diff --git a/toonz/sources/include/toonz/tcolumnfx.h b/toonz/sources/include/toonz/tcolumnfx.h
index 861bb80..148cd56 100644
--- a/toonz/sources/include/toonz/tcolumnfx.h
+++ b/toonz/sources/include/toonz/tcolumnfx.h
@@ -281,4 +281,11 @@ private:
   TOutputFx &operator=(const TOutputFx &);
 };
 
+//*******************************************************************************************
+//    TColumnFx functions
+//*******************************************************************************************
+
+bool isSubsheetChainOnColumn0(TXsheet *topXsheet, TXsheet *subsheet,
+                              int frame);
+
 #endif  // TCOLUMNFX_H
diff --git a/toonz/sources/include/traster.h b/toonz/sources/include/traster.h
index d55c324..b7ad6f5 100644
--- a/toonz/sources/include/traster.h
+++ b/toonz/sources/include/traster.h
@@ -452,6 +452,13 @@ typedef TRasterPT<TPixelCY> TRasterYUV422P;
 
 //=========================================================
 
+// functions
+
+// trastercentroid.cpp
+TPoint computeCentroid(const TRaster32P &r);
+
+//=========================================================
+
 //=========================================================
 
 #endif  //__T_RASTER_INCLUDED
diff --git a/toonz/sources/toonzlib/autoclose.cpp b/toonz/sources/toonzlib/autoclose.cpp
index 2defef5..36bfadf 100644
--- a/toonz/sources/toonzlib/autoclose.cpp
+++ b/toonz/sources/toonzlib/autoclose.cpp
@@ -549,7 +549,7 @@ void TAutocloser::Imp::findMeetingPoints(
 
 /*------------------------------------------------------------------------*/
 
-bool allMarked(const std::vector<bool> &marks, int index) {
+static bool allMarked(const std::vector<bool> &marks, int index) {
   int i;
 
   for (i = index + 1; i < (int)marks.size(); i++)
diff --git a/toonz/sources/toonzlib/fill.cpp b/toonz/sources/toonzlib/fill.cpp
index 620a108..b90a286 100644
--- a/toonz/sources/toonzlib/fill.cpp
+++ b/toonz/sources/toonzlib/fill.cpp
@@ -456,11 +456,11 @@ void fill(const TRaster32P &ras, const TRaster32P &ref,
 
 //-----------------------------------------------------------------------------
 
-void rectFill(const TRaster32P &ras, const TRect &r, const TPixel32 &color) {}
+static void rectFill(const TRaster32P &ras, const TRect &r, const TPixel32 &color) {}
 
 //-----------------------------------------------------------------------------
 
-TPoint nearestInk(const TRasterCM32P &r, const TPoint &p, int ray) {
+static TPoint nearestInk(const TRasterCM32P &r, const TPoint &p, int ray) {
   int i, j;
   TPixelCM32 *buf = (TPixelCM32 *)r->getRawData();
 
diff --git a/toonz/sources/toonzlib/fxcommand.cpp b/toonz/sources/toonzlib/fxcommand.cpp
index 73cca22..33c677c 100644
--- a/toonz/sources/toonzlib/fxcommand.cpp
+++ b/toonz/sources/toonzlib/fxcommand.cpp
@@ -2036,8 +2036,8 @@ QString DeleteLinksUndo::getHistoryString() {
 
 //=============================================================
 
-void deleteLinks(const std::list<TFxCommand::Link> &links,
-                 TXsheetHandle *xshHandle) {
+static void deleteLinks(const std::list<TFxCommand::Link> &links,
+                        TXsheetHandle *xshHandle) {
   std::auto_ptr<FxCommandUndo> undo(new DeleteLinksUndo(links, xshHandle));
   if (undo->isConsistent()) {
     undo->redo();
@@ -2298,8 +2298,8 @@ QString DeleteFxOrColumnUndo::getHistoryString() {
 
 //=============================================================
 
-void deleteFxs(const std::list<TFxP> &fxs, TXsheetHandle *xshHandle,
-               TFxHandle *fxHandle) {
+static void deleteFxs(const std::list<TFxP> &fxs, TXsheetHandle *xshHandle,
+                      TFxHandle *fxHandle) {
   TUndoManager *undoManager = TUndoManager::manager();
   TXsheet *xsh              = xshHandle->getXsheet();
 
@@ -2345,8 +2345,8 @@ void TFxCommand::removeOutputFx(TFx *fx, TXsheetHandle *xshHandle,
 //    Delete Columns  command
 //**********************************************************************
 
-void deleteColumns(const std::list<int> &columns, TXsheetHandle *xshHandle,
-                   TFxHandle *fxHandle) {
+static void deleteColumns(const std::list<int> &columns, TXsheetHandle *xshHandle,
+                          TFxHandle *fxHandle) {
   TUndoManager *undoManager = TUndoManager::manager();
 
   undoManager->beginBlock();
diff --git a/toonz/sources/toonzlib/preferences.cpp b/toonz/sources/toonzlib/preferences.cpp
index 8e766a2..e5fd106 100644
--- a/toonz/sources/toonzlib/preferences.cpp
+++ b/toonz/sources/toonzlib/preferences.cpp
@@ -919,7 +919,7 @@ void Preferences::setViewValues(int shrink, int step) {
 
 //-----------------------------------------------------------------
 
-void setCurrentUnits(std::string measureName, std::string units) {
+static void setCurrentUnits(std::string measureName, std::string units) {
   TMeasure *m = TMeasureManager::instance()->get(measureName);
   if (!m) return;
   TUnit *u = m->getUnit(::to_wstring(units));
diff --git a/toonz/sources/toonzlib/sandor_fxs/CIL.cpp b/toonz/sources/toonzlib/sandor_fxs/CIL.cpp
index 08ea736..f741c28 100644
--- a/toonz/sources/toonzlib/sandor_fxs/CIL.cpp
+++ b/toonz/sources/toonzlib/sandor_fxs/CIL.cpp
@@ -76,7 +76,7 @@ void CCIL::strToColorIndex(const char *s, CCIL &cil, const int maxIndex) {
   }
 }
 
