Refactor: Moved Combo/ListBox functions from imgui.cpp to imgui_widgets.cpp (#2036)

imgui.cpp

@@ -10732,213 +10732,6 @@ bool ImGui::InputInt4(const char* label, int v[4], ImGuiInputTextFlags extra_fla
     return InputScalarN(label, ImGuiDataType_S32, v, 4, NULL, NULL, "%d", extra_flags);
 }
 
-static float CalcMaxPopupHeightFromItemCount(int items_count)
-{
-    ImGuiContext& g = *GImGui;
-    if (items_count <= 0)
-        return FLT_MAX;
-    return (g.FontSize + g.Style.ItemSpacing.y) * items_count - g.Style.ItemSpacing.y + (g.Style.WindowPadding.y * 2);
-}
-
-bool ImGui::BeginCombo(const char* label, const char* preview_value, ImGuiComboFlags flags)
-{
-    // Always consume the SetNextWindowSizeConstraint() call in our early return paths
-    ImGuiContext& g = *GImGui;
-    ImGuiCond backup_next_window_size_constraint = g.NextWindowData.SizeConstraintCond;
-    g.NextWindowData.SizeConstraintCond = 0;
-
-    ImGuiWindow* window = GetCurrentWindow();
-    if (window->SkipItems)
-        return false;
-
-    IM_ASSERT((flags & (ImGuiComboFlags_NoArrowButton | ImGuiComboFlags_NoPreview)) != (ImGuiComboFlags_NoArrowButton | ImGuiComboFlags_NoPreview)); // Can't use both flags together
-
-    const ImGuiStyle& style = g.Style;
-    const ImGuiID id = window->GetID(label);
-
-    const float arrow_size = (flags & ImGuiComboFlags_NoArrowButton) ? 0.0f : GetFrameHeight();
-    const ImVec2 label_size = CalcTextSize(label, NULL, true);
-    const float w = (flags & ImGuiComboFlags_NoPreview) ? arrow_size : CalcItemWidth();
-    const ImRect frame_bb(window->DC.CursorPos, window->DC.CursorPos + ImVec2(w, label_size.y + style.FramePadding.y*2.0f));
-    const ImRect total_bb(frame_bb.Min, frame_bb.Max + ImVec2(label_size.x > 0.0f ? style.ItemInnerSpacing.x + label_size.x : 0.0f, 0.0f));
-    ItemSize(total_bb, style.FramePadding.y);
-    if (!ItemAdd(total_bb, id, &frame_bb))
-        return false;
-
-    bool hovered, held;
-    bool pressed = ButtonBehavior(frame_bb, id, &hovered, &held);
-    bool popup_open = IsPopupOpen(id);
-
-    const ImRect value_bb(frame_bb.Min, frame_bb.Max - ImVec2(arrow_size, 0.0f));
-    const ImU32 frame_col = GetColorU32(hovered ? ImGuiCol_FrameBgHovered : ImGuiCol_FrameBg);
-    RenderNavHighlight(frame_bb, id);
-    if (!(flags & ImGuiComboFlags_NoPreview))
-        window->DrawList->AddRectFilled(frame_bb.Min, ImVec2(frame_bb.Max.x - arrow_size, frame_bb.Max.y), frame_col, style.FrameRounding, ImDrawCornerFlags_Left);
-    if (!(flags & ImGuiComboFlags_NoArrowButton))
-    {
-        window->DrawList->AddRectFilled(ImVec2(frame_bb.Max.x - arrow_size, frame_bb.Min.y), frame_bb.Max, GetColorU32((popup_open || hovered) ? ImGuiCol_ButtonHovered : ImGuiCol_Button), style.FrameRounding, (w <= arrow_size) ? ImDrawCornerFlags_All : ImDrawCornerFlags_Right);
-        RenderArrow(ImVec2(frame_bb.Max.x - arrow_size + style.FramePadding.y, frame_bb.Min.y + style.FramePadding.y), ImGuiDir_Down);
-    }
-    RenderFrameBorder(frame_bb.Min, frame_bb.Max, style.FrameRounding);
-    if (preview_value != NULL && !(flags & ImGuiComboFlags_NoPreview))
-        RenderTextClipped(frame_bb.Min + style.FramePadding, value_bb.Max, preview_value, NULL, NULL, ImVec2(0.0f,0.0f));
-    if (label_size.x > 0)
-        RenderText(ImVec2(frame_bb.Max.x + style.ItemInnerSpacing.x, frame_bb.Min.y + style.FramePadding.y), label);
-
-    if ((pressed || g.NavActivateId == id) && !popup_open)
-    {
-        if (window->DC.NavLayerCurrent == 0)
