.MousePos;
+        ImRect r_avoid;
+        if (!g.NavDisableHighlight && g.NavDisableMouseHover && !(g.IO.ConfigFlags & ImGuiConfigFlags_NavEnableSetMousePos))
+            r_avoid = ImRect(ref_pos.x - 16, ref_pos.y - 8, ref_pos.x + 16, ref_pos.y + 8);
+        else
+            r_avoid = ImRect(ref_pos.x - 16, ref_pos.y - 8, ref_pos.x + 24 * sc, ref_pos.y + 24 * sc); // FIXME: Hard-coded based on mouse cursor shape expectation. Exact dimension not very important.
+        ImVec2 pos = FindBestWindowPosForPopupEx(ref_pos, window->Size, &window->AutoPosLastDirection, r_screen, r_avoid);
+        if (window->AutoPosLastDirection == ImGuiDir_None)
+            pos = ref_pos + ImVec2(2, 2); // If there's not enough room, for tooltip we prefer avoiding the cursor at all cost even if it means that part of the tooltip won't be visible.
+        return pos;
+    }
+    IM_ASSERT(0);
+    return window->Pos;
+}
+
 static void SetWindowConditionAllowFlags(ImGuiWindow* window, ImGuiCond flags, bool enabled)
 {
     window->SetWindowPosAllowFlags       = enabled ? (window->SetWindowPosAllowFlags       | flags) : (window->SetWindowPosAllowFlags       & ~flags);
@@ -5870,43 +5916,13 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
 
         const bool window_pos_with_pivot = (window->SetWindowPosVal.x != FLT_MAX && window->HiddenFrames == 0);
         if (window_pos_with_pivot)
-        {
-            // Position given a pivot (e.g. for centering)
-            SetWindowPos(window, ImMax(style.DisplaySafeAreaPadding, window->SetWindowPosVal - window->SizeFull * window->SetWindowPosPivot), 0);
-        }
-        else if (flags & ImGuiWindowFlags_ChildMenu)
-        {
-            // Child menus typically request _any_ position within the parent menu item, and then our FindBestPopupWindowPos() function will move the new menu outside the parent bounds.
-            // This is how we end up with child menus appearing (most-commonly) on the right of the parent menu.
-            IM_ASSERT(window_pos_set_by_api);
-            float horizontal_overlap = style.ItemSpacing.x; // We want some overlap to convey the relative depth of each popup (currently the amount of overlap it is hard-coded to style.ItemSpacing.x, may need to introduce another style value).
-            ImGuiWindow* parent_menu = parent_window_in_stack;
-            ImRect rect_to_avoid;
-            if (parent_menu->DC.MenuBarAppending)
-                rect_to_avoid = ImRect(-FLT_MAX, parent_menu->Pos.y + parent_menu->TitleBarHeight(), FLT_MAX, parent_menu->Pos.y + parent_menu->TitleBarHeight() + parent_menu->MenuBarHeight());
-            else
-                rect_to_avoid = ImRect(parent_menu->Pos.x + horizontal_overlap, -FLT_MAX, parent_menu->Pos.x + parent_menu->Size.x - horizontal_overlap - parent_menu->ScrollbarSizes.x, FLT_MAX);
-            window->PosFloat = FindBestWindowPosForPopup(window->PosFloat, window->Size, &window->AutoPosLastDirection, rect_to_avoid);
-        }
+            SetWindowPos(window, ImMax(style.DisplaySafeAreaPadding, window->SetWindowPosVal - window->SizeFull * window->SetWindowPosPivot), 0); // Position given a pivot (e.g. for centering)
+        else if ((flags & ImGuiWindowFlags_ChildMenu) != 0)
+            window->PosFloat = FindBestWindowPosForPopup(window);
         else if ((flags & ImGuiWindowFlags_Popup) != 0 && !window_pos_set_by_api && window_just_appearing_after_hidden_for_resize)
-        {
-            ImRect rect_to_avoid(window->PosFloat.x - 1, window->PosFloat.y - 1, window->PosFloat.x + 1, window->PosFloat.y + 1);
-            window->PosFloat = FindBestWindowPosForPopup(window->PosFloat, window->Size, &window->AutoPosLastDirection, rect_to_avoid);
-        }
-        else  if ((flags & ImGuiWindowFlags_Tooltip) != 0 && !window_pos_set_by_api && !window_is_child_tooltip)
-        {
-            // Position tooltip (always follow mouse but avoid cursor)
-            float sc = g.Style.MouseCursorScale;
-            ImVec2 ref_pos = (!g.NavDisableHighlight && g.NavDisableMouseHover) ? NavCalcPreferredMousePos() : g.IO.MousePos;
-            ImRect rect_to_avoid;
-            if (!g.NavDisableHighlight && g.NavDisableMouseHover && !(g.IO.ConfigFlags & ImGuiConfigFlags_NavEnableSetMousePos))
-                rect_to_avoid = ImRect(ref_pos.x - 16, ref_pos.y - 8, ref_pos.x + 16, ref_pos.y + 8); 
-            else
-                rect_to_avoid = ImRect(ref_pos.x - 16, ref_pos.y - 8, ref_pos.x + 24 * sc, ref_pos.y + 24 * sc); // FIXME: Hard-coded based on mouse cursor shape expectation. Exact dimension not very important.
-            window->PosFloat = FindBestWindowPosForPopup(ref_pos, window->Size, &window->AutoPosLastDirection, rect_to_avoid);
-            if (window->AutoPosLastDirection == ImGuiDir_None)
-                window->PosFloat = ref_pos + ImVec2(2,2); // If there's not enough room, for tooltip we prefer avoiding the cursor at all cost even if it means that part of the tooltip won't be visible.
-        }
+            window->PosFloat = FindBestWindowPosForPopup(window);
+        else if ((flags & ImGuiWindowFlags_Tooltip) != 0 && !window_pos_set_by_api && !window_is_child_tooltip)
+            window->PosFloat = FindBestWindowPosForPopup(window);
 
         // Clamp position so it stays visible
         if (!(flags & ImGuiWindowFlags_ChildWindow) && !(flags & ImGuiWindowFlags_Tooltip))
@@ -10761,7 +10777,8 @@ bool ImGui::BeginCombo(const char* label, const char* preview_value, ImGuiComboF
             ImVec2 size_expected = CalcSizeAfterConstraint(popup_window, CalcSizeAutoFit(popup_window, size_contents));
             if (flags & ImGuiComboFlags_PopupAlignLeft)
                 popup_window->AutoPosLastDirection = ImGuiDir_Left;
-            ImVec2 pos = FindBestWindowPosForPopup(frame_bb.GetBL(), size_expected, &popup_window->AutoPosLastDirection, frame_bb, ImGuiPopupPositionPolicy_ComboBox);
+            ImRect r_outer = FindScreenRectForWindow(popup_window);
+            ImVec2 pos = FindBestWindowPosForPopupEx(frame_bb.GetBL(), size_expected, &popup_window->AutoPosLastDirection, r_outer, frame_bb, ImGuiPopupPositionPolicy_ComboBox);
             SetNextWindowPos(pos);
         }