Helper and example to implement serializer for imgui style.

Example.cpp

//-------------------------------------------------------------------------------------------------
// Serialization helpers
//-------------------------------------------------------------------------------------------------
template <typename T>
static T& locStyleAdapter(T& aValue) { return aValue; }
static GC_Vector2f& locStyleAdapter(ImVec2& aValue) { return *(GC_Vector2f*)&aValue; }
static GC_Vector2f const& locStyleAdapter(ImVec2 const& aValue) { return *(GC_Vector2f const*)&aValue; }
static GC_Vector4f& locStyleAdapter(ImVec4& aValue) { return *(GC_Vector4f*)&aValue; }
static GC_Vector4f const& locStyleAdapter(ImVec4 const& aValue) { return *(GC_Vector4f const*)&aValue; }

//-------------------------------------------------------------------------------------------------
static GC_DynamicMap locSaveStyle(ImGuiStyle const& aStyle)
{
	GC_DynamicMap map;
#define IMPLEMENT_STYLE(name) map.Set(#name, locStyleAdapter(aStyle.name));
#define IMPLEMENT_COLOR(name) map.Set(#name, locStyleAdapter(aStyle.Colors[name]));
#include "GT_StyleSerializeHelper.inl"
#undef IMPLEMENT_COLOR
#undef IMPLEMENT_STYLE

	map.Set("ColorButtonPosition", (int)aStyle.ColorButtonPosition);
	map.Set("WindowMenuButtonPosition", (int)aStyle.WindowMenuButtonPosition);
	return map;
}
//-------------------------------------------------------------------------------------------------
static void locLoadStyle(GC_DynamicMap aMap, ImGuiStyle& aStyleOut)
{
#define IMPLEMENT_STYLE(name) aMap.Get(#name, locStyleAdapter(aStyleOut.name));
#define IMPLEMENT_COLOR(name) aMap.Get(#name, locStyleAdapter(aStyleOut.Colors[name]));
#include "GT_StyleSerializeHelper.inl"
#undef IMPLEMENT_COLOR
#undef IMPLEMENT_STYLE

	int tmp = aStyleOut.ColorButtonPosition;
	aMap.Get("ColorButtonPosition", tmp);
	aStyleOut.ColorButtonPosition = tmp;

	tmp = aStyleOut.WindowMenuButtonPosition;
	aMap.Get("WindowMenuButtonPosition", tmp);
	aStyleOut.WindowMenuButtonPosition = tmp;
}

ImGuiStyleAdapter.inl

//-------------------------------------------------------------------------------------------------
// Helper to quickly adapt code to imgui styles
//-------------------------------------------------------------------------------------------------

IMPLEMENT_STYLE(Alpha                   )
IMPLEMENT_STYLE(WindowPadding           )
IMPLEMENT_STYLE(WindowRounding          )
IMPLEMENT_STYLE(WindowBorderSize        )
IMPLEMENT_STYLE(WindowMinSize           )
IMPLEMENT_STYLE(WindowTitleAlign        )
IMPLEMENT_STYLE(WindowMenuButtonPosition)
IMPLEMENT_STYLE(ChildRounding           )
IMPLEMENT_STYLE(ChildBorderSize         )
IMPLEMENT_STYLE(PopupRounding           )
IMPLEMENT_STYLE(PopupBorderSize         )
IMPLEMENT_STYLE(FramePadding            )
IMPLEMENT_STYLE(FrameRounding           )
IMPLEMENT_STYLE(FrameBorderSize         )
IMPLEMENT_STYLE(ItemSpacing             )
IMPLEMENT_STYLE(ItemInnerSpacing        )
IMPLEMENT_STYLE(TouchExtraPadding       )
IMPLEMENT_STYLE(IndentSpacing           )
IMPLEMENT_STYLE(ColumnsMinSpacing       )
IMPLEMENT_STYLE(ScrollbarSize           )
IMPLEMENT_STYLE(ScrollbarRounding       )
IMPLEMENT_STYLE(GrabMinSize             )
IMPLEMENT_STYLE(GrabRounding            )
IMPLEMENT_STYLE(TabRounding             )
IMPLEMENT_STYLE(TabBorderSize           )
IMPLEMENT_STYLE(TabMinWidthForUnselectedCloseButton)
IMPLEMENT_STYLE(ColorButtonPosition     )
IMPLEMENT_STYLE(ButtonTextAlign         )
IMPLEMENT_STYLE(SelectableTextAlign     )
IMPLEMENT_STYLE(DisplayWindowPadding    )
IMPLEMENT_STYLE(DisplaySafeAreaPadding  )
IMPLEMENT_STYLE(MouseCursorScale        )
IMPLEMENT_STYLE(AntiAliasedLines        )
IMPLEMENT_STYLE(AntiAliasedFill         )
IMPLEMENT_STYLE(CurveTessellationTol    )
IMPLEMENT_STYLE(CircleSegmentMaxError   )