-            window->NavLastIds[0] = id;
-        OpenPopupEx(id);
-        popup_open = true;
-    }
-
-    if (!popup_open)
-        return false;
-
-    if (backup_next_window_size_constraint)
-    {
-        g.NextWindowData.SizeConstraintCond = backup_next_window_size_constraint;
-        g.NextWindowData.SizeConstraintRect.Min.x = ImMax(g.NextWindowData.SizeConstraintRect.Min.x, w);
-    }
-    else
-    {
-        if ((flags & ImGuiComboFlags_HeightMask_) == 0)
-            flags |= ImGuiComboFlags_HeightRegular;
-        IM_ASSERT(ImIsPowerOfTwo(flags & ImGuiComboFlags_HeightMask_));    // Only one
-        int popup_max_height_in_items = -1;
-        if (flags & ImGuiComboFlags_HeightRegular)     popup_max_height_in_items = 8;
-        else if (flags & ImGuiComboFlags_HeightSmall)  popup_max_height_in_items = 4;
-        else if (flags & ImGuiComboFlags_HeightLarge)  popup_max_height_in_items = 20;
-        SetNextWindowSizeConstraints(ImVec2(w, 0.0f), ImVec2(FLT_MAX, CalcMaxPopupHeightFromItemCount(popup_max_height_in_items)));
-    }
-
-    char name[16];
-    ImFormatString(name, IM_ARRAYSIZE(name), "##Combo_%02d", g.CurrentPopupStack.Size); // Recycle windows based on depth
-
-    // Peak into expected window size so we can position it
-    if (ImGuiWindow* popup_window = FindWindowByName(name))
-        if (popup_window->WasActive)
-        {
-            ImVec2 size_expected = CalcWindowExpectedSize(popup_window);
-            if (flags & ImGuiComboFlags_PopupAlignLeft)
-                popup_window->AutoPosLastDirection = ImGuiDir_Left;
-            ImRect r_outer = GetWindowAllowedExtentRect(popup_window);
-            ImVec2 pos = FindBestWindowPosForPopupEx(frame_bb.GetBL(), size_expected, &popup_window->AutoPosLastDirection, r_outer, frame_bb, ImGuiPopupPositionPolicy_ComboBox);
-            SetNextWindowPos(pos);
-        }
-
-    // Horizontally align ourselves with the framed text
-    ImGuiWindowFlags window_flags = ImGuiWindowFlags_AlwaysAutoResize | ImGuiWindowFlags_Popup | ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoSavedSettings;
-    PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(style.FramePadding.x, style.WindowPadding.y));
-    bool ret = Begin(name, NULL, window_flags);
-    PopStyleVar();
-    if (!ret)
-    {
-        EndPopup();
-        IM_ASSERT(0);   // This should never happen as we tested for IsPopupOpen() above
-        return false;
-    }
-    return true;
-}
-
-void ImGui::EndCombo()
-{
-    EndPopup();
-}
-
-// Getter for the old Combo() API: const char*[]
-static bool Items_ArrayGetter(void* data, int idx, const char** out_text)
-{
-    const char* const* items = (const char* const*)data;
-    if (out_text)
-        *out_text = items[idx];
-    return true;
-}
-
-// Getter for the old Combo() API: "item1\0item2\0item3\0"
-static bool Items_SingleStringGetter(void* data, int idx, const char** out_text)
-{
-    // FIXME-OPT: we could pre-compute the indices to fasten this. But only 1 active combo means the waste is limited.
-    const char* items_separated_by_zeros = (const char*)data;
-    int items_count = 0;
-    const char* p = items_separated_by_zeros;
-    while (*p)
-    {
-        if (idx == items_count)
-            break;
-        p += strlen(p) + 1;
-        items_count++;
-    }
-    if (!*p)
-        return false;
-    if (out_text)
-        *out_text = p;
-    return true;
-}
-
-// Old API, prefer using BeginCombo() nowadays if you can.
