diff --git a/src/lib/sw_engine/tvgSwCommon.h b/src/lib/sw_engine/tvgSwCommon.h
index 0bc0052d..0b800815 100644
--- a/src/lib/sw_engine/tvgSwCommon.h
+++ b/src/lib/sw_engine/tvgSwCommon.h
@@ -53,25 +53,30 @@ struct SwPoint
 {
     SwCoord x, y;
 
-    SwPoint& operator+=(const SwPoint& rhs) {
+    SwPoint& operator+=(const SwPoint& rhs)
+    {
         x += rhs.x;
         y += rhs.y;
         return *this;
     }
 
-    SwPoint operator+(const SwPoint& rhs) const {
+    SwPoint operator+(const SwPoint& rhs) const
+    {
         return {x + rhs.x, y + rhs.y};
     }
 
-    SwPoint operator-(const SwPoint& rhs) const {
+    SwPoint operator-(const SwPoint& rhs) const
+    {
         return {x - rhs.x, y - rhs.y};
     }
 
-    bool operator==(const SwPoint& rhs ) const {
+    bool operator==(const SwPoint& rhs ) const
+    {
         return (x == rhs.x && y == rhs.y);
     }
 
-    bool operator!=(const SwPoint& rhs) const {
+    bool operator!=(const SwPoint& rhs) const
+    {
         return (x != rhs.x || y != rhs.y);
     }
 
@@ -125,6 +130,11 @@ struct SwRleData
 struct SwBBox
 {
     SwPoint min, max;
+
+    void reset()
+    {
+        min.x = min.y = max.x = max.y = 0;
+    }
 };
 
 struct SwFill
@@ -286,12 +296,13 @@ SwFixed mathLength(const SwPoint& pt);
 bool mathSmallCubic(const SwPoint* base, SwFixed& angleIn, SwFixed& angleMid, SwFixed& angleOut);
 SwFixed mathMean(SwFixed angle1, SwFixed angle2);
 SwPoint mathTransform(const Point* to, const Matrix* transform);
+bool mathUpdateOutlineBBox(const SwOutline* outline, SwBBox& bbox, const SwSize& clip);
 
 void shapeReset(SwShape* shape);
 bool shapeGenOutline(SwShape* shape, const Shape* sdata, unsigned tid, const Matrix* transform);
 bool shapePrepare(SwShape* shape, const Shape* sdata, unsigned tid, const SwSize& clip, const Matrix* transform, SwBBox& bbox);
 bool shapePrepared(const SwShape* shape);
-bool shapeGenRle(SwShape* shape, const Shape* sdata, const SwSize& clip, bool antiAlias, bool hasComposite);
+bool shapeGenRle(SwShape* shape, const Shape* sdata, bool antiAlias, bool hasComposite);
 void shapeDelOutline(SwShape* shape, uint32_t tid);
 void shapeResetStroke(SwShape* shape, const Shape* sdata, const Matrix* transform);
 bool shapeGenStrokeRle(SwShape* shape, const Shape* sdata, unsigned tid, const Matrix* transform, const SwSize& clip, SwBBox& bbox);
@@ -311,7 +322,7 @@ void strokeFree(SwStroke* stroke);
 
 bool imagePrepare(SwImage* image, const Picture* pdata, unsigned tid, const SwSize& clip, const Matrix* transform, SwBBox& bbox);
 bool imagePrepared(const SwImage* image);
-bool imageGenRle(SwImage* image, TVG_UNUSED const Picture* pdata, const SwSize& clip, const SwBBox& bbox, bool antiAlias, bool hasComposite);
+bool imageGenRle(SwImage* image, TVG_UNUSED const Picture* pdata, const SwBBox& bbox, bool antiAlias, bool hasComposite);
 void imageDelOutline(SwImage* image, uint32_t tid);
 void imageReset(SwImage* image);
 bool imageGenOutline(SwImage* image, const Picture* pdata, unsigned tid, const Matrix* transform);
@@ -323,7 +334,7 @@ void fillFree(SwFill* fill);
 void fillFetchLinear(const SwFill* fill, uint32_t* dst, uint32_t y, uint32_t x, uint32_t offset, uint32_t len);
 void fillFetchRadial(const SwFill* fill, uint32_t* dst, uint32_t y, uint32_t x, uint32_t len);
 
