A sizing function, or NULL
Deprecated: Use rsvg.handle.Handle.renderDocument instead. This function was deprecated because when the size_func is used, it makes it unclear when the librsvg functions which call the size_func will use the size computed originally, or the callback-specified size, or whether it refers to the whole SVG or to just a sub-element of it. It is easier, and unambiguous, to use code similar to the example above.
Sets the sizing function for the handle, which can be used to override the size that librsvg computes for SVG images. The size_func is called from the following functions:
Librsvg computes the size of the SVG being rendered, and passes it to the size_func, which may then modify these values to set the final size of the generated image.