diff --git a/src/renderer/gl_engine/tvgGlGeometry.cpp b/src/renderer/gl_engine/tvgGlGeometry.cpp
index c266c12b..97cf2ce8 100644
--- a/src/renderer/gl_engine/tvgGlGeometry.cpp
+++ b/src/renderer/gl_engine/tvgGlGeometry.cpp
@@ -57,55 +57,52 @@ bool GlGeometry::tesselate(const RenderShape& rshape, RenderUpdateFlag flag)
 
 bool GlGeometry::tesselate(const RenderSurface* image, RenderUpdateFlag flag)
 {
-    if (flag & RenderUpdateFlag::Image) {
-        fill.clear();
+    if (!(flag & RenderUpdateFlag::Image)) return true;
 
-        fill.vertex.reserve(5 * 4);
-        fill.index.reserve(6);
+    fill.clear();
 
-        float left = 0.f;
-        float top = 0.f;
-        float right = image->w;
-        float bottom = image->h;
+    fill.vertex.reserve(5 * 4);
+    fill.index.reserve(6);
 
-        // left top point
-        fill.vertex.push(left);
-        fill.vertex.push(top);
+    auto left = 0.f;
+    auto top = 0.f;
+    auto right = float(image->w);
+    auto bottom = float(image->h);
 
-        fill.vertex.push(0.f);
-        fill.vertex.push(1.f);
-        // left bottom point
-        fill.vertex.push(left);
-        fill.vertex.push(bottom);
+    // left top point
+    fill.vertex.push(left);
+    fill.vertex.push(top);
 
-        fill.vertex.push(0.f);
-        fill.vertex.push(0.f);
-        // right top point
-        fill.vertex.push(right);
-        fill.vertex.push(top);
+    fill.vertex.push(0.f);
+    fill.vertex.push(1.f);
+    // left bottom point
+    fill.vertex.push(left);
+    fill.vertex.push(bottom);
 
-        fill.vertex.push(1.f);
-        fill.vertex.push(1.f);
-        // right bottom point
-        fill.vertex.push(right);
-        fill.vertex.push(bottom);
+    fill.vertex.push(0.f);
+    fill.vertex.push(0.f);
+    // right top point
+    fill.vertex.push(right);
+    fill.vertex.push(top);
 
-        fill.vertex.push(1.f);
-        fill.vertex.push(0.f);
+    fill.vertex.push(1.f);
+    fill.vertex.push(1.f);
+    // right bottom point
+    fill.vertex.push(right);
+    fill.vertex.push(bottom);
 
-        fill.index.push(0);
-        fill.index.push(1);
-        fill.index.push(2);
+    fill.vertex.push(1.f);
+    fill.vertex.push(0.f);
 
-        fill.index.push(2);
-        fill.index.push(1);
-        fill.index.push(3);
+    fill.index.push(0);
+    fill.index.push(1);
+    fill.index.push(2);
 
-        bounds.x = 0;
-        bounds.y = 0;
-        bounds.w = image->w;
-        bounds.h = image->h;
-    }
+    fill.index.push(2);
+    fill.index.push(1);
+    fill.index.push(3);
+
+    bounds = {{0, 0}, {int32_t(image->w), int32_t(image->h)}};
 
     return true;
 }
@@ -155,31 +152,20 @@ GlStencilMode GlGeometry::getStencilMode(RenderUpdateFlag flag)
 
 RenderRegion GlGeometry::getBounds() const
 {
-    if (tvg::identity(&matrix)) {
-        return bounds;
-    } else {
-        Point lt{static_cast<float>(bounds.x), static_cast<float>(bounds.y)};
-        Point lb{static_cast<float>(bounds.x), static_cast<float>(bounds.y + bounds.h)};
-        Point rt{static_cast<float>(bounds.x + bounds.w), static_cast<float>(bounds.y)};
-        Point rb{static_cast<float>(bounds.x + bounds.w), static_cast<float>(bounds.y + bounds.h)};
+    if (tvg::identity(&matrix)) return bounds;
 
-        lt *= matrix;
-        lb *= matrix;
-        rt *= matrix;
-        rb *= matrix;
+    auto lt = Point{float(bounds.min.x), float(bounds.min.y)} * matrix;
+    auto lb = Point{float(bounds.min.x), float(bounds.max.y)} * matrix;
+    auto rt = Point{float(bounds.max.x), float(bounds.min.y)} * matrix;
+    auto rb = Point{float(bounds.max.x), float(bounds.max.y)} * matrix;
 
-        float left = min(min(lt.x, lb.x), min(rt.x, rb.x));
-        float top = min(min(lt.y, lb.y), min(rt.y, rb.y));
-        float right = max(max(lt.x, lb.x), max(rt.x, rb.x));
-        float bottom = max(max(lt.y, lb.y), max(rt.y, rb.y));
+    auto left = min(min(lt.x, lb.x), min(rt.x, rb.x));
+    auto top = min(min(lt.y, lb.y), min(rt.y, rb.y));
+    auto right = max(max(lt.x, lb.x), max(rt.x, rb.x));
+    auto bottom = max(max(lt.y, lb.y), max(rt.y, rb.y));
+
+    auto bounds = RenderRegion {{int32_t(floor(left)), int32_t(floor(top))}, {int32_t(ceil(right)), int32_t(ceil(bottom))}};
+    if (bounds.valid()) return bounds;
+    return this->bounds;
 
-        auto bounds = RenderRegion {
-            static_cast<int32_t>(floor(left)),
-            static_cast<int32_t>(floor(top)),
-            static_cast<int32_t>(ceil(right - floor(left))),
-            static_cast<int32_t>(ceil(bottom - floor(top))),
-        };
-        if (bounds.w < 0 || bounds.h < 0) return this->bounds;
-        else return bounds;
-    }
 }
\ No newline at end of file
diff --git a/src/renderer/gl_engine/tvgGlRenderPass.cpp b/src/renderer/gl_engine/tvgGlRenderPass.cpp
index 743b5abd..e20ffe10 100644
--- a/src/renderer/gl_engine/tvgGlRenderPass.cpp
+++ b/src/renderer/gl_engine/tvgGlRenderPass.cpp
@@ -52,17 +52,17 @@ void GlRenderPass::addRenderTask(GlRenderTask* task)
 
 void GlRenderPass::getMatrix(float *dst, const Matrix &matrix) const
 {
-    const auto& vp = getViewport();
-
     Matrix postMatrix{};
     tvg::identity(&postMatrix);
-    translate(&postMatrix, {(float)-vp.x, (float)-vp.y});
+
+    const auto& vp = getViewport();
+    translate(&postMatrix, {(float)-vp.sx(), (float)-vp.sy()});
 
     auto m = postMatrix * matrix;
 
     float modelMatrix[16];
     GET_MATRIX44(m, modelMatrix);
-    MVP_MATRIX(vp.w, vp.h);
+    MVP_MATRIX(vp.w(), vp.h());
 
     MULTIPLY_MATRIX(mvp, modelMatrix, dst);
 }
diff --git a/src/renderer/gl_engine/tvgGlRenderPass.h b/src/renderer/gl_engine/tvgGlRenderPass.h
index 96890f06..b9c4f89e 100644
--- a/src/renderer/gl_engine/tvgGlRenderPass.h
+++ b/src/renderer/gl_engine/tvgGlRenderPass.h
@@ -62,10 +62,7 @@ public:
         }
 
         auto task = new T(program, targetFbo, mFbo, std::move(mTasks));
-
-        const auto& vp = mFbo->getViewport();
-
-        task->setRenderSize(static_cast<uint32_t>(vp.w), static_cast<uint32_t>(vp.h));
+        task->setRenderSize(mFbo->getViewport().w(),  mFbo->getViewport().h());
 
         return task;
     }
diff --git a/src/renderer/gl_engine/tvgGlRenderTarget.cpp b/src/renderer/gl_engine/tvgGlRenderTarget.cpp
index 9c2ae4a6..d4dbf5de 100644
--- a/src/renderer/gl_engine/tvgGlRenderTarget.cpp
+++ b/src/renderer/gl_engine/tvgGlRenderTarget.cpp
@@ -107,23 +107,20 @@ uint32_t alignPow2(uint32_t value)
 
 GlRenderTarget* GlRenderTargetPool::getRenderTarget(const RenderRegion& vp, GLuint resolveId)
 {
-    uint32_t width = static_cast<uint32_t>(vp.w);
-    uint32_t height = static_cast<uint32_t>(vp.h);
+    auto width = vp.w();
+    auto height = vp.h();
 
     // pow2 align width and height
     if (width >= mMaxWidth) width = mMaxWidth;
     else width = alignPow2(width);
-
     if (width >= mMaxWidth) width = mMaxWidth;
 
     if (height >= mMaxHeight) height = mMaxHeight;
     else height = alignPow2(height);
-
     if (height >= mMaxHeight) height = mMaxHeight;
 
     for (uint32_t i = 0; i < mPool.count; i++) {
         auto rt = mPool[i];
-
         if (rt->getWidth() == width && rt->getHeight() == height) {
             rt->setViewport(vp);
             return rt;
diff --git a/src/renderer/gl_engine/tvgGlRenderTask.cpp b/src/renderer/gl_engine/tvgGlRenderTask.cpp
index 0464b35f..c978febf 100644
--- a/src/renderer/gl_engine/tvgGlRenderTask.cpp
+++ b/src/renderer/gl_engine/tvgGlRenderTask.cpp
@@ -24,6 +24,9 @@
 #include "tvgGlProgram.h"
 #include "tvgGlRenderPass.h"
 
+/************************************************************************/
+/* GlRenderTask Class Implementation                                    */
+/************************************************************************/
 
 GlRenderTask::GlRenderTask(GlProgram* program, GlRenderTask* other): mProgram(program)
 {
@@ -33,6 +36,7 @@ GlRenderTask::GlRenderTask(GlProgram* program, GlRenderTask* other): mProgram(pr
     mIndexCount = other->mIndexCount;
 }
 
+
 void GlRenderTask::run()
 {
     // bind shader
@@ -45,7 +49,7 @@ void GlRenderTask::run()
     }
 
     // setup scissor rect
-    GL_CHECK(glScissor(mViewport.x, mViewport.y, mViewport.w, mViewport.h));
+    GL_CHECK(glScissor(mViewport.sx(), mViewport.sy(), mViewport.sw(), mViewport.sh()));
 
     // setup attribute layout
     for (uint32_t i = 0; i < mVertexLayout.count; i++) {
@@ -81,36 +85,44 @@ void GlRenderTask::run()
     }
 }
 
+
 void GlRenderTask::addVertexLayout(const GlVertexLayout &layout)
 {
     mVertexLayout.push(layout);
 }
 
+
 void GlRenderTask::addBindResource(const GlBindingResource &binding)
 {
     mBindingResources.push(binding);
 }
 
+
 void GlRenderTask::setDrawRange(uint32_t offset, uint32_t count)
 {
     mIndexOffset = offset;
     mIndexCount = count;
 }
 
+
 void GlRenderTask::setViewport(const RenderRegion &viewport)
 {
     mViewport = viewport;
-    if (mViewport.w < 0) {
-        mViewport.w = 0;
-    }
-
-    if (mViewport.h < 0) {
-        mViewport.h = 0;
-    }
+    if (mViewport.max.x < mViewport.min.x) mViewport.max.x = mViewport.min.x;
+    if (mViewport.max.y < mViewport.min.y) mViewport.max.y = mViewport.min.y;
 }
 
+
+/************************************************************************/
+/* GlStencilCoverTask Class Implementation                              */
+/************************************************************************/
+
 GlStencilCoverTask::GlStencilCoverTask(GlRenderTask* stencil, GlRenderTask* cover, GlStencilMode mode)
- :GlRenderTask(nullptr), mStencilTask(stencil), mCoverTask(cover), mStencilMode(mode) {}
+ :GlRenderTask(nullptr), mStencilTask(stencil), mCoverTask(cover), mStencilMode(mode)
+ {
+
+ }
+
 
 GlStencilCoverTask::~GlStencilCoverTask()
 {
@@ -118,6 +130,7 @@ GlStencilCoverTask::~GlStencilCoverTask()
     delete mCoverTask;
 }
 
+
 void GlStencilCoverTask::run()
 {
     GL_CHECK(glEnable(GL_STENCIL_TEST));
@@ -151,12 +164,18 @@ void GlStencilCoverTask::run()
     GL_CHECK(glDisable(GL_STENCIL_TEST));
 }
 
+
 void GlStencilCoverTask::normalizeDrawDepth(int32_t maxDepth)
 {
     mCoverTask->normalizeDrawDepth(maxDepth);
     mStencilTask->normalizeDrawDepth(maxDepth);
 }
 