-bool ImGui::Combo(const char* label, int* current_item, bool (*items_getter)(void*, int, const char**), void* data, int items_count, int popup_max_height_in_items)
-{
-    ImGuiContext& g = *GImGui;
-
-    // Call the getter to obtain the preview string which is a parameter to BeginCombo()
-    const char* preview_value = NULL;
-    if (*current_item >= 0 && *current_item < items_count)
-        items_getter(data, *current_item, &preview_value);
-
-    // The old Combo() API exposed "popup_max_height_in_items". The new more general BeginCombo() API doesn't have/need it, but we emulate it here.
-    if (popup_max_height_in_items != -1 && !g.NextWindowData.SizeConstraintCond)
-        SetNextWindowSizeConstraints(ImVec2(0,0), ImVec2(FLT_MAX, CalcMaxPopupHeightFromItemCount(popup_max_height_in_items)));
-
-    if (!BeginCombo(label, preview_value, ImGuiComboFlags_None))
-        return false;
-
-    // Display items
-    // FIXME-OPT: Use clipper (but we need to disable it on the appearing frame to make sure our call to SetItemDefaultFocus() is processed)
-    bool value_changed = false;
-    for (int i = 0; i < items_count; i++)
-    {
-        PushID((void*)(intptr_t)i);
-        const bool item_selected = (i == *current_item);
-        const char* item_text;
-        if (!items_getter(data, i, &item_text))
-            item_text = "*Unknown item*";
-        if (Selectable(item_text, item_selected))
-        {
-            value_changed = true;
-            *current_item = i;
-        }
-        if (item_selected)
-            SetItemDefaultFocus();
-        PopID();
-    }
-
-    EndCombo();
-    return value_changed;
-}
-
-// Combo box helper allowing to pass an array of strings.
-bool ImGui::Combo(const char* label, int* current_item, const char* const items[], int items_count, int height_in_items)
-{
-    const bool value_changed = Combo(label, current_item, Items_ArrayGetter, (void*)items, items_count, height_in_items);
-    return value_changed;
-}
-
-// Combo box helper allowing to pass all items in a single string literal holding multiple zero-terminated items "item1\0item2\0" 
-bool ImGui::Combo(const char* label, int* current_item, const char* items_separated_by_zeros, int height_in_items)
-{
-    int items_count = 0;
-    const char* p = items_separated_by_zeros;       // FIXME-OPT: Avoid computing this, or at least only when combo is open
-    while (*p)
-    {
-        p += strlen(p) + 1;
-        items_count++;
-    }
-    bool value_changed = Combo(label, current_item, Items_SingleStringGetter, (void*)items_separated_by_zeros, items_count, height_in_items);
-    return value_changed;
-}
-
 // Tip: pass an empty label (e.g. "##dummy") then you can use the space to draw other text or image.
 // But you need to make sure the ID is unique, e.g. enclose calls in PushID/PopID or use ##unique_id.
 bool ImGui::Selectable(const char* label, bool selected, ImGuiSelectableFlags flags, const ImVec2& size_arg)
@@ -11042,108 +10835,6 @@ bool ImGui::Selectable(const char* label, bool* p_selected, ImGuiSelectableFlags
     return false;
 }
 
-// FIXME: Rename to BeginListBox()
-// Helper to calculate the size of a listbox and display a label on the right.
-// Tip: To have a list filling the entire window width, PushItemWidth(-1) and pass an empty label "##empty"
-bool ImGui::ListBoxHeader(const char* label, const ImVec2& size_arg)
-{
-    ImGuiWindow* window = GetCurrentWindow();
-    if (window->SkipItems)
-        return false;
-
-    const ImGuiStyle& style = GetStyle();
-    const ImGuiID id = GetID(label);
-    const ImVec2 label_size = CalcTextSize(label, NULL, true);
-
-    // Size default to hold ~7 items. Fractional number of items helps seeing that we can scroll down/up without looking at scrollbar.
