105 lines
3.6 KiB
Java
105 lines
3.6 KiB
Java
/*
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* Copyright (C) 2021 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.internal.view;
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import static android.util.MathUtils.constrain;
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import static java.lang.Math.max;
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import static java.lang.Math.min;
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import android.annotation.NonNull;
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import android.graphics.Rect;
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import android.os.CancellationSignal;
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import android.webkit.WebView;
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import java.util.function.Consumer;
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/**
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* ScrollCapture for WebView.
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*/
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public class WebViewCaptureHelper implements ScrollCaptureViewHelper<WebView> {
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private static final String TAG = "WebViewScrollCapture";
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private final Rect mRequestWebViewLocal = new Rect();
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private final Rect mWebViewBounds = new Rect();
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private int mOriginScrollY;
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private int mOriginScrollX;
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@Override
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public boolean onAcceptSession(@NonNull WebView view) {
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return view.isVisibleToUser()
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&& (view.getContentHeight() * view.getScale()) > view.getHeight();
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}
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@Override
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public void onPrepareForStart(@NonNull WebView view, @NonNull Rect scrollBounds) {
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mOriginScrollX = view.getScrollX();
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mOriginScrollY = view.getScrollY();
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}
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@NonNull
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@Override
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public void onScrollRequested(@NonNull WebView view, @NonNull Rect scrollBounds,
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@NonNull Rect requestRect, CancellationSignal cancellationSignal,
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Consumer<ScrollResult> resultConsumer) {
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int scrollDelta = view.getScrollY() - mOriginScrollY;
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ScrollResult result = new ScrollResult();
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result.requestedArea = new Rect(requestRect);
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result.availableArea = new Rect();
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result.scrollDelta = scrollDelta;
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mWebViewBounds.set(0, 0, view.getWidth(), view.getHeight());
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if (!view.isVisibleToUser()) {
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resultConsumer.accept(result);
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}
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// Map the request into local coordinates
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mRequestWebViewLocal.set(requestRect);
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mRequestWebViewLocal.offset(0, -scrollDelta);
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// Offset to center the rect vertically, clamp to available content
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int upLimit = min(0, -view.getScrollY());
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int contentHeightPx = (int) (view.getContentHeight() * view.getScale());
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int downLimit = max(0, (contentHeightPx - view.getHeight()) - view.getScrollY());
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int scrollToCenter = mRequestWebViewLocal.centerY() - mWebViewBounds.centerY();
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int scrollMovement = constrain(scrollToCenter, upLimit, downLimit);
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// Scroll and update relative based on the new position
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view.scrollBy(mOriginScrollX, scrollMovement);
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scrollDelta = view.getScrollY() - mOriginScrollY;
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mRequestWebViewLocal.offset(0, -scrollMovement);
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result.scrollDelta = scrollDelta;
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if (mRequestWebViewLocal.intersect(mWebViewBounds)) {
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result.availableArea = new Rect(mRequestWebViewLocal);
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result.availableArea.offset(0, result.scrollDelta);
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}
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resultConsumer.accept(result);
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}
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@Override
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public void onPrepareForEnd(@NonNull WebView view) {
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view.scrollTo(mOriginScrollX, mOriginScrollY);
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}
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}
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