BeginChild: Upgraded 'bool border = true' parameter to use a ImGuiChildFlags type and the ImGuiChildFlags_Border value. (toward ocornut#1666, ocornut#1496, ocornut#1395, ocornut#1710)

Author: ocornut

docs/CHANGELOG.txt

@@ -42,6 +42,16 @@ HOW TO UPDATE?
 
 Breaking changes:
 
+ - BeginChild(): Upgraded 'bool border = false' parameter to 'ImGuiChildFlags flags'.
+   Added ImGuiChildFlags_Border value. As with our prior "bool-to-flags" API updates,
+   the ImGuiChildFlags_Border value is guaranteed to be == true forever to ensure a
+   smoother transition, meaning all existing calls will still work.
+   If you want to neatly transition your call sites:
+      Before:  BeginChild("Name", size, true)
+      After:   BeginChild("Name", size, ImGuiChildFlags_Border)
+      Before:  BeginChild("Name", size, false)
+      After:   BeginChild("Name", size) or BeginChild("Name", 0) or BeginChild("Name", size, ImGuiChildFlags_None)
+   Kept inline redirection function with strongly typed bool versions (will obsolete).
  - Debug Tools: Renamed ShowStackToolWindow() ("Stack Tool") to ShowIDStackToolWindow() ("ID Stack Tool"),
    as earlier name was misleading. Kept inline redirection function. (#4631)
  - IO: Removed io.MetricsActiveAllocations introduced in 1.63, was displayed in Metrics and unlikely to
@@ -68,6 +78,7 @@ Breaking changes:
 Other changes:
 
 - Windows:
+  - BeginChild(): Added ImGuiChildFlags_Border as a replacement for 'bool border = true' parameter.
   - BeginChild(): Internal name used by child windows now omits the hash/id if the child
     window is submitted in root of id stack of parent window. Makes debugging/metrics easier
     and shorter to read in many cases.

imgui.cpp

@@ -424,6 +424,11 @@ CODE
  When you are not sure about an old symbol or function name, try using the Search/Find function of your IDE to look for comments or references in all imgui files.
  You can read releases logs https://github.com/ocornut/imgui/releases for more details.
 
+ - 2023/11/02 (1.90.0) - BeginChild: upgraded 'bool border = true' parameter to 'ImGuiChildFlags flags' type, added ImGuiChildFlags_Border equivalent. As with our prior "bool-to-flags" API updates, the ImGuiChildFlags_Border value is guaranteed to be == true forever to ensure a smoother transition, meaning all existing calls will still work.
+                           - old: BeginChild("Name", size, true)
+                           - new: BeginChild("Name", size, ImGuiChildFlags_Border)
+                           - old: BeginChild("Name", size, false)
+                           - new: BeginChild("Name", size) or BeginChild("Name", 0) or BeginChild("Name", size, ImGuiChildFlags_None)
  - 2023/09/27 (1.90.0) - io: removed io.MetricsActiveAllocations introduced in 1.63. Same as 'g.DebugMemAllocCount - g.DebugMemFreeCount' (still displayed in Metrics, unlikely to be accessed by end-user).
  - 2023/09/26 (1.90.0) - debug tools: Renamed ShowStackToolWindow() ("Stack Tool") to ShowIDStackToolWindow() ("ID Stack Tool"), as earlier name was misleading. Kept inline redirection function. (#4631)
  - 2023/09/15 (1.90.0) - ListBox, Combo: changed signature of "name getter" callback in old one-liner ListBox()/Combo() apis. kept inline redirection function (will obsolete).
@@ -5414,22 +5419,23 @@ ImVec2 ImGui::GetItemRectSize()
     return g.LastItemData.Rect.GetSize();
 }
 
-bool ImGui::BeginChild(const char* str_id, const ImVec2& size_arg, bool border, ImGuiWindowFlags window_flags)
+bool ImGui::BeginChild(const char* str_id, const ImVec2& size_arg, ImGuiChildFlags child_flags, ImGuiWindowFlags window_flags)
 {
     ImGuiID id = GetCurrentWindow()->GetID(str_id);
-    return BeginChildEx(str_id, id, size_arg, border, window_flags);
+    return BeginChildEx(str_id, id, size_arg, child_flags, window_flags);
 }
 
