code: func (i *Image) readPixelsFromGPU() {
  	pix := i.image.Pixels()
  	i.basePixels = &Pixels{
  		pixels: pix,
  		length: len(pix),
  	}
  	i.drawTrianglesHistory = nil
  	i.stale = false
  }
docs: // readPixelsFromGPU reads the pixels from GPU and resolves the image's 'stale' state.