Я использую пример кода изОсмысление мультитача для увеличения изображения. На ScaleListener я добавилScaleGestureDetector.getFocusX() and getFocusY()для контента, чтобы увеличить фокусную точку жеста. Работает нормально.

The problem is, on first multitouch the entire Image drawing position is changing to the current touch point and zooming it from there. Could you help me to resolve this issue?

Вот мой пример кода для TouchImageView.

public class TouchImageViewSample extends ImageView {

private Paint borderPaint = null;
private Paint backgroundPaint = null;

private float mPosX = 0f;
private float mPosY = 0f;

private float mLastTouchX;
private float mLastTouchY;
private static final int INVALID_POINTER_ID = -1;
private static final String LOG_TAG = "TouchImageView";

// The ‘active pointer’ is the one currently moving our object.
private int mActivePointerId = INVALID_POINTER_ID;

public TouchImageViewSample(Context context) {
    this(context, null, 0);
}

public TouchImageViewSample(Context context, AttributeSet attrs) {
    this(context, attrs, 0);
}

private ScaleGestureDetector mScaleDetector;
private float mScaleFactor = 1.f;

// Existing code ...
public TouchImageViewSample(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    // Create our ScaleGestureDetector
    mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());

    borderPaint = new Paint();
    borderPaint.setARGB(255, 255, 128, 0);
    borderPaint.setStyle(Paint.Style.STROKE);
    borderPaint.setStrokeWidth(4);

    backgroundPaint = new Paint();
    backgroundPaint.setARGB(32, 255, 255, 255);
    backgroundPaint.setStyle(Paint.Style.FILL);

}

@Override
public boolean onTouchEvent(MotionEvent ev) {
    // Let the ScaleGestureDetector inspect all events.
    mScaleDetector.onTouchEvent(ev);

    final int action = ev.getAction();
    switch (action & MotionEvent.ACTION_MASK) {
    case MotionEvent.ACTION_DOWN: {
        final float x = ev.getX();
        final float y = ev.getY();

        mLastTouchX = x;
        mLastTouchY = y;

        mActivePointerId = ev.getPointerId(0);
        break;
    }

    case MotionEvent.ACTION_MOVE: {
        final int pointerIndex = ev.findPointerIndex(mActivePointerId);
        final float x = ev.getX(pointerIndex);
        final float y = ev.getY(pointerIndex);

        // Only move if the ScaleGestureDetector isn't processing a gesture.
        if (!mScaleDetector.isInProgress()) {
            final float dx = x - mLastTouchX;
            final float dy = y - mLastTouchY;

            mPosX += dx;
            mPosY += dy;

            invalidate();
        }

        mLastTouchX = x;
        mLastTouchY = y;
        break;
    }

    case MotionEvent.ACTION_UP: {
        mActivePointerId = INVALID_POINTER_ID;
        break;
    }

    case MotionEvent.ACTION_CANCEL: {
        mActivePointerId = INVALID_POINTER_ID;
        break;
    }

    case MotionEvent.ACTION_POINTER_UP: {
        final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
        final int pointerId = ev.getPointerId(pointerIndex);
        if (pointerId == mActivePointerId) {
            // This was our active pointer going up. Choose a new
            // active pointer and adjust accordingly.
            final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
            mLastTouchX = ev.getX(newPointerIndex);
            mLastTouchY = ev.getY(newPointerIndex);
            mActivePointerId = ev.getPointerId(newPointerIndex);
        }
        break;
    }
    }

    return true;
}

/*
 * (non-Javadoc)
 * 
 * @see android.view.View#draw(android.graphics.Canvas)
 */
@Override
public void draw(Canvas canvas) {
    super.draw(canvas);
    canvas.drawRect(0, 0, getWidth() - 1, getHeight() - 1, borderPaint);
}

@Override
public void onDraw(Canvas canvas) {
    canvas.drawRect(0, 0, getWidth() - 1, getHeight() - 1, backgroundPaint);
    if (this.getDrawable() != null) {
        canvas.save();
        canvas.translate(mPosX, mPosY);

        Matrix matrix = new Matrix();
        matrix.postScale(mScaleFactor, mScaleFactor, pivotPointX,
                pivotPointY);
        // canvas.setMatrix(matrix);

        canvas.drawBitmap(
                ((BitmapDrawable) this.getDrawable()).getBitmap(), matrix,
                null);

        // this.getDrawable().draw(canvas);
        canvas.restore();
    }
}

/*
 * (non-Javadoc)
 * 
 * @see
 * android.widget.ImageView#setImageDrawable(android.graphics.drawable.Drawable
 * )
 */
@Override
public void setImageDrawable(Drawable drawable) {
    // Constrain to given size but keep aspect ratio
    int width = drawable.getIntrinsicWidth();
    int height = drawable.getIntrinsicHeight();
    mLastTouchX = mPosX = 0;
    mLastTouchY = mPosY = 0;

    int borderWidth = (int) borderPaint.getStrokeWidth();
    mScaleFactor = Math.min(((float) getLayoutParams().width - borderWidth)
            / width, ((float) getLayoutParams().height - borderWidth)
            / height);
    pivotPointX = (((float) getLayoutParams().width - borderWidth) - (int) (width * mScaleFactor)) / 2;
    pivotPointY = (((float) getLayoutParams().height - borderWidth) - (int) (height * mScaleFactor)) / 2;
    super.setImageDrawable(drawable);
}

float pivotPointX = 0f;
float pivotPointY = 0f;

private class ScaleListener extends
        ScaleGestureDetector.SimpleOnScaleGestureListener {

    @Override
    public boolean onScale(ScaleGestureDetector detector) {
        mScaleFactor *= detector.getScaleFactor();

        pivotPointX = detector.getFocusX();
        pivotPointY = detector.getFocusY();

        Log.d(LOG_TAG, "mScaleFactor " + mScaleFactor);
        Log.d(LOG_TAG, "pivotPointY " + pivotPointY + ", pivotPointX= "
                + pivotPointX);
        mScaleFactor = Math.max(0.05f, mScaleFactor);

        invalidate();
        return true;
    }
}

И вот как я использовал это в своей деятельности.

ImageView imageView = (ImageView) findViewById(R.id.imgView);

int hMargin = (int) (displayMetrics.widthPixels * .10);
int vMargin = (int) (displayMetrics.heightPixels * .10);

RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(displayMetrics.widthPixels - (hMargin * 2), (int)(displayMetrics.heightPixels - btnCamera.getHeight()) - (vMargin * 2));
params.leftMargin = hMargin;
params.topMargin =  vMargin;
imageView.setLayoutParams(params);
imageView.setImageDrawable(drawable);