-bool ImGui::BeginChild(ImGuiID id, const ImVec2& size_arg, bool border, ImGuiWindowFlags window_flags)
+bool ImGui::BeginChild(ImGuiID id, const ImVec2& size_arg, ImGuiChildFlags child_flags, ImGuiWindowFlags window_flags)
 {
-    IM_ASSERT(id != 0);
-    return BeginChildEx(NULL, id, size_arg, border, window_flags);
+    return BeginChildEx(NULL, id, size_arg, child_flags, window_flags);
 }
 
-bool ImGui::BeginChildEx(const char* name, ImGuiID id, const ImVec2& size_arg, bool border, ImGuiWindowFlags window_flags)
+bool ImGui::BeginChildEx(const char* name, ImGuiID id, const ImVec2& size_arg, ImGuiChildFlags child_flags, ImGuiWindowFlags window_flags)
 {
     ImGuiContext& g = *GImGui;
     ImGuiWindow* parent_window = g.CurrentWindow;
+    IM_ASSERT(id != 0);
+
     window_flags |= ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoSavedSettings | ImGuiWindowFlags_ChildWindow;
     window_flags |= (parent_window->Flags & ImGuiWindowFlags_NoMove);  // Inherit the NoMove flag
 
@@ -5452,7 +5458,7 @@ bool ImGui::BeginChildEx(const char* name, ImGuiID id, const ImVec2& size_arg, b
         ImFormatStringToTempBuffer(&temp_window_name, NULL, "%s/%08X", parent_window->Name, id);
 
     const float backup_border_size = g.Style.ChildBorderSize;
-    if (!border)
+    if ((child_flags & ImGuiChildFlags_Border) == 0)
         g.Style.ChildBorderSize = 0.0f;
 
     // Begin into window
@@ -5532,7 +5538,7 @@ bool ImGui::BeginChildFrame(ImGuiID id, const ImVec2& size, ImGuiWindowFlags ext
     PushStyleVar(ImGuiStyleVar_ChildRounding, style.FrameRounding);
     PushStyleVar(ImGuiStyleVar_ChildBorderSize, style.FrameBorderSize);
     PushStyleVar(ImGuiStyleVar_WindowPadding, style.FramePadding);
-    bool ret = BeginChild(id, size, true, ImGuiWindowFlags_NoMove | ImGuiWindowFlags_AlwaysUseWindowPadding | extra_flags);
+    bool ret = BeginChild(id, size, ImGuiChildFlags_Border, ImGuiWindowFlags_NoMove | ImGuiWindowFlags_AlwaysUseWindowPadding | extra_flags);
     PopStyleVar(3);
     PopStyleColor();
     return ret;
@@ -14787,7 +14793,7 @@ void ImGui::ShowDebugLogWindow(bool* p_open)
     SameLine();
     if (SmallButton("Copy"))
         SetClipboardText(g.DebugLogBuf.c_str());
-    BeginChild("##log", ImVec2(0.0f, 0.0f), true, ImGuiWindowFlags_AlwaysVerticalScrollbar | ImGuiWindowFlags_AlwaysHorizontalScrollbar);
+    BeginChild("##log", ImVec2(0.0f, 0.0f), ImGuiChildFlags_Border, ImGuiWindowFlags_AlwaysVerticalScrollbar | ImGuiWindowFlags_AlwaysHorizontalScrollbar);
 
     ImGuiListClipper clipper;
     clipper.Begin(g.DebugLogIndex.size());

imgui.h

@@ -24,7 +24,7 @@
 // Library Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals, e.g. '#if IMGUI_VERSION_NUM >= 12345')
 #define IMGUI_VERSION       "1.90 WIP"
-#define IMGUI_VERSION_NUM   18996
+#define IMGUI_VERSION_NUM   18997
 #define IMGUI_HAS_TABLE
 
