Menu window size is erroneously clamped to main viewport size

[arnaud-neny]

Version/Branch of Dear ImGui:

Version 1.90.8, Branch: docking

Back-ends:

imgui_impl_win32.cpp + imgui_impl_dx12.cpp

Compiler, OS:

Windows 10 + MSVC 2022

Full config/build information:

Dear ImGui 1.90.8 (19080)
--------------------------------
sizeof(size_t): 8, sizeof(ImDrawIdx): 2, sizeof(ImDrawVert): 20
define: __cplusplus=199711
define: _WIN32
define: _WIN64
define: _MSC_VER=1940
define: _MSVC_LANG=201402
define: IMGUI_HAS_VIEWPORT
define: IMGUI_HAS_DOCK
--------------------------------
io.BackendPlatformName: imgui_impl_win32
io.BackendRendererName: imgui_impl_dx12
io.ConfigFlags: 0x00000443
 NavEnableKeyboard
 NavEnableGamepad
 DockingEnable
 ViewportsEnable
io.ConfigViewportsNoDecoration
io.ConfigInputTextCursorBlink
io.ConfigWindowsResizeFromEdges
io.ConfigMemoryCompactTimer = 60.0
io.BackendFlags: 0x00001C0E
 HasMouseCursors
 HasSetMousePos
 PlatformHasViewports
 HasMouseHoveredViewport
 RendererHasVtxOffset
 RendererHasViewports
--------------------------------
io.Fonts: 1 fonts, Flags: 0x00000000, TexSize: 512,64
io.DisplaySize: 120.00,11.00
io.DisplayFramebufferScale: 1.00,1.00
--------------------------------
style.WindowPadding: 8.00,8.00
style.WindowBorderSize: 1.00
style.FramePadding: 4.00,3.00
style.FrameRounding: 0.00
style.FrameBorderSize: 0.00
style.ItemSpacing: 8.00,4.00
style.ItemInnerSpacing: 4.00,4.00

Details:

Hi!

There is an issue related only to the docking branch with the function CalcWindowAutoFitSize
It's always using the main viewport to define the size_max in some cases. One at least is happening here:

• pop out the "Dear ImGui Demo" window
• resize the main window until it has the smallest size possible
• open "Menu" in the "Dear ImGui Demo"
• go to any menu item with context such "Open Recent"

Thank you!

Screenshots/Video:

Minimal, Complete and Verifiable Example code:

No response

[arnaud-neny]

This issue has been introduced in the 1.90.3

[ocornut]

Related to #7287, #7063

[ocornut]

I think the fix may be to use:

        const bool is_child_not_popup = (window->Flags & ImGuiWindowFlags_ChildWindow) && !(window->Flags & ImGuiWindowFlags_Popup);
        ImVec2 size_min = CalcWindowMinSize(window);
        ImVec2 size_max = (window->ViewportOwned || is_child_not_popup) ? ImVec2(FLT_MAX, FLT_MAX) : ImGui::GetMainViewport()->WorkSize - style.DisplaySafeAreaPadding * 2.0f;
        const int monitor_idx = window->ViewportAllowPlatformMonitorExtend;
        if (monitor_idx >= 0 && monitor_idx < g.PlatformIO.Monitors.Size && !is_child_not_popup)
            size_max = g.PlatformIO.Monitors[monitor_idx].WorkSize - style.DisplaySafeAreaPadding * 2.0f;

But I would need to add more tests for the past cases were stumbled into before validating this is good. It's currently too complex/subtle to understand the reasons behind that logic.

[ocornut]

Should be fixed by a028c2d. Thanks for reporting!