+
+/************************************************************************/
+/* GlComposeTask Class Implementation                                   */
+/************************************************************************/
+
 GlComposeTask::GlComposeTask(GlProgram* program, GLuint target, GlRenderTarget* fbo, Array<GlRenderTask*>&& tasks)
  :GlRenderTask(program) ,mTargetFbo(target), mFbo(fbo), mTasks()
 {
@@ -164,12 +183,14 @@ GlComposeTask::GlComposeTask(GlProgram* program, GLuint target, GlRenderTarget*
     tasks.clear();
 }
 
+
 GlComposeTask::~GlComposeTask()
 {
     ARRAY_FOREACH(p, mTasks) delete(*p);
     mTasks.clear();
 }
 
+
 void GlComposeTask::run()
 {
     GL_CHECK(glBindFramebuffer(GL_FRAMEBUFFER, getSelfFbo()));
@@ -209,29 +230,43 @@ void GlComposeTask::run()
     onResolve();
 }
 
-GLuint GlComposeTask::getSelfFbo() { return mFbo->getFboId(); }
 
-GLuint GlComposeTask::getResolveFboId() { return mFbo->getResolveFboId(); }
+GLuint GlComposeTask::getSelfFbo()
+{
+    return mFbo->getFboId();
+}
 
-void GlComposeTask::onResolve() {
+
+GLuint GlComposeTask::getResolveFboId()
+{
+    return mFbo->getResolveFboId();
+}
+
+
+void GlComposeTask::onResolve()
+{
     GL_CHECK(glBindFramebuffer(GL_READ_FRAMEBUFFER, getSelfFbo()));
     GL_CHECK(glBindFramebuffer(GL_DRAW_FRAMEBUFFER, getResolveFboId()));
-
-
     GL_CHECK(glBlitFramebuffer(0, 0, mRenderWidth, mRenderHeight, 0, 0, mRenderWidth, mRenderHeight, GL_COLOR_BUFFER_BIT, GL_NEAREST));
 }
 
+
+/************************************************************************/
+/* GlBlitTask Class Implementation                                      */
+/************************************************************************/
+
 GlBlitTask::GlBlitTask(GlProgram* program, GLuint target, GlRenderTarget* fbo, Array<GlRenderTask*>&& tasks)
  : GlComposeTask(program, target, fbo, std::move(tasks)), mColorTex(fbo->getColorTexture())
 {
 }
 
+
 void GlBlitTask::run()
 {
     GlComposeTask::run();
 
     GL_CHECK(glBindFramebuffer(GL_FRAMEBUFFER, getTargetFbo()));
-    GL_CHECK(glViewport(mTargetViewport.x, mTargetViewport.y, mTargetViewport.w, mTargetViewport.h));
+    GL_CHECK(glViewport(mTargetViewport.x(), mTargetViewport.y(), mTargetViewport.w(), mTargetViewport.h()));
 
     if (mClearBuffer) {
         GL_CHECK(glClearColor(0, 0, 0, 0));
@@ -246,16 +281,24 @@ void GlBlitTask::run()
     GlRenderTask::run();
 }
 
+
+/************************************************************************/
+/* GlDrawBlitTask Class Implementation                                  */
+/************************************************************************/
+
+
 GlDrawBlitTask::GlDrawBlitTask(GlProgram* program, GLuint target, GlRenderTarget* fbo, Array<GlRenderTask*>&& tasks)
  : GlComposeTask(program, target, fbo, std::move(tasks))
 {
 }
 
+
 GlDrawBlitTask::~GlDrawBlitTask()
 {
     if (mPrevTask) delete mPrevTask;
 }
 
+
 void GlDrawBlitTask::run()
 {
     if (mPrevTask) mPrevTask->run();
@@ -269,15 +312,22 @@ void GlDrawBlitTask::run()
     GlRenderTask::run();
 }
 
+
+/************************************************************************/
+/* GlClipTask Class Implementation                                      */
+/************************************************************************/
+
 GlClipTask::GlClipTask(GlRenderTask* clip, GlRenderTask* mask)
  :GlRenderTask(nullptr), mClipTask(clip), mMaskTask(mask) {}
 
+
 GlClipTask::~GlClipTask()
 {
     delete mClipTask;
     delete mMaskTask;
 }
 
+
 void GlClipTask::run()
 {
     GL_CHECK(glEnable(GL_STENCIL_TEST));
@@ -304,14 +354,22 @@ void GlClipTask::run()
     GL_CHECK(glDisable(GL_STENCIL_TEST));
 }
 
+
 void GlClipTask::normalizeDrawDepth(int32_t maxDepth)
 {
     mClipTask->normalizeDrawDepth(maxDepth);
     mMaskTask->normalizeDrawDepth(maxDepth);
 }
 
+/************************************************************************/
+/* GlSimpleBlendTask Class Implementation                               */
+/************************************************************************/
+
 GlSimpleBlendTask::GlSimpleBlendTask(BlendMethod method, GlProgram* program)
- : GlRenderTask(program), mBlendMethod(method) {}
+ : GlRenderTask(program), mBlendMethod(method)
+ {
+ }
+
 
 void GlSimpleBlendTask::run()
 {
@@ -332,8 +390,17 @@ void GlSimpleBlendTask::run()
     glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
 }
 
+
+/************************************************************************/
+/* GlComplexBlendTask Class Implementation                              */
+/************************************************************************/
+
+
 GlComplexBlendTask::GlComplexBlendTask(GlProgram* program, GlRenderTarget* dstFbo, GlRenderTarget* dstCopyFbo, GlRenderTask* stencilTask, GlComposeTask* composeTask)
- : GlRenderTask(program), mDstFbo(dstFbo), mDstCopyFbo(dstCopyFbo), mStencilTask(stencilTask), mComposeTask(composeTask) {}
+ : GlRenderTask(program), mDstFbo(dstFbo), mDstCopyFbo(dstCopyFbo), mStencilTask(stencilTask), mComposeTask(composeTask)
+ {
+ }
+
 
 GlComplexBlendTask::~GlComplexBlendTask()
 {
@@ -341,6 +408,7 @@ GlComplexBlendTask::~GlComplexBlendTask()
     delete mComposeTask;
 }
 
+
 void GlComplexBlendTask::run()
 {
     mComposeTask->run();
@@ -349,12 +417,11 @@ void GlComplexBlendTask::run()
     GL_CHECK(glBindFramebuffer(GL_READ_FRAMEBUFFER, mDstFbo->getFboId()));
     GL_CHECK(glBindFramebuffer(GL_DRAW_FRAMEBUFFER, mDstCopyFbo->getResolveFboId()));
 
-    GL_CHECK(glViewport(0, 0, mDstFbo->getViewport().w, mDstFbo->getViewport().h));
-    GL_CHECK(glScissor(0, 0, mDstFbo->getViewport().w, mDstFbo->getViewport().h));
+    GL_CHECK(glViewport(0, 0, mDstFbo->getViewport().w(), mDstFbo->getViewport().h()));
+    GL_CHECK(glScissor(0, 0, mDstFbo->getViewport().w(), mDstFbo->getViewport().h()));
     
     const auto& vp = getViewport();
-
-    GL_CHECK(glBlitFramebuffer(vp.x, vp.y, vp.x + vp.w, vp.y + vp.h, 0, 0, vp.w, vp.h, GL_COLOR_BUFFER_BIT, GL_LINEAR));
+    GL_CHECK(glBlitFramebuffer(vp.min.x, vp.min.y, vp.max.x, vp.max.y, 0, 0, vp.w(), vp.h(), GL_COLOR_BUFFER_BIT, GL_LINEAR));
 
     GL_CHECK(glBindFramebuffer(GL_FRAMEBUFFER, mDstFbo->getFboId()));
 
@@ -381,12 +448,17 @@ void GlComplexBlendTask::run()
     GL_CHECK(glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA));
 }
 
+
 void GlComplexBlendTask::normalizeDrawDepth(int32_t maxDepth)
 {
     mStencilTask->normalizeDrawDepth(maxDepth);
     GlRenderTask::normalizeDrawDepth(maxDepth);
 }
 
+/************************************************************************/
+/* GlGaussianBlurTask Class Implementation                              */
+/************************************************************************/
+
 void GlGaussianBlurTask::run()
 {
     const auto vp = getViewport();
@@ -439,6 +511,9 @@ void GlGaussianBlurTask::run()
     GL_CHECK(glEnable(GL_BLEND));
 }
 
+/************************************************************************/
+/* GlEffectDropShadowTask Class Implementation                          */
+/************************************************************************/
 
 void GlEffectDropShadowTask::run()
 {
@@ -492,6 +567,9 @@ void GlEffectDropShadowTask::run()
     GL_CHECK(glEnable(GL_BLEND));
 }
 
+/************************************************************************/
+/* GlEffectColorTransformTask Class Implementation                      */
+/************************************************************************/
 
 void GlEffectColorTransformTask::run()
 {
diff --git a/src/renderer/gl_engine/tvgGlRenderTask.h b/src/renderer/gl_engine/tvgGlRenderTask.h
index d6fa93f2..6254292a 100644
--- a/src/renderer/gl_engine/tvgGlRenderTask.h
+++ b/src/renderer/gl_engine/tvgGlRenderTask.h
@@ -130,12 +130,10 @@ public:
 
 protected:
     GLuint getTargetFbo() { return mTargetFbo; }
-
     GLuint getSelfFbo();
-
     GLuint getResolveFboId();
-
     void onResolve();
+
 private:
     GLuint mTargetFbo;
     GlRenderTarget* mFbo;
diff --git a/src/renderer/gl_engine/tvgGlRenderer.cpp b/src/renderer/gl_engine/tvgGlRenderer.cpp
index 67bc60cb..19a64da0 100644
--- a/src/renderer/gl_engine/tvgGlRenderer.cpp
+++ b/src/renderer/gl_engine/tvgGlRenderer.cpp
@@ -183,10 +183,10 @@ void GlRenderer::drawPrimitive(GlShape& sdata, const RenderColor& c, RenderUpdat
         bbox.intersect(vp);
     }
 
-    auto x = bbox.x - vp.x;
-    auto y = bbox.y - vp.y;
-    auto w = bbox.w;
-    auto h = bbox.h;
+    auto x = bbox.sx() - vp.sx();
+    auto y = bbox.sy() - vp.sy();
+    auto w = bbox.sw();
+    auto h = bbox.sh();
 
     GlRenderTask* task = nullptr;
     if (mBlendMethod != BlendMethod::Normal && !complexBlend) task = new GlSimpleBlendTask(mBlendMethod, mPrograms[RT_Color]);
@@ -199,7 +199,8 @@ void GlRenderer::drawPrimitive(GlShape& sdata, const RenderColor& c, RenderUpdat
         return;
     }
 
-    task->setViewport({x, vp.h - y - h, w, h});
+    y = vp.sh() - y - h;
+    task->setViewport({{x, y}, {x + w, y + h}});
 
     GlRenderTask* stencilTask = nullptr;
 
@@ -268,7 +269,6 @@ void GlRenderer::drawPrimitive(GlShape& sdata, const Fill* fill, RenderUpdateFla
 {
     auto vp = currentPass()->getViewport();
     auto bbox = sdata.geometry.viewport;
-
     bbox.intersect(vp);
 
     const Fill::ColorStop* stops = nullptr;
@@ -277,13 +277,9 @@ void GlRenderer::drawPrimitive(GlShape& sdata, const Fill* fill, RenderUpdateFla
 
     GlRenderTask* task = nullptr;
 
-    if (fill->type() == Type::LinearGradient) {
-        task = new GlRenderTask(mPrograms[RT_LinGradient]);
-    } else if (fill->type() == Type::RadialGradient) {
-        task = new GlRenderTask(mPrograms[RT_RadGradient]);
-    } else {
-        return;
-    }
+    if (fill->type() == Type::LinearGradient) task = new GlRenderTask(mPrograms[RT_LinGradient]);
+    else if (fill->type() == Type::RadialGradient) task = new GlRenderTask(mPrograms[RT_RadGradient]);
+    else return;
 
     task->setDrawDepth(depth);
 
@@ -293,13 +289,11 @@ void GlRenderer::drawPrimitive(GlShape& sdata, const Fill* fill, RenderUpdateFla
     }
 
     auto complexBlend = beginComplexBlending(bbox, sdata.geometry.getBounds());
-
     if (complexBlend) vp = currentPass()->getViewport();
 