-SwRleData* rleRender(SwRleData* rle, const SwOutline* outline, const SwBBox& bbox, const SwSize& clip, bool antiAlias);
+SwRleData* rleRender(SwRleData* rle, const SwOutline* outline, const SwBBox& bbox, bool antiAlias);
 void rleFree(SwRleData* rle);
 void rleReset(SwRleData* rle);
 void rleClipPath(SwRleData *rle, const SwRleData *clip);
diff --git a/src/lib/sw_engine/tvgSwImage.cpp b/src/lib/sw_engine/tvgSwImage.cpp
index f8d7f5eb..80a139f2 100644
--- a/src/lib/sw_engine/tvgSwImage.cpp
+++ b/src/lib/sw_engine/tvgSwImage.cpp
@@ -27,63 +27,6 @@
 /************************************************************************/
 
 
-static void _initBBox(SwBBox& bbox)
-{
-    bbox.min.x = bbox.min.y = 0;
-    bbox.max.x = bbox.max.y = 0;
-}
-
-
-static bool _updateBBox(const SwOutline* outline, SwBBox& bbox, const SwSize& clip)
-{
-    if (!outline) return false;
-
-    auto pt = outline->pts;
-
-    if (outline->ptsCnt <= 0) {
-        _initBBox(bbox);
-        return false;
-    }
-
-    auto xMin = pt->x;
-    auto xMax = pt->x;
-    auto yMin = pt->y;
-    auto yMax = pt->y;
-
-    ++pt;
-
-    for(uint32_t i = 1; i < outline->ptsCnt; ++i, ++pt) {
-        if (xMin > pt->x) xMin = pt->x;
-        if (xMax < pt->x) xMax = pt->x;
-        if (yMin > pt->y) yMin = pt->y;
-        if (yMax < pt->y) yMax = pt->y;
-    }
-    bbox.min.x = xMin >> 6;
-    bbox.max.x = (xMax + 63) >> 6;
-    bbox.min.y = yMin >> 6;
-    bbox.max.y = (yMax + 63) >> 6;
-
-    bbox.min.x = max(bbox.min.x, TO_SWCOORD(0));
-    bbox.min.y = max(bbox.min.y, TO_SWCOORD(0));
-    bbox.max.x = min(bbox.max.x, clip.w);
-    bbox.max.y = min(bbox.max.y, clip.h);
-
-    if (xMax - xMin < 1 && yMax - yMin < 1) return false;
-
-    return true;
-}
-
-
-static bool _checkValid(const SwOutline* outline, const SwBBox& bbox, const SwSize& clip)
-{
-    if (outline->ptsCnt == 0 || outline->cntrsCnt <= 0) return false;
-
-    //Check boundary
-    if (bbox.min.x >= clip.w || bbox.min.y >= clip.h || bbox.max.x <= 0 || bbox.max.y <= 0) return false;
-
-    return true;
-}
-
 
 /************************************************************************/
 /* External Class Implementation                                        */
@@ -93,10 +36,11 @@ static bool _checkValid(const SwOutline* outline, const SwBBox& bbox, const SwSi
 bool imagePrepare(SwImage* image, const Picture* pdata, unsigned tid, const SwSize& clip, const Matrix* transform, SwBBox& bbox)
 {
     if (!imageGenOutline(image, pdata, tid, transform)) return false;
+    if (!mathUpdateOutlineBBox(image->outline, bbox, clip))  return false;
 
-    if (!_updateBBox(image->outline, bbox, clip))  return false;
-
-    if (!_checkValid(image->outline, bbox, clip)) return false;
+    //Guarantee boundary from mathUpdateOutlineBBox()
+    bbox.min.x = max(bbox.min.x, TO_SWCOORD(0));
+    bbox.min.y = max(bbox.min.y, TO_SWCOORD(0));
 
