src/com/android/browser/EdgeSwipeModel.java

/*
 * Copyright (c) 2015, The Linux Foundation. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 *       copyright notice, this list of conditions and the following
 *       disclaimer in the documentation and/or other materials provided
 *       with the distribution.
 *     * Neither the name of The Linux Foundation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

package com.android.browser;

import android.graphics.Bitmap;
import android.util.SparseArray;
import android.webkit.ValueCallback;

public class EdgeSwipeModel {
    private SparseArray<Bitmap> mBitmaps;
    private Tab mTab;
    private TitleBar mBar;

    private static final int mMinProgress = 85;

    private static final int mMaxBitmaps = 5;

    public EdgeSwipeModel(Tab tab, TitleBar bar) {
        mTab = tab;
        mBar = bar;
        mBitmaps = new SparseArray<>();
    }

    public void updateSnapshot(final int index) {
        if (mBitmaps.get(index) != null) {
            return;
        }

        int captureIndex = mTab.getCaptureIndex(index);

        boolean bitmapExists = mTab.getWebView().hasSnapshot(captureIndex);

        if (!mTab.isFirstVisualPixelPainted()) {
            fetchSnapshot(index);
            return;
        }

        int progress = mBar.getProgressView().getProgressPercent();

        if (bitmapExists && progress < mMinProgress) {
            fetchSnapshot(index);
            return;
        }

        mTab.getWebView().captureSnapshot(captureIndex,
                new ValueCallback<Bitmap>() {
                    @Override
                    public void onReceiveValue(Bitmap value) {
                        mBitmaps.put(index, value);
                    }
                }
        );
    }

    public void fetchSnapshot(final int index) {
        if (mBitmaps.get(index) != null) {
            return;
        }

        int captureIndex = mTab.getCaptureIndex(index);

        mTab.getWebView().getSnapshot(captureIndex,
                new ValueCallback<Bitmap>() {
                    @Override
                    public void onReceiveValue(Bitmap bitmap) {
                        mBitmaps.put(index, bitmap);
                    }
                }
        );
    }

    public Bitmap readSnapshot(int index) {
        if (index < 0) {
            return null;
        }

        if (index > (mTab.getWebView().copyBackForwardList().getSize() - 1)) {
            return null;
        }

        return mBitmaps.get(index);
    }

    public void deleteSnapshot(int index) {
        mBitmaps.delete(index);
    }

    public void cleanup() {
        mBitmaps.clear();
    }
}