-    auto x = bbox.x - vp.x;
-    auto y = bbox.y - vp.y;
-
-    task->setViewport({x, vp.h - y - bbox.h, bbox.w, bbox.h});
+    auto x = bbox.sx() - vp.sx();
+    auto y = vp.sh() - (bbox.sy() - vp.sy()) - bbox.sh();
+    task->setViewport({{x, y}, {x + bbox.sw(), y + bbox.sh()}});
 
     GlRenderTask* stencilTask = nullptr;
     GlStencilMode stencilMode = sdata.geometry.getStencilMode(flag);
@@ -498,22 +492,18 @@ void GlRenderer::drawClip(Array<RenderData>& clips)
 
     for (uint32_t i = 0; i < clips.count; ++i) {
         auto sdata = static_cast<GlShape*>(clips[i]);
-
         auto clipTask = new GlRenderTask(mPrograms[RT_Stencil]);
-
         clipTask->setDrawDepth(clipDepths[i]);
 
         auto flag = (sdata->geometry.stroke.vertex.count > 0) ? RenderUpdateFlag::Stroke : RenderUpdateFlag::Path;
         sdata->geometry.draw(clipTask, &mGpuBuffer, flag);
 
         auto bbox = sdata->geometry.viewport;
-
         bbox.intersect(vp);
 
-        auto x = bbox.x - vp.x;
-        auto y = bbox.y - vp.y;
-
-        clipTask->setViewport({x, vp.h - y - bbox.h, bbox.w, bbox.h});
+        auto x = bbox.sx() - vp.sx();
+        auto y = vp.sh() - (bbox.sy() - vp.sy()) - bbox.sh();
+        clipTask->setViewport({{x, y}, {x + bbox.sw(), y + bbox.sh()}});
 
         float matrix44[16];
         currentPass()->getMatrix(matrix44, sdata->geometry.matrix);
@@ -529,7 +519,7 @@ void GlRenderer::drawClip(Array<RenderData>& clips)
         maskTask->addVertexLayout(GlVertexLayout{0, 2, 2 * sizeof(float), identityVertexOffset});
         maskTask->addBindResource(GlBindingResource{0, loc, mGpuBuffer.getBufferId(), mat4Offset, 16 * sizeof(float), });
         maskTask->setDrawRange(identityIndexOffset, 6);
-        maskTask->setViewport({0, 0, static_cast<int32_t>(vp.w), static_cast<int32_t>(vp.h)});
+        maskTask->setViewport({{0, 0}, {vp.sw(), vp.sh()}});
 
         currentPass()->addRenderTask(new GlClipTask(clipTask, maskTask));
     }
@@ -543,11 +533,10 @@ GlRenderPass* GlRenderer::currentPass()
 
 bool GlRenderer::beginComplexBlending(const RenderRegion& vp, RenderRegion bounds)
 {
-    if (vp.w == 0 || vp.h == 0) return false;
+    if (vp.invalid()) return false;
 
     bounds.intersect(vp);
-
-    if (bounds.w == 0 || bounds.h == 0) return false;
+    if (bounds.invalid()) return false;
 
     if (mBlendMethod == BlendMethod::Normal || mBlendMethod == BlendMethod::Add || mBlendMethod == BlendMethod::Darken || mBlendMethod == BlendMethod::Lighten) return false;
 
@@ -573,37 +562,26 @@ void GlRenderer::endBlendingCompose(GlRenderTask* stencilTask, const Matrix& mat
     if (mBlendPool.count < 2) mBlendPool.push(new GlRenderTargetPool(surface.w, surface.h));
     auto dstCopyFbo = mBlendPool[1]->getRenderTarget(vp);
 
-    {
-        const auto& passVp = currentPass()->getViewport();
-
-        auto x = vp.x;
-        auto y = vp.y;
-        auto w = vp.w;
-        auto h = vp.h;
-
-        stencilTask->setViewport({x, passVp.h - y - h, w, h});
-    }
+    auto x = vp.sx();
+    auto y = currentPass()->getViewport().sh() - vp.sy() - vp.sh();
+    stencilTask->setViewport({{x, y}, {x + vp.sw(), y + vp.sh()}});
 
     stencilTask->setDrawDepth(currentPass()->nextDrawDepth());
 
-    {
-        // set view matrix
-        float matrix44[16];
-        currentPass()->getMatrix(matrix44, matrix);
-        uint32_t viewOffset = mGpuBuffer.push(matrix44, 16 * sizeof(float), true);
-        stencilTask->addBindResource(GlBindingResource{
-            0,
-            stencilTask->getProgram()->getUniformBlockIndex("Matrix"),
-            mGpuBuffer.getBufferId(),
-            viewOffset,
-            16 * sizeof(float),
-        });
-    }
+    // set view matrix
+    float matrix44[16];
+    currentPass()->getMatrix(matrix44, matrix);
+    uint32_t viewOffset = mGpuBuffer.push(matrix44, 16 * sizeof(float), true);
+    stencilTask->addBindResource(GlBindingResource{
+        0,
+        stencilTask->getProgram()->getUniformBlockIndex("Matrix"),
+        mGpuBuffer.getBufferId(),
+        viewOffset,
+        16 * sizeof(float),
+    });
 
     auto task = new GlComplexBlendTask(getBlendProgram(), currentPass()->getFbo(), dstCopyFbo, stencilTask, composeTask);
-
     prepareCmpTask(task, vp, blendPass->getFboWidth(), blendPass->getFboHeight());
-
     task->setDrawDepth(currentPass()->nextDrawDepth());
 
     // src and dst texture
@@ -634,8 +612,7 @@ GlProgram* GlRenderer::getBlendProgram()
 
 void GlRenderer::prepareBlitTask(GlBlitTask* task)
 {
-    RenderRegion region{0, 0, static_cast<int32_t>(surface.w), static_cast<int32_t>(surface.h)};
-    prepareCmpTask(task, region, surface.w, surface.h);
+    prepareCmpTask(task, {{0, 0}, {int32_t(surface.w), int32_t(surface.h)}}, surface.w, surface.h);
     task->addBindResource(GlBindingResource{0, task->getColorTexture(), task->getProgram()->getUniformLocation("uSrcTexture")});
 }
 
@@ -650,13 +627,13 @@ void GlRenderer::prepareCmpTask(GlRenderTask* task, const RenderRegion& vp, uint
     auto taskVp = vp;
     taskVp.intersect(passVp);
 
-    auto x = taskVp.x - passVp.x;
-    auto y = taskVp.y - passVp.y;
-    auto w = taskVp.w;
-    auto h = taskVp.h;
+    auto x = taskVp.sx() - passVp.sx();
+    auto y = taskVp.sy() - passVp.sy();
+    auto w = taskVp.sw();
+    auto h = taskVp.sh();
 
-    float rw = static_cast<float>(passVp.w);
-    float rh = static_cast<float>(passVp.h);
+    float rw = static_cast<float>(passVp.w());
+    float rh = static_cast<float>(passVp.h());
 
     float l = static_cast<float>(x);
     float t = static_cast<float>(rh - y);
@@ -707,10 +684,9 @@ void GlRenderer::prepareCmpTask(GlRenderTask* task, const RenderRegion& vp, uint
 
     task->addVertexLayout(GlVertexLayout{0, 2, 4 * sizeof(float), vertexOffset});
     task->addVertexLayout(GlVertexLayout{1, 2, 4 * sizeof(float), vertexOffset + 2 * sizeof(float)});
-
     task->setDrawRange(indexOffset, indices.count);
-
-    task->setViewport({x, static_cast<int32_t>((passVp.h - y - h)), w, h});
+    y = (passVp.sh() - y - h);
+    task->setViewport({{x, y}, {x + w, y + h}});
 }
 
 
@@ -743,11 +719,11 @@ void GlRenderer::endRenderPass(RenderCompositor* cmp)
         if (program && !selfPass->isEmpty() && !maskPass->isEmpty()) {
             auto prev_task = maskPass->endRenderPass<GlComposeTask>(nullptr, currentPass()->getFboId());
             prev_task->setDrawDepth(currentPass()->nextDrawDepth());
-            prev_task->setRenderSize(static_cast<uint32_t>(glCmp->bbox.w), static_cast<uint32_t>(glCmp->bbox.h));
+            prev_task->setRenderSize(glCmp->bbox.w(), glCmp->bbox.h());
             prev_task->setViewport(glCmp->bbox);
 
             auto compose_task = selfPass->endRenderPass<GlDrawBlitTask>(program, currentPass()->getFboId());
-            compose_task->setRenderSize(static_cast<uint32_t>(glCmp->bbox.w), static_cast<uint32_t>(glCmp->bbox.h));
+            compose_task->setRenderSize(glCmp->bbox.w(), glCmp->bbox.h());
             compose_task->setPrevTask(prev_task);
 
             prepareCmpTask(compose_task, glCmp->bbox, selfPass->getFboWidth(), selfPass->getFboHeight());
@@ -756,7 +732,7 @@ void GlRenderer::endRenderPass(RenderCompositor* cmp)
             compose_task->addBindResource(GlBindingResource{1, maskPass->getTextureId(), program->getUniformLocation("uMaskTexture")});
 
             compose_task->setDrawDepth(currentPass()->nextDrawDepth());
-            compose_task->setParentSize(static_cast<uint32_t>(currentPass()->getViewport().w), static_cast<uint32_t>(currentPass()->getViewport().h));
+            compose_task->setParentSize(currentPass()->getViewport().w(), currentPass()->getViewport().h());
             currentPass()->addRenderTask(compose_task);
         }
 
@@ -769,7 +745,7 @@ void GlRenderer::endRenderPass(RenderCompositor* cmp)
 
         if (!renderPass->isEmpty()) {
             auto task = renderPass->endRenderPass<GlDrawBlitTask>(mPrograms[RT_Image], currentPass()->getFboId());
-            task->setRenderSize(static_cast<uint32_t>(glCmp->bbox.w), static_cast<uint32_t>(glCmp->bbox.h));
+            task->setRenderSize(glCmp->bbox.w(), glCmp->bbox.h());
             prepareCmpTask(task, glCmp->bbox, renderPass->getFboWidth(), renderPass->getFboHeight());
             task->setDrawDepth(currentPass()->nextDrawDepth());
 
@@ -797,7 +773,7 @@ void GlRenderer::endRenderPass(RenderCompositor* cmp)
 
             // texture id
             task->addBindResource(GlBindingResource{0, renderPass->getTextureId(), task->getProgram()->getUniformLocation("uTexture")});
-            task->setParentSize(static_cast<uint32_t>(currentPass()->getViewport().w), static_cast<uint32_t>(currentPass()->getViewport().h));
+            task->setParentSize(currentPass()->getViewport().w(), currentPass()->getViewport().h());
             currentPass()->addRenderTask(std::move(task));
         }
         delete(renderPass);
@@ -836,7 +812,7 @@ bool GlRenderer::target(void* context, int32_t id, uint32_t w, uint32_t h)
 
     currentContext();
 