 /*
@@ -191,6 +191,7 @@ typedef int ImDrawListFlags;        // -> enum ImDrawListFlags_      // Flags: f
 typedef int ImFontAtlasFlags;       // -> enum ImFontAtlasFlags_     // Flags: for ImFontAtlas build
 typedef int ImGuiBackendFlags;      // -> enum ImGuiBackendFlags_    // Flags: for io.BackendFlags
 typedef int ImGuiButtonFlags;       // -> enum ImGuiButtonFlags_     // Flags: for InvisibleButton()
+typedef int ImGuiChildFlags;        // -> enum ImGuiChildFlags_      // Flags: for BeginChild()
 typedef int ImGuiColorEditFlags;    // -> enum ImGuiColorEditFlags_  // Flags: for ColorEdit4(), ColorPicker4() etc.
 typedef int ImGuiConfigFlags;       // -> enum ImGuiConfigFlags_     // Flags: for io.ConfigFlags
 typedef int ImGuiComboFlags;        // -> enum ImGuiComboFlags_      // Flags: for BeginCombo()
@@ -343,8 +344,8 @@ namespace ImGui
     //   [Important: due to legacy reason, this is inconsistent with most other functions such as BeginMenu/EndMenu,
     //    BeginPopup/EndPopup, etc. where the EndXXX call should only be called if the corresponding BeginXXX function
     //    returned true. Begin and BeginChild are the only odd ones out. Will be fixed in a future update.]
-    IMGUI_API bool          BeginChild(const char* str_id, const ImVec2& size = ImVec2(0, 0), bool border = false, ImGuiWindowFlags window_flags = 0);
-    IMGUI_API bool          BeginChild(ImGuiID id, const ImVec2& size = ImVec2(0, 0), bool border = false, ImGuiWindowFlags window_flags = 0);
+    IMGUI_API bool          BeginChild(const char* str_id, const ImVec2& size = ImVec2(0, 0), ImGuiChildFlags child_flags = 0, ImGuiWindowFlags window_flags = 0);
+    IMGUI_API bool          BeginChild(ImGuiID id, const ImVec2& size = ImVec2(0, 0), ImGuiChildFlags child_flags = 0, ImGuiWindowFlags window_flags = 0);
     IMGUI_API void          EndChild();
 
     // Windows Utilities
@@ -1010,6 +1011,14 @@ enum ImGuiWindowFlags_
     ImGuiWindowFlags_ChildMenu              = 1 << 28,  // Don't use! For internal use by BeginMenu()
 };
 
+// Flags for ImGui::BeginChild()
+// (Legacy: bit 0 must always correspond to ImGuiChildFlags_Border to be backward compatible with old API using 'bool border'.
+enum ImGuiChildFlags_
+{
+    ImGuiChildFlags_None                    = 0,
+    ImGuiChildFlags_Border                  = 1 << 0,   // Show an outer border and enable WindowPadding. (Important: this is always == 1 for legacy reason)
+};
+
 // Flags for ImGui::InputText()
 // (Those are per-item flags. There are shared flags in ImGuiIO: io.ConfigInputTextCursorBlink and io.ConfigInputTextEnterKeepActive)
 enum ImGuiInputTextFlags_
@@ -3114,6 +3123,8 @@ namespace ImGui
 namespace ImGui
 {
     // OBSOLETED in 1.90.0 (from September 2023)
+    static inline bool  BeginChild(const char* str_id, const ImVec2& size_arg, bool border, ImGuiWindowFlags window_flags) { return BeginChild(str_id, size_arg, border ? ImGuiChildFlags_Border : ImGuiChildFlags_None, window_flags); }
+    static inline bool  BeginChild(ImGuiID id, const ImVec2& size_arg, bool border, ImGuiWindowFlags window_flags)         { return BeginChild(id, size_arg, border ? ImGuiChildFlags_Border : ImGuiChildFlags_None, window_flags);     }
     static inline void  ShowStackToolWindow(bool* p_open = NULL)                            { ShowIDStackToolWindow(p_open); }
     IMGUI_API bool      ListBox(const char* label, int* current_item, bool (*old_callback)(void* user_data, int idx, const char** out_text), void* user_data, int items_count, int height_in_items = -1);
     IMGUI_API bool      Combo(const char* label, int* current_item, bool (*old_callback)(void* user_data, int idx, const char** out_text), void* user_data, int items_count, int popup_max_height_in_items = -1);