-int cilCompare(const void *a, const void *b) {
+static int cilCompare(const void *a, const void *b) {
   int *aa;
   int *bb;
   aa = (int *)a;
diff --git a/toonz/sources/toonzlib/sandor_fxs/CallCircle.cpp b/toonz/sources/toonzlib/sandor_fxs/CallCircle.cpp
index d658c89..4f53721 100644
--- a/toonz/sources/toonzlib/sandor_fxs/CallCircle.cpp
+++ b/toonz/sources/toonzlib/sandor_fxs/CallCircle.cpp
@@ -15,7 +15,7 @@
 // Construction/Destruction
 //////////////////////////////////////////////////////////////////////
 
-int callcircle_xydwCompare(const void *a, const void *b) {
+static int callcircle_xydwCompare(const void *a, const void *b) {
   SXYDW *aa = (SXYDW *)a;
   SXYDW *bb = (SXYDW *)b;
 
diff --git a/toonz/sources/toonzlib/sandor_fxs/EraseContour.cpp b/toonz/sources/toonzlib/sandor_fxs/EraseContour.cpp
index 42a2d82..46c1927 100644
--- a/toonz/sources/toonzlib/sandor_fxs/EraseContour.cpp
+++ b/toonz/sources/toonzlib/sandor_fxs/EraseContour.cpp
@@ -132,7 +132,7 @@ void CEraseContour::eraseInkColors() {
       }
 }
 
-int erasecontour_xydwCompare(const void *a, const void *b) {
+static int erasecontour_xydwCompare(const void *a, const void *b) {
   SXYDW *aa = (SXYDW *)a;
   SXYDW *bb = (SXYDW *)b;
 
diff --git a/toonz/sources/toonzlib/sandor_fxs/PatternPosition.cpp b/toonz/sources/toonzlib/sandor_fxs/PatternPosition.cpp
index 0d92c50..8de9f56 100644
--- a/toonz/sources/toonzlib/sandor_fxs/PatternPosition.cpp
+++ b/toonz/sources/toonzlib/sandor_fxs/PatternPosition.cpp
@@ -32,7 +32,7 @@ bool CPatternPosition::isInSet(const int nbSet, const int *set, const int val) {
   return false;
 }
 
-int pp_intCompare(const void *a, const void *b) {
+static int pp_intCompare(const void *a, const void *b) {
   int *aa = (int *)a;
   int *bb = (int *)b;
 
diff --git a/toonz/sources/toonzlib/sandor_fxs/SDirection.cpp b/toonz/sources/toonzlib/sandor_fxs/SDirection.cpp
index 9dd14c1..edbdfa4 100644
--- a/toonz/sources/toonzlib/sandor_fxs/SDirection.cpp
+++ b/toonz/sources/toonzlib/sandor_fxs/SDirection.cpp
@@ -255,7 +255,7 @@ void CSDirection::equalizeDir(UCHAR *sel, const int d) {
     }
 }
 
-UCHAR getRadius(const double angle, const double r[4]) {
+static UCHAR getRadius(const double angle, const double r[4]) {
   double p, q;
   if (angle >= 0.0 && angle < 45.0) {
     q = angle / 45.0;
diff --git a/toonz/sources/toonzlib/sandor_fxs/YOMBInputParam.cpp b/toonz/sources/toonzlib/sandor_fxs/YOMBInputParam.cpp
index 186392b..925616c 100644
--- a/toonz/sources/toonzlib/sandor_fxs/YOMBInputParam.cpp
+++ b/toonz/sources/toonzlib/sandor_fxs/YOMBInputParam.cpp
@@ -94,7 +94,7 @@ void CYOMBInputParam::strToColorIndex(const char *s, COLOR_INDEX_LIST &cil,
   }
 }
 
-int ushortCompare(const void *a, const void *b) {
+static int ushortCompare(const void *a, const void *b) {
   unsigned short *aa;
   unsigned short *bb;
   aa = (unsigned short *)a;
diff --git a/toonz/sources/toonzlib/sandor_fxs/blend.cpp b/toonz/sources/toonzlib/sandor_fxs/blend.cpp
index 0c0d2d8..ca84b24 100644
--- a/toonz/sources/toonzlib/sandor_fxs/blend.cpp
+++ b/toonz/sources/toonzlib/sandor_fxs/blend.cpp
@@ -303,9 +303,9 @@ inline void getFactors(int tone, double &inkFactor, double &paintFactor) {
 //---------------------------------------------------------------------------------
 
 // Copies the cmIn paint and ink colors to the output rasters.
-void buildLayers(const TRasterCM32P &cmIn,
-                 const std::vector<TPixel32> &palColors, TRaster32P &inkRaster,
-                 TRaster32P &paintRaster) {
+static void buildLayers(const TRasterCM32P &cmIn,
+                        const std::vector<TPixel32> &palColors, TRaster32P &inkRaster,
+                        TRaster32P &paintRaster) {
   // Separate cmIn by copying the ink & paint colors directly to the layer
   // rasters.
   TPixelCM32 *cmPix, *cmBegin = (TPixelCM32 *)cmIn->getRawData();
diff --git a/toonz/sources/toonzlib/sandor_fxs/calligraph.cpp b/toonz/sources/toonzlib/sandor_fxs/calligraph.cpp
index 195a55b..dd21f04 100644
--- a/toonz/sources/toonzlib/sandor_fxs/calligraph.cpp
+++ b/toonz/sources/toonzlib/sandor_fxs/calligraph.cpp
@@ -39,9 +39,9 @@ extern "C" {
                  inr->ly - border - 1, 0, 0)
 
 // ----- CALLIGRAPH for UCHAR pixels (range 0-255) --------------------------
-void calligraphUC(const RASTER *inr, RASTER *outr, CCallParam &par,
-                  const int border,
-                  bool isOutBorder)  // throw(SMemAllocError,SWriteRasterError)
+static void calligraphUC(const RASTER *inr, RASTER *outr, CCallParam &par,
+                         const int border,
+                         bool isOutBorder)  // throw(SMemAllocError,SWriteRasterError)
 {
   try {
     SRECT rect = {border, border, inr->lx - border - 1, inr->ly - border - 1};
@@ -90,9 +90,9 @@ void calligraphUC(const RASTER *inr, RASTER *outr, CCallParam &par,
 }
 
