给bitmap添加一个背景，实现centerCrop效果

private Bitmap getCenterCropBitmap(int fillColor,int roundWidth,int roundHeight, Bitmap bitmap) {

Bitmap output = Bitmap.createBitmap(roundWidth, roundHeight, Bitmap.Config.ARGB_8888);

Canvas canvas =new Canvas(output);

RectF outerRect =new RectF(0,0, roundWidth, roundHeight);

Paint paint =new Paint(Paint.ANTI_ALIAS_FLAG);

paint.setColor(fillColor);

paint.setStyle(Paint.Style.FILL);

canvas.drawRoundRect(outerRect,0,0, paint);

int bitmapWidth = bitmap.getWidth();

int bitmapHeight = bitmap.getHeight();

float oldsc = roundWidth / (float) roundHeight;

float newsc = bitmapWidth / (float) bitmapHeight;

if (oldsc > newsc) {

int newHei = roundHeight;

int newWid = newHei * bitmapWidth / bitmapHeight;

Bitmap newBit = Bitmap.createScaledBitmap(bitmap, newWid, newHei,true);

if (newBit !=null) {

canvas.drawBitmap(newBit, (roundWidth - newWid) /2,0, paint);

}

}else if (oldsc < newsc) {

int newWid = roundWidth;

int newHei = newWid * bitmapHeight / bitmapWidth;

Bitmap newBit = Bitmap.createScaledBitmap(bitmap, newWid, newHei,true);

if (newBit !=null) {

canvas.drawBitmap(newBit,0, (roundHeight - newHei) /2, paint);

}

}else {

int newWid = roundWidth;

int newHei = newWid;

Bitmap newBit = Bitmap.createScaledBitmap(bitmap, newWid, newHei,true);

if (newBit !=null) {

canvas.drawBitmap(newBit,0,0, paint);

}

}

canvas.save();

canvas.restore();

return output;

}