imgui_demo.cpp

@@ -2591,7 +2591,7 @@ static void ShowDemoWindowWidgets()
         static bool embed_all_inside_a_child_window = false;
         ImGui::Checkbox("Embed everything inside a child window for testing _RootWindow flag.", &embed_all_inside_a_child_window);
         if (embed_all_inside_a_child_window)
-            ImGui::BeginChild("outer_child", ImVec2(0, ImGui::GetFontSize() * 20.0f), true);
+            ImGui::BeginChild("outer_child", ImVec2(0, ImGui::GetFontSize() * 20.0f), ImGuiChildFlags_Border);
 
         // Testing IsWindowFocused() function with its various flags.
         ImGui::BulletText(
@@ -2639,7 +2639,7 @@ static void ShowDemoWindowWidgets()
             ImGui::IsWindowHovered(ImGuiHoveredFlags_AnyWindow),
             ImGui::IsWindowHovered(ImGuiHoveredFlags_Stationary));
 
-        ImGui::BeginChild("child", ImVec2(0, 50), true);
+        ImGui::BeginChild("child", ImVec2(0, 50), ImGuiChildFlags_Border);
         ImGui::Text("This is another child window for testing the _ChildWindows flag.");
         ImGui::EndChild();
         if (embed_all_inside_a_child_window)
@@ -2723,7 +2723,7 @@ static void ShowDemoWindowLayout()
             ImGuiWindowFlags window_flags = ImGuiWindowFlags_HorizontalScrollbar;
             if (disable_mouse_wheel)
                 window_flags |= ImGuiWindowFlags_NoScrollWithMouse;
-            ImGui::BeginChild("ChildL", ImVec2(ImGui::GetContentRegionAvail().x * 0.5f, 260), false, window_flags);
+            ImGui::BeginChild("ChildL", ImVec2(ImGui::GetContentRegionAvail().x * 0.5f, 260), ImGuiChildFlags_None, window_flags);
             for (int i = 0; i < 100; i++)
                 ImGui::Text("%04d: scrollable region", i);
             ImGui::EndChild();
@@ -2739,7 +2739,7 @@ static void ShowDemoWindowLayout()
             if (!disable_menu)
                 window_flags |= ImGuiWindowFlags_MenuBar;
             ImGui::PushStyleVar(ImGuiStyleVar_ChildRounding, 5.0f);
-            ImGui::BeginChild("ChildR", ImVec2(0, 260), true, window_flags);
+            ImGui::BeginChild("ChildR", ImVec2(0, 260), ImGuiChildFlags_Border, window_flags);
             if (!disable_menu && ImGui::BeginMenuBar())
             {
                 if (ImGui::BeginMenu("Menu"))
@@ -2780,14 +2780,15 @@ static void ShowDemoWindowLayout()
 
             ImGui::SetCursorPosX(ImGui::GetCursorPosX() + (float)offset_x);
             ImGui::PushStyleColor(ImGuiCol_ChildBg, IM_COL32(255, 0, 0, 100));
-            ImGui::BeginChild("Red", ImVec2(200, 100), true, ImGuiWindowFlags_None);
+            ImGui::BeginChild("Red", ImVec2(200, 100), ImGuiChildFlags_Border, ImGuiWindowFlags_None);
+            ImGui::PopStyleColor();
+
             for (int n = 0; n < 50; n++)
                 ImGui::Text("Some test %d", n);
             ImGui::EndChild();
             bool child_is_hovered = ImGui::IsItemHovered();
             ImVec2 child_rect_min = ImGui::GetItemRectMin();
             ImVec2 child_rect_max = ImGui::GetItemRectMax();
-            ImGui::PopStyleColor();
             ImGui::Text("Hovered: %d", child_is_hovered);
             ImGui::Text("Rect of child window is: (%.0f,%.0f) (%.0f,%.0f)", child_rect_min.x, child_rect_min.y, child_rect_max.x, child_rect_max.y);
         }
@@ -3176,7 +3177,7 @@ static void ShowDemoWindowLayout()
 
