Method IsItemHovered

tutorials/common/imgui/imgui.cpp:3629–3697

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

// - 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
bool ImGui::IsItemHovered(ImGuiHoveredFlags flags)
{
    ImGuiContext& g = *GImGui;
    ImGuiWindow* window = g.CurrentWindow;
    if (g.NavDisableMouseHover && !g.NavDisableHighlight && !(flags & ImGuiHoveredFlags_NoNavOverride))
    {
        if ((g.LastItemData.InFlags & ImGuiItemFlags_Disabled) && !(flags & ImGuiHoveredFlags_AllowWhenDisabled))
            return false;
        if (!IsItemFocused())
            return false;
    }
    else
    {
        // Test for bounding box overlap, as updated as ItemAdd()
        ImGuiItemStatusFlags status_flags = g.LastItemData.StatusFlags;
        if (!(status_flags & ImGuiItemStatusFlags_HoveredRect))
            return false;
        IM_ASSERT((flags & (ImGuiHoveredFlags_AnyWindow | ImGuiHoveredFlags_RootWindow | ImGuiHoveredFlags_ChildWindows | ImGuiHoveredFlags_NoPopupHierarchy)) == 0);   // Flags not supported by this function

        // Done with rectangle culling so we can perform heavier checks now
        // Test if we are hovering the right window (our window could be behind another window)
        // [2021/03/02] Reworked / reverted the revert, finally. Note we want e.g. BeginGroup/ItemAdd/EndGroup to work as well. (#3851)
        // [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. Until a solution is found I believe reverting to the test from 2017/09/27 is safe since this was
        // the test that has been running for a long while.
        if (g.HoveredWindow != window && (status_flags & ImGuiItemStatusFlags_HoveredWindow) == 0)
            if ((flags & ImGuiHoveredFlags_AllowWhenOverlapped) == 0)
                return false;

        // Test if another item is active (e.g. being dragged)
        if ((flags & ImGuiHoveredFlags_AllowWhenBlockedByActiveItem) == 0)
            if (g.ActiveId != 0 && g.ActiveId != g.LastItemData.ID && !g.ActiveIdAllowOverlap && g.ActiveId != window->MoveId)
                return false;

        // Test if interactions on this window are blocked by an active popup or modal.
        // The ImGuiHoveredFlags_AllowWhenBlockedByPopup flag will be tested here.
        if (!IsWindowContentHoverable(window, flags) && !(g.LastItemData.InFlags & ImGuiItemFlags_NoWindowHoverableCheck))
            return false;

        // Test if the item is disabled
        if ((g.LastItemData.InFlags & ImGuiItemFlags_Disabled) && !(flags & ImGuiHoveredFlags_AllowWhenDisabled))
            return false;

        // Special handling for calling after Begin() which represent the title bar or tab.
        // When the window is collapsed (SkipItems==true) that last item will never be overwritten so we need to detect the case.
        if (g.LastItemData.ID == window->MoveId && window->WriteAccessed)
            return false;
    }

    // Handle hover delay
    // (some ideas: https://www.nngroup.com/articles/timing-exposing-content)
    float delay;
    if (flags & ImGuiHoveredFlags_DelayNormal)
        delay = g.IO.HoverDelayNormal;
    else if (flags & ImGuiHoveredFlags_DelayShort)
        delay = g.IO.HoverDelayShort;
    else
        delay = 0.0f;