     return true;
 }
@@ -108,9 +52,9 @@ bool imagePrepared(const SwImage* image)
 }
 
 
-bool imageGenRle(SwImage* image, TVG_UNUSED const Picture* pdata, const SwSize& clip, const SwBBox& bbox, bool antiAlias, TVG_UNUSED bool hasComposite)
+bool imageGenRle(SwImage* image, TVG_UNUSED const Picture* pdata, const SwBBox& bbox, bool antiAlias, TVG_UNUSED bool hasComposite)
 {
-    if ((image->rle = rleRender(image->rle, image->outline, bbox, clip, antiAlias))) return true;
+    if ((image->rle = rleRender(image->rle, image->outline, bbox, antiAlias))) return true;
 
     return false;
 }
diff --git a/src/lib/sw_engine/tvgSwMath.cpp b/src/lib/sw_engine/tvgSwMath.cpp
index 60e36aad..03f9cbf2 100644
--- a/src/lib/sw_engine/tvgSwMath.cpp
+++ b/src/lib/sw_engine/tvgSwMath.cpp
@@ -427,3 +427,46 @@ SwPoint mathTransform(const Point* to, const Matrix* transform)
 
     return {TO_SWCOORD(tx), TO_SWCOORD(ty)};
 }
+
+
+bool mathUpdateOutlineBBox(const SwOutline* outline, SwBBox& bbox, const SwSize& clip)
+{
+    if (!outline) return false;
+
+    auto pt = outline->pts;
+
+    if (outline->ptsCnt == 0 || outline->cntrsCnt <= 0) {
+        bbox.reset();
+        return false;
+    }
+
+    auto xMin = pt->x;
+    auto xMax = pt->x;
+    auto yMin = pt->y;
+    auto yMax = pt->y;
+
+    ++pt;
+
+    for(uint32_t i = 1; i < outline->ptsCnt; ++i, ++pt) {
+        if (xMin > pt->x) xMin = pt->x;
+        if (xMax < pt->x) xMax = pt->x;
+        if (yMin > pt->y) yMin = pt->y;
+        if (yMax < pt->y) yMax = pt->y;
+    }
+    bbox.min.x = xMin >> 6;
+    bbox.max.x = (xMax + 63) >> 6;
+    bbox.min.y = yMin >> 6;
+    bbox.max.y = (yMax + 63) >> 6;
+
+    //Guarantee surface boundary
+    bbox.max.x = min(bbox.max.x, clip.w);
+    bbox.max.y = min(bbox.max.y, clip.h);
+
+    //Check valid region
+    if (bbox.max.x - bbox.min.x < 1 && bbox.max.y - bbox.min.y < 1) return false;
+
+    //Check boundary
+    if (bbox.min.x >= clip.w || bbox.min.y >= clip.h || bbox.max.x <= 0 || bbox.max.y <= 0) return false;
+
+    return true;
+}
\ No newline at end of file
diff --git a/src/lib/sw_engine/tvgSwRenderer.cpp b/src/lib/sw_engine/tvgSwRenderer.cpp
index fe679169..549f6746 100644
--- a/src/lib/sw_engine/tvgSwRenderer.cpp
+++ b/src/lib/sw_engine/tvgSwRenderer.cpp
@@ -100,7 +100,7 @@ struct SwShapeTask : SwTask
                        shape outline below stroke could be full covered by stroke drawing.
                        Thus it turns off antialising in that condition. */
                     auto antiAlias = (strokeAlpha == 255 && strokeWidth > 2) ? false : true;
-                    if (!shapeGenRle(&shape, sdata, clip, antiAlias, clips.count > 0 ? true : false)) goto err;
+                    if (!shapeGenRle(&shape, sdata, antiAlias, clips.count > 0 ? true : false)) goto err;
                     ++addStroking;
                 }
             }
@@ -189,7 +189,7 @@ struct SwImageTask : SwTask
 
             //Clip Path?
             if (clips.count > 0) {
-                if (!imageGenRle(&image, pdata, clip, bbox, false, true)) goto end;
+                if (!imageGenRle(&image, pdata, bbox, false, true)) goto end;
                 if (image.rle) {
                     for (auto clip = clips.data; clip < (clips.data + clips.count); ++clip) {
                         auto clipper = &static_cast<SwShapeTask*>(*clip)->shape;
diff --git a/src/lib/sw_engine/tvgSwRle.cpp b/src/lib/sw_engine/tvgSwRle.cpp
index 27906c4b..5c4719a4 100644
--- a/src/lib/sw_engine/tvgSwRle.cpp
+++ b/src/lib/sw_engine/tvgSwRle.cpp
@@ -87,8 +87,6 @@ struct RleWorker
     Cell** yCells;
     SwCoord yCnt;
 