-    ImVec2 size = CalcItemSize(size_arg, CalcItemWidth(), GetTextLineHeightWithSpacing() * 7.4f + style.ItemSpacing.y);
-    ImVec2 frame_size = ImVec2(size.x, ImMax(size.y, label_size.y));
-    ImRect frame_bb(window->DC.CursorPos, window->DC.CursorPos + frame_size);
-    ImRect bb(frame_bb.Min, frame_bb.Max + ImVec2(label_size.x > 0.0f ? style.ItemInnerSpacing.x + label_size.x : 0.0f, 0.0f));
-    window->DC.LastItemRect = bb; // Forward storage for ListBoxFooter.. dodgy.
-
-    BeginGroup();
-    if (label_size.x > 0)
-        RenderText(ImVec2(frame_bb.Max.x + style.ItemInnerSpacing.x, frame_bb.Min.y + style.FramePadding.y), label);
-
-    BeginChildFrame(id, frame_bb.GetSize());
-    return true;
-}
-
-// FIXME: Rename to BeginListBox()
-bool ImGui::ListBoxHeader(const char* label, int items_count, int height_in_items)
-{
-    // Size default to hold ~7 items. Fractional number of items helps seeing that we can scroll down/up without looking at scrollbar.
-    // We don't add +0.40f if items_count <= height_in_items. It is slightly dodgy, because it means a dynamic list of items will make the widget resize occasionally when it crosses that size.
-    // I am expecting that someone will come and complain about this behavior in a remote future, then we can advise on a better solution.
-    if (height_in_items < 0)
-        height_in_items = ImMin(items_count, 7);
-    float height_in_items_f = height_in_items < items_count ? (height_in_items + 0.40f) : (height_in_items + 0.00f);
-
-    // We include ItemSpacing.y so that a list sized for the exact number of items doesn't make a scrollbar appears. We could also enforce that by passing a flag to BeginChild().
-    ImVec2 size;
-    size.x = 0.0f;
-    size.y = GetTextLineHeightWithSpacing() * height_in_items_f + GetStyle().ItemSpacing.y;
-    return ListBoxHeader(label, size);
-}
-
-// FIXME: Rename to EndListBox()
-void ImGui::ListBoxFooter()
-{
-    ImGuiWindow* parent_window = GetCurrentWindow()->ParentWindow;
-    const ImRect bb = parent_window->DC.LastItemRect;
-    const ImGuiStyle& style = GetStyle();
-
-    EndChildFrame();
-
-    // Redeclare item size so that it includes the label (we have stored the full size in LastItemRect)
-    // We call SameLine() to restore DC.CurrentLine* data
-    SameLine();
-    parent_window->DC.CursorPos = bb.Min;
-    ItemSize(bb, style.FramePadding.y);
-    EndGroup();
-}
-
-bool ImGui::ListBox(const char* label, int* current_item, const char* const items[], int items_count, int height_items)
-{
-    const bool value_changed = ListBox(label, current_item, Items_ArrayGetter, (void*)items, items_count, height_items);
-    return value_changed;
-}
-
-bool ImGui::ListBox(const char* label, int* current_item, bool (*items_getter)(void*, int, const char**), void* data, int items_count, int height_in_items)
-{
-    if (!ListBoxHeader(label, items_count, height_in_items))
-        return false;
-
-    // Assume all items have even height (= 1 line of text). If you need items of different or variable sizes you can create a custom version of ListBox() in your code without using the clipper.
-    ImGuiContext& g = *GImGui;
-    bool value_changed = false;
-    ImGuiListClipper clipper(items_count, GetTextLineHeightWithSpacing()); // We know exactly our line height here so we pass it as a minor optimization, but generally you don't need to.
