RangeSelect/MultiSelect: move shared logic to MultiSelectItemHeader().

No logic change AFAIK but added an indent level in MultiSelectItemHeader(). Logic changes will come in next commit.

imgui_demo.cpp

@@ -3399,7 +3399,8 @@ static void ShowDemoWindowMultiSelect()
                         ImGui::SetNextItemSelectionUserData(n);
                         if (widget_type == WidgetType_Selectable)
                         {
-                            ImGui::Selectable(label, item_is_selected);
+                            ImGuiSelectableFlags selectable_flags = ImGuiSelectableFlags_None;
+                            ImGui::Selectable(label, item_is_selected, selectable_flags);
                             if (item_curr_idx_to_focus == n)
                                 ImGui::SetKeyboardFocusHere(-1);
 

imgui_internal.h

@@ -3356,7 +3356,7 @@ namespace ImGui
     IMGUI_API int           TypingSelectFindBestLeadingMatch(ImGuiTypingSelectRequest* req, int items_count, const char* (*get_item_name_func)(void*, int), void* user_data);
 
     // Multi-Select API
-    IMGUI_API void          MultiSelectItemHeader(ImGuiID id, bool* p_selected);
+    IMGUI_API void          MultiSelectItemHeader(ImGuiID id, bool* p_selected, ImGuiButtonFlags* p_button_flags);
     IMGUI_API void          MultiSelectItemFooter(ImGuiID id, bool* p_selected, bool* p_pressed);
 
     // Internal Columns API (this is not exposed because we will encourage transitioning to the Tables API)

imgui_widgets.cpp

@@ -6356,19 +6356,11 @@ bool ImGui::TreeNodeBehavior(ImGuiID id, ImGuiTreeNodeFlags flags, const char* l
     // Multi-selection support (header)
     if (is_multi_select)
     {
-        MultiSelectItemHeader(id, &selected);
-        button_flags |= ImGuiButtonFlags_NoHoveredOnFocus;
+        // Handle multi-select + alter button flags for it
+        MultiSelectItemHeader(id, &selected, &button_flags);
 
-        // We absolutely need to distinguish open vs select so this is the default when multi-select is enabled.
+        // We absolutely need to distinguish open vs select so comes by default
         flags |= ImGuiTreeNodeFlags_OpenOnArrow;
-
-        // To handle drag and drop of multiple items we need to avoid clearing selection on click.
-        // Enabling this test makes actions using CTRL+SHIFT delay their effect on MouseUp which is annoying, but it allows drag and drop of multiple items.
-        // FIXME-MULTISELECT: Consider opt-in for drag and drop behavior in ImGuiMultiSelectFlags?
-        if (!selected || (g.ActiveId == id && g.ActiveIdHasBeenPressedBefore))
-            button_flags = (button_flags | ImGuiButtonFlags_PressedOnClick) & ~ImGuiButtonFlags_PressedOnClickRelease;
-        else
-            button_flags |= ImGuiButtonFlags_PressedOnClickRelease;
     }
     else
     {
@@ -6705,15 +6697,8 @@ bool ImGui::Selectable(const char* label, bool selected, ImGuiSelectableFlags fl
     const bool was_selected = selected;
     if (is_multi_select)
     {
-        MultiSelectItemHeader(id, &selected);
-        button_flags |= ImGuiButtonFlags_NoHoveredOnFocus;
-
-        // To handle drag and drop of multiple items we need to avoid clearing selection on click.
-        // Enabling this test makes actions using CTRL+SHIFT delay their effect on the mouse release which is annoying, but it allows drag and drop of multiple items.
-        if (!selected || (g.ActiveId == id && g.ActiveIdHasBeenPressedBefore))
-            button_flags |= ImGuiButtonFlags_PressedOnClick;
-        else
-            button_flags |= ImGuiButtonFlags_PressedOnClickRelease;
+        // Handle multi-select + alter button flags for it
+        MultiSelectItemHeader(id, &selected, &button_flags);
     }
 
     bool hovered, held;
@@ -7154,21 +7139,21 @@ void ImGui::SetNextItemSelectionUserData(ImGuiSelectionUserData selection_user_d
     }
 }
 
-void ImGui::MultiSelectItemHeader(ImGuiID id, bool* p_selected)
+void ImGui::MultiSelectItemHeader(ImGuiID id, bool* p_selected, ImGuiButtonFlags* p_button_flags)
 {
     ImGuiContext& g = *GImGui;
     ImGuiMultiSelectTempData* ms = g.CurrentMultiSelect;
-    if (!ms->IsFocused)
-        return;
-    ImGuiMultiSelectState* storage = ms->Storage;
 
-    IM_ASSERT(g.NextItemData.FocusScopeId == g.CurrentFocusScopeId && "Forgot to call SetNextItemSelectionUserData() prior to item, required in BeginMultiSelect()/EndMultiSelect() scope");
+    bool selected = *p_selected;
+    if (ms->IsFocused)
+    {
+        ImGuiMultiSelectState* storage = ms->Storage;
         ImGuiSelectionUserData item_data = g.NextItemData.SelectionUserData;
+        IM_ASSERT(g.NextItemData.FocusScopeId == g.CurrentFocusScopeId && "Forgot to call SetNextItemSelectionUserData() prior to item, required in BeginMultiSelect()/EndMultiSelect() scope");
 
         // Apply Clear/SelectAll requests requested by BeginMultiSelect().
         // This is only useful if the user hasn't processed them already, and this only works if the user isn't using the clipper.
         // If you are using a clipper (aka not submitting every element of the list) you need to process the Clear/SelectAll request after calling BeginMultiSelect()
-    bool selected = *p_selected;
         if (ms->BeginIO.RequestClear)
             selected = false;
         else if (ms->BeginIO.RequestSelectAll)
@@ -7198,10 +7183,22 @@ void ImGui::MultiSelectItemHeader(ImGuiID id, bool* p_selected)
             else if ((ms->KeyMods & ImGuiMod_Ctrl) == 0)
                 selected = false;
         }
-
         *p_selected = selected;
     }
 
+    // Alter button behavior flags
+    // To handle drag and drop of multiple items we need to avoid clearing selection on click.
+    // Enabling this test makes actions using CTRL+SHIFT delay their effect on MouseUp which is annoying, but it allows drag and drop of multiple items.
+    // FIXME-MULTISELECT: Consider opt-in for drag and drop behavior in ImGuiMultiSelectFlags?
+    ImGuiButtonFlags button_flags = *p_button_flags;
+    button_flags |= ImGuiButtonFlags_NoHoveredOnFocus;
+    if (!selected || (g.ActiveId == id && g.ActiveIdHasBeenPressedBefore))
+        button_flags = (button_flags | ImGuiButtonFlags_PressedOnClick) & ~ImGuiButtonFlags_PressedOnClickRelease;
+    else
+        button_flags |= ImGuiButtonFlags_PressedOnClickRelease;
+    *p_button_flags = button_flags;
+}
+
 void ImGui::MultiSelectItemFooter(ImGuiID id, bool* p_selected, bool* p_pressed)
 {
     ImGuiContext& g = *GImGui;