govips选项结构如何设置白色背景

Question

https://github.com/davidbyttow/govips Option

// Option is a type that is passed to internal libvips functions
type Option struct {
    Name   string
    ref    interface{}
    gvalue C.GValue
    closer func(gv *C.GValue)
    output bool
}

Fail to figure out how I can add a Option to embed in Go to set the white background

x := 100 - imgRef.Width()/2
y := 100 - imgRef.Height()/2
img, err := vips.Embed(imgRef.Image(), x, y, 200, 200, background)

I only know it's possible looking at de cli verion, but how to translate it into a Go Option struct is a mystery for me

$ vips embed
embed an image in a larger image
usage:
   embed in out x y width height
where:
   in           - Input image, input VipsImage
   out          - Output image, output VipsImage
   x            - Left edge of input in output, input gint
                            default: 0
                            min: -1000000000, max: 1000000000
   y            - Top edge of input in output, input gint
                            default: 0
                            min: -1000000000, max: 1000000000
   width        - Image width in pixels, input gint
                            default: 1
                            min: 1, max: 1000000000
   height       - Image height in pixels, input gint
                            default: 1
                            min: 1, max: 1000000000
optional arguments:
   extend       - How to generate the extra pixels, input VipsExtend
                            default: black
                            allowed: black, copy, repeat, mirror, white, background
   background   - Colour for background pixels, input VipsArrayDouble
operation flags: sequential-unbuffered 

Answer 1

x := 100 - imgRef.Width()/2
y := 100 - imgRef.Height()/2
img, err := vips.Embed(imgRef.Image(), x, y, 200, 200, vips.InputString("extend", "white"))

Found it, alleluia!