-    while (clipper.Step())
-        for (int i = clipper.DisplayStart; i < clipper.DisplayEnd; i++)
-        {
-            const bool item_selected = (i == *current_item);
-            const char* item_text;
-            if (!items_getter(data, i, &item_text))
-                item_text = "*Unknown item*";
-
-            PushID(i);
-            if (Selectable(item_text, item_selected))
-            {
-                *current_item = i;
-                value_changed = true;
-            }
-            if (item_selected)
-                SetItemDefaultFocus();
-            PopID();
-        }
-    ListBoxFooter();
-    if (value_changed)
-        MarkItemEdited(g.CurrentWindow->DC.LastItemId);
-
-    return value_changed;
-}
-
 bool ImGui::MenuItem(const char* label, const char* shortcut, bool selected, bool enabled)
 {
     ImGuiWindow* window = GetCurrentWindow();

imgui_widgets.cpp

@@ -892,6 +892,212 @@ void ImGui::Bullet()
 // - Combo()
 //-------------------------------------------------------------------------
 
+static float CalcMaxPopupHeightFromItemCount(int items_count)
+{
+    ImGuiContext& g = *GImGui;
+    if (items_count <= 0)
+        return FLT_MAX;
+    return (g.FontSize + g.Style.ItemSpacing.y) * items_count - g.Style.ItemSpacing.y + (g.Style.WindowPadding.y * 2);
+}
+
+bool ImGui::BeginCombo(const char* label, const char* preview_value, ImGuiComboFlags flags)
+{
+    // Always consume the SetNextWindowSizeConstraint() call in our early return paths
+    ImGuiContext& g = *GImGui;
+    ImGuiCond backup_next_window_size_constraint = g.NextWindowData.SizeConstraintCond;
+    g.NextWindowData.SizeConstraintCond = 0;
+
+    ImGuiWindow* window = GetCurrentWindow();
+    if (window->SkipItems)
+        return false;
+
+    IM_ASSERT((flags & (ImGuiComboFlags_NoArrowButton | ImGuiComboFlags_NoPreview)) != (ImGuiComboFlags_NoArrowButton | ImGuiComboFlags_NoPreview)); // Can't use both flags together
+
+    const ImGuiStyle& style = g.Style;
+    const ImGuiID id = window->GetID(label);
+
+    const float arrow_size = (flags & ImGuiComboFlags_NoArrowButton) ? 0.0f : GetFrameHeight();
+    const ImVec2 label_size = CalcTextSize(label, NULL, true);
+    const float w = (flags & ImGuiComboFlags_NoPreview) ? arrow_size : CalcItemWidth();
+    const ImRect frame_bb(window->DC.CursorPos, window->DC.CursorPos + ImVec2(w, label_size.y + style.FramePadding.y*2.0f));
+    const ImRect total_bb(frame_bb.Min, frame_bb.Max + ImVec2(label_size.x > 0.0f ? style.ItemInnerSpacing.x + label_size.x : 0.0f, 0.0f));
+    ItemSize(total_bb, style.FramePadding.y);
+    if (!ItemAdd(total_bb, id, &frame_bb))
+        return false;
+
+    bool hovered, held;
+    bool pressed = ButtonBehavior(frame_bb, id, &hovered, &held);
+    bool popup_open = IsPopupOpen(id);
+
+    const ImRect value_bb(frame_bb.Min, frame_bb.Max - ImVec2(arrow_size, 0.0f));
+    const ImU32 frame_col = GetColorU32(hovered ? ImGuiCol_FrameBgHovered : ImGuiCol_FrameBg);
+    RenderNavHighlight(frame_bb, id);
+    if (!(flags & ImGuiComboFlags_NoPreview))
+        window->DrawList->AddRectFilled(frame_bb.Min, ImVec2(frame_bb.Max.x - arrow_size, frame_bb.Max.y), frame_col, style.FrameRounding, ImDrawCornerFlags_Left);
+    if (!(flags & ImGuiComboFlags_NoArrowButton))
+    {
+        window->DrawList->AddRectFilled(ImVec2(frame_bb.Max.x - arrow_size, frame_bb.Min.y), frame_bb.Max, GetColorU32((popup_open || hovered) ? ImGuiCol_ButtonHovered : ImGuiCol_Button), style.FrameRounding, (w <= arrow_size) ? ImDrawCornerFlags_All : ImDrawCornerFlags_Right);
+        RenderArrow(ImVec2(frame_bb.Max.x - arrow_size + style.FramePadding.y, frame_bb.Min.y + style.FramePadding.y), ImGuiDir_Down);
+    }
+    RenderFrameBorder(frame_bb.Min, frame_bb.Max, style.FrameRounding);
+    if (preview_value != NULL && !(flags & ImGuiComboFlags_NoPreview))
