Android Bitmap contour

问题

I'm trying to draw the contour of my drawable,
I tried to use Blur, as in this page:
How to make glow effect around a bitmap?
Its effect is not what I want,
I want a "solid" contour,
not blurred.

anyone knows how?

回答1:

There is no outline type filter or mask that I can find, while blur and shadow mask are not very strong. Hence you could create your own effect by using color filter and scale. This example would create a red contour

ColorFilter filter;
filter = new PorterDuffColorFilter(0xFFFF0000, PorterDuff.Mode.SRC_IN);         

paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setColorFilter(filter);

canvas.save();
canvas.scale(1.1f, 1.1f,imageCenterX , imageCenterY);
canvas.drawBitmap(image, imageX, imageY, paint);
canvas.restore();

canvas.drawBitmap(image, imageX, imageY, null);

It is fast enough for a game frame animation, I've tested it.

来源：https://stackoverflow.com/questions/6764412/android-bitmap-contour