-    mRootTarget.setViewport({0, 0, static_cast<int32_t>(surface.w), static_cast<int32_t>(surface.h)});
+    mRootTarget.setViewport({{0, 0}, {int32_t(surface.w), int32_t(surface.h)}});
     mRootTarget.init(surface.w, surface.h, mTargetFboId);
 
     return true;
@@ -864,7 +840,7 @@ bool GlRenderer::sync()
     prepareBlitTask(task);
 
     task->mClearBuffer = mClearBuffer;
-    task->setTargetViewport({0, 0, static_cast<int32_t>(surface.w), static_cast<int32_t>(surface.h)});
+    task->setTargetViewport({{0, 0}, {int32_t(surface.w), int32_t(surface.h)}});
 
     if (mGpuBuffer.flushToGPU()) {
         mGpuBuffer.bind();
@@ -935,20 +911,11 @@ bool GlRenderer::beginComposite(RenderCompositor* cmp, MaskMethod method, uint8_
     cmp->opacity = opacity;
 
     uint32_t index = mRenderPassStack.count - 1;
-
-    if (index >= mComposePool.count) {
-        mComposePool.push( new GlRenderTargetPool(surface.w, surface.h));
-    }
+    if (index >= mComposePool.count) mComposePool.push( new GlRenderTargetPool(surface.w, surface.h));
 
     auto glCmp = static_cast<GlCompositor*>(cmp);
-
-    if (glCmp->bbox.w > 0 && glCmp->bbox.h > 0) {
-        auto renderTarget = mComposePool[index]->getRenderTarget(glCmp->bbox);
-        mRenderPassStack.push(new GlRenderPass(renderTarget));
-    } else {
-        // empty render pass
-        mRenderPassStack.push(new GlRenderPass(nullptr));
-    }
+    if (glCmp->bbox.valid()) mRenderPassStack.push(new GlRenderPass(mComposePool[index]->getRenderTarget(glCmp->bbox)));
+    else mRenderPassStack.push(new GlRenderPass(nullptr));
 
     return true;
 }
@@ -1069,12 +1036,12 @@ bool GlRenderer::effectGaussianBlurRegion(RenderEffectGaussianBlur* effect)
 {
     auto gaussianBlur = (GlGaussianBlur*)effect->rd;
     if (effect->direction != 2) {
-        effect->extend.x = -gaussianBlur->extend;
-        effect->extend.w = +gaussianBlur->extend * 2;
+        effect->extend.min.x = -gaussianBlur->extend;
+        effect->extend.max.x = +gaussianBlur->extend;
     }
     if (effect->direction != 1) {
-        effect->extend.y = -gaussianBlur->extend;
-        effect->extend.h = +gaussianBlur->extend * 2;
+        effect->extend.min.y = -gaussianBlur->extend;
+        effect->extend.max.y = +gaussianBlur->extend;
     }
     return true;
 };
@@ -1083,10 +1050,10 @@ bool GlRenderer::effectGaussianBlurRegion(RenderEffectGaussianBlur* effect)
 bool GlRenderer::effectDropShadowRegion(RenderEffectDropShadow* effect)
 {
     auto gaussianBlur = (GlDropShadow*)effect->rd;
-    effect->extend.x = -gaussianBlur->extend;
-    effect->extend.w = +gaussianBlur->extend * 2;
-    effect->extend.y = -gaussianBlur->extend;
-    effect->extend.h = +gaussianBlur->extend * 2;
+    effect->extend.min.x = -gaussianBlur->extend;
+    effect->extend.max.x = +gaussianBlur->extend;
+    effect->extend.min.y = -gaussianBlur->extend;
+    effect->extend.max.y = +gaussianBlur->extend;
     return true;
 };
 
@@ -1136,7 +1103,6 @@ bool GlRenderer::render(TVG_UNUSED RenderCompositor* cmp, const RenderEffect* ef
     auto voffset = mGpuBuffer.push((void*)vdata, sizeof(vdata));
     auto ioffset = mGpuBuffer.pushIndex((void*)idata, sizeof(idata));
 
-    // effect gaussian blur
     if (effect->type == SceneEffect::GaussianBlur) {
         // get gaussian programs
         GlProgram* programHorz = mPrograms[RT_GaussianHorz];
@@ -1152,7 +1118,7 @@ bool GlRenderer::render(TVG_UNUSED RenderCompositor* cmp, const RenderEffect* ef
         // create gaussian blur tasks
         auto gaussianTask = new GlGaussianBlurTask(dstFbo, dstCopyFbo0, dstCopyFbo1);
         gaussianTask->effect = (RenderEffectGaussianBlur*)effect;
-        gaussianTask->setViewport({0, 0, vp.w, vp.h});
+        gaussianTask->setViewport({{0, 0}, {vp.sw(), vp.sh()}});
         // horizontal blur task and geometry
         gaussianTask->horzTask = new GlRenderTask(programHorz);
         gaussianTask->horzTask->addBindResource(GlBindingResource{0, programHorz->getUniformBlockIndex("Gaussian"), mGpuBuffer.getBufferId(), blurOffset, sizeof(GlGaussianBlur)});
@@ -1165,8 +1131,7 @@ bool GlRenderer::render(TVG_UNUSED RenderCompositor* cmp, const RenderEffect* ef
         gaussianTask->vertTask->setDrawRange(ioffset, 6);
         // add task to render pipeline
         pass->addRenderTask(gaussianTask);
-    } // effect drop shadow
-    else if (effect->type == SceneEffect::DropShadow) {
+    } else if (effect->type == SceneEffect::DropShadow) {
         // get programs
         GlProgram* program = mPrograms[RT_DropShadow];
         GlProgram* programHorz = mPrograms[RT_GaussianHorz];
@@ -1182,7 +1147,7 @@ bool GlRenderer::render(TVG_UNUSED RenderCompositor* cmp, const RenderEffect* ef
         // create gaussian blur tasks
         auto task = new GlEffectDropShadowTask(program, dstFbo, dstCopyFbo0, dstCopyFbo1);
         task->effect = (RenderEffectDropShadow*)effect;
-        task->setViewport({0, 0, vp.w, vp.h});
+        task->setViewport({{0, 0}, {vp.sw(), vp.sh()}});
         task->addBindResource(GlBindingResource{0, program->getUniformBlockIndex("DropShadow"), mGpuBuffer.getBufferId(), paramsOffset, sizeof(GlDropShadow)});
         task->addVertexLayout(GlVertexLayout{0, 2, 2 * sizeof(float), voffset});
         task->setDrawRange(ioffset, 6);
@@ -1198,8 +1163,7 @@ bool GlRenderer::render(TVG_UNUSED RenderCompositor* cmp, const RenderEffect* ef
         task->vertTask->setDrawRange(ioffset, 6);
         // add task to render pipeline
         pass->addRenderTask(task);
-    } // effect fill, tint, tritone
-    else if ((effect->type == SceneEffect::Fill) || (effect->type == SceneEffect::Tint) || (effect->type == SceneEffect::Tritone)) {
+    } else if ((effect->type == SceneEffect::Fill) || (effect->type == SceneEffect::Tint) || (effect->type == SceneEffect::Tritone)) {
         GlProgram* program{};
         if (effect->type == SceneEffect::Fill) program = mPrograms[RT_EffectFill];
         else if (effect->type == SceneEffect::Tint) program = mPrograms[RT_EffectTint];
@@ -1213,7 +1177,7 @@ bool GlRenderer::render(TVG_UNUSED RenderCompositor* cmp, const RenderEffect* ef
         auto paramsOffset = mGpuBuffer.push(params, sizeof(GlEffectParams), true);
         // create and setup task
         auto task = new GlEffectColorTransformTask(program, dstFbo, dstCopyFbo);
-        task->setViewport({0, 0, vp.w, vp.h});
+        task->setViewport({{0, 0}, {vp.sw(), vp.sh()}});
         task->addBindResource(GlBindingResource{0, program->getUniformBlockIndex("Params"), mGpuBuffer.getBufferId(), paramsOffset, sizeof(GlEffectParams)});
         task->addVertexLayout(GlVertexLayout{0, 2, 2 * sizeof(float), voffset});
         task->setDrawRange(ioffset, 6);
@@ -1256,25 +1220,18 @@ bool GlRenderer::blend(BlendMethod method)
 bool GlRenderer::renderImage(void* data)
 {
     auto sdata = static_cast<GlShape*>(data);
-
     if (!sdata) return false;
 
-    if (currentPass()->isEmpty()) return true;
+    if (currentPass()->isEmpty() || !(sdata->updateFlag & RenderUpdateFlag::Image)) return true;
 
-    if ((sdata->updateFlag & RenderUpdateFlag::Image) == 0) return true;
     auto vp = currentPass()->getViewport();
-
     auto bbox = sdata->geometry.viewport;
-
     bbox.intersect(vp);
+    if (bbox.invalid()) return true;
 
-    if (bbox.w <= 0 || bbox.h <= 0) return true;
-
-    auto x = bbox.x - vp.x;
-    auto y = bbox.y - vp.y;
-
-
-    int32_t drawDepth = currentPass()->nextDrawDepth();
+    auto x = bbox.sx() - vp.sx();
+    auto y = bbox.sy() - vp.sy();
+    auto drawDepth = currentPass()->nextDrawDepth();
 
     if (!sdata->clips.empty()) drawClip(sdata->clips);
 
@@ -1287,7 +1244,6 @@ bool GlRenderer::renderImage(void* data)
     }
 
     bool complexBlend = beginComplexBlending(bbox, sdata->geometry.getBounds());
-
     if (complexBlend) vp = currentPass()->getViewport();
 
     // matrix buffer
@@ -1316,7 +1272,11 @@ bool GlRenderer::renderImage(void* data)
     // texture id
     task->addBindResource(GlBindingResource{0, sdata->texId, task->getProgram()->getUniformLocation("uTexture")});
 
-    task->setViewport({x, vp.h - y - bbox.h, bbox.w, bbox.h});
+    y = vp.sh() - y - bbox.sh();
+    auto x2 = x + bbox.sw();
+    auto y2 = y + bbox.sh();
+
+    task->setViewport({{x, y}, {x2, y2}});
 
     currentPass()->addRenderTask(task);
 
@@ -1332,33 +1292,25 @@ bool GlRenderer::renderImage(void* data)
 
 bool GlRenderer::renderShape(RenderData data)
 {
-    auto sdata = static_cast<GlShape*>(data);
-
     if (currentPass()->isEmpty()) return true;
 
+    auto sdata = static_cast<GlShape*>(data);
     if (sdata->updateFlag == RenderUpdateFlag::None) return true;
 
-    const auto& vp = currentPass()->getViewport();
-
     auto bbox = sdata->geometry.viewport;
-    bbox.intersect(vp);
-
-    if (bbox.w <= 0 || bbox.h <= 0) return true;
+    bbox.intersect(currentPass()->getViewport());
+    if (bbox.invalid()) return true;
 
     int32_t drawDepth1 = 0, drawDepth2 = 0;
 
-    size_t flags = static_cast<size_t>(sdata->updateFlag);
-
-    if (flags == 0) return false;
-
-    if (flags & (RenderUpdateFlag::Gradient | RenderUpdateFlag::Color)) drawDepth1 = currentPass()->nextDrawDepth();
-
-    if (flags & (RenderUpdateFlag::Stroke | RenderUpdateFlag::GradientStroke)) drawDepth2 = currentPass()->nextDrawDepth();
+    if (sdata->updateFlag == RenderUpdateFlag::None) return false;
+    if (sdata->updateFlag & (RenderUpdateFlag::Gradient | RenderUpdateFlag::Color)) drawDepth1 = currentPass()->nextDrawDepth();
+    if (sdata->updateFlag & (RenderUpdateFlag::Stroke | RenderUpdateFlag::GradientStroke)) drawDepth2 = currentPass()->nextDrawDepth();
 
     if (!sdata->clips.empty()) drawClip(sdata->clips);
 
     auto processFill = [&]() {
-        if (flags & (RenderUpdateFlag::Color | RenderUpdateFlag::Gradient)) {
+        if (sdata->updateFlag & (RenderUpdateFlag::Color | RenderUpdateFlag::Gradient)) {
             if (const auto& gradient = sdata->rshape->fill) {
                 drawPrimitive(*sdata, gradient, RenderUpdateFlag::Gradient, drawDepth1);
             } else if (sdata->rshape->color.a > 0) {
@@ -1369,7 +1321,7 @@ bool GlRenderer::renderShape(RenderData data)
 
     auto processStroke = [&]() {
         if (!sdata->rshape->stroke) return;
-        if (flags & (RenderUpdateFlag::Stroke | RenderUpdateFlag::GradientStroke)) {
+        if (sdata->updateFlag & (RenderUpdateFlag::Stroke | RenderUpdateFlag::GradientStroke)) {
             if (const auto& gradient = sdata->rshape->strokeFill()) {
                 drawPrimitive(*sdata, gradient, RenderUpdateFlag::GradientStroke, drawDepth2);
             } else if (sdata->rshape->stroke->color.a > 0) {
diff --git a/src/renderer/gl_engine/tvgGlTessellator.cpp b/src/renderer/gl_engine/tvgGlTessellator.cpp
index dc583261..d263e64e 100644
--- a/src/renderer/gl_engine/tvgGlTessellator.cpp
+++ b/src/renderer/gl_engine/tvgGlTessellator.cpp
@@ -1516,12 +1516,7 @@ void Stroker::stroke(const RenderShape *rshape, const RenderPath& path)
 
 RenderRegion Stroker::bounds() const
 {
-    return RenderRegion {
-        static_cast<int32_t>(floor(mLeftTop.x)),
-        static_cast<int32_t>(floor(mLeftTop.y)),
-        static_cast<int32_t>(ceil(mRightBottom.x - floor(mLeftTop.x))),
-        static_cast<int32_t>(ceil(mRightBottom.y - floor(mLeftTop.y))),
-    };
+    return {{int32_t(floor(mLeftTop.x)), int32_t(floor(mLeftTop.y))}, {int32_t(ceil(mRightBottom.x)), int32_t(ceil(mRightBottom.y))}};
 }
 
 
@@ -2197,26 +2192,15 @@ void BWTessellator::tessellate(const RenderPath& path, const Matrix& matrix)
 
