func Scale(dst screen.Drawer, dr image.Rectangle, src screen.Texture, sr image.Rectangle, op draw.Op, opts *screen.DrawOptions) {
	rx := float64(dr.Dx()) / float64(sr.Dx())
	ry := float64(dr.Dy()) / float64(sr.Dy())
	dst.Draw(f64.Aff3{
		rx, 0, float64(dr.Min.X) - rx*float64(sr.Min.X),
		0, ry, float64(dr.Min.Y) - ry*float64(sr.Min.Y),
	}, src, sr, op, opts)
}
Scale implements the Scale method of the screen.Drawer interface by calling
the Draw method of that same interface.
package drawer  
import (
	"image"
	"image/draw"
	"golang.org/x/exp/shiny/screen"
	"golang.org/x/image/math/f64"
)
func Copy(dst screen.Drawer, dp image.Point, src screen.Texture, sr image.Rectangle, op draw.Op, opts *screen.DrawOptions) {
	dst.Draw(f64.Aff3{
		1, 0, float64(dp.X - sr.Min.X),
		0, 1, float64(dp.Y - sr.Min.Y),
	}, src, sr, op, opts)
}