In this solution new Chart object is created and sized under new parent of visualtree. In my case such approach would cause a lot of problems since I would have to take already generated control with various bindings move it.

Such approach would violate many of application current used patterns not mentioning tons of possible errors. I have many different charts in with different parameters. Some have static series that are binded to properties, other generates variable number of series from bindings.

Is there any simple solution to render xamchart control to image of any size without manipulating visualtree?

I have found such solution on the internet but unfortunately it is poor one in case of printing. In this solution the size and proportions of the printed control are dependent on the current size of the window. If someone by coincidence will have little window on the printout there will be stretched image with awfully large pixels.

That is why I was referring to  UltraChart.RenderPdfFriendlyGraphics where the control is fully rendered according to given proportions. In WPF method you just copy-paste actual rendered state of the control.