如何应用动态阿尔法面具在Android文本 [英] How to apply dynamic alpha mask to a Text on Android
问题描述
我希望具有可绘制形状为圆形或任何一个动态阿尔法口罩,并将其应用到Android上drawed文本。 下面是我想要一个例子:
I want to make a dynamic alpha mask with drawable shapes as circles or whatever, and apply it to a drawed text on Android. Here is an example of what i want :
我想,使其与 setXfermode(新PorterDuffXfermode(Mode.SRC_IN))
,但我无法得到它的工作。
这里是code我在的OnDraw(帆布油画)
方法:
I am trying to make it with setXfermode(new PorterDuffXfermode(Mode.SRC_IN))
, but i can't get it work.
Here is the code I have in onDraw(Canvas canvas)
method :
Paint paint = new Paint();
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(Color.WHITE);
canvas.drawCircle(50, 50, 50, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
paint.setColor(Color.RED);
canvas.drawText("hello", 0, 50, paint);
在此先感谢您的帮助
Thanks in advance for your help
推荐答案
尝试单独创建源和掩模位图。大多数我见过的例子涉及使用两个位图,并使用drawBitmap进行屏蔽。
Try creating your source and mask bitmaps separately. Most of the examples I have seen involve using two bitmaps and using drawBitmap to perform the masking.
我使用PorterDuff.Mode.DST_IN供漆,然后绘制源图像(无漆),随后用掩模图像(与涂料)。事情是这样的:
I use PorterDuff.Mode.DST_IN for the paint, then draw the source image (with no paint) followed by the mask image (with the paint). Something like this:
Bitmap bitmapOut = Bitmap.createBitmap(sizeX, sizeY,
Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmapOut);
Paint xferPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
xferPaint.setColor(Color.BLACK);
xferPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
canvas.drawBitmap(sourceImage, 0, 0, null);
canvas.drawBitmap(alphaMask, 0, 0, xferPaint);
在这一点上,bitmapOut包含我的蒙面形象。
At this point, bitmapOut contains my masked image.
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