 // ----- CALLIGRAPH for USHORT pixels (range 0-65535) ------------------------
-void calligraphUS(const RASTER *inr, RASTER *outr, CCallParam &par,
-                  const int border,
-                  bool isOutBorder)  // throw(SMemAllocError,SWriteRasterError)
+static void calligraphUS(const RASTER *inr, RASTER *outr, CCallParam &par,
+                         const int border,
+                         bool isOutBorder)  // throw(SMemAllocError,SWriteRasterError)
 {
   try {
     SRECT rect = {border, border, inr->lx - border - 1, inr->ly - border - 1};
diff --git a/toonz/sources/toonzlib/sandor_fxs/calligraph.h b/toonz/sources/toonzlib/sandor_fxs/calligraph.h
index 6f8c722..936343d 100644
--- a/toonz/sources/toonzlib/sandor_fxs/calligraph.h
+++ b/toonz/sources/toonzlib/sandor_fxs/calligraph.h
@@ -3,7 +3,15 @@
 #ifndef __CALLIGRAPH_H_
 #define __CALLIGRAPH_H_
 
-int calligraph(RASTER *, RASTER *, const int border, int argc,
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int calligraph(const RASTER *inr, RASTER *outr, const int border, int argc,
                const char *argv[], const int shrink, bool isOutBorder);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif
diff --git a/toonz/sources/toonzlib/sandor_fxs/patternmap.cpp b/toonz/sources/toonzlib/sandor_fxs/patternmap.cpp
index d7a6653..c4da195 100644
--- a/toonz/sources/toonzlib/sandor_fxs/patternmap.cpp
+++ b/toonz/sources/toonzlib/sandor_fxs/patternmap.cpp
@@ -31,7 +31,6 @@
 using namespace std;
 
 #ifdef __cplusplus
-
 extern "C" {
 #endif
 
@@ -44,10 +43,9 @@ extern "C" {
 
 // ----- PatternMapping for UCHAR pixels (range 0-255)
 // --------------------------
-void patternmapUC(
+static void patternmapUC(
     const RASTER *iras, RASTER *oras, CPatternMapParam &pmP, const int border,
-    RASTER
-        *imgContour)  // throw (SMemAllocError,SWriteRasterError,SFileReadError)
+    RASTER *imgContour)  // throw (SMemAllocError,SWriteRasterError,SFileReadError)
 {
   try {
     SRECT rect = {border, border, iras->lx - border - 1, iras->ly - border - 1};
@@ -125,10 +123,9 @@ void patternmapUC(
 
 // ----- PatternMapping for USHORT pixels (range 0-255)
 // --------------------------
-void patternmapUS(
+static void patternmapUS(
     const RASTER *iras, RASTER *oras, CPatternMapParam &pmP, const int border,
-    RASTER
-        *imgContour)  // throw (SMemAllocError,SWriteRasterError,SFileReadError)
+    RASTER *imgContour)  // throw (SMemAllocError,SWriteRasterError,SFileReadError)
 {
   try {
     SRECT rect = {border, border, iras->lx - border - 1, iras->ly - border - 1};
diff --git a/toonz/sources/toonzlib/sandor_fxs/patternmap.h b/toonz/sources/toonzlib/sandor_fxs/patternmap.h
index 402f81d..f3d8036 100644
--- a/toonz/sources/toonzlib/sandor_fxs/patternmap.h
+++ b/toonz/sources/toonzlib/sandor_fxs/patternmap.h
@@ -3,7 +3,15 @@
 #ifndef __PATTERNMAP_H_
 #define __PATTERNMAP_H_
 
-int patternmap(RASTER *, RASTER *, const int border, int argc,
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int patternmap(const RASTER *, RASTER *, const int border, int argc,
                const char *argv[], const int shrink, RASTER *imgContour);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif
diff --git a/toonz/sources/toonzlib/scenefx.cpp b/toonz/sources/toonzlib/scenefx.cpp
index 2c429d3..91eb5d4 100644
--- a/toonz/sources/toonzlib/scenefx.cpp
+++ b/toonz/sources/toonzlib/scenefx.cpp
@@ -318,8 +318,8 @@ bool getColumnPlacement(TAffine &aff, TXsheet *xsh, double row, int col,
 
 //-------------------------------------------------------------------
 
-bool getColumnPlacement(PlacedFx &pf, TXsheet *xsh, double row, int col,
-                        bool isPreview) {
+static bool getColumnPlacement(PlacedFx &pf, TXsheet *xsh, double row, int col,
+                               bool isPreview) {
   if (col < 0) return false;
   TStageObject *pegbar = xsh->getStageObject(TStageObjectId::ColumnId(col));
   TAffine objAff       = pegbar->getPlacement(row);
@@ -344,8 +344,8 @@ bool getColumnPlacement(PlacedFx &pf, TXsheet *xsh, double row, int col,
 
 //-------------------------------------------------------------------
 /*-- Objectの位置を得る --*/
-bool getStageObjectPlacement(TAffine &aff, TXsheet *xsh, double row,
-                             TStageObjectId &id, bool isPreview) {
+static bool getStageObjectPlacement(TAffine &aff, TXsheet *xsh, double row,
+                                    TStageObjectId &id, bool isPreview) {
   TStageObject *pegbar = xsh->getStageObjectTree()->getStageObject(id, false);
   if (!pegbar) return false;
 
@@ -398,7 +398,7 @@ TStageObjectId getMotionObjectId(MotionObjectType type, int index) {
 
