Gets the preferred aspect ratio the this would like to be displayed at.
The aspect ratio is the width divided by the height, so a value of 0.5 means that the this prefers to be displayed twice as high as it is wide. Consumers of this interface can use this to preserve aspect ratio when displaying the paintable.
This is a purely informational value and does not in any way limit the values that may be passed to [method@Gdk.Paintable.snapshot].
Usually when a this returns nonzero values from [method@Gdk.Paintable.get_intrinsic_width] and [ method@Gdk.Paintable.get_intrinsic_height] the aspect ratio should conform to those values, though that is not required.
If the this does not have a preferred aspect ratio, it returns 0. Negative values are never returned.
the intrinsic aspect ratio of this or 0 if none.