我在下面的代码中使用了清晰的图像部分，
Paint round_brush;
class TouchView extends View
{
Paint pTouch;
int X = -100;
int Y = -100;
Canvas c2;
public TouchView(Context context, Bitmap background_bitmap_, Bitmap foreground_bitmap_)
{
super(context);
setFocusable(true);
setFocusableInTouchMode(true);
background_bitmap = null;
foreground_bitmap = null;
background_bitmap = background_bitmap_;
foreground_bitmap = foreground_bitmap_.copy(Bitmap.Config.ARGB_8888, true);
c2 = new Canvas(foreground_bitmap);
pTouch = new Paint(); //Paint.ANTI_ALIAS_FLAG
pTouch.setAlpha(0xFF);
pTouch.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
pTouch.setColor(Color.TRANSPARENT);
//pTouch.setMaskFilter(new BlurMaskFilter(15, Blur.NORMAL));
setLayerType(View.LAYER_TYPE_SOFTWARE, null);
round_brush = new Paint();
// smooths out the edges of what is being drawn
round_brush.setAntiAlias(true);
// set color
round_brush.setColor(Color.GRAY);
// set style
round_brush.setStyle(Paint.Style.STROKE);
// set stroke
round_brush.setStrokeWidth(4);
}
@Override
public boolean onTouchEvent(MotionEvent ev)
{
switch (ev.getAction())
{
case MotionEvent.ACTION_DOWN:
{
X = (int) ev.getX();
Y = (int) ev.getY();
invalidate();
break;
}
case MotionEvent.ACTION_MOVE:
{
X = (int) ev.getX();
Y = (int) ev.getY();
invalidate();
break;
}
case MotionEvent.ACTION_UP:
break;
}
return true;
}
@Override
public void onDraw(Canvas canvas)
{
super.onDraw(canvas);
//draw background
canvas.drawBitmap(background_bitmap, new Matrix(), null);
//cropping part of above image
c2.drawCircle(X, Y, brushSize, pTouch);
canvas.drawCircle(X, Y, brushSize, round_brush);
//draw the overlay over the background
canvas.drawBitmap(foreground_bitmap, new Matrix(), null);
}
}
当我在4.4或更低的设备上测试时，它按预期工作，一切都很好！但在5.0或以上的设备上它绘制黑色圆圈！为什么？怎么了？ 5.0或以上设备是否有特殊条件？
我的测试设备结果，