 //-------------------------------------------------------------------
 
-TPointD getColumnSpeed(TXsheet *xsh, double row, int col, bool isPreview) {
+static TPointD getColumnSpeed(TXsheet *xsh, double row, int col, bool isPreview) {
   TAffine aff;
   TPointD a, b;
   const double h = 0.001;
@@ -427,10 +427,10 @@ TPointD getColumnSpeed(TXsheet *xsh, double row, int col, bool isPreview) {
 /*-- オブジェクトの軌跡を、基準点との差分で得る
         objectId: 移動の参考にするオブジェクト。自分自身の場合はNoneId
 --*/
-QList<TPointD> getColumnMotionPoints(TXsheet *xsh, double row, int col,
-                                     TStageObjectId &objectId, bool isPreview,
-                                     double shutterStart, double shutterEnd,
-                                     int traceResolution) {
+static QList<TPointD> getColumnMotionPoints(TXsheet *xsh, double row, int col,
+                                            TStageObjectId &objectId, bool isPreview,
+                                            double shutterStart, double shutterEnd,
+                                            int traceResolution) {
   /*-- 前後フレームが共に０なら空のリストを返す --*/
   if (shutterStart == 0.0 && shutterEnd == 0.0) return QList<TPointD>();
 
diff --git a/toonz/sources/toonzlib/scriptbinding.cpp b/toonz/sources/toonzlib/scriptbinding.cpp
index a8d1ab3..6a4de11 100644
--- a/toonz/sources/toonzlib/scriptbinding.cpp
+++ b/toonz/sources/toonzlib/scriptbinding.cpp
@@ -137,7 +137,7 @@ public:
   }
 };
 
-void deffoo(QScriptEngine &engine) {
+static void deffoo(QScriptEngine &engine) {
   QScriptValue f = engine.newFunction(
       Dummy<ToonzRasterConverter, &ToonzRasterConverter::convert>::dummy);
   engine.globalObject()
diff --git a/toonz/sources/toonzlib/scriptbinding_outline_vectorizer.cpp b/toonz/sources/toonzlib/scriptbinding_outline_vectorizer.cpp
index 0c760cd..da3a3f9 100644
--- a/toonz/sources/toonzlib/scriptbinding_outline_vectorizer.cpp
+++ b/toonz/sources/toonzlib/scriptbinding_outline_vectorizer.cpp
@@ -22,9 +22,9 @@ QScriptValue OutlineVectorizer::ctor(QScriptContext *context,
   return create(engine, new OutlineVectorizer());
 }
 
-QScriptValue vectorizeImage(QScriptContext *context, QScriptEngine *engine,
-                            const TImageP &src, TPalette *palette,
-                            NewOutlineConfiguration *parameters) {
+static QScriptValue vectorizeImage(QScriptContext *context, QScriptEngine *engine,
+                                   const TImageP &src, TPalette *palette,
+                                   NewOutlineConfiguration *parameters) {
   VectorizerCore vc;
   TAffine dpiAff;
   double factor = Stage::inch;
diff --git a/toonz/sources/toonzlib/scriptbinding_rasterizer.cpp b/toonz/sources/toonzlib/scriptbinding_rasterizer.cpp
index 51a5367..4b1cc39 100644
--- a/toonz/sources/toonzlib/scriptbinding_rasterizer.cpp
+++ b/toonz/sources/toonzlib/scriptbinding_rasterizer.cpp
@@ -27,9 +27,9 @@ QScriptValue Rasterizer::ctor(QScriptContext *context, QScriptEngine *engine) {
   return create(engine, new Rasterizer());
 }
 
-TToonzImageP vectorToToonzRaster(const TVectorImageP &vi,
-                                 const TDimension &size, const TAffine &aff,
-                                 const TPointD &dpi) {
+static TToonzImageP vectorToToonzRaster(const TVectorImageP &vi,
+                                        const TDimension &size, const TAffine &aff,
+                                        const TPointD &dpi) {
   /*
 TScale sc(dpi.x/Stage::inch, dpi.y/Stage::inch);
 TRectD bbox = sc*vi->getBBox();
@@ -47,9 +47,9 @@ TDimension size(bbox.getLx(), bbox.getLy());
   return ti;
 }
 
-TImageP renderVectorImage(TOfflineGL *glContext, const TVectorRenderData &rd,
-                          const TPointD &dpi, const TImageP &img,
-                          const TPixel32 &color) {
+static TImageP renderVectorImage(TOfflineGL *glContext, const TVectorRenderData &rd,
+                                 const TPointD &dpi, const TImageP &img,
+                                 const TPixel32 &color) {
   glContext->clear(color);
   glContext->draw(img, rd);
   TRasterImageP rimg(glContext->getRaster());
@@ -57,8 +57,8 @@ TImageP renderVectorImage(TOfflineGL *glContext, const TVectorRenderData &rd,
   return rimg;
 }
 
-void setFrame(QScriptEngine *engine, QScriptValue &level, const TFrameId &fid,
-              const TImageP &drawing) {
+static void setFrame(QScriptEngine *engine, QScriptValue &level, const TFrameId &fid,
+                     const TImageP &drawing) {
   QScriptValueList args;
   args << QString::fromStdString(fid.expand())
        << Wrapper::create(engine, new Image(drawing.getPointer()));
diff --git a/toonz/sources/toonzlib/scriptbinding_renderer.cpp b/toonz/sources/toonzlib/scriptbinding_renderer.cpp
index be96689..a4f41c7 100644
--- a/toonz/sources/toonzlib/scriptbinding_renderer.cpp
+++ b/toonz/sources/toonzlib/scriptbinding_renderer.cpp
@@ -21,8 +21,8 @@ namespace TScriptBinding {
 
 //=======================================================
 
-QScriptValue getScene(QScriptContext *context, const QScriptValue &sceneArg,
-                      Scene *&scene) {
+static QScriptValue getScene(QScriptContext *context, const QScriptValue &sceneArg,
+                             Scene *&scene) {
   scene = qscriptvalue_cast<Scene *>(sceneArg);
   if (!scene)
     return context->throwError(
@@ -33,7 +33,7 @@ QScriptValue getScene(QScriptContext *context, const QScriptValue &sceneArg,
   return QScriptValue();
 }
 
-void valueToIntList(const QScriptValue &arr, QList<int> &list) {
+static void valueToIntList(const QScriptValue &arr, QList<int> &list) {
   list.clear();
   if (arr.isArray()) {
     int length = arr.property("length").toInteger();
diff --git a/toonz/sources/toonzlib/stage.cpp b/toonz/sources/toonzlib/stage.cpp
index edcc991..08e3d19 100644
--- a/toonz/sources/toonzlib/stage.cpp
+++ b/toonz/sources/toonzlib/stage.cpp
@@ -453,8 +453,8 @@ void StageBuilder::addCell(PlayerSet &players, ToonzScene *scene, TXsheet *xsh,
 