-    SwSize clip;
-
     bool invalid;
     bool antiAlias;
 };
@@ -161,8 +159,7 @@ static void _horizLine(RleWorker& rw, SwCoord x, SwCoord y, SwCoord area, SwCoor
     y += rw.cellMin.y;
 
     //Clip Y range
-    if (y < 0) return;
-    if (y >= rw.clip.h) return;
+    if (y < 0 || y >= rw.cellMax.y) return;
 
     /* compute the coverage line's coverage, depending on the outline fill rule */
     /* the coverage percentage is area/(PIXEL_BITS*PIXEL_BITS*2) */
@@ -200,7 +197,7 @@ static void _horizLine(RleWorker& rw, SwCoord x, SwCoord y, SwCoord area, SwCoor
 
             //Clip x range
             SwCoord xOver = 0;
-            if (x + acount >= rw.clip.w) xOver -= (x + acount - rw.clip.w);
+            if (x + acount >= rw.cellMax.x) xOver -= (x + acount - rw.cellMax.x);
             if (x < 0) xOver += x;
 
             //span->len += (acount + xOver) - 1;
@@ -219,7 +216,7 @@ static void _horizLine(RleWorker& rw, SwCoord x, SwCoord y, SwCoord area, SwCoor
 
         //Clip x range
         SwCoord xOver = 0;
-        if (x + acount >= rw.clip.w) xOver -= (x + acount - rw.clip.w);
+        if (x + acount >= rw.cellMax.x) xOver -= (x + acount - rw.cellMax.x);
         if (x < 0) {
             xOver += x;
             x = 0;
@@ -785,7 +782,7 @@ void _replaceClipSpan(SwRleData *rle, SwSpan* clippedSpans, uint32_t size)
 /* External Class Implementation                                        */
 /************************************************************************/
 
-SwRleData* rleRender(SwRleData* rle, const SwOutline* outline, const SwBBox& bbox, const SwSize& clip, bool antiAlias)
+SwRleData* rleRender(SwRleData* rle, const SwOutline* outline, const SwBBox& bbox, bool antiAlias)
 {
     constexpr auto RENDER_POOL_SIZE = 16384L;
     constexpr auto BAND_SIZE = 40;
@@ -812,7 +809,6 @@ SwRleData* rleRender(SwRleData* rle, const SwOutline* outline, const SwBBox& bbo
     rw.outline = const_cast<SwOutline*>(outline);
     rw.bandSize = rw.bufferSize / (sizeof(Cell) * 8);  //bandSize: 64
     rw.bandShoot = 0;
-    rw.clip = clip;
     rw.antiAlias = antiAlias;
 
     if (!rle) rw.rle = reinterpret_cast<SwRleData*>(calloc(1, sizeof(SwRleData)));
diff --git a/src/lib/sw_engine/tvgSwShape.cpp b/src/lib/sw_engine/tvgSwShape.cpp
index afb7f1cd..cd951ddd 100644
--- a/src/lib/sw_engine/tvgSwShape.cpp
+++ b/src/lib/sw_engine/tvgSwShape.cpp
@@ -157,59 +157,6 @@ static void _outlineClose(SwOutline& outline)
 }
 
