Add support for ensuring sprite content size does not change on new t…

…exture (#1897)

* Add support for ensuring sprite content size does not change on new texture

* Use better method name for enabling sprite dynamic sizing

core/2d/Sprite.cpp

@@ -415,7 +415,10 @@ void Sprite::setTextureRect(const Rect& rect, bool rotated, const Vec2& untrimme
 {
     _rectRotated = rotated;
 
-    Node::setContentSize(untrimmedSize);
+    if (_autoSizeEnabled || _contentSize == Vec2::ZERO)
+    {
+        Node::setContentSize(untrimmedSize);
+    }
     _originalContentSize = untrimmedSize;
 
     setVertexRect(rect);

core/2d/Sprite.h

@@ -625,6 +625,14 @@ class AX_DLL Sprite : public Node, public TextureProtocol
 
     void setAutoUpdatePS(bool bVal) { _autoUpdatePS = bVal; }
 
+    /**
+     * Indicate if the sprite content size can change if new textures are applied to
+     * the sprite.
+     *
+     * @param enabled True if the sprite can change size on new frames/textures
+     */
+    void setAutoSize(bool enabled) { _autoSizeEnabled = enabled; }
+
 protected:
     virtual void updateColor() override;
     virtual void setTextureCoords(const Rect& rect);
@@ -703,6 +711,8 @@ class AX_DLL Sprite : public Node, public TextureProtocol
     bool _stretchEnabled = true;
     bool _autoUpdatePS   = true;
 
+    bool _autoSizeEnabled = true;
+
 private:
     AX_DISALLOW_COPY_AND_ASSIGN(Sprite);
 };