common picture: implement duplicate() method.

src/examples/testDuplicate.cpp

@@ -77,7 +77,19 @@ void tvgDrawCmds(tvg::Canvas* canvas)
         canvas->push(move(scene2));
     }
 
+    //Duplicate Picture
+    {
+        auto picture1 = tvg::Picture::gen();
+        picture1->load(EXAMPLE_DIR"/tiger.svg");
+        picture1->translate(370, 370);
+        picture1->scale(0.25);
 
+        auto picture2 = unique_ptr<tvg::Picture>(static_cast<tvg::Picture*>(picture1->duplicate()));
+        picture2->translate(550, 550);
+
+        canvas->push(move(picture1));
+        canvas->push(move(picture2));
+    }
 }
 
 

src/lib/tvgPaint.h

@@ -153,7 +153,7 @@ namespace tvg
             auto ret = smethod->duplicate();
 
             //duplicate Transform
-            if (rTransform) {
+            if (ret && rTransform) {
                 ret->pImpl->rTransform = new RenderTransform();
                 if (ret->pImpl->rTransform) {
                     *ret->pImpl->rTransform = *rTransform;

src/lib/tvgPictureImpl.h

@@ -43,16 +43,22 @@ struct Picture::Impl
         return true;
     }
 
-    bool update(RenderMethod &renderer, const RenderTransform* transform, RenderUpdateFlag flag)
+    void reload()
     {
-        if (loader) {
+        if (loader && !paint) {
             auto scene = loader->data();
             if (scene) {
-                this->paint = scene.release();
+                paint = scene.release();
-                if (!this->paint) return false;
+                if (!paint) return;
                 loader->close();
             }
         }
+    }
+
+
+    bool update(RenderMethod &renderer, const RenderTransform* transform, RenderUpdateFlag flag)
+    {
+        reload();
 
         if (!paint) return false;
 
@@ -107,8 +113,15 @@ struct Picture::Impl
 
     Paint* duplicate()
     {
-        //TODO:
+        reload();
-        return nullptr;
+
+        if (!paint) return nullptr;
+        auto ret = Picture::gen();
+        if (!ret) return nullptr;
+        auto dup = ret.get()->pImpl;
+        dup->paint = paint->duplicate();
+
+        return ret.release();
     }
 };