minimize the height when use just half circle (forexample)

[alkiswanee]

my application just need 120deg from the circle , but the script need the full circle diameter as a layaoutframe height as in the shape :

total height of arc area = (min (height,width)-padding/2) >> arc diameter ..
but height 2 is not scrollable in (scroll view) .. and i dont need this area because my arc is not a full circle ..
how i can erase this (2) area .. or make it scrollable in framelayout ??

[longshishui]

Here is my solution for your reference. FYI.

1. Declare a global variable.

private int minSize = 0;

2. Create a method to calculate the height of the arc.

private int getArcHeight(int min) {
    int angle = 180 - mSweepAngle / 2;
    double arc = Math.PI * 2 / 360 * (angle);
    int arcHeight = (int) ((Math.cos(arc) + 1) * (min / 2));
    return arcHeight;
}

3. Override onMeasure() and give a min height.

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

    int height = getDefaultSize(getSuggestedMinimumHeight(),
            heightMeasureSpec);
    final int width = getDefaultSize(getSuggestedMinimumWidth(),
            widthMeasureSpec);
    final int min = Math.min(width, height);
    float top = 0;
    float left = 0;
    float right = 0;
    float bottom = 0;
    int arcDiameter = 0;
    minSize = min;
    arcDiameter = min - getPaddingLeft();

    mTranslateX = (int) (width * 0.5f);
    mTranslateY = (int) (min * 0.5f);

    mArcRadius = arcDiameter / 2;
    top = min / 2 - (arcDiameter / 2);
    left = width / 2 - (arcDiameter / 2);
    right = (left + arcDiameter);
    bottom = (top + arcDiameter);
    mArcRect.set(left, top, right, bottom);
    int newHeight = (int) (getArcHeight(minSize) + top);

    int arcStart = (int) mProgressSweep + mStartAngle + mRotation + 90;
    mThumbXPos = (int) (mArcRadius * Math.cos(Math.toRadians(arcStart)));
    mThumbYPos = (int) (mArcRadius * Math.sin(Math.toRadians(arcStart)));

    setTouchInSide(mTouchInside);
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);

    // Set view height
    setMeasuredDimension(width, newHeight);
}

4. Override onDraw() and adjust canvas size.

@Override
protected void onDraw(Canvas canvas) {
    if (!mClockwise) {
        canvas.scale(-1, 1, mArcRect.centerX(), mArcRect.centerY());
    }

    // Draw the arcs
    final int arcStart = mStartAngle + mAngleOffset + mRotation;
    final int arcSweep = mSweepAngle;

    // Erase the area 2
    double newHeight = getArcHeight(minSize) + getPaddingLeft() / 2;
    canvas.clipRect(0, 0, getMeasuredWidth(), (int) (newHeight), Region.Op.INTERSECT);
    // Set a conspicuous background, just for test.
    canvas.drawColor(Color.RED);
    canvas.drawArc(mArcRect, arcStart, arcSweep, false, mArcPaint);
    canvas.drawArc(mArcRect, arcStart, mProgressSweep, false,
            mProgressPaint);
    if (mEnabled) {
        // Draw the thumb nail
        canvas.translate(mTranslateX - mThumbXPos, mTranslateY - mThumbYPos);
        mThumb.draw(canvas);
    }
}

This is a demo screenshot.

The red rectangle represents the view's bounds.