+        RenderTextClipped(frame_bb.Min + style.FramePadding, value_bb.Max, preview_value, NULL, NULL, ImVec2(0.0f,0.0f));
+    if (label_size.x > 0)
+        RenderText(ImVec2(frame_bb.Max.x + style.ItemInnerSpacing.x, frame_bb.Min.y + style.FramePadding.y), label);
+
+    if ((pressed || g.NavActivateId == id) && !popup_open)
+    {
+        if (window->DC.NavLayerCurrent == 0)
+            window->NavLastIds[0] = id;
+        OpenPopupEx(id);
+        popup_open = true;
+    }
+
+    if (!popup_open)
+        return false;
+
+    if (backup_next_window_size_constraint)
+    {
+        g.NextWindowData.SizeConstraintCond = backup_next_window_size_constraint;
+        g.NextWindowData.SizeConstraintRect.Min.x = ImMax(g.NextWindowData.SizeConstraintRect.Min.x, w);
+    }
+    else
+    {
+        if ((flags & ImGuiComboFlags_HeightMask_) == 0)
+            flags |= ImGuiComboFlags_HeightRegular;
+        IM_ASSERT(ImIsPowerOfTwo(flags & ImGuiComboFlags_HeightMask_));    // Only one
+        int popup_max_height_in_items = -1;
+        if (flags & ImGuiComboFlags_HeightRegular)     popup_max_height_in_items = 8;
+        else if (flags & ImGuiComboFlags_HeightSmall)  popup_max_height_in_items = 4;
+        else if (flags & ImGuiComboFlags_HeightLarge)  popup_max_height_in_items = 20;
+        SetNextWindowSizeConstraints(ImVec2(w, 0.0f), ImVec2(FLT_MAX, CalcMaxPopupHeightFromItemCount(popup_max_height_in_items)));
+    }
+
+    char name[16];
+    ImFormatString(name, IM_ARRAYSIZE(name), "##Combo_%02d", g.CurrentPopupStack.Size); // Recycle windows based on depth
+
+    // Peak into expected window size so we can position it
+    if (ImGuiWindow* popup_window = FindWindowByName(name))
+        if (popup_window->WasActive)
+        {
+            ImVec2 size_expected = CalcWindowExpectedSize(popup_window);
+            if (flags & ImGuiComboFlags_PopupAlignLeft)
+                popup_window->AutoPosLastDirection = ImGuiDir_Left;
+            ImRect r_outer = GetWindowAllowedExtentRect(popup_window);
+            ImVec2 pos = FindBestWindowPosForPopupEx(frame_bb.GetBL(), size_expected, &popup_window->AutoPosLastDirection, r_outer, frame_bb, ImGuiPopupPositionPolicy_ComboBox);
+            SetNextWindowPos(pos);
+        }
+
+    // Horizontally align ourselves with the framed text
+    ImGuiWindowFlags window_flags = ImGuiWindowFlags_AlwaysAutoResize | ImGuiWindowFlags_Popup | ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoSavedSettings;
+    PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(style.FramePadding.x, style.WindowPadding.y));
+    bool ret = Begin(name, NULL, window_flags);
+    PopStyleVar();
+    if (!ret)
+    {
+        EndPopup();
+        IM_ASSERT(0);   // This should never happen as we tested for IsPopupOpen() above
+        return false;
+    }
+    return true;
+}
+
+void ImGui::EndCombo()
+{
+    EndPopup();
+}
+
+// Getter for the old Combo() API: const char*[]
+static bool Items_ArrayGetter(void* data, int idx, const char** out_text)
+{
+    const char* const* items = (const char* const*)data;
+    if (out_text)
+        *out_text = items[idx];
+    return true;
+}
+
+// Getter for the old Combo() API: "item1\0item2\0item3\0"
+static bool Items_SingleStringGetter(void* data, int idx, const char** out_text)
+{
+    // FIXME-OPT: we could pre-compute the indices to fasten this. But only 1 active combo means the waste is limited.
+    const char* items_separated_by_zeros = (const char*)data;
+    int items_count = 0;
+    const char* p = items_separated_by_zeros;
+    while (*p)
+    {
+        if (idx == items_count)
+            break;
+        p += strlen(p) + 1;
+        items_count++;
+    }
+    if (!*p)
+        return false;
+    if (out_text)
+        *out_text = p;
+    return true;
+}
+
+// Old API, prefer using BeginCombo() nowadays if you can.
