/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License
*/
package com.android.systemui.statusbar.stack;
/**
* A functor which can be queried for offset given the number of items before it.
*/
public abstract class StackIndentationFunctor {
protected int mTotalTransitionDistance;
protected int mDistanceToPeekStart;
protected int mMaxItemsInStack;
protected int mPeekSize;
protected boolean mStackStartsAtPeek;
/**
* @param maxItemsInStack The maximum number of items which should be visible at the same time,
* i.e the function returns totalTransitionDistance for the element with
* index maxItemsInStack
* @param peekSize The visual appearance of this is how far the cards in the stack peek
* out below the top card and it is measured in real pixels.
* Note that the visual appearance does not necessarily always correspond to
* the actual visual distance below the top card but is a maximum,
* achieved when the next card just starts transitioning into the stack and
* the stack is full.
* If distanceToPeekStart is 0, we directly start at the peek, otherwise the
* first element transitions between 0 and distanceToPeekStart.
* Visualization:
* --------------------------------------------------- ---
* | | |
* | FIRST ITEM | | <- distanceToPeekStart
* | | |
* |---------------------------------------------------| --- ---
* |__________________SECOND ITEM______________________| | <- peekSize
* |===================================================| _|_
*
* @param distanceToPeekStart The distance to the start of the peak.
*/
StackIndentationFunctor(int maxItemsInStack, int peekSize, int distanceToPeekStart) {
mDistanceToPeekStart = distanceToPeekStart;
mStackStartsAtPeek = mDistanceToPeekStart == 0;
mMaxItemsInStack = maxItemsInStack;
mPeekSize = peekSize;
updateTotalTransitionDistance();
}
private void updateTotalTransitionDistance() {
mTotalTransitionDistance = mDistanceToPeekStart + mPeekSize;
}
public void setPeekSize(int mPeekSize) {
this.mPeekSize = mPeekSize;
updateTotalTransitionDistance();
}
public void setDistanceToPeekStart(int distanceToPeekStart) {
mDistanceToPeekStart = distanceToPeekStart;
mStackStartsAtPeek = mDistanceToPeekStart == 0;
updateTotalTransitionDistance();
}
/**
* Gets the offset of this Functor given a the quantity of items before it
*
* @param itemsBefore how many items are already in the stack before this element
* @return the offset
*/
public abstract float getValue(float itemsBefore);
}