以下代码中,可以保存当前的globalAlpha属性的是?
C.
function saveDrawingSurface() { drawingSurfaceImageData = context.getImageData(0, 0, mycanvas.width, mycanvas.height); } saveDrawingSurface();
D.
function restoreDrawingSurface() { context.putImageData(drawingSurfaceImageData, 0, 0); } restoreDrawingSurface();