 //-----------------------------------------------------------------------------
 
-bool alreadyAdded(TXsheet *xsh, int row, int index,
-                  const std::vector<int> &rows, int col) {
+static bool alreadyAdded(TXsheet *xsh, int row, int index,
+                         const std::vector<int> &rows, int col) {
   int i;
   for (i = 0; i < index; i++)
     if (xsh->getCell(rows[i], col) == xsh->getCell(rows[index], col))
diff --git a/toonz/sources/toonzlib/stagevisitor.cpp b/toonz/sources/toonzlib/stagevisitor.cpp
index 9464fad..351693b 100644
--- a/toonz/sources/toonzlib/stagevisitor.cpp
+++ b/toonz/sources/toonzlib/stagevisitor.cpp
@@ -31,6 +31,7 @@
 #include "toonz/stageplayer.h"
 #include "toonz/stage.h"
 #include "toonz/stage2.h"
+#include "toonz/tcolumnfx.h"
 #include "toonz/txsheet.h"
 #include "toonz/txshsimplelevel.h"
 #include "toonz/txshchildlevel.h"
@@ -681,9 +682,9 @@ void RasterPainter::drawRasterImages(QPainter &p, QPolygon cameraPol) {
   m_nodes.clear();
 }
 
-void buildAutocloseImage(TVectorImage *vaux, TVectorImage *vi,
-                         const std::vector<std::pair<int, double>> &startPoints,
-                         const std::vector<std::pair<int, double>> &endPoints) {
+static void buildAutocloseImage(TVectorImage *vaux, TVectorImage *vi,
+                                const std::vector<std::pair<int, double>> &startPoints,
+                                const std::vector<std::pair<int, double>> &endPoints) {
   for (UINT i = 0; i < startPoints.size(); i++) {
     TThickPoint p1 = vi->getStroke(startPoints[i].first)
                          ->getThickPoint(startPoints[i].second);
@@ -702,7 +703,7 @@ void buildAutocloseImage(TVectorImage *vaux, TVectorImage *vi,
 
 TEnv::DoubleVar AutocloseFactor("InknpaintAutocloseFactor", 4.0);
 
-void drawAutocloses(TVectorImage *vi, TVectorRenderData &rd) {
+static void drawAutocloses(TVectorImage *vi, TVectorRenderData &rd) {
   static TPalette *plt = 0;
   if (!plt) {
     plt = new TPalette();
@@ -861,9 +862,6 @@ void RasterPainter::onVectorImage(TVectorImage *vi,
   delete cf;
 }
 
-//-----------------------------------------------------------------------------
-
-bool isSubsheetChainOnColumn0(TXsheet *topXsheet, TXsheet *subsheet, int frame);
 
 //-----------------------------------------------------
 
diff --git a/toonz/sources/toonzlib/studiopalette.cpp b/toonz/sources/toonzlib/studiopalette.cpp
index 54c0558..1847833 100644
--- a/toonz/sources/toonzlib/studiopalette.cpp
+++ b/toonz/sources/toonzlib/studiopalette.cpp
@@ -218,7 +218,7 @@ TFilePath StudioPalette::getProjectPalettesRoot() {
 
 //-------------------------------------------------------------------
 
-bool loadRefImg(TPalette *palette, TFilePath dir) {
+static bool loadRefImg(TPalette *palette, TFilePath dir) {
   assert(palette);
   TFilePath fp = palette->getRefImgPath();
   if (fp == TFilePath() || !TSystem::doesExistFileOrLevel(fp)) return false;
@@ -463,7 +463,7 @@ TFilePath StudioPalette::importPalette(const TFilePath &dstFolder,
 
 //-------------------------------------------------------------------
 
-void foobar(std::wstring paletteId) { table.erase(paletteId); }
+static void foobar(std::wstring paletteId) { table.erase(paletteId); }
 
 TFilePath StudioPalette::getPalettePath(std::wstring paletteId) {
   std::map<std::wstring, TFilePath>::iterator it = table.find(paletteId);
diff --git a/toonz/sources/toonzlib/tcenterlineadjustments.cpp b/toonz/sources/toonzlib/tcenterlineadjustments.cpp
index 2ca46b7..45a96ee 100644
--- a/toonz/sources/toonzlib/tcenterlineadjustments.cpp
+++ b/toonz/sources/toonzlib/tcenterlineadjustments.cpp
@@ -270,7 +270,7 @@ inline void findRoads(const Sequence &s) {
 //--------------------------------------------------------------------------
 
 // Find the 'roads' of the current Graph.
-void findRoads(const JointSequenceGraph &JSGraph) {
+static void findRoads(const JointSequenceGraph &JSGraph) {
   unsigned int i, j;
 
   // For all Sequence of currGraph, extract roads
diff --git a/toonz/sources/toonzlib/tcenterlinecolors.cpp b/toonz/sources/toonzlib/tcenterlinecolors.cpp
index 9d783cb..47796d8 100644
--- a/toonz/sources/toonzlib/tcenterlinecolors.cpp
+++ b/toonz/sources/toonzlib/tcenterlinecolors.cpp
@@ -38,7 +38,7 @@ namespace boost_c = boost::container;
 
 //--------------------------------------------------------------------------
 
-TPixelCM32 pixel(const TRasterCM32 &ras, int x, int y) {
+static TPixelCM32 pixel(const TRasterCM32 &ras, int x, int y) {
   // Seems that raster access was not very much double-checked at the time
   // I wrote this. Too bad. Enforcing it now.
 
@@ -47,9 +47,9 @@ TPixelCM32 pixel(const TRasterCM32 &ras, int x, int y) {
 
 //--------------------------------------------------------------------------
 
-T3DPointD firstInkChangePosition(const TRasterCM32P &ras,
-                                 const T3DPointD &start, const T3DPointD &end,
-                                 int threshold) {
+static T3DPointD firstInkChangePosition(const TRasterCM32P &ras,
+                                        const T3DPointD &start, const T3DPointD &end,
+                                        int threshold) {
   double dist = norm(end - start);
 
   int sampleMax = tceil(dist), sampleCount = sampleMax + 1;
@@ -114,8 +114,8 @@ T3DPointD firstInkChangePosition(const TRasterCM32P &ras,
 // NOTA: La struttura a grafo J-S 'superiore' non viene alterata qui dentro.
 // Eventualm. da fare fuori.
 
