func fitCropScale(i image.Image, r image.Rectangle) image.Image {
wantRatio := float64(r.Bounds().Dx()) / float64(r.Bounds().Dy())
haveRatio := float64(i.Bounds().Dx()) / float64(i.Bounds().Dy())
sliceRect := image.Rectangle{}
if haveRatio > wantRatio {
wantwidth := wantRatio * float64(i.Bounds().Dy())
sliceRect = image.Rect(i.Bounds().Dx()/2-int(wantwidth/2), 0, i.Bounds().Dx()/2+int(wantwidth/2), i.Bounds().Dy())
} else {
wantheight := float64(i.Bounds().Dx()) / wantRatio
sliceRect = image.Rect(0, i.Bounds().Dy()/2-int(wantheight/2), i.Bounds().Dx(), i.Bounds().Dy()/2+int(wantheight/2))
}
return imaging.Resize(imaging.Crop(i, sliceRect), r.Dx(), r.Dy(), imaging.Lanczos)
}