Canvasの外側を丸く塗る
/** * @param canvas */ private void setBlackEdge(Canvas canvas) { float w = canvas.getWidth(); float h = canvas.getHeight(); int[] colors = new int[] { 0x00000000, 0x00000000, 0xFF000000 }; RectF rect = new RectF(0, 0, w, h); // create a paint with a RadialGradient RadialGradient shader = new RadialGradient(w / 2, h / 2, w / 2, colors, null, TileMode.CLAMP); Paint paint = new Paint(); paint.setDither(true); paint.setAntiAlias(true); paint.setFilterBitmap(true); paint.setShader(shader); // paint the rectangle with said gradient canvas.drawRect(rect, paint); }