 RenderRegion BWTessellator::bounds() const
 {
-    return RenderRegion {
-        static_cast<int32_t>(floor(bbox.min.x)),
-        static_cast<int32_t>(floor(bbox.min.y)),
-        static_cast<int32_t>(ceil(bbox.max.x - floor(bbox.min.x))),
-        static_cast<int32_t>(ceil(bbox.max.y - floor(bbox.min.y))),
-    };
+    return {{int32_t(floor(bbox.min.x)), int32_t(floor(bbox.min.y))}, {int32_t(ceil(bbox.max.x)), int32_t(ceil(bbox.max.y))}};
 }
 
 
 uint32_t BWTessellator::pushVertex(float x, float y)
 {
     auto index = _pushVertex(mBuffer->vertex, x, y);
-
-    if (index == 0) {
-        bbox.max = bbox.min = {x, y};
-    } else {
-        bbox.min = {std::min(bbox.min.x, x), std::min(bbox.min.y, y)};
-        bbox.max = {std::max(bbox.max.x, x), std::max(bbox.max.y, y)};
-    }
-
+    if (index == 0) bbox.max = bbox.min = {x, y};
+    else bbox = {{std::min(bbox.min.x, x), std::min(bbox.min.y, y)}, {std::max(bbox.max.x, x), std::max(bbox.max.y, y)}};
     return index;
 }
 
diff --git a/src/renderer/gl_engine/tvgGlTessellator.h b/src/renderer/gl_engine/tvgGlTessellator.h
index 44fbab41..a4ad1f36 100644
--- a/src/renderer/gl_engine/tvgGlTessellator.h
+++ b/src/renderer/gl_engine/tvgGlTessellator.h
@@ -156,7 +156,7 @@ private:
     void pushTriangle(uint32_t a, uint32_t b, uint32_t c);
 
     GlGeometryBuffer* mBuffer;
-    BBox bbox = {{}, {}};
+    BBox bbox = {};
 };
 
 }  // namespace tvg
diff --git a/src/renderer/sw_engine/tvgSwPostEffect.cpp b/src/renderer/sw_engine/tvgSwPostEffect.cpp
index 32debffb..410b3f5a 100644
--- a/src/renderer/sw_engine/tvgSwPostEffect.cpp
+++ b/src/renderer/sw_engine/tvgSwPostEffect.cpp
@@ -141,12 +141,12 @@ bool effectGaussianBlurRegion(RenderEffectGaussianBlur* params)
     auto extra = static_cast<SwGaussianBlur*>(params->rd)->extends;
 
     if (params->direction != 2) {
-        region.x = -extra;
-        region.w = extra * 2;
+        region.min.x = -extra;
+        region.max.x = extra;
     }
     if (params->direction != 1) {
-        region.y = -extra;
-        region.h = extra * 2;
+        region.min.y = -extra;
+        region.max.y = extra;
     }
 
     return true;
@@ -299,15 +299,14 @@ bool effectDropShadowRegion(RenderEffectDropShadow* params)
     auto& offset = static_cast<SwDropShadow*>(params->rd)->offset;
     auto extra = static_cast<SwDropShadow*>(params->rd)->extends;
 
-    region.x = -extra;
-    region.w = extra * 2;
-    region.y = -extra;
-    region.h = extra * 2;
+    region.min = {-extra, -extra};
+    region.max = {extra, extra};
 
-    region.x = std::min(region.x + (int32_t)offset.x, region.x);
-    region.y = std::min(region.y + (int32_t)offset.y, region.y);
-    region.w += abs(offset.x);
-    region.h += abs(offset.y);
+    if (offset.x < 0) region.min.x += (int32_t) offset.x;
+    else region.max.x += offset.x;
+
+    if (offset.y < 0) region.min.y += (int32_t) offset.y;
+    else region.max.y += offset.y;
 
     return true;
 }
diff --git a/src/renderer/sw_engine/tvgSwRenderer.cpp b/src/renderer/sw_engine/tvgSwRenderer.cpp
index e097e1a5..b7cc684b 100644
--- a/src/renderer/sw_engine/tvgSwRenderer.cpp
+++ b/src/renderer/sw_engine/tvgSwRenderer.cpp
@@ -54,14 +54,10 @@ struct SwTask : Task
         done();
 
         RenderRegion region;
-
-        //Range over?
-        region.x = bbox.min.x > 0 ? bbox.min.x : 0;
-        region.y = bbox.min.y > 0 ? bbox.min.y : 0;
-        region.w = bbox.max.x - region.x;
-        region.h = bbox.max.y - region.y;
-        if (region.w < 0) region.w = 0;
-        if (region.h < 0) region.h = 0;
+        region.min.x = bbox.min.x > 0 ? bbox.min.x : 0;
+        region.min.y = bbox.min.y > 0 ? bbox.min.y : 0;
+        region.max.x = bbox.max.x > bbox.min.x ? bbox.max.x : bbox.min.x;
+        region.max.y = bbox.max.y > bbox.min.y ? bbox.max.y : bbox.min.y;
 
         return region;
     }
@@ -570,38 +566,40 @@ SwSurface* SwRenderer::request(int channelSize, bool square)
 
 RenderCompositor* SwRenderer::target(const RenderRegion& region, ColorSpace cs, CompositionFlag flags)
 {
-    auto x = region.x;
-    auto y = region.y;
-    auto w = region.w;
-    auto h = region.h;
+    auto min = region.min;
+    auto max = region.max;
+
     auto sw = static_cast<int32_t>(surface->w);
     auto sh = static_cast<int32_t>(surface->h);
 
     //Out of boundary
-    if (x >= sw || y >= sh || x + w < 0 || y + h < 0) return nullptr;
+    if (min.x >= sw || min.y >= sh || max.x < 0 || max.y < 0) return nullptr;
 
     auto cmp = request(CHANNEL_SIZE(cs), (flags & CompositionFlag::PostProcessing));
 
     //Boundary Check
-    if (x < 0) x = 0;
-    if (y < 0) y = 0;
-    if (x + w > sw) w = (sw - x);
-    if (y + h > sh) h = (sh - y);
+    if (min.x < 0) min.x = 0;
+    if (min.y < 0) min.y = 0;
+    if (max.x > sw) max.x = (sw - min.x);
+    if (max.y > sh) max.y = (sh - min.y);
+
+    auto w = max.x - min.x;
+    auto h = max.y - min.y;
 
     if (w == 0 || h == 0) return nullptr;
 
     cmp->compositor->recoverSfc = surface;
     cmp->compositor->recoverCmp = surface->compositor;
     cmp->compositor->valid = false;
-    cmp->compositor->bbox.min.x = x;
-    cmp->compositor->bbox.min.y = y;
-    cmp->compositor->bbox.max.x = x + w;
-    cmp->compositor->bbox.max.y = y + h;
+    cmp->compositor->bbox.min.x = min.x;
+    cmp->compositor->bbox.min.y = min.y;
+    cmp->compositor->bbox.max.x = max.x;
+    cmp->compositor->bbox.max.y = max.y;
 
     /* TODO: Currently, only blending might work.
        Blending and composition must be handled together. */
     auto color = (surface->blender && !surface->compositor) ? 0x00ffffff : 0x00000000;
-    rasterClear(cmp, x, y, w, h, color);
+    rasterClear(cmp, min.x, min.y, w, h, color);
 
     //Switch render target
     surface = cmp;
@@ -737,10 +735,10 @@ void* SwRenderer::prepareCommon(SwTask* task, const Matrix& transform, const Arr
     task->surface = surface;
     task->mpool = mpool;
     task->flags = flags;
-    task->bbox.min.x = std::max(static_cast<SwCoord>(0), static_cast<SwCoord>(vport.x));
-    task->bbox.min.y = std::max(static_cast<SwCoord>(0), static_cast<SwCoord>(vport.y));
-    task->bbox.max.x = std::min(static_cast<SwCoord>(surface->w), static_cast<SwCoord>(vport.x + vport.w));
-    task->bbox.max.y = std::min(static_cast<SwCoord>(surface->h), static_cast<SwCoord>(vport.y + vport.h));
+    task->bbox.min.x = std::max(static_cast<SwCoord>(0), static_cast<SwCoord>(vport.min.x));
+    task->bbox.min.y = std::max(static_cast<SwCoord>(0), static_cast<SwCoord>(vport.min.y));
+    task->bbox.max.x = std::min(static_cast<SwCoord>(surface->w), static_cast<SwCoord>(vport.max.x));
+    task->bbox.max.y = std::min(static_cast<SwCoord>(surface->h), static_cast<SwCoord>(vport.max.y));
 
     if (!task->pushed) {
         task->pushed = true;
diff --git a/src/renderer/tvgCanvas.h b/src/renderer/tvgCanvas.h
index 5c794bab..ba5cc5ed 100644
--- a/src/renderer/tvgCanvas.h
+++ b/src/renderer/tvgCanvas.h
@@ -31,7 +31,7 @@ struct Canvas::Impl
 {
     Scene* scene;
     RenderMethod* renderer;
-    RenderRegion vport = {0, 0, INT32_MAX, INT32_MAX};
+    RenderRegion vport = {{0, 0}, {INT32_MAX, INT32_MAX}};
     Status status = Status::Synced;
 
     Impl() : scene(Scene::gen())
@@ -119,11 +119,11 @@ struct Canvas::Impl
     {
         if (status != Status::Damaged && status != Status::Synced) return Result::InsufficientCondition;
 
-        RenderRegion val = {x, y, w, h};
+        RenderRegion val = {{x, y}, {x + w, y + h}};
         //intersect if the target buffer is already set.
         auto surface = renderer->mainSurface();
         if (surface && surface->w > 0 && surface->h > 0) {
-            val.intersect({0, 0, (int32_t)surface->w, (int32_t)surface->h});
+            val.intersect({{0, 0}, {(int32_t)surface->w, (int32_t)surface->h}});
         }
         if (vport == val) return Result::Success;
         renderer->viewport(val);
diff --git a/src/renderer/tvgGlCanvas.cpp b/src/renderer/tvgGlCanvas.cpp
index d66af6ad..39d26ffe 100644
--- a/src/renderer/tvgGlCanvas.cpp
+++ b/src/renderer/tvgGlCanvas.cpp
@@ -51,7 +51,7 @@ Result GlCanvas::target(void* context, int32_t id, uint32_t w, uint32_t h, Color
     if (!renderer) return Result::MemoryCorruption;
 
     if (!renderer->target(context, id, w, h)) return Result::Unknown;
-    pImpl->vport = {0, 0, (int32_t)w, (int32_t)h};
+    pImpl->vport = {{0, 0}, {(int32_t)w, (int32_t)h}};
     renderer->viewport(pImpl->vport);
 
     //Paints must be updated again with this new target.
diff --git a/src/renderer/tvgPaint.cpp b/src/renderer/tvgPaint.cpp
index e4d9d26e..497bf983 100644
--- a/src/renderer/tvgPaint.cpp
+++ b/src/renderer/tvgPaint.cpp
@@ -58,7 +58,7 @@ static Result _clipRect(RenderMethod* renderer, const Point* pts, const Matrix&
         if (tmp[i].y > max.y) max.y = tmp[i].y;
     }
 
-    float region[4] = {float(before.x), float(before.x + before.w), float(before.y), float(before.y + before.h)};
+    float region[4] = {float(before.min.x), float(before.max.x), float(before.min.y), float(before.max.y)};
 
     //figure out if the clipper is a superset of the current viewport(before) region
     if (min.x <= region[0] && max.x >= region[1] && min.y <= region[2] && max.y >= region[3]) {
@@ -66,7 +66,7 @@ static Result _clipRect(RenderMethod* renderer, const Point* pts, const Matrix&
         return Result::Success;
     //figure out if the clipper is totally outside of the viewport
     } else if (max.x <= region[0] || min.x >= region[1] || max.y <= region[2] || min.y >= region[3]) {
-        renderer->viewport({0, 0, 0, 0});
+        renderer->viewport({});
         return Result::Success;
     }
     return Result::InsufficientCondition;
@@ -122,13 +122,13 @@ static Result _compFastTrack(RenderMethod* renderer, Paint* cmpTarget, const Mat
         if (v1.x > v2.x) std::swap(v1.x, v2.x);
         if (v1.y > v2.y) std::swap(v1.y, v2.y);
 
-        after.x = static_cast<int32_t>(nearbyint(v1.x));
-        after.y = static_cast<int32_t>(nearbyint(v1.y));
-        after.w = static_cast<int32_t>(nearbyint(v2.x)) - after.x;
-        after.h = static_cast<int32_t>(nearbyint(v2.y)) - after.y;
+        after.min.x = static_cast<int32_t>(nearbyint(v1.x));
+        after.min.y = static_cast<int32_t>(nearbyint(v1.y));
+        after.max.x = static_cast<int32_t>(nearbyint(v2.x));
+        after.max.y = static_cast<int32_t>(nearbyint(v2.y));
 