+bool ImGui::Combo(const char* label, int* current_item, bool (*items_getter)(void*, int, const char**), void* data, int items_count, int popup_max_height_in_items)
+{
+    ImGuiContext& g = *GImGui;
+
+    // Call the getter to obtain the preview string which is a parameter to BeginCombo()
+    const char* preview_value = NULL;
+    if (*current_item >= 0 && *current_item < items_count)
+        items_getter(data, *current_item, &preview_value);
+
+    // The old Combo() API exposed "popup_max_height_in_items". The new more general BeginCombo() API doesn't have/need it, but we emulate it here.
+    if (popup_max_height_in_items != -1 && !g.NextWindowData.SizeConstraintCond)
+        SetNextWindowSizeConstraints(ImVec2(0,0), ImVec2(FLT_MAX, CalcMaxPopupHeightFromItemCount(popup_max_height_in_items)));
+
+    if (!BeginCombo(label, preview_value, ImGuiComboFlags_None))
+        return false;
+
+    // Display items
+    // FIXME-OPT: Use clipper (but we need to disable it on the appearing frame to make sure our call to SetItemDefaultFocus() is processed)
+    bool value_changed = false;
+    for (int i = 0; i < items_count; i++)
+    {
+        PushID((void*)(intptr_t)i);
+        const bool item_selected = (i == *current_item);
+        const char* item_text;
+        if (!items_getter(data, i, &item_text))
+            item_text = "*Unknown item*";
+        if (Selectable(item_text, item_selected))
+        {
+            value_changed = true;
+            *current_item = i;
+        }
+        if (item_selected)
+            SetItemDefaultFocus();
+        PopID();
+    }
+
+    EndCombo();
+    return value_changed;
+}
+
+// Combo box helper allowing to pass an array of strings.
+bool ImGui::Combo(const char* label, int* current_item, const char* const items[], int items_count, int height_in_items)
+{
+    const bool value_changed = Combo(label, current_item, Items_ArrayGetter, (void*)items, items_count, height_in_items);
+    return value_changed;
+}
+
+// Combo box helper allowing to pass all items in a single string literal holding multiple zero-terminated items "item1\0item2\0" 
+bool ImGui::Combo(const char* label, int* current_item, const char* items_separated_by_zeros, int height_in_items)
+{
+    int items_count = 0;
+    const char* p = items_separated_by_zeros;       // FIXME-OPT: Avoid computing this, or at least only when combo is open
+    while (*p)
+    {
+        p += strlen(p) + 1;
+        items_count++;
+    }
+    bool value_changed = Combo(label, current_item, Items_SingleStringGetter, (void*)items_separated_by_zeros, items_count, height_in_items);
+    return value_changed;
+}
 
 //-------------------------------------------------------------------------
 // WIDGETS: Data Type and Data Formatting Helpers [Internal]
@@ -1048,6 +1254,107 @@ void ImGui::Bullet()
 // - ListBoxFooter()
 //-------------------------------------------------------------------------
 
+// FIXME: Rename to BeginListBox()
+// Helper to calculate the size of a listbox and display a label on the right.
+// Tip: To have a list filling the entire window width, PushItemWidth(-1) and pass an empty label "##empty"
+bool ImGui::ListBoxHeader(const char* label, const ImVec2& size_arg)
+{
+    ImGuiWindow* window = GetCurrentWindow();
+    if (window->SkipItems)
+        return false;
+
+    const ImGuiStyle& style = GetStyle();
+    const ImGuiID id = GetID(label);
+    const ImVec2 label_size = CalcTextSize(label, NULL, true);
+
+    // Size default to hold ~7 items. Fractional number of items helps seeing that we can scroll down/up without looking at scrollbar.