-void sampleColor(const TRasterCM32P &ras, int threshold, Sequence &seq,
-                 Sequence &seqOpposite, SequenceList &singleSequences) {
+static void sampleColor(const TRasterCM32P &ras, int threshold, Sequence &seq,
+                        Sequence &seqOpposite, SequenceList &singleSequences) {
   SkeletonGraph *currGraph = seq.m_graphHolder;
 
   // Calculate sequence parametrization
@@ -469,8 +469,8 @@ inline void applyStrokeIndices(VectorizerCoreGlobals *globals) {
 //--------------------------------------------------------------------------
 
 // Find predominant ink color in a circle of given radius and center
-int getInkPredominance(const TRasterCM32P &ras, TPalette *palette, int x, int y,
-                       int radius, int threshold) {
+static int getInkPredominance(const TRasterCM32P &ras, TPalette *palette, int x, int y,
+                              int radius, int threshold) {
   int i, j;
   int mx, my, Mx, My;
   std::vector<int> inksFound(palette->getStyleCount());
@@ -511,8 +511,8 @@ int getInkPredominance(const TRasterCM32P &ras, TPalette *palette, int x, int y,
             input graph node.
   \return   The predominant branch color if found, \p -1 otherwise.
 */
-int getBranchPredominance(const TRasterCM32P &ras, TPalette *palette,
-                          JointSequenceGraph::Node &node) {
+static int getBranchPredominance(const TRasterCM32P &ras, TPalette *palette,
+                                 JointSequenceGraph::Node &node) {
   struct locals {
     static inline bool valueLess(const std::pair<int, int> &a,
                                  const std::pair<int, int> &b) {
@@ -548,9 +548,9 @@ int getBranchPredominance(const TRasterCM32P &ras, TPalette *palette,
 
 // NOTA: Da implementare una versione in grado di ordinare *pienamente* la
 // vector image.
-void sortJS(JointSequenceGraph *js,
-            std::vector<std::pair<int, TStroke *>> &toOrder,
-            const TRasterCM32P &ras, TPalette *palette) {
+static void sortJS(JointSequenceGraph *js,
+                   std::vector<std::pair<int, TStroke *>> &toOrder,
+                   const TRasterCM32P &ras, TPalette *palette) {
   enum { SORTED = 0x10 };
 
   std::vector<std::pair<unsigned int, int>> nodesToDo;
diff --git a/toonz/sources/toonzlib/tcenterlinepolygonizer.cpp b/toonz/sources/toonzlib/tcenterlinepolygonizer.cpp
index d8b0319..00d877f 100644
--- a/toonz/sources/toonzlib/tcenterlinepolygonizer.cpp
+++ b/toonz/sources/toonzlib/tcenterlinepolygonizer.cpp
@@ -304,8 +304,8 @@ inline void setSignature(Signaturemap &ras, const RawBorder &border, int val) {
 // Keeping B on the right of our path-seeking direction, we may either turn
 // left or right at these points.
 
-RawBorder *extractPath(Signaturemap &ras, int x0, int y0, int pathType,
-                       int xOuterPixel, int despeckling) {
+static RawBorder *extractPath(Signaturemap &ras, int x0, int y0, int pathType,
+                              int xOuterPixel, int despeckling) {
   RawBorder *path = new RawBorder;
   int x, y;
   short dirX, dirY;
@@ -389,8 +389,8 @@ RawBorder *extractPath(Signaturemap &ras, int x0, int y0, int pathType,
 
 //--------------------------------------------------------------------------
 
-BorderList *extractBorders(const TRasterP &ras, int threshold,
-                           int despeckling) {
+static BorderList *extractBorders(const TRasterP &ras, int threshold,
+                                  int despeckling) {
   Signaturemap byteImage(ras, threshold);
 
   BorderList *borderHierarchy = new BorderList;
diff --git a/toonz/sources/toonzlib/tcenterlineskeletonizer.cpp b/toonz/sources/toonzlib/tcenterlineskeletonizer.cpp
index c853aa5..0705e75 100644
--- a/toonz/sources/toonzlib/tcenterlineskeletonizer.cpp
+++ b/toonz/sources/toonzlib/tcenterlineskeletonizer.cpp
@@ -1653,9 +1653,9 @@ inline void Event::processSpecialEvent() {
 //    Straight Skeleton mains
 //-------------------------------
 
-SkeletonGraph *skeletonize(ContourFamily &regionContours,
-                           VectorizationContext &context,
-                           VectorizerCore *thisVectorizer) {
+static SkeletonGraph *skeletonize(ContourFamily &regionContours,
+                                  VectorizationContext &context,
+                                  VectorizerCore *thisVectorizer) {
   SkeletonGraph *output = context.m_output = new SkeletonGraph;
 
   context.prepareContours(regionContours);
diff --git a/toonz/sources/toonzlib/tcenterlinevectorizer.cpp b/toonz/sources/toonzlib/tcenterlinevectorizer.cpp
index 1c58e1a..5db93d7 100644
--- a/toonz/sources/toonzlib/tcenterlinevectorizer.cpp
+++ b/toonz/sources/toonzlib/tcenterlinevectorizer.cpp
@@ -64,7 +64,7 @@ inline void deleteSkeletonList(SkeletonList *skeleton) {
 
 //========================================================================
 
-TVectorImageP copyStrokes(std::vector<TStroke *> &strokes) {
+static TVectorImageP copyStrokes(std::vector<TStroke *> &strokes) {
   unsigned int i;
   TVectorImageP result = new TVectorImage;
 
@@ -88,7 +88,7 @@ inline TThickPoint randomized(const TThickPoint &P) {
 //------------------------------------------------------------------------
 
