Popups: Fixed resizable popup minimum size being too small. Standardized CalcWindowMinSize() logic a bit more. (#73290

Amend e2035a514, 623bff23ce, 923535240, etc.

docs/CHANGELOG.txt

@@ -45,6 +45,8 @@ Other changes:
 
 - Menus, Popups: Fixed an issue where hovering a parent-menu upward would
   erroneously close the window. (#7325, #7287, #7063)
+- Popups: Fixed resizable popup minimum size being too small. Standardized minimum
+  size logic. (#7329).
 - Tables: Angled headers: fixed support for multi-line labels. (#6917)
 - Tables: Angled headers: various fixes to accurately handle CellPadding changes. (#6917)
 - Tables: Angled headers: properly registers horizontal component of angled headers

imgui.cpp

@@ -5676,22 +5676,25 @@ static ImGuiWindow* CreateNewWindow(const char* name, ImGuiWindowFlags flags)
 
 static inline ImVec2 CalcWindowMinSize(ImGuiWindow* window)
 {
-    // Popups, menus and childs bypass style.WindowMinSize by default, but we give then a non-zero minimum size to facilitate understanding problematic cases (e.g. empty popups)
-    // FIXME: the if/else could probably be removed, "reduce artifacts" section for all windows.
+    // We give windows non-zero minimum size to facilitate understanding problematic cases (e.g. empty popups)
+    // FIXME: Essentially we want to restrict manual resizing to WindowMinSize+Decoration, and allow api resizing to be smaller.
+    // Perhaps should tend further a neater test for this.
     ImGuiContext& g = *GImGui;
     ImVec2 size_min;
-    if (window->Flags & (ImGuiWindowFlags_Popup | ImGuiWindowFlags_ChildMenu | ImGuiWindowFlags_ChildWindow))
+    if ((window->Flags & ImGuiWindowFlags_ChildWindow) && !(window->Flags & ImGuiWindowFlags_Popup))
     {
         size_min.x = (window->ChildFlags & ImGuiChildFlags_ResizeX) ? g.Style.WindowMinSize.x : 4.0f;
         size_min.y = (window->ChildFlags & ImGuiChildFlags_ResizeY) ? g.Style.WindowMinSize.y : 4.0f;
     }
     else
     {
-        ImGuiWindow* window_for_height = window;
         size_min.x = ((window->Flags & ImGuiWindowFlags_AlwaysAutoResize) == 0) ? g.Style.WindowMinSize.x : 4.0f;
         size_min.y = ((window->Flags & ImGuiWindowFlags_AlwaysAutoResize) == 0) ? g.Style.WindowMinSize.y : 4.0f;
-        size_min.y = ImMax(size_min.y, window_for_height->TitleBarHeight() + window_for_height->MenuBarHeight() + ImMax(0.0f, g.Style.WindowRounding - 1.0f)); // Reduce artifacts with very small windows
     }
+
+    // Reduce artifacts with very small windows
+    ImGuiWindow* window_for_height = window;
+    size_min.y = ImMax(size_min.y, window_for_height->TitleBarHeight() + window_for_height->MenuBarHeight() + ImMax(0.0f, g.Style.WindowRounding - 1.0f));
     return size_min;
 }
 
@@ -6755,6 +6758,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
 #endif
 
         // Handle manual resize: Resize Grips, Borders, Gamepad
+        // FIXME: _ChildWindow + _Popup windows may want resize grips.
         int border_hovered = -1, border_held = -1;
         ImU32 resize_grip_col[4] = {};
         const int resize_grip_count = (window->Flags & ImGuiWindowFlags_ChildWindow) ? 0 : g.IO.ConfigWindowsResizeFromEdges ? 2 : 1; // Allow resize from lower-left if we have the mouse cursor feedback for it.