             const ImGuiWindowFlags child_flags = enable_extra_decorations ? ImGuiWindowFlags_MenuBar : 0;
             const ImGuiID child_id = ImGui::GetID((void*)(intptr_t)i);
-            const bool child_is_visible = ImGui::BeginChild(child_id, ImVec2(child_w, 200.0f), true, child_flags);
+            const bool child_is_visible = ImGui::BeginChild(child_id, ImVec2(child_w, 200.0f), ImGuiChildFlags_Border, child_flags);
             if (ImGui::BeginMenuBar())
             {
                 ImGui::TextUnformatted("abc");
@@ -3223,7 +3224,7 @@ static void ShowDemoWindowLayout()
             float child_height = ImGui::GetTextLineHeight() + style.ScrollbarSize + style.WindowPadding.y * 2.0f;
             ImGuiWindowFlags child_flags = ImGuiWindowFlags_HorizontalScrollbar | (enable_extra_decorations ? ImGuiWindowFlags_AlwaysVerticalScrollbar : 0);
             ImGuiID child_id = ImGui::GetID((void*)(intptr_t)i);
-            bool child_is_visible = ImGui::BeginChild(child_id, ImVec2(-100, child_height), true, child_flags);
+            bool child_is_visible = ImGui::BeginChild(child_id, ImVec2(-100, child_height), ImGuiChildFlags_Border, child_flags);
             if (scroll_to_off)
                 ImGui::SetScrollX(scroll_to_off_px);
             if (scroll_to_pos)
@@ -3265,7 +3266,7 @@ static void ShowDemoWindowLayout()
         ImGui::PushStyleVar(ImGuiStyleVar_FrameRounding, 3.0f);
         ImGui::PushStyleVar(ImGuiStyleVar_FramePadding, ImVec2(2.0f, 1.0f));
         ImVec2 scrolling_child_size = ImVec2(0, ImGui::GetFrameHeightWithSpacing() * 7 + 30);
-        ImGui::BeginChild("scrolling", scrolling_child_size, true, ImGuiWindowFlags_HorizontalScrollbar);
+        ImGui::BeginChild("scrolling", scrolling_child_size, ImGuiChildFlags_Border, ImGuiWindowFlags_HorizontalScrollbar);
         for (int line = 0; line < lines; line++)
         {
             // Display random stuff. For the sake of this trivial demo we are using basic Button() + SameLine()
@@ -3409,7 +3410,7 @@ static void ShowDemoWindowLayout()
             }
             if (show_child)
             {
-                ImGui::BeginChild("child", ImVec2(0, 0), true);
+                ImGui::BeginChild("child", ImVec2(0, 0), ImGuiChildFlags_Border);
                 ImGui::EndChild();
             }
             ImGui::End();
@@ -5958,7 +5959,7 @@ static void ShowDemoWindowColumns()
     {
         ImGui::SetNextWindowContentSize(ImVec2(1500.0f, 0.0f));
         ImVec2 child_size = ImVec2(0, ImGui::GetFontSize() * 20.0f);
-        ImGui::BeginChild("##ScrollingRegion", child_size, false, ImGuiWindowFlags_HorizontalScrollbar);
+        ImGui::BeginChild("##ScrollingRegion", child_size, ImGuiChildFlags_None, ImGuiWindowFlags_HorizontalScrollbar);
         ImGui::Columns(10);
 
         // Also demonstrate using clipper for large vertical lists
@@ -6575,7 +6576,7 @@ void ImGui::ShowStyleEditor(ImGuiStyle* ref)
                 "Left-click on color square to open color picker,\n"
                 "Right-click to open edit options menu.");
 
