Modal popups no longer have a sensible minium size

[ZingBallyhoo]

Version/Branch of Dear ImGui:

Version 1.90.4 WIP (19031), Branch: master

Back-ends:

imgui_impl_win32.cpp + imgui_impl_dx11.cpp

Compiler, OS:

Windows 10 + MSVC

Full config/build information:

Dear ImGui 1.90.4 WIP (19031)
--------------------------------
sizeof(size_t): 8, sizeof(ImDrawIdx): 2, sizeof(ImDrawVert): 20
define: __cplusplus=199711
define: _WIN32
define: _WIN64
define: _MSC_VER=1938
define: _MSVC_LANG=201402
--------------------------------
io.BackendPlatformName: imgui_impl_win32
io.BackendRendererName: imgui_impl_dx11
io.ConfigFlags: 0x00000003
 NavEnableKeyboard
 NavEnableGamepad
io.ConfigInputTextCursorBlink
io.ConfigWindowsResizeFromEdges
io.ConfigMemoryCompactTimer = 60.0
io.BackendFlags: 0x0000000E
 HasMouseCursors
 HasSetMousePos
 RendererHasVtxOffset
--------------------------------
io.Fonts: 1 fonts, Flags: 0x00000000, TexSize: 512,64
io.DisplaySize: 1264.00,761.00
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:

My Issue/Question:

Introduced in commit e2035a5 (part of 1.90.0)

Current version of culprit code:

imgui/imgui.cpp

Line 5683 in 8a14b71

if (window->Flags & (ImGuiWindowFlags_Popup | ImGuiWindowFlags_ChildMenu | ImGuiWindowFlags_ChildWindow))

Very likely that Modals should be excluded from the small-size path.

Screenshots/Video:

Current Behavior	Expected Behavior
2024-02-17.20-24-16.mp4	2024-02-17.20-26-40.mp4

Minimal, Complete and Verifiable Example code:

if (ImGui::Button("Open popup")) ImGui::OpenPopup("Popup");

ImGui::PushStyleVar(ImGuiStyleVar_WindowRounding, 10); // to highlight rendering issues
if (ImGui::BeginPopupModal("Popup", nullptr, 0))
{
    if (ImGui::Button("Close")) ImGui::CloseCurrentPopup();
    ImGui::EndPopup();
}
ImGui::PopStyleVar();

[ocornut]

Thank you @ZingBallyhoo for your detailed and accurate bug report (and the other one too).

I have pushed a fix e78ce72 + amended TestSuite (ocornut/imgui_test_engine@9ad4dee).

Basically the cases to consider are:

• Window with ImGuiWindowFlags_Popup flag
  • BeginPopup() used ImGuiWindowFlags_AlwaysAutoResize anyway -> no change
  • BeginPopupEx() (internal) without auto-resize: FIXED
  • BeginPopupModal(): FIXED (what you reported)
• Window with ImGuiWindowFlags_ChildMenu flag:
  • Always used ImGuiWindowFlags_AlwaysAutoResize, lead, to same case.
• Window with ImGuiWindowFlags_ChildWindow:
  • ImGuiWindowFlags_AlwaysAutoResize is always
  • Kept code path for now. Essentially we want to know if manual resize is possible, we can talk tend toward that.

This aligns with the fact that in 623bff2 I noted that CalcWindowMinSize() should probably be simplified further.

[ZingBallyhoo]

Thanks for the fixes!