+    ImVec2 size = CalcItemSize(size_arg, CalcItemWidth(), GetTextLineHeightWithSpacing() * 7.4f + style.ItemSpacing.y);
+    ImVec2 frame_size = ImVec2(size.x, ImMax(size.y, label_size.y));
+    ImRect frame_bb(window->DC.CursorPos, window->DC.CursorPos + frame_size);
+    ImRect bb(frame_bb.Min, frame_bb.Max + ImVec2(label_size.x > 0.0f ? style.ItemInnerSpacing.x + label_size.x : 0.0f, 0.0f));
+    window->DC.LastItemRect = bb; // Forward storage for ListBoxFooter.. dodgy.
+
+    BeginGroup();
+    if (label_size.x > 0)
+        RenderText(ImVec2(frame_bb.Max.x + style.ItemInnerSpacing.x, frame_bb.Min.y + style.FramePadding.y), label);
+
+    BeginChildFrame(id, frame_bb.GetSize());
+    return true;
+}
+
+// FIXME: Rename to BeginListBox()
+bool ImGui::ListBoxHeader(const char* label, int items_count, int height_in_items)
+{
+    // Size default to hold ~7 items. Fractional number of items helps seeing that we can scroll down/up without looking at scrollbar.
+    // We don't add +0.40f if items_count <= height_in_items. It is slightly dodgy, because it means a dynamic list of items will make the widget resize occasionally when it crosses that size.
+    // I am expecting that someone will come and complain about this behavior in a remote future, then we can advise on a better solution.
+    if (height_in_items < 0)
+        height_in_items = ImMin(items_count, 7);
+    float height_in_items_f = height_in_items < items_count ? (height_in_items + 0.40f) : (height_in_items + 0.00f);
+
+    // We include ItemSpacing.y so that a list sized for the exact number of items doesn't make a scrollbar appears. We could also enforce that by passing a flag to BeginChild().
+    ImVec2 size;
+    size.x = 0.0f;
+    size.y = GetTextLineHeightWithSpacing() * height_in_items_f + GetStyle().ItemSpacing.y;
+    return ListBoxHeader(label, size);
+}
+
+// FIXME: Rename to EndListBox()
+void ImGui::ListBoxFooter()
+{
+    ImGuiWindow* parent_window = GetCurrentWindow()->ParentWindow;
+    const ImRect bb = parent_window->DC.LastItemRect;
+    const ImGuiStyle& style = GetStyle();
+
+    EndChildFrame();
+
+    // Redeclare item size so that it includes the label (we have stored the full size in LastItemRect)
+    // We call SameLine() to restore DC.CurrentLine* data
+    SameLine();
+    parent_window->DC.CursorPos = bb.Min;
+    ItemSize(bb, style.FramePadding.y);
+    EndGroup();
+}
+
+bool ImGui::ListBox(const char* label, int* current_item, const char* const items[], int items_count, int height_items)
+{
+    const bool value_changed = ListBox(label, current_item, Items_ArrayGetter, (void*)items, items_count, height_items);
+    return value_changed;
+}
+
+bool ImGui::ListBox(const char* label, int* current_item, bool (*items_getter)(void*, int, const char**), void* data, int items_count, int height_in_items)
+{
+    if (!ListBoxHeader(label, items_count, height_in_items))
+        return false;
+
+    // Assume all items have even height (= 1 line of text). If you need items of different or variable sizes you can create a custom version of ListBox() in your code without using the clipper.
+    ImGuiContext& g = *GImGui;
+    bool value_changed = false;
+    ImGuiListClipper clipper(items_count, GetTextLineHeightWithSpacing()); // We know exactly our line height here so we pass it as a minor optimization, but generally you don't need to.
+    while (clipper.Step())
+        for (int i = clipper.DisplayStart; i < clipper.DisplayEnd; i++)
+        {
+            const bool item_selected = (i == *current_item);
+            const char* item_text;
+            if (!items_getter(data, i, &item_text))
+                item_text = "*Unknown item*";
+
+            PushID(i);
+            if (Selectable(item_text, item_selected))
+            {
+                *current_item = i;
+                value_changed = true;
+            }
+            if (item_selected)
+                SetItemDefaultFocus();
+            PopID();
+        }
+    ListBoxFooter();
+    if (value_changed)
+        MarkItemEdited(g.CurrentWindow->DC.LastItemId);
+
+    return value_changed;
+}
 
 //-------------------------------------------------------------------------
 // WIDGETS: Data Plotting