-        if (after.w < 0) after.w = 0;
-        if (after.h < 0) after.h = 0;
+        if (after.max.x < after.min.x) after.max.x = after.min.x;
+        if (after.max.y < after.min.y) after.max.y = after.min.y;
 
         after.intersect(before);
         renderer->viewport(after);
@@ -185,7 +185,7 @@ bool Paint::Impl::render(RenderMethod* renderer)
         PAINT_METHOD(region, bounds(renderer));
 
         if (MASK_REGION_MERGING(maskData->method)) region.add(PAINT(maskData->target)->bounds(renderer));
-        if (region.w == 0 || region.h == 0) return true;
+        if (region.invalid()) return true;
         cmp = renderer->target(region, MASK_TO_COLORSPACE(renderer, maskData->method), CompositionFlag::Masking);
         if (renderer->beginComposite(cmp, MaskMethod::None, 255)) {
             maskData->target->pImpl->render(renderer);
diff --git a/src/renderer/tvgPicture.h b/src/renderer/tvgPicture.h
index 5a032c5a..b52a1418 100644
--- a/src/renderer/tvgPicture.h
+++ b/src/renderer/tvgPicture.h
@@ -273,7 +273,7 @@ struct PictureImpl : Picture
     {
         if (impl.rd) return renderer->region(impl.rd);
         if (vector) return vector->pImpl->bounds(renderer);
-        return {0, 0, 0, 0};
+        return {};
     }
 
     Result load(ImageLoader* loader)
diff --git a/src/renderer/tvgRender.cpp b/src/renderer/tvgRender.cpp
index 2a4ee4cc..78d7b41a 100644
--- a/src/renderer/tvgRender.cpp
+++ b/src/renderer/tvgRender.cpp
@@ -106,33 +106,14 @@ bool RenderPath::bounds(Matrix* m, float* x, float* y, float* w, float* h)
 
 void RenderRegion::intersect(const RenderRegion& rhs)
 {
-    auto x1 = x + w;
-    auto y1 = y + h;
-    auto x2 = rhs.x + rhs.w;
-    auto y2 = rhs.y + rhs.h;
+    if (min.x < rhs.min.x) min.x = rhs.min.x;
+    if (min.y < rhs.min.y) min.y = rhs.min.y;
+    if (max.x > rhs.max.x) max.x = rhs.max.x;
+    if (max.y > rhs.max.y) max.y = rhs.max.y;
 
-    x = (x > rhs.x) ? x : rhs.x;
-    y = (y > rhs.y) ? y : rhs.y;
-    w = ((x1 < x2) ? x1 : x2) - x;
-    h = ((y1 < y2) ? y1 : y2) - y;
-
-    if (w < 0) w = 0;
-    if (h < 0) h = 0;
-}
-
-
-void RenderRegion::add(const RenderRegion& rhs)
-{
-    if (rhs.x < x) {
-        w += (x - rhs.x);
-        x = rhs.x;
-    }
-    if (rhs.y < y) {
-        h += (y - rhs.y);
-        y = rhs.y;
-    }
-    if (rhs.x + rhs.w > x + w) w = (rhs.x + rhs.w) - x;
-    if (rhs.y + rhs.h > y + h) h = (rhs.y + rhs.h) - y;
+    // Not intersected: collapse to zero-area region
+    if (max.x < min.x) max.x = min.x;
+    if (max.y < min.y) max.y = min.y;
 }
 
 /************************************************************************/
diff --git a/src/renderer/tvgRender.h b/src/renderer/tvgRender.h
index 5491f746..46bd0e82 100644
--- a/src/renderer/tvgRender.h
+++ b/src/renderer/tvgRender.h
@@ -94,16 +94,47 @@ struct RenderCompositor
 
 struct RenderRegion
 {
-    int32_t x, y, w, h;
+    struct {
+        int32_t x, y;
+    } min;
+
+    struct {
+        int32_t x, y;
+    } max;
+
+    static constexpr RenderRegion intersect(const RenderRegion& lhs, const RenderRegion& rhs)
+    {
+        return {{std::max(lhs.min.x, rhs.min.x), std::max(lhs.min.y, rhs.min.y)}, {std::min(lhs.max.x, rhs.max.x), std::min(lhs.max.y, rhs.max.y)}};
+    }
 
     void intersect(const RenderRegion& rhs);
-    void add(const RenderRegion& rhs);
+
+    void add(const RenderRegion& rhs)
+    {
+        if (rhs.min.x < min.x) min.x = rhs.min.x;
+        if (rhs.min.y < min.y) min.y = rhs.min.y;
+        if (rhs.max.x > max.x) max.x = rhs.max.x;
+        if (rhs.max.y > max.y) max.y = rhs.max.y;
+    }
 
     bool operator==(const RenderRegion& rhs) const
     {
-        if (x == rhs.x && y == rhs.y && w == rhs.w && h == rhs.h) return true;
-        return false;
+        return (min.x == rhs.min.x && min.y == rhs.min.y && max.x == rhs.max.x && max.y == rhs.max.y);
     }
+
+    void reset() { min.x = min.y = max.x = max.y = 0; }
+    bool valid() const { return (max.x > min.x && max.y > min.y); }
+    bool invalid() const { return !valid(); }
+
+    int32_t sx() const { return min.x; }
+    int32_t sy() const { return min.y; }
+    int32_t sw() const { return max.x - min.x; }
+    int32_t sh() const { return max.y - min.y; }
+
+    uint32_t x() const { return (uint32_t) sx(); }
+    uint32_t y() const { return (uint32_t) sy(); }
+    uint32_t w() const { return (uint32_t) sw(); }
+    uint32_t h() const { return (uint32_t) sh(); }
 };
 
 struct RenderPath
@@ -272,7 +303,7 @@ struct RenderShape
 struct RenderEffect
 {
     RenderData rd = nullptr;
-    RenderRegion extend = {0, 0, 0, 0};
+    RenderRegion extend{};
     SceneEffect type;
     bool valid = false;
 
diff --git a/src/renderer/tvgScene.h b/src/renderer/tvgScene.h
index 8f4395b0..506bb876 100644
--- a/src/renderer/tvgScene.h
+++ b/src/renderer/tvgScene.h
@@ -64,7 +64,7 @@ struct SceneImpl : Scene
 {
     Paint::Impl impl;
     list<Paint*> paints;     //children list
-    RenderRegion vport = {0, 0, INT32_MAX, INT32_MAX};
+    RenderRegion vport = {};
     Array<RenderEffect*>* effects = nullptr;
     uint8_t compFlag = CompositionFlag::Invalid;
     uint8_t opacity;         //for composition
@@ -159,40 +159,34 @@ struct SceneImpl : Scene
 
     RenderRegion bounds(RenderMethod* renderer) const
     {
-        if (paints.empty()) return {0, 0, 0, 0};
-
-        int32_t x1 = INT32_MAX;
-        int32_t y1 = INT32_MAX;
-        int32_t x2 = 0;
-        int32_t y2 = 0;
+        if (paints.empty()) return {};
 
+        //Merge regions
+        RenderRegion pRegion = {{INT32_MAX, INT32_MAX}, {0, 0}};
         for (auto paint : paints) {
             auto region = paint->pImpl->bounds(renderer);
-
-            //Merge regions
-            if (region.x < x1) x1 = region.x;
-            if (x2 < region.x + region.w) x2 = (region.x + region.w);
-            if (region.y < y1) y1 = region.y;
-            if (y2 < region.y + region.h) y2 = (region.y + region.h);
+            if (region.min.x < pRegion.min.x) pRegion.min.x = region.min.x;
+            if (pRegion.max.x < region.max.x) pRegion.max.x = region.max.x;
+            if (region.min.y < pRegion.min.y) pRegion.min.y = region.min.y;
+            if (pRegion.max.y < region.max.y) pRegion.max.y = region.max.y;
         }
 
         //Extends the render region if post effects require
-        int32_t ex = 0, ey = 0, ew = 0, eh = 0;
+        RenderRegion eRegion{};
         if (effects) {
             ARRAY_FOREACH(p, *effects) {
                 auto effect = *p;
-                if (effect->valid && renderer->region(effect)) {
-                    ex = std::min(ex, effect->extend.x);
-                    ey = std::min(ey, effect->extend.y);
-                    ew = std::max(ew, effect->extend.w);
-                    eh = std::max(eh, effect->extend.h);
-                }
+                if (effect->valid && renderer->region(effect)) eRegion.add(effect->extend);
             }
         }
 
-        auto ret = RenderRegion{x1 + ex, y1 + ey, (x2 - x1) + ew, (y2 - y1) + eh};
-        ret.intersect(this->vport);
-        return ret;
+        pRegion.min.x += eRegion.min.x;
+        pRegion.min.y += eRegion.min.y;
+        pRegion.max.x += eRegion.max.x;
+        pRegion.max.y += eRegion.max.y;
+
+        pRegion.intersect(this->vport);
+        return pRegion;
     }
 
     Result bounds(Point* pt4, Matrix& m, bool obb, bool stroking)
diff --git a/src/renderer/tvgShape.h b/src/renderer/tvgShape.h
index 72d81454..0adb92aa 100644
--- a/src/renderer/tvgShape.h
+++ b/src/renderer/tvgShape.h
@@ -114,7 +114,7 @@ struct ShapeImpl : Shape
 
     RenderRegion bounds(RenderMethod* renderer)
     {
-        if (!impl.rd) return {0, 0, 0, 0};
+        if (!impl.rd) return {};
         return renderer->region(impl.rd);
     }
 
diff --git a/src/renderer/tvgSwCanvas.cpp b/src/renderer/tvgSwCanvas.cpp
index 9e64bfce..44f3a491 100644
--- a/src/renderer/tvgSwCanvas.cpp
+++ b/src/renderer/tvgSwCanvas.cpp
@@ -54,7 +54,7 @@ Result SwCanvas::target(uint32_t* buffer, uint32_t stride, uint32_t w, uint32_t
     if (!renderer) return Result::MemoryCorruption;
 
     if (!renderer->target(buffer, stride, w, h, cs)) return Result::InvalidArguments;
-    pImpl->vport = {0, 0, (int32_t)w, (int32_t)h};
+    pImpl->vport = {{0, 0}, {(int32_t)w, (int32_t)h}};
     renderer->viewport(pImpl->vport);
 
     //FIXME: The value must be associated with an individual canvas instance.
diff --git a/src/renderer/tvgWgCanvas.cpp b/src/renderer/tvgWgCanvas.cpp
index 5d074199..39928239 100644
--- a/src/renderer/tvgWgCanvas.cpp
+++ b/src/renderer/tvgWgCanvas.cpp
@@ -55,7 +55,7 @@ Result WgCanvas::target(void* device, void* instance, void* target, uint32_t w,
     if (!renderer) return Result::MemoryCorruption;
 
     if (!renderer->target((WGPUDevice)device, (WGPUInstance)instance, target, w, h, type)) return Result::Unknown;
-    pImpl->vport = {0, 0, (int32_t)w, (int32_t)h};
+    pImpl->vport = {{0, 0}, {(int32_t)w, (int32_t)h}};
     renderer->viewport(pImpl->vport);
 
     //Paints must be updated again with this new target.
diff --git a/src/renderer/wg_engine/tvgWgCompositor.cpp b/src/renderer/wg_engine/tvgWgCompositor.cpp
index bc61b3eb..4211a65b 100644
--- a/src/renderer/wg_engine/tvgWgCompositor.cpp
+++ b/src/renderer/wg_engine/tvgWgCompositor.cpp
@@ -117,18 +117,13 @@ void WgCompositor::resize(WgContext& context, uint32_t width, uint32_t height) {
 
 RenderRegion WgCompositor::shrinkRenderRegion(RenderRegion& rect)
 {
-    // cut viewport to screen dimensions
-    int32_t xmin = std::max(0, std::min((int32_t)width, rect.x));
-    int32_t ymin = std::max(0, std::min((int32_t)height, rect.y));
-    int32_t xmax = std::max(xmin, std::min((int32_t)width, rect.x + rect.w));
-    int32_t ymax = std::max(ymin, std::min((int32_t)height, rect.y + rect.h));
-    return { xmin, ymin, xmax - xmin, ymax - ymin };
+    return RenderRegion::intersect(rect, {{0, 0}, {(int32_t)width, (int32_t)height}});
 }
 
 
 void WgCompositor::copyTexture(const WgRenderStorage* dst, const WgRenderStorage* src)
 {
-    const RenderRegion region = { 0, 0, (int32_t)src->width, (int32_t)src->height };
+    const RenderRegion region = {{0, 0}, {(int32_t)src->width, (int32_t)src->height}};
     copyTexture(dst, src, region);
 }
 
