/**
* Performs all necessary operations needed for dragging.
*
* @param event
*/
private void performDrag(MotionEvent event) {
mMatrix.set(mSavedMatrix);
OnChartGestureListener l = mChart.getOnChartGestureListener();
float dX, dY;
// check if axis is inverted
if (mChart.isAnyAxisInverted()
&& mClosestDataSetToTouch != null
&& mChart.getAxis(mClosestDataSetToTouch.getAxisDependency()).isInverted()) {
// if there is an inverted horizontalbarchart
if (mChart instanceof HorizontalBarChart) {
dX = -(event.getX() - mTouchStartPoint.x);
dY = event.getY() - mTouchStartPoint.y;
} else {
dX = event.getX() - mTouchStartPoint.x;
dY = -(event.getY() - mTouchStartPoint.y);
}
} else {
dX = event.getX() - mTouchStartPoint.x;
dY = event.getY() - mTouchStartPoint.y;
}
mMatrix.postTranslate(dX, dY);
if (l != null) l.onChartTranslate(event, dX, dY);
}
/**
* returns the correct translation depending on the provided x and y touch points
*
* @param x
* @param y
* @return
*/
public PointF getTrans(float x, float y) {
ViewPortHandler vph = mChart.getViewPortHandler();
float xTrans = x - vph.offsetLeft();
float yTrans = 0f;
// check if axis is inverted
if (mChart.isAnyAxisInverted()
&& mClosestDataSetToTouch != null
&& mChart.isInverted(mClosestDataSetToTouch.getAxisDependency())) {
yTrans = -(y - vph.offsetTop());
} else {
yTrans = -(mChart.getMeasuredHeight() - y - vph.offsetBottom());
}
return new PointF(xTrans, yTrans);
}