Android nine patch - allow only a specific area of a background drawable to stretch

Question

How does one go about creating a View that has boundaries with triangular perforations ?

I\'ve been using background drawables to achieve this so

Answer 1

You can draw a zigzag path in background of your view

Rect rectZigzag = new Rect();
private Path pathZigzag = new Path();
private Paint paintZigzag;
private void init(){
    this.paintZigzag = new Paint();
    this.paintZigzag.setColor(zigzagBackgroundColor);
    this.paintZigzag.setStyle(Style.FILL);
}


private void drawZigzag() {
    float left = rectZigzag.left;
    float right = rectZigzag.right;
    float top = rectZigzag.top;
    float bottom = rectZigzag.bottom;
    int width = (int) (right - left);

    pathZigzag.moveTo(right, bottom);
    pathZigzag.lineTo(right, top);
    pathZigzag.lineTo(left, top);
    pathZigzag.lineTo(left, bottom);

    int h = zigzagHeight;
    int seed = 2 * h;
    int count = width / seed;
    int diff = width - (seed * count);
    int sideDiff = diff / 2;


    float x = (float) (seed / 2);
    float upHeight = bottom - h;
    float downHeight = bottom;

    for (int i = 0; i < count; i++) {
        int startSeed = (i * seed) + sideDiff + (int) left;
        int endSeed = startSeed + seed;

        if (i == 0) {
            startSeed = (int) left + sideDiff;
        } else if (i == count - 1) {
            endSeed = endSeed + sideDiff;
        }

        this.pathZigzag.lineTo(startSeed + x, upHeight);
        this.pathZigzag.lineTo(endSeed, downHeight);
    }
}

refrence