@@ -138,9 +133,9 @@ void WgCompositor::copyTexture(const WgRenderStorage* dst, const WgRenderStorage
     assert(dst);
     assert(src);
     assert(commandEncoder);
-    const WGPUImageCopyTexture texSrc { .texture = src->texture, .origin = { .x = (uint32_t)region.x, .y = (uint32_t)region.y } };
-    const WGPUImageCopyTexture texDst { .texture = dst->texture, .origin = { .x = (uint32_t)region.x, .y = (uint32_t)region.y } };
-    const WGPUExtent3D copySize { .width = (uint32_t)region.w, .height = (uint32_t)region.h, .depthOrArrayLayers = 1 };
+    const WGPUImageCopyTexture texSrc { .texture = src->texture, .origin = { .x = region.x(), .y = region.y() } };
+    const WGPUImageCopyTexture texDst { .texture = dst->texture, .origin = { .x = region.x(), .y = region.y() } };
+    const WGPUExtent3D copySize { .width = region.w(), .height = region.h(), .depthOrArrayLayers = 1 };
     wgpuCommandEncoderCopyTextureToTexture(commandEncoder, &texSrc, &texDst, &copySize);
 }
 
@@ -257,7 +252,7 @@ void WgCompositor::composeScene(WgContext& context, WgRenderStorage* src, WgRend
     assert(mask);
     assert(renderPassEncoder);
     RenderRegion rect = shrinkRenderRegion(cmp->aabb);
-    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, rect.x, rect.y, rect.w, rect.h);
+    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, rect.x(), rect.y(), rect.w(), rect.h());
     wgpuRenderPassEncoderSetStencilReference(renderPassEncoder, 0);
     wgpuRenderPassEncoderSetBindGroup(renderPassEncoder, 0, src->bindGroupTexure, 0, nullptr);
     wgpuRenderPassEncoderSetBindGroup(renderPassEncoder, 1, mask->bindGroupTexure, 0, nullptr);
@@ -293,10 +288,8 @@ void WgCompositor::drawShape(WgContext& context, WgRenderDataShape* renderData)
     assert(renderData);
     assert(renderPassEncoder);
     assert(renderData->meshGroupShapes.meshes.count == renderData->meshGroupShapesBBox.meshes.count);
-    if (renderData->renderSettingsShape.skip) return;
-    if (renderData->meshGroupShapes.meshes.count == 0) return;
-    if ((renderData->viewport.w <= 0) || (renderData->viewport.h <= 0)) return;
-    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, renderData->viewport.x, renderData->viewport.y, renderData->viewport.w, renderData->viewport.h);
+    if (renderData->renderSettingsShape.skip || renderData->meshGroupShapes.meshes.count == 0 || renderData->viewport.invalid()) return;
+    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, renderData->viewport.x(), renderData->viewport.y(), renderData->viewport.w(), renderData->viewport.h());
     // setup stencil rules
     WGPURenderPipeline stencilPipeline = (renderData->fillRule == FillRule::NonZero) ? pipelines.nonzero : pipelines.evenodd;
     wgpuRenderPassEncoderSetStencilReference(renderPassEncoder, 0);
@@ -331,16 +324,14 @@ void WgCompositor::blendShape(WgContext& context, WgRenderDataShape* renderData,
     assert(renderData);
     assert(renderPassEncoder);
     assert(renderData->meshGroupShapes.meshes.count == renderData->meshGroupShapesBBox.meshes.count);
-    if (renderData->renderSettingsShape.skip) return;
-    if (renderData->meshGroupShapes.meshes.count == 0) return;
-    if ((renderData->viewport.w <= 0) || (renderData->viewport.h <= 0)) return;
+    if (renderData->renderSettingsShape.skip || renderData->meshGroupShapes.meshes.count == 0 || renderData->viewport.invalid()) return;
     // copy current render target data to dst storage
     WgRenderStorage *target = currentTarget;
     endRenderPass();
     copyTexture(&storageTemp0, target);
     beginRenderPass(commandEncoder, target, false);
     // render shape with blend settings
-    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, renderData->viewport.x, renderData->viewport.y, renderData->viewport.w, renderData->viewport.h);
+    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, renderData->viewport.x(), renderData->viewport.y(), renderData->viewport.w(), renderData->viewport.h());
     // setup stencil rules
     WGPURenderPipeline stencilPipeline = (renderData->fillRule == FillRule::NonZero) ? pipelines.nonzero : pipelines.evenodd;
     wgpuRenderPassEncoderSetStencilReference(renderPassEncoder, 0);
@@ -377,10 +368,9 @@ void WgCompositor::clipShape(WgContext& context, WgRenderDataShape* renderData)
     assert(renderData);
     assert(renderPassEncoder);
     assert(renderData->meshGroupShapes.meshes.count == renderData->meshGroupShapesBBox.meshes.count);
-    if (renderData->renderSettingsShape.skip) return;
-    if (renderData->meshGroupShapes.meshes.count == 0) return;
-    if ((renderData->viewport.w <= 0) || (renderData->viewport.h <= 0)) return;
-    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, renderData->viewport.x, renderData->viewport.y, renderData->viewport.w, renderData->viewport.h);
+    if (renderData->renderSettingsShape.skip || renderData->meshGroupShapes.meshes.count == 0 || renderData->viewport.invalid()) return;
+
+    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, renderData->viewport.x(), renderData->viewport.y(), renderData->viewport.w(), renderData->viewport.h());
     // setup stencil rules
     WGPURenderPipeline stencilPipeline = (renderData->fillRule == FillRule::NonZero) ? pipelines.nonzero : pipelines.evenodd;
     wgpuRenderPassEncoderSetStencilReference(renderPassEncoder, 0);
@@ -420,10 +410,9 @@ void WgCompositor::drawStrokes(WgContext& context, WgRenderDataShape* renderData
     assert(renderData);
     assert(renderPassEncoder);
     assert(renderData->meshGroupStrokes.meshes.count == renderData->meshGroupStrokesBBox.meshes.count);
-    if (renderData->renderSettingsStroke.skip) return;
-    if (renderData->meshGroupStrokes.meshes.count == 0) return;
-    if ((renderData->viewport.w <= 0) || (renderData->viewport.h <= 0)) return;
-    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, renderData->viewport.x, renderData->viewport.y, renderData->viewport.w, renderData->viewport.h);
+    if (renderData->renderSettingsStroke.skip || renderData->meshGroupStrokes.meshes.count == 0 || renderData->viewport.invalid()) return;
+
+    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, renderData->viewport.x(), renderData->viewport.y(), renderData->viewport.w(), renderData->viewport.h());
     // draw strokes to stencil (first pass)
     for (uint32_t i = 0; i < renderData->meshGroupStrokes.meshes.count; i++) {
         // setup stencil rules
@@ -459,15 +448,14 @@ void WgCompositor::blendStrokes(WgContext& context, WgRenderDataShape* renderDat
     assert(renderData);
     assert(renderPassEncoder);
     assert(renderData->meshGroupStrokes.meshes.count == renderData->meshGroupStrokesBBox.meshes.count);
-    if (renderData->renderSettingsStroke.skip) return;
-    if (renderData->meshGroupStrokes.meshes.count == 0) return;
-    if ((renderData->viewport.w <= 0) || (renderData->viewport.h <= 0)) return;
+    if (renderData->renderSettingsStroke.skip || renderData->meshGroupStrokes.meshes.count == 0 || renderData->viewport.invalid()) return;
+
     // copy current render target data to dst storage
     WgRenderStorage *target = currentTarget;
     endRenderPass();
     copyTexture(&storageTemp0, target);
     beginRenderPass(commandEncoder, target, false);
-    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, renderData->viewport.x, renderData->viewport.y, renderData->viewport.w, renderData->viewport.h);
+    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, renderData->viewport.x(), renderData->viewport.y(), renderData->viewport.w(), renderData->viewport.h());
     // draw strokes to stencil (first pass)
     for (uint32_t i = 0; i < renderData->meshGroupStrokes.meshes.count; i++) {
         // setup stencil rules
@@ -507,8 +495,8 @@ void WgCompositor::clipStrokes(WgContext& context, WgRenderDataShape* renderData
     assert(renderData->meshGroupStrokes.meshes.count == renderData->meshGroupStrokesBBox.meshes.count);
     if (renderData->renderSettingsStroke.skip) return;
     if (renderData->meshGroupStrokes.meshes.count == 0) return;
-    if ((renderData->viewport.w <= 0) || (renderData->viewport.h <= 0)) return;
-    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, renderData->viewport.x, renderData->viewport.y, renderData->viewport.w, renderData->viewport.h);
+    if (renderData->viewport.invalid()) return;
+    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, renderData->viewport.x(), renderData->viewport.y(), renderData->viewport.w(), renderData->viewport.h());
     // draw strokes to stencil (first pass)
     for (uint32_t i = 0; i < renderData->meshGroupStrokes.meshes.count; i++) {
         // setup stencil rules
@@ -548,8 +536,8 @@ void WgCompositor::drawImage(WgContext& context, WgRenderDataPicture* renderData
 {
     assert(renderData);
     assert(renderPassEncoder);
-    if ((renderData->viewport.w <= 0) || (renderData->viewport.h <= 0)) return;
-    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, renderData->viewport.x, renderData->viewport.y, renderData->viewport.w, renderData->viewport.h);
+    if (renderData->viewport.invalid()) return;
+    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, renderData->viewport.x(), renderData->viewport.y(), renderData->viewport.w(), renderData->viewport.h());
     // draw stencil
     wgpuRenderPassEncoderSetStencilReference(renderPassEncoder, 255);
     wgpuRenderPassEncoderSetBindGroup(renderPassEncoder, 0, bindGroupViewMat, 0, nullptr);
@@ -570,8 +558,8 @@ void WgCompositor::blendImage(WgContext& context, WgRenderDataPicture* renderDat
 {
     assert(renderData);
     assert(renderPassEncoder);
-    if ((renderData->viewport.w <= 0) || (renderData->viewport.h <= 0)) return;
-    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, renderData->viewport.x, renderData->viewport.y, renderData->viewport.w, renderData->viewport.h);
+    if (renderData->viewport.invalid()) return;
+    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, renderData->viewport.x(), renderData->viewport.y(), renderData->viewport.w(), renderData->viewport.h());
     // copy current render target data to dst storage
     WgRenderStorage *target = currentTarget;
     endRenderPass();
@@ -599,8 +587,8 @@ void WgCompositor::clipImage(WgContext& context, WgRenderDataPicture* renderData
 {
     assert(renderData);
     assert(renderPassEncoder);
-    if ((renderData->viewport.w <= 0) || (renderData->viewport.h <= 0)) return;
-    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, renderData->viewport.x, renderData->viewport.y, renderData->viewport.w, renderData->viewport.h);
+    if (renderData->viewport.invalid()) return;
+    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, renderData->viewport.x(), renderData->viewport.y(), renderData->viewport.w(), renderData->viewport.h());
     // setup stencil rules
     wgpuRenderPassEncoderSetStencilReference(renderPassEncoder, 255);
     wgpuRenderPassEncoderSetBindGroup(renderPassEncoder, 0, bindGroupViewMat, 0, nullptr);
@@ -629,7 +617,7 @@ void WgCompositor::drawScene(WgContext& context, WgRenderStorage* scene, WgCompo
     assert(currentTarget);
     // draw scene
     RenderRegion rect = shrinkRenderRegion(compose->aabb);
-    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, rect.x, rect.y, rect.w, rect.h);
+    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, rect.x(), rect.y(), rect.w(), rect.h());
     wgpuRenderPassEncoderSetStencilReference(renderPassEncoder, 0);
     wgpuRenderPassEncoderSetBindGroup(renderPassEncoder, 0, scene->bindGroupTexure, 0, nullptr);
     wgpuRenderPassEncoderSetBindGroup(renderPassEncoder, 1, bindGroupOpacities[compose->opacity], 0, nullptr);
@@ -651,7 +639,7 @@ void WgCompositor::blendScene(WgContext& context, WgRenderStorage* scene, WgComp
     // blend scene
     uint32_t blendMethodInd = (uint32_t)compose->blend;
     RenderRegion rect = shrinkRenderRegion(compose->aabb);
-    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, rect.x, rect.y, rect.w, rect.h);
+    wgpuRenderPassEncoderSetScissorRect(renderPassEncoder, rect.x(), rect.y(), rect.w(), rect.h());
     wgpuRenderPassEncoderSetStencilReference(renderPassEncoder, 0);
     wgpuRenderPassEncoderSetBindGroup(renderPassEncoder, 0, scene->bindGroupTexure, 0, nullptr);
     wgpuRenderPassEncoderSetBindGroup(renderPassEncoder, 1, storageTemp0.bindGroupTexure, 0, nullptr);
@@ -784,7 +772,7 @@ bool WgCompositor::gaussianBlur(WgContext& context, WgRenderStorage* dst, const
             wgpuComputePassEncoderSetBindGroup(computePassEncoder, 2, renderData->bindGroupParams, 0, nullptr);
             wgpuComputePassEncoderSetBindGroup(computePassEncoder, 3, viewport->bindGroupViewport, 0, nullptr);
             wgpuComputePassEncoderSetPipeline(computePassEncoder, pipelines.gaussian_horz);
-            wgpuComputePassEncoderDispatchWorkgroups(computePassEncoder, (aabb.w - 1) / 128 + 1, aabb.h, 1);
+            wgpuComputePassEncoderDispatchWorkgroups(computePassEncoder, (aabb.sw() - 1) / 128 + 1, aabb.sh(), 1);
             std::swap(sbuff, dbuff);
         }
         // vertical blur
@@ -794,7 +782,7 @@ bool WgCompositor::gaussianBlur(WgContext& context, WgRenderStorage* dst, const
             wgpuComputePassEncoderSetBindGroup(computePassEncoder, 2, renderData->bindGroupParams, 0, nullptr);
             wgpuComputePassEncoderSetBindGroup(computePassEncoder, 3, viewport->bindGroupViewport, 0, nullptr);
             wgpuComputePassEncoderSetPipeline(computePassEncoder, pipelines.gaussian_vert);
-            wgpuComputePassEncoderDispatchWorkgroups(computePassEncoder, aabb.w, (aabb.h - 1) / 128 + 1, 1);
+            wgpuComputePassEncoderDispatchWorkgroups(computePassEncoder, aabb.sw(), (aabb.sh() - 1) / 128 + 1, 1);
             std::swap(sbuff, dbuff);
         }
     }
@@ -834,7 +822,7 @@ bool WgCompositor::dropShadow(WgContext& context, WgRenderStorage* dst, const Re
         wgpuComputePassEncoderSetBindGroup(computePassEncoder, 2, renderDataParams->bindGroupParams, 0, nullptr);
         wgpuComputePassEncoderSetBindGroup(computePassEncoder, 3, viewport->bindGroupViewport, 0, nullptr);
         wgpuComputePassEncoderSetPipeline(computePassEncoder, pipelines.gaussian_horz);
-        wgpuComputePassEncoderDispatchWorkgroups(computePassEncoder, (aabb.w - 1) / 128 + 1, aabb.h, 1);
+        wgpuComputePassEncoderDispatchWorkgroups(computePassEncoder, (aabb.sw() - 1) / 128 + 1, aabb.h(), 1);
         std::swap(sbuff, dbuff);
         // vertical blur
         wgpuComputePassEncoderSetBindGroup(computePassEncoder, 0, sbuff->bindGroupRead, 0, nullptr);
@@ -842,7 +830,7 @@ bool WgCompositor::dropShadow(WgContext& context, WgRenderStorage* dst, const Re
         wgpuComputePassEncoderSetBindGroup(computePassEncoder, 2, renderDataParams->bindGroupParams, 0, nullptr);
         wgpuComputePassEncoderSetBindGroup(computePassEncoder, 3, viewport->bindGroupViewport, 0, nullptr);
         wgpuComputePassEncoderSetPipeline(computePassEncoder, pipelines.gaussian_vert);
-        wgpuComputePassEncoderDispatchWorkgroups(computePassEncoder, aabb.w, (aabb.h - 1) / 128 + 1, 1);
+        wgpuComputePassEncoderDispatchWorkgroups(computePassEncoder, aabb.sw(), (aabb.sh() - 1) / 128 + 1, 1);
         std::swap(sbuff, dbuff);
         wgpuComputePassEncoderEnd(computePassEncoder);
         wgpuComputePassEncoderRelease(computePassEncoder);
@@ -857,7 +845,7 @@ bool WgCompositor::dropShadow(WgContext& context, WgRenderStorage* dst, const Re
         wgpuComputePassEncoderSetBindGroup(computePassEncoder, 2, renderDataParams->bindGroupParams, 0, nullptr);
         wgpuComputePassEncoderSetBindGroup(computePassEncoder, 3, viewport->bindGroupViewport, 0, nullptr);
         wgpuComputePassEncoderSetPipeline(computePassEncoder, pipelines.dropshadow);
-        wgpuComputePassEncoderDispatchWorkgroups(computePassEncoder, (aabb.w - 1) / 128 + 1, aabb.h, 1);
+        wgpuComputePassEncoderDispatchWorkgroups(computePassEncoder, (aabb.sw() - 1) / 128 + 1, aabb.h(), 1);
         wgpuComputePassEncoderEnd(computePassEncoder);
         wgpuComputePassEncoderRelease(computePassEncoder);
     }
@@ -882,7 +870,7 @@ bool WgCompositor::fillEffect(WgContext& context, WgRenderStorage* dst, const Re
     wgpuComputePassEncoderSetBindGroup(computePassEncoder, 2, static_cast<WgRenderDataEffectParams*>(params->rd)->bindGroupParams, 0, nullptr);
     wgpuComputePassEncoderSetBindGroup(computePassEncoder, 3, compose->rdViewport->bindGroupViewport, 0, nullptr);
     wgpuComputePassEncoderSetPipeline(computePassEncoder, pipelines.fill_effect);
-    wgpuComputePassEncoderDispatchWorkgroups(computePassEncoder, (compose->aabb.w - 1) / 128 + 1, compose->aabb.h, 1);
+    wgpuComputePassEncoderDispatchWorkgroups(computePassEncoder, (compose->aabb.sw() - 1) / 128 + 1, compose->aabb.sh(), 1);
     wgpuComputePassEncoderEnd(computePassEncoder);
     wgpuComputePassEncoderRelease(computePassEncoder);
 
