add grab output mipmap level feature

src/core/view/qglview.h

@@ -164,6 +164,8 @@ public:
 	void setGrabFormats(QFlags<Renderer::GrabFormat> f) { grab_formats = f; }
 	QImage getImage() const { return renderer_.getImage(); }
 	QVector<QVector4D> getImageF() const { return renderer_.getImageF(); }
+	void setGrabImageMipmap(int level);
+	void setGrabImageFMipmap(int level);
 
 	void setShadowMapSize(QSize sz);
 	void setTextureMapSize(QSize sz);