/**
* draw top/left half
*
* @param canvas
*/
private void drawPreviousHalf(Canvas canvas) {
final View v = viewForPage(getCurrentPageFloor());
canvas.save();
canvas.clipRect(isFlippingVertically() ? mTopRect : mLeftRect);
// if the view does not exist, skip drawing it
if (v != null) {
setDrawWithLayer(v, true);
v.draw(canvas);
}
drawPreviousShadow(canvas);
canvas.restore();
}