@@ -906,7 +894,7 @@ bool WgCompositor::tintEffect(WgContext& context, WgRenderStorage* dst, const Re
     wgpuComputePassEncoderSetBindGroup(computePassEncoder, 2, static_cast<WgRenderDataEffectParams*>(params->rd)->bindGroupParams, 0, nullptr);
     wgpuComputePassEncoderSetBindGroup(computePassEncoder, 3, compose->rdViewport->bindGroupViewport, 0, nullptr);
     wgpuComputePassEncoderSetPipeline(computePassEncoder, pipelines.tint_effect);
-    wgpuComputePassEncoderDispatchWorkgroups(computePassEncoder, (compose->aabb.w - 1) / 128 + 1, compose->aabb.h, 1);
+    wgpuComputePassEncoderDispatchWorkgroups(computePassEncoder, (compose->aabb.sw() - 1) / 128 + 1, compose->aabb.sh(), 1);
     wgpuComputePassEncoderEnd(computePassEncoder);
     wgpuComputePassEncoderRelease(computePassEncoder);
 
@@ -929,7 +917,7 @@ bool WgCompositor::tritoneEffect(WgContext& context, WgRenderStorage* dst, const
     wgpuComputePassEncoderSetBindGroup(computePassEncoder, 2, static_cast<WgRenderDataEffectParams*>(params->rd)->bindGroupParams, 0, nullptr);
     wgpuComputePassEncoderSetBindGroup(computePassEncoder, 3, compose->rdViewport->bindGroupViewport, 0, nullptr);
     wgpuComputePassEncoderSetPipeline(computePassEncoder, pipelines.tritone_effect);
-    wgpuComputePassEncoderDispatchWorkgroups(computePassEncoder, (compose->aabb.w - 1) / 128 + 1, compose->aabb.h, 1);
+    wgpuComputePassEncoderDispatchWorkgroups(computePassEncoder, (compose->aabb.sw() - 1) / 128 + 1, compose->aabb.sh(), 1);
     wgpuComputePassEncoderEnd(computePassEncoder);
     wgpuComputePassEncoderRelease(computePassEncoder);
 
diff --git a/src/renderer/wg_engine/tvgWgRenderer.cpp b/src/renderer/wg_engine/tvgWgRenderer.cpp
index 74d71c48..f4f9374a 100644
--- a/src/renderer/wg_engine/tvgWgRenderer.cpp
+++ b/src/renderer/wg_engine/tvgWgRenderer.cpp
@@ -259,14 +259,9 @@ RenderRegion WgRenderer::region(RenderData data)
     if (renderData->type() == Type::Shape) {
         auto& v1 = renderData->aabb.min;
         auto& v2 = renderData->aabb.max;
-        RenderRegion renderRegion;
-        renderRegion.x = static_cast<int32_t>(nearbyint(v1.x));
-        renderRegion.y = static_cast<int32_t>(nearbyint(v1.y));
-        renderRegion.w = static_cast<int32_t>(nearbyint(v2.x)) - renderRegion.x;
-        renderRegion.h = static_cast<int32_t>(nearbyint(v2.y)) - renderRegion.y;
-        return renderRegion;
+        return {{int32_t(nearbyint(v1.x)), int32_t(nearbyint(v1.y))}, {int32_t(nearbyint(v2.x)), int32_t(nearbyint(v2.y))}};
     }
-    return { 0, 0, (int32_t)mTargetSurface.w, (int32_t)mTargetSurface.h };
+    return {{0, 0}, {(int32_t)mTargetSurface.w, (int32_t)mTargetSurface.h}};
 }
 
 
@@ -586,12 +581,12 @@ bool WgRenderer::region(RenderEffect* effect)
         auto gaussian = (RenderEffectGaussianBlur*)effect;
         auto renderData = (WgRenderDataEffectParams*)gaussian->rd;
         if (gaussian->direction != 2) {
-            gaussian->extend.x = -renderData->extend;
-            gaussian->extend.w = +renderData->extend * 2;
+            gaussian->extend.min.x = -renderData->extend;
+            gaussian->extend.max.x = +renderData->extend;
         }
         if (gaussian->direction != 1) {
-            gaussian->extend.y = -renderData->extend;
-            gaussian->extend.h = +renderData->extend * 2;
+            gaussian->extend.min.y = -renderData->extend;
+            gaussian->extend.max.y = +renderData->extend;
         }
         return true;
     } else
@@ -599,10 +594,10 @@ bool WgRenderer::region(RenderEffect* effect)
     if (effect->type == SceneEffect::DropShadow) {
         auto dropShadow = (RenderEffectDropShadow*)effect;
         auto renderData = (WgRenderDataEffectParams*)dropShadow->rd;
-        dropShadow->extend.x = -(renderData->extend + std::abs(renderData->offset.x));
-        dropShadow->extend.w = +(renderData->extend + std::abs(renderData->offset.x)) * 2;
-        dropShadow->extend.y = -(renderData->extend + std::abs(renderData->offset.y));
-        dropShadow->extend.h = +(renderData->extend + std::abs(renderData->offset.y)) * 2;
+        dropShadow->extend.min.x = -(renderData->extend + std::abs(renderData->offset.x));
+        dropShadow->extend.max.x = +(renderData->extend + std::abs(renderData->offset.x));
+        dropShadow->extend.min.y = -(renderData->extend + std::abs(renderData->offset.y));
+        dropShadow->extend.max.y = +(renderData->extend + std::abs(renderData->offset.y));
         return true;
     }
     return false;
diff --git a/src/renderer/wg_engine/tvgWgShaderTypes.cpp b/src/renderer/wg_engine/tvgWgShaderTypes.cpp
index a6e8e19a..7f99c189 100644
--- a/src/renderer/wg_engine/tvgWgShaderTypes.cpp
+++ b/src/renderer/wg_engine/tvgWgShaderTypes.cpp
@@ -118,10 +118,10 @@ void WgShaderTypeVec4f::update(const RenderColor& c)
 
 void WgShaderTypeVec4f::update(const RenderRegion& r)
 {
-    vec[0] = r.x; // left
-    vec[1] = r.y; // top
-    vec[2] = r.x + r.w - 1; // right
-    vec[3] = r.y + r.h - 1; // bottom
+    vec[0] = r.min.x;
+    vec[1] = r.min.y;
+    vec[2] = r.max.x - 1;
+    vec[3] = r.max.y - 1;
 }
 
 //************************************************************************