diff --git a/src/renderer/tvgCanvas.h b/src/renderer/tvgCanvas.h
index a1556702..cdad9ede 100644
--- a/src/renderer/tvgCanvas.h
+++ b/src/renderer/tvgCanvas.h
@@ -28,10 +28,13 @@
 
 struct Canvas::Impl
 {
+    enum Status : uint8_t {Synced = 0, Updating, Drawing};
+
     list<Paint*> paints;
     RenderMethod* renderer;
+    Status status = Status::Synced;
+
     bool refresh = false;   //if all paints should be updated by force.
-    bool drawing = false;   //on drawing condition?
 
     Impl(RenderMethod* pRenderer) : renderer(pRenderer)
     {
@@ -62,7 +65,7 @@ struct Canvas::Impl
     Result push(unique_ptr<Paint> paint)
     {
         //You can not push paints during rendering.
-        if (drawing) return Result::InsufficientCondition;
+        if (status == Status::Drawing) return Result::InsufficientCondition;
 
         auto p = paint.release();
         if (!p) return Result::MemoryCorruption;
@@ -75,12 +78,12 @@ struct Canvas::Impl
     Result clear(bool free)
     {
         //Clear render target before drawing
-        if (!renderer || !renderer->clear()) return Result::InsufficientCondition;
+        if (!renderer->clear()) return Result::InsufficientCondition;
 
         //Free paints
         if (free) clearPaints();
 
-        drawing = false;
+        status = Status::Synced;
 
         return Result::Success;
     }
@@ -92,7 +95,7 @@ struct Canvas::Impl
 
     Result update(Paint* paint, bool force)
     {
-        if (paints.empty() || drawing || !renderer) return Result::InsufficientCondition;
+        if (paints.empty() || status == Status::Drawing) return Result::InsufficientCondition;
 
         Array<RenderData> clips;
         auto flag = RenderUpdateFlag::None;
@@ -106,12 +109,13 @@ struct Canvas::Impl
             }
             refresh = false;
         }
+        status = Status::Updating;
         return Result::Success;
     }
 
     Result draw()
     {
-        if (drawing || paints.empty() || !renderer || !renderer->preRender()) return Result::InsufficientCondition;
+        if (status == Status::Drawing || paints.empty() || !renderer->preRender()) return Result::InsufficientCondition;
 
         bool rendered = false;
         for (auto paint : paints) {
@@ -120,17 +124,16 @@ struct Canvas::Impl
 
         if (!rendered || !renderer->postRender()) return Result::InsufficientCondition;
 
-        drawing = true;
-
+        status = Status::Drawing;
         return Result::Success;
     }
 
     Result sync()
     {
-        if (!drawing) return Result::InsufficientCondition;
+        if (status == Status::Synced) return Result::InsufficientCondition;
 
         if (renderer->sync()) {
-            drawing = false;
+            status = Status::Synced;
             return Result::Success;
         }