-            ImGui::BeginChild("##colors", ImVec2(0, 0), true, ImGuiWindowFlags_AlwaysVerticalScrollbar | ImGuiWindowFlags_AlwaysHorizontalScrollbar | ImGuiWindowFlags_NavFlattened);
+            ImGui::BeginChild("##colors", ImVec2(0, 0), ImGuiChildFlags_Border, ImGuiWindowFlags_AlwaysVerticalScrollbar | ImGuiWindowFlags_AlwaysHorizontalScrollbar | ImGuiWindowFlags_NavFlattened);
             ImGui::PushItemWidth(ImGui::GetFontSize() * -12);
             for (int i = 0; i < ImGuiCol_COUNT; i++)
             {
@@ -6802,7 +6803,7 @@ static void ShowExampleMenuFile()
     {
         static bool enabled = true;
         ImGui::MenuItem("Enabled", "", &enabled);
-        ImGui::BeginChild("child", ImVec2(0, 60), true);
+        ImGui::BeginChild("child", ImVec2(0, 60), ImGuiChildFlags_Border);
         for (int i = 0; i < 10; i++)
             ImGui::Text("Scrolling Text %d", i);
         ImGui::EndChild();
@@ -6968,7 +6969,7 @@ struct ExampleAppConsole
 
         // Reserve enough left-over height for 1 separator + 1 input text
         const float footer_height_to_reserve = ImGui::GetStyle().ItemSpacing.y + ImGui::GetFrameHeightWithSpacing();
-        if (ImGui::BeginChild("ScrollingRegion", ImVec2(0, -footer_height_to_reserve), false, ImGuiWindowFlags_HorizontalScrollbar))
+        if (ImGui::BeginChild("ScrollingRegion", ImVec2(0, -footer_height_to_reserve), ImGuiChildFlags_None, ImGuiWindowFlags_HorizontalScrollbar))
         {
             if (ImGui::BeginPopupContextWindow())
             {
@@ -7279,7 +7280,7 @@ struct ExampleAppLog
 
         ImGui::Separator();
 
-        if (ImGui::BeginChild("scrolling", ImVec2(0, 0), false, ImGuiWindowFlags_HorizontalScrollbar))
+        if (ImGui::BeginChild("scrolling", ImVec2(0, 0), ImGuiChildFlags_None, ImGuiWindowFlags_HorizontalScrollbar))
         {
             if (clear)
                 Clear();
@@ -7398,7 +7399,7 @@ static void ShowExampleAppLayout(bool* p_open)
         // Left
         static int selected = 0;
         {
-            ImGui::BeginChild("left pane", ImVec2(150, 0), true);
+            ImGui::BeginChild("left pane", ImVec2(150, 0), ImGuiChildFlags_Border);
             for (int i = 0; i < 100; i++)
             {
                 // FIXME: Good candidate to use ImGuiSelectableFlags_SelectOnNav
@@ -7967,7 +7968,7 @@ static void ShowExampleAppCustomRendering(bool* p_open)
             // To use a child window instead we could use, e.g:
             //      ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(0, 0));      // Disable padding
             //      ImGui::PushStyleColor(ImGuiCol_ChildBg, IM_COL32(50, 50, 50, 255));  // Set a background color
-            //      ImGui::BeginChild("canvas", ImVec2(0.0f, 0.0f), true, ImGuiWindowFlags_NoMove);
+            //      ImGui::BeginChild("canvas", ImVec2(0.0f, 0.0f), ImGuiChildFlags_Border, ImGuiWindowFlags_NoMove);
             //      ImGui::PopStyleColor();
             //      ImGui::PopStyleVar();
             //      [...]

imgui_internal.h

@@ -3006,7 +3006,7 @@ namespace ImGui
     IMGUI_API void          LogSetNextTextDecoration(const char* prefix, const char* suffix);
 
     // Popups, Modals, Tooltips
-    IMGUI_API bool          BeginChildEx(const char* name, ImGuiID id, const ImVec2& size_arg, bool border, ImGuiWindowFlags window_flags);
+    IMGUI_API bool          BeginChildEx(const char* name, ImGuiID id, const ImVec2& size_arg, ImGuiChildFlags child_flags, ImGuiWindowFlags window_flags);
     IMGUI_API void          OpenPopupEx(ImGuiID id, ImGuiPopupFlags popup_flags = ImGuiPopupFlags_None);
     IMGUI_API void          ClosePopupToLevel(int remaining, bool restore_focus_to_window_under_popup);
     IMGUI_API void          ClosePopupsOverWindow(ImGuiWindow* ref_window, bool restore_focus_to_window_under_popup);