Demo: changed default framed item width to use Min(GetFontSize() * 12, GetContentRegionAvail().x * 0.40f).

docs/CHANGELOG.txt

@@ -131,6 +131,7 @@ Other changes:
   of WantVisible. This is set in the same structure because activating text input generally
   requires providing a window to the backend. (#8584, #6341)
 - Misc: added extra operators to ImVec4 in IMGUI_DEFINE_MATH_OPERATORS block. (#8510) [@gan74]
+- Demo: changed default framed item width to use Min(GetFontSize() * 12, GetContentRegionAvail().x * 0.40f).
 - Backends: Win32: Fixed an issue where externally losing mouse capture (due to e.g. focus loss)
   would fail to claim it again the next subsequent click. (#8594)
 - Backends: SDL2, SDL3, OSX: Fill gamepad inputs and set ImGuiBackendFlags_HasGamepad

imgui.cpp

@@ -7563,12 +7563,6 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         window->InnerClipRect.Max.y = ImFloor(window->InnerRect.Max.y - window->WindowBorderSize * 0.5f);
         window->InnerClipRect.ClipWithFull(host_rect);
 
-        // Default item width. Make it proportional to window size if window manually resizes
-        if (window->Size.x > 0.0f && !(flags & ImGuiWindowFlags_Tooltip) && !(flags & ImGuiWindowFlags_AlwaysAutoResize))
-            window->ItemWidthDefault = ImTrunc(window->Size.x * 0.65f);
-        else
-            window->ItemWidthDefault = ImTrunc(g.FontSize * 16.0f);
-
         // SCROLLING
 
         // Lock down maximum scrolling
@@ -7681,6 +7675,11 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         window->DC.LayoutType = ImGuiLayoutType_Vertical;
         window->DC.ParentLayoutType = parent_window ? parent_window->DC.LayoutType : ImGuiLayoutType_Vertical;
 
+        // Default item width. Make it proportional to window size if window manually resizes
+        if (window->Size.x > 0.0f && !(flags & ImGuiWindowFlags_Tooltip) && !(flags & ImGuiWindowFlags_AlwaysAutoResize))
+            window->ItemWidthDefault = ImTrunc(window->Size.x * 0.65f);
+        else
+            window->ItemWidthDefault = ImTrunc(g.FontSize * 16.0f);
         window->DC.ItemWidth = window->ItemWidthDefault;
         window->DC.TextWrapPos = -1.0f; // disabled
         window->DC.ItemWidthStack.resize(0);

imgui_demo.cpp

@@ -410,9 +410,19 @@ void ImGui::ShowDemoWindow(bool* p_open)
         return;
     }
 
-    // Most "big" widgets share a common width settings by default. See 'Demo->Layout->Widgets Width' for details.
-    ImGui::PushItemWidth(ImGui::GetFontSize() * -12);           // e.g. Leave a fixed amount of width for labels (by passing a negative value), the rest goes to widgets.
-    //ImGui::PushItemWidth(-ImGui::GetWindowWidth() * 0.35f);   // e.g. Use 2/3 of the space for widgets and 1/3 for labels (right align)
+    // Most framed widgets share a common width settings. Remaining width is used for the label.
+    // The width of the frame may be changed with PushItemWidth() or SetNextItemWidth().
+    // - Positive value for absolute size, negative value for right-alignment.
+    // - The default value is about GetWindowWidth() * 0.65f.
+    // - See 'Demo->Layout->Widgets Width' for details.
+    // Here we change the frame width based on how much width we want to give to the label.
+    const float label_width_base = ImGui::GetFontSize() * 12;               // Some amount of width for label, based on font size.
+    const float label_width_max = ImGui::GetContentRegionAvail().x * 0.40f; // ...but always leave some room for framed widgets.
+    const float label_width = IM_MIN(label_width_base, label_width_max);
+    ImGui::PushItemWidth(-label_width);                                     // Right-align: framed items will leave 'label_width' available for the label.
+    //ImGui::PushItemWidth(ImGui::GetContentRegionAvail().x * 0.40f);       // e.g. Use 40% width for framed widgets, leaving 60% width for labels.
+    //ImGui::PushItemWidth(-ImGui::GetContentRegionAvail().x * 0.40f);      // e.g. Use 40% width for labels, leaving 60% width for framed widgets.
+    //ImGui::PushItemWidth(ImGui::GetFontSize() * -12);                     // e.g. Use XXX width for labels, leaving the rest for framed widgets.
 
     // Menu Bar
     DemoWindowMenuBar(&demo_data);
@@ -4426,6 +4436,17 @@ static void DemoWindowLayout()
         }
         ImGui::PopItemWidth();
 
+        ImGui::Text("SetNextItemWidth/PushItemWidth(-Min(GetContentRegionAvail().x * 0.40f, GetFontSize() * 12))");
+        ImGui::PushItemWidth(-IM_MIN(ImGui::GetFontSize() * 12, ImGui::GetContentRegionAvail().x * 0.40f));
+        ImGui::DragFloat("float##4a", &f);
+        if (show_indented_items)
+        {
+            ImGui::Indent();
+            ImGui::DragFloat("float (indented)##4b", &f);
+            ImGui::Unindent();
+        }
+        ImGui::PopItemWidth();
+
         // Demonstrate using PushItemWidth to surround three items.
         // Calling SetNextItemWidth() before each of them would have the same effect.
         ImGui::Text("SetNextItemWidth/PushItemWidth(-FLT_MIN)");