Question

怎么用canvas在bitmap上画个边框？

我需要给Bitmap搞个圆角，然后再添加个边框给它，下面的代码是弄圆角的，但是不知道怎么用canvas给bitmap添加边框，any ideas?Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Config.ARGB_8888); Canvas canvas = new Canvas(output); final Paint paint = new Paint(); final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight()); final RectF rectF = new RectF(rect); paint.setAntiAlias(true); canvas.drawARGB(0, 0, 0, 0); canvas.drawRoundRect(rectF, 20.0f, 20.0f, paint); paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); canvas.drawBitmap(bitmap, rect, rect, paint); return output;

Answer 1

一般都是使用path把canvas剪切成一个圆角矩形的，然后再绘制边框和图片apidemo里面有些例子可以参考

Answer 2

一般都是使用path把canvas剪切成一个圆角矩形的，
然后再绘制边框和图片apidemo里面有些例子可以参考

Answer 3

Bitmapoutput=Bitmap.createBitmap(bitmap.getWidth(),bitmap.getHeight(),Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
final RectF rectF = new RectF(rect);
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
canvas.drawRoundRect(rectF, 20.0f, 20.0f, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
return output;