 // Give stroke extremities a random shake. May help for region computing.
-void randomizeExtremities(TVectorImageP vi) {
+static void randomizeExtremities(TVectorImageP vi) {
   unsigned int i;
   for (i = 0; i < vi->getStrokeCount(); ++i) {
     TThickPoint P = vi->getStroke(i)->getControlPoint(0);
diff --git a/toonz/sources/toonzlib/tcolumnfx.cpp b/toonz/sources/toonzlib/tcolumnfx.cpp
index 99820e8..f9597c8 100644
--- a/toonz/sources/toonzlib/tcolumnfx.cpp
+++ b/toonz/sources/toonzlib/tcolumnfx.cpp
@@ -183,7 +183,7 @@ std::string getAlias(TXsheet *xsh, double frame, const TRenderSettings &info) {
 //    Local namespace  -  Colormap (Sandor) Fxs stuff
 //****************************************************************************************
 
-bool vectorMustApplyCmappedFx(const std::vector<TRasterFxRenderDataP> &fxs) {
+static bool vectorMustApplyCmappedFx(const std::vector<TRasterFxRenderDataP> &fxs) {
   std::vector<TRasterFxRenderDataP>::const_iterator ft, fEnd(fxs.end());
   for (ft = fxs.begin(); ft != fEnd; ++ft) {
     PaletteFilterFxRenderData *paletteFilterData =
@@ -220,7 +220,7 @@ Will have to inquire further, though...
 
 //-------------------------------------------------------------------
 
-bool mustApplySandorFx(const std::vector<TRasterFxRenderDataP> &fxs) {
+static bool mustApplySandorFx(const std::vector<TRasterFxRenderDataP> &fxs) {
   std::vector<TRasterFxRenderDataP>::const_iterator ft, fEnd(fxs.end());
   for (ft = fxs.begin(); ft != fEnd; ++ft) {
     SandorFxRenderData *sandorData =
@@ -233,7 +233,7 @@ bool mustApplySandorFx(const std::vector<TRasterFxRenderDataP> &fxs) {
 
 //-------------------------------------------------------------------
 
-int getEnlargement(const std::vector<TRasterFxRenderDataP> &fxs, double scale) {
+static int getEnlargement(const std::vector<TRasterFxRenderDataP> &fxs, double scale) {
   int enlargement = 1;
 
   std::vector<TRasterFxRenderDataP>::const_iterator ft, fEnd(fxs.end());
@@ -287,8 +287,8 @@ int getEnlargement(const std::vector<TRasterFxRenderDataP> &fxs, double scale) {
 
 //-------------------------------------------------------------------
 
-void applyPaletteFilter(TPalette *&plt, bool keep, const set<int> &colors,
-                        const TPalette *srcPlt) {
+static void applyPaletteFilter(TPalette *&plt, bool keep, const set<int> &colors,
+                               const TPalette *srcPlt) {
   if (colors.empty()) return;
 
   if (!plt) plt = srcPlt->clone();
@@ -309,7 +309,7 @@ void applyPaletteFilter(TPalette *&plt, bool keep, const set<int> &colors,
 
 //-------------------------------------------------------------------
 
-TPalette *getPliPalette(const TFilePath &path) {
+static TPalette *getPliPalette(const TFilePath &path) {
   TLevelReaderP levelReader = TLevelReaderP(path);
   if (!levelReader.getPointer()) return 0;
 
@@ -348,7 +348,7 @@ inline void sortCmappedFxs(std::vector<TRasterFxRenderDataP> &fxs) {
 
 //-------------------------------------------------------------------
 
-std::vector<int> getAllBut(std::vector<int> &colorIds) {
+static std::vector<int> getAllBut(std::vector<int> &colorIds) {
   assert(TPixelCM32::getMaxInk() == TPixelCM32::getMaxPaint());
 
   std::vector<int> curColorIds;
@@ -378,9 +378,9 @@ std::vector<int> getAllBut(std::vector<int> &colorIds) {
 //! that of
 //! optimizing memory usage, please avoid copying the entire image buffer...
 
-TImageP applyCmappedFx(TToonzImageP &ti,
-                       const std::vector<TRasterFxRenderDataP> &fxs, int frame,
-                       double scale) {
+static TImageP applyCmappedFx(TToonzImageP &ti,
+                              const std::vector<TRasterFxRenderDataP> &fxs, int frame,
+                              double scale) {
   TImageP result = ti;
   TTile resultTile;  // Just a quick wrapper to the ImageCache
   TPalette *inPalette, *tempPlt;
@@ -671,8 +671,8 @@ TImageP applyCmappedFx(TToonzImageP &ti,
 
 //-------------------------------------------------------------------
 
-void applyCmappedFx(TVectorImageP &vi,
-                    const std::vector<TRasterFxRenderDataP> &fxs, int frame) {
+static void applyCmappedFx(TVectorImageP &vi,
+                           const std::vector<TRasterFxRenderDataP> &fxs, int frame) {
   TRasterP ras;
   bool keep = false;
   TPaletteP modPalette;
diff --git a/toonz/sources/toonzlib/tcolumnfxset.cpp b/toonz/sources/toonzlib/tcolumnfxset.cpp
index 2352716..9a0ea37 100644
--- a/toonz/sources/toonzlib/tcolumnfxset.cpp
+++ b/toonz/sources/toonzlib/tcolumnfxset.cpp
@@ -113,7 +113,7 @@ void TFxSet::loadData(TIStream &is) {
   }
 }
 
-TFx *getActualFx(TFx *fx) {
+static TFx *getActualFx(TFx *fx) {
   // Zerary fxs and zerary COLUMN fxs are separate, and fx port connections
   // are stored in the actual zerary fx.
   // It's sad - couldn't we do something about it?
diff --git a/toonz/sources/toonzlib/toonzimageutils.cpp b/toonz/sources/toonzlib/toonzimageutils.cpp
index 8ecda4a..74fd793 100644
--- a/toonz/sources/toonzlib/toonzimageutils.cpp
+++ b/toonz/sources/toonzlib/toonzimageutils.cpp
@@ -202,10 +202,10 @@ TRectD ToonzImageUtils::convertRasterToWorld(const TRect area,
 
