func WhiteBG(gc *draw2d.ImageGraphicContext, xsize, ysize float64) {
gc.BeginPath()
gc.MoveTo(0, 0)
gc.LineTo(xsize, 0)
gc.LineTo(xsize, ysize)
gc.LineTo(0, ysize)
gc.LineTo(0, 0)
gc.Close()
gc.SetFillColor(color.RGBA{255, 255, 255, 0xff})
gc.Fill()
}
func DrawCircle(gc *draw2d.ImageGraphicContext, x, y float64) {
gc.ArcTo(x, y, 3, 3, 0, 2*math.Pi)
gc.SetFillColor(color.RGBA{255, 0, 0, 255})
gc.FillStroke()
}