 
-static void _initBBox(SwBBox& bbox)
-{
-    bbox.min.x = bbox.min.y = 0;
-    bbox.max.x = bbox.max.y = 0;
-}
-
-
-static bool _updateBBox(const SwOutline* outline, SwBBox& bbox)
-{
-    if (!outline) return false;
-
-    auto pt = outline->pts;
-
-    if (outline->ptsCnt <= 0) {
-        _initBBox(bbox);
-        return false;
-    }
-
-    auto xMin = pt->x;
-    auto xMax = pt->x;
-    auto yMin = pt->y;
-    auto yMax = pt->y;
-
-    ++pt;
-
-    for(uint32_t i = 1; i < outline->ptsCnt; ++i, ++pt) {
-        if (xMin > pt->x) xMin = pt->x;
-        if (xMax < pt->x) xMax = pt->x;
-        if (yMin > pt->y) yMin = pt->y;
-        if (yMax < pt->y) yMax = pt->y;
-    }
-    bbox.min.x = xMin >> 6;
-    bbox.max.x = (xMax + 63) >> 6;
-    bbox.min.y = yMin >> 6;
-    bbox.max.y = (yMax + 63) >> 6;
-
-    if (xMax - xMin < 1 && yMax - yMin < 1) return false;
-
-    return true;
-}
-
-
-static bool _checkValid(const SwOutline* outline, const SwBBox& bbox, const SwSize& clip)
-{
-    if (outline->ptsCnt == 0 || outline->cntrsCnt <= 0) return false;
-
-    //Check boundary
-    if (bbox.min.x >= clip.w || bbox.min.y >= clip.h || bbox.max.x <= 0 || bbox.max.y <= 0) return false;
-
-    return true;
-}
-
-
 static void _dashLineTo(SwDashStroke& dash, const Point* to, const Matrix* transform)
 {
     _growOutlinePoint(*dash.outline, dash.outline->ptsCnt >> 1);
@@ -423,10 +370,7 @@ bool _fastTrack(const SwOutline* outline)
 bool shapePrepare(SwShape* shape, const Shape* sdata, unsigned tid, const SwSize& clip, const Matrix* transform, SwBBox& bbox)
 {
     if (!shapeGenOutline(shape, sdata, tid, transform)) return false;
-
-    if (!_updateBBox(shape->outline, shape->bbox)) return false;
-
-    if (!_checkValid(shape->outline, shape->bbox, clip)) return false;
+    if (!mathUpdateOutlineBBox(shape->outline, shape->bbox, clip)) return false;
 
     bbox = shape->bbox;
 
@@ -440,7 +384,7 @@ bool shapePrepared(const SwShape* shape)
 }
 
 
-bool shapeGenRle(SwShape* shape, TVG_UNUSED const Shape* sdata, const SwSize& clip, bool antiAlias, bool hasComposite)
+bool shapeGenRle(SwShape* shape, TVG_UNUSED const Shape* sdata, bool antiAlias, bool hasComposite)
 {
     //FIXME: Should we draw it?
     //Case: Stroke Line
@@ -449,7 +393,7 @@ bool shapeGenRle(SwShape* shape, TVG_UNUSED const Shape* sdata, const SwSize& cl
     //Case A: Fast Track Rectangle Drawing
     if (!hasComposite && (shape->rect = _fastTrack(shape->outline))) return true;
     //Case B: Normale Shape RLE Drawing
-    if ((shape->rle = rleRender(shape->rle, shape->outline, shape->bbox, clip, antiAlias))) return true;
+    if ((shape->rle = rleRender(shape->rle, shape->outline, shape->bbox, antiAlias))) return true;
 
     return false;
 }
@@ -467,7 +411,7 @@ void shapeReset(SwShape* shape)
     rleReset(shape->rle);
     rleReset(shape->strokeRle);
     shape->rect = false;
-    _initBBox(shape->bbox);
+    shape->bbox.reset();
 }
 
 
@@ -622,14 +566,12 @@ bool shapeGenStrokeRle(SwShape* shape, const Shape* sdata, unsigned tid, const M
         goto fail;
     }
 
-    _updateBBox(strokeOutline, bbox);
-
-    if (!_checkValid(strokeOutline, bbox, clip)) {
+    if (!mathUpdateOutlineBBox(strokeOutline, bbox, clip)) {
         ret = false;
         goto fail;
     }
 
-    shape->strokeRle = rleRender(shape->strokeRle, strokeOutline, bbox, clip, true);
+    shape->strokeRle = rleRender(shape->strokeRle, strokeOutline, bbox, true);
 
 fail:
     if (freeOutline) {
@@ -689,5 +631,4 @@ void shapeDelStrokeFill(SwShape* shape)
     if (!shape->stroke->fill) return;
     fillFree(shape->stroke->fill);
     shape->stroke->fill = nullptr;
-}
-
+}
\ No newline at end of file