IMPLEMENT_COLOR(ImGuiCol_Text)                  
IMPLEMENT_COLOR(ImGuiCol_TextDisabled)           
IMPLEMENT_COLOR(ImGuiCol_WindowBg)               
IMPLEMENT_COLOR(ImGuiCol_ChildBg)                
IMPLEMENT_COLOR(ImGuiCol_PopupBg)                
IMPLEMENT_COLOR(ImGuiCol_Border)                 
IMPLEMENT_COLOR(ImGuiCol_BorderShadow)           
IMPLEMENT_COLOR(ImGuiCol_FrameBg)                
IMPLEMENT_COLOR(ImGuiCol_FrameBgHovered)         
IMPLEMENT_COLOR(ImGuiCol_FrameBgActive)          
IMPLEMENT_COLOR(ImGuiCol_TitleBg)                
IMPLEMENT_COLOR(ImGuiCol_TitleBgActive)          
IMPLEMENT_COLOR(ImGuiCol_TitleBgCollapsed)       
IMPLEMENT_COLOR(ImGuiCol_MenuBarBg)              
IMPLEMENT_COLOR(ImGuiCol_ScrollbarBg)            
IMPLEMENT_COLOR(ImGuiCol_ScrollbarGrab)          
IMPLEMENT_COLOR(ImGuiCol_ScrollbarGrabHovered)   
IMPLEMENT_COLOR(ImGuiCol_ScrollbarGrabActive)    
IMPLEMENT_COLOR(ImGuiCol_CheckMark)              
IMPLEMENT_COLOR(ImGuiCol_SliderGrab)             
IMPLEMENT_COLOR(ImGuiCol_SliderGrabActive)       
IMPLEMENT_COLOR(ImGuiCol_Button)                 
IMPLEMENT_COLOR(ImGuiCol_ButtonHovered)          
IMPLEMENT_COLOR(ImGuiCol_ButtonActive)           
IMPLEMENT_COLOR(ImGuiCol_Header)                 
IMPLEMENT_COLOR(ImGuiCol_HeaderHovered)          
IMPLEMENT_COLOR(ImGuiCol_HeaderActive)           
IMPLEMENT_COLOR(ImGuiCol_Separator)              
IMPLEMENT_COLOR(ImGuiCol_SeparatorHovered)       
IMPLEMENT_COLOR(ImGuiCol_SeparatorActive)        
IMPLEMENT_COLOR(ImGuiCol_ResizeGrip)             
IMPLEMENT_COLOR(ImGuiCol_ResizeGripHovered)      
IMPLEMENT_COLOR(ImGuiCol_ResizeGripActive)       
IMPLEMENT_COLOR(ImGuiCol_Tab)                    
IMPLEMENT_COLOR(ImGuiCol_TabHovered)             
IMPLEMENT_COLOR(ImGuiCol_TabActive)              
IMPLEMENT_COLOR(ImGuiCol_TabUnfocused)           
IMPLEMENT_COLOR(ImGuiCol_TabUnfocusedActive)     
IMPLEMENT_COLOR(ImGuiCol_DockingPreview)         
IMPLEMENT_COLOR(ImGuiCol_DockingEmptyBg)         
IMPLEMENT_COLOR(ImGuiCol_PlotLines)              
IMPLEMENT_COLOR(ImGuiCol_PlotLinesHovered)       
IMPLEMENT_COLOR(ImGuiCol_PlotHistogram)          
IMPLEMENT_COLOR(ImGuiCol_PlotHistogramHovered)   
IMPLEMENT_COLOR(ImGuiCol_TextSelectedBg)         
IMPLEMENT_COLOR(ImGuiCol_DragDropTarget)         
IMPLEMENT_COLOR(ImGuiCol_NavHighlight)           
IMPLEMENT_COLOR(ImGuiCol_NavWindowingHighlight)  
IMPLEMENT_COLOR(ImGuiCol_NavWindowingDimBg)      
IMPLEMENT_COLOR(ImGuiCol_ModalWindowDimBg)       

//-------------------------------------------------------------------------------------------------
// If this fails then it means the structure changed and previous values need to be changed
//-------------------------------------------------------------------------------------------------
static_assert(sizeof(ImGuiStyle) == 984, "ImGuiStyle changed, update serializer.");