question: public void updateDeltas ( int deltaX , int deltaY ) { if ( mLeftBorderActive ) { mDeltaX = Math . max ( - mBaselineX , deltaX ) ; mDeltaX = Math . min ( mBaselineWidth - 2 * mTouchTargetWidth , mDeltaX ) ; } else if ( mRightBorderActive ) { mDeltaX = Math . min ( mDragLayer . getWidth ( ) - ( mBaselineX + mBaselineWidth ) , deltaX ) ; mDeltaX = Math . max ( - mBaselineWidth + 2 * mTouchTargetWidth , mDeltaX ) ; } if ( mTopBorderActive ) { mDeltaY = Math . max ( - mBaselineY , deltaY ) ; mDeltaY = Math . min ( mBaselineHeight - 2 * mTouchTargetWidth , mDeltaY ) ; } else if ( mBottomBorderActive ) { mDeltaY = Math . min ( mDragLayer . getHeight ( ) - ( mBaselineY + mBaselineHeight ) , deltaY ) ; mDeltaY = Math . max ( - mBaselineHeight + 2 * mTouchTargetWidth , mDeltaY ) ; } }
target:  Here we bound the deltas such that the frame cannot be stretched beyond the extents of the CellLayout, and such that the frame's borders can't cross.