 // overlaying inks, blend inks always "lose" on normal inks
 
-TRect fastAddInkStroke(const TToonzImageP &ti, TStroke *stroke, int inkId,
-                       bool selective, bool filled, TRectD clip,
-                       bool doAntialiasing       = true,
-                       const set<int> &blendInks = set<int>()) {
+static TRect fastAddInkStroke(const TToonzImageP &ti, TStroke *stroke, int inkId,
+                              bool selective, bool filled, TRectD clip,
+                              bool doAntialiasing       = true,
+                              const set<int> &blendInks = set<int>()) {
   TRasterCM32P ras = ti->getRaster();
   TOfflineGL *gl   = 0;
 
diff --git a/toonz/sources/toonzlib/toonzscene.cpp b/toonz/sources/toonzlib/toonzscene.cpp
index 354620b..61e98cd 100644
--- a/toonz/sources/toonzlib/toonzscene.cpp
+++ b/toonz/sources/toonzlib/toonzscene.cpp
@@ -283,7 +283,7 @@ void fixBiancoProblem(ToonzScene *scene, TXsheet *xsh) {
 
 //=============================================================================
 
-void deleteAllUntitledScenes() {
+static void deleteAllUntitledScenes() {
   TFilePath tempDir = getUntitledScenesDir();
   try {
     if (TFileStatus(tempDir).isDirectory()) {
@@ -948,7 +948,7 @@ struct LevelType {
 
 //-----------------------------------------------------------------------------
 
-LevelType getLevelType(const TFilePath &fp) {
+static LevelType getLevelType(const TFilePath &fp) {
   LevelType ret;
   ret.m_ltype        = UNKNOWN_XSHLEVEL;
   ret.m_oldLevelFlag = false;
diff --git a/toonz/sources/toonzlib/toutlinevectorizer.cpp b/toonz/sources/toonzlib/toutlinevectorizer.cpp
index 7e3ea80..b6aa75f 100644
--- a/toonz/sources/toonzlib/toutlinevectorizer.cpp
+++ b/toonz/sources/toonzlib/toutlinevectorizer.cpp
@@ -128,7 +128,7 @@ public:
 
 //---------------------------------------------------------
 
-double computeDistance2(Node *na, Node *nb) {
+static double computeDistance2(Node *na, Node *nb) {
   assert(na->m_pixel);
   assert(nb->m_pixel);
   TPointD d = convert(na->m_pixel->m_pos - nb->m_pixel->m_pos);
@@ -137,7 +137,7 @@ double computeDistance2(Node *na, Node *nb) {
 
 //---------------------------------------------------------
 
-void renormalizeImage(TVectorImage *vi) {
+static void renormalizeImage(TVectorImage *vi) {
   int i, j;
   int n = vi->getStrokeCount();
   std::vector<ControlPoint> points;
@@ -832,7 +832,7 @@ TVectorImageP VectorizerCore::outlineVectorize(
 
 //=========================================================
 
-bool isPointInRegion(TPointD p, TRegion *r) {
+static bool isPointInRegion(TPointD p, TRegion *r) {
   int i;
   for (i = 0; i < 5; i++) {
     double stepX = i * 0.2;
@@ -856,9 +856,9 @@ bool isPointInRegion(TPointD p, TRegion *r) {
 
 //(Daniele) Aggiunti controlli per evitare uscite dai bounds
 
-bool isNearestInkOrPaintInRegion(bool findInk, const TRasterCM32P &ras,
-                                 TRegion *r, const TAffine &aff,
-                                 const TPoint &p) {
+static bool isNearestInkOrPaintInRegion(bool findInk, const TRasterCM32P &ras,
+                                        TRegion *r, const TAffine &aff,
+                                        const TPoint &p) {
   bool isTheLastSquare = false;
   int mx, my, Mx, My;
   int i;
diff --git a/toonz/sources/toonzlib/trastercentroid.cpp b/toonz/sources/toonzlib/trastercentroid.cpp
index b055528..4f538ab 100644
--- a/toonz/sources/toonzlib/trastercentroid.cpp
+++ b/toonz/sources/toonzlib/trastercentroid.cpp
@@ -271,7 +271,7 @@ static int find_next_seed(const TRasterGR8P &r, int first_seed, UCHAR *&seed,
 
 /*------------------------------------------------------------------------*/
 
-void doComputeCentroid(const TRasterGR8P &r, TPoint &cp) {
+static void doComputeCentroid(const TRasterGR8P &r, TPoint &cp) {
   int preseed, displ, prewalker, code;
   UCHAR *seed, *walker;
   int x_num = 0, y_num = 0, den = 0;
diff --git a/toonz/sources/toonzlib/tstageobject.cpp b/toonz/sources/toonzlib/tstageobject.cpp
index ca3dffb..dcedd02 100644
--- a/toonz/sources/toonzlib/tstageobject.cpp
+++ b/toonz/sources/toonzlib/tstageobject.cpp
@@ -46,7 +46,7 @@ using namespace std;
 #ifdef _WIN32
 #pragma optimize("", off)
 #endif
-TAffine makeRotation(double ang) { return TRotation(ang); }
+static TAffine makeRotation(double ang) { return TRotation(ang); }
 #ifdef _WIN32
 #pragma optimize("", on)
 #endif
diff --git a/toonz/sources/toonzlib/txshsimplelevel.cpp b/toonz/sources/toonzlib/txshsimplelevel.cpp
index 490450e..edb8df6 100644
--- a/toonz/sources/toonzlib/txshsimplelevel.cpp
+++ b/toonz/sources/toonzlib/txshsimplelevel.cpp
@@ -1013,7 +1013,7 @@ void getLoadingLevelRange(TFrameId &fromFid, TFrameId &toFid) {
   toFid   = loadingLevelRange.m_toFid;
 }
 
-TFilePath getLevelPathAndSetNameWithPsdLevelName(TXshSimpleLevel *xshLevel) {
+static TFilePath getLevelPathAndSetNameWithPsdLevelName(TXshSimpleLevel *xshLevel) {
   TFilePath retfp = xshLevel->getPath();
 
   QString name     = QString::fromStdWString(retfp.getWideName());
@@ -1358,7 +1358,7 @@ void TXshSimpleLevel::save() {
 
 //-----------------------------------------------------------------------------
 
-void saveBackup(TFilePath path) {
+static void saveBackup(TFilePath path) {
   try {
     TFilePath backup = path.withName(path.getName() + "_backup");
     if (TSystem::doesExistFileOrLevel(backup))