AndroidフィレットカスタムView

シナリオ1:
四角いフィレットは自由に設定できます

public class MMMImageView extends ImageView {
    public MMMImageView(Context context) {
        super(context);
    }

    public MMMImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MMMImageView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    //     x,y  
    private float[] radiusArray = { 50f, 50f, 50f, 0f, 50f, 50f, 50f, 50f };
    private Paint bitmapPaint = new Paint(Paint.ANTI_ALIAS_FLAG);

    private Bitmap makeRoundRectFrame(int w, int h) {
        Bitmap bm = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
        Canvas c = new Canvas(bm);
        Path path = new Path();
        path.addRoundRect(new RectF(0, 0, w, h), radiusArray, Path.Direction.CW);
        Paint bitmapPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        bitmapPaint.setColor(Color.GREEN); //     ，      。
        c.drawPath(path, bitmapPaint);
        return bm;
    }
    Bitmap bitmapFrame;
    @Override
    protected void onDraw(Canvas canvas) {
        //        
        final int w = getWidth();
        final int h = getHeight();
        Bitmap bitmapOriginal = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
        Canvas c = new Canvas(bitmapOriginal);

        super.onDraw(c);

        if (bitmapFrame == null) {
            bitmapFrame = makeRoundRectFrame(w, h);
        }

        int sc = canvas.saveLayer(0, 0, w, h, null, Canvas.ALL_SAVE_FLAG);

        canvas.drawBitmap(bitmapFrame, 0, 0, bitmapPaint);
        //   Xfermode   （  bitmapFrame       bitmapOriginal）
        bitmapPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        canvas.drawBitmap(bitmapOriginal, 0, 0, bitmapPaint);

        bitmapPaint.setXfermode(null);
        canvas.restoreToCount(sc);
    }
}

シナリオ2:

public class CornerView extends View {
    private final RectF roundRect = new RectF();
    private float rect_adius = 600;
    private final Paint maskPaint = new Paint();
    private final Paint zonePaint = new Paint();

    public CornerView(Context context) {
        super(context);
        init();
    }

    public CornerView(Context context,  AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public CornerView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }


    private void init() {
        maskPaint.setAntiAlias(true);
        maskPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        //
        zonePaint.setAntiAlias(true);
        zonePaint.setColor(Color.WHITE);
        //
        float density = getResources().getDisplayMetrics().density;
        rect_adius = rect_adius * density;
    }

    public void setCorner(float adius) {
        rect_adius = adius;
        invalidate();
    }

    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        super.onLayout(changed, left, top, right, bottom);
        int w = getWidth();
        int h = getHeight();
        roundRect.set(0, 0, w, h);
    }

    @Override
    public void draw(Canvas canvas) {
        canvas.saveLayer(roundRect, zonePaint, Canvas.ALL_SAVE_FLAG);
        canvas.drawRoundRect(roundRect, rect_adius, rect_adius, zonePaint);
        canvas.saveLayer(roundRect, maskPaint, Canvas.ALL_SAVE_FLAG);
        super.draw(canvas);
        canvas.restore();
    }
}