namespace custom {
bool tab( const char* icon, const char* label, bool selected );
bool subtab( const char* label, bool selected );
void begin_child( const char* name, ImVec2 size );
void end_child( );
bool collapse_button( bool collapsed );
void ImRotateStart( );
ImVec2 ImRotationCenter( );
void ImRotateEnd( float rad, ImVec2 center = ImRotationCenter( ) );