michael@0: /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: package org.mozilla.gecko.gfx;
michael@0: 
michael@0: import org.mozilla.gecko.GeckoAppShell;
michael@0: import org.mozilla.gecko.GeckoEvent;
michael@0: import org.mozilla.gecko.gfx.LayerView.DrawListener;
michael@0: import org.mozilla.gecko.Tab;
michael@0: import org.mozilla.gecko.Tabs;
michael@0: import org.mozilla.gecko.ZoomConstraints;
michael@0: import org.mozilla.gecko.mozglue.RobocopTarget;
michael@0: import org.mozilla.gecko.mozglue.generatorannotations.WrapElementForJNI;
michael@0: import org.mozilla.gecko.EventDispatcher;
michael@0: import org.mozilla.gecko.util.FloatUtils;
michael@0: 
michael@0: import android.content.Context;
michael@0: import android.graphics.PointF;
michael@0: import android.graphics.RectF;
michael@0: import android.os.SystemClock;
michael@0: import android.util.DisplayMetrics;
michael@0: import android.util.Log;
michael@0: 
michael@0: import java.util.ArrayList;
michael@0: import java.util.List;
michael@0: 
michael@0: class GeckoLayerClient implements LayerView.Listener, PanZoomTarget
michael@0: {
michael@0:     private static final String LOGTAG = "GeckoLayerClient";
michael@0: 
michael@0:     private LayerRenderer mLayerRenderer;
michael@0:     private boolean mLayerRendererInitialized;
michael@0: 
michael@0:     private Context mContext;
michael@0:     private IntSize mScreenSize;
michael@0:     private IntSize mWindowSize;
michael@0:     private DisplayPortMetrics mDisplayPort;
michael@0: 
michael@0:     private boolean mRecordDrawTimes;
michael@0:     private final DrawTimingQueue mDrawTimingQueue;
michael@0: 
michael@0:     private VirtualLayer mRootLayer;
michael@0: 
michael@0:     /* The Gecko viewport as per the UI thread. Must be touched only on the UI thread.
michael@0:      * If any events being sent to Gecko that are relative to the Gecko viewport position,
michael@0:      * they must (a) be relative to this viewport, and (b) be sent on the UI thread to
michael@0:      * avoid races. As long as these two conditions are satisfied, and the events being
michael@0:      * sent to Gecko are processed in FIFO order, the events will properly be relative
michael@0:      * to the Gecko viewport position. Note that if Gecko updates its viewport independently,
michael@0:      * we get notified synchronously and also update this on the UI thread.
michael@0:      */
michael@0:     private ImmutableViewportMetrics mGeckoViewport;
michael@0: 
michael@0:     /*
michael@0:      * The viewport metrics being used to draw the current frame. This is only
michael@0:      * accessed by the compositor thread, and so needs no synchronisation.
michael@0:      */
michael@0:     private ImmutableViewportMetrics mFrameMetrics;
michael@0: 
michael@0:     private List<DrawListener> mDrawListeners;
michael@0: 
michael@0:     /* Used as temporaries by syncViewportInfo */
michael@0:     private final ViewTransform mCurrentViewTransform;
michael@0:     private final RectF mCurrentViewTransformMargins;
michael@0: 
michael@0:     /* Used as the return value of progressiveUpdateCallback */
michael@0:     private final ProgressiveUpdateData mProgressiveUpdateData;
michael@0:     private DisplayPortMetrics mProgressiveUpdateDisplayPort;
michael@0:     private boolean mLastProgressiveUpdateWasLowPrecision;
michael@0:     private boolean mProgressiveUpdateWasInDanger;
michael@0: 
michael@0:     private boolean mForceRedraw;
michael@0: 
michael@0:     /* The current viewport metrics.
michael@0:      * This is volatile so that we can read and write to it from different threads.
michael@0:      * We avoid synchronization to make getting the viewport metrics from
michael@0:      * the compositor as cheap as possible. The viewport is immutable so
michael@0:      * we don't need to worry about anyone mutating it while we're reading from it.
michael@0:      * Specifically:
michael@0:      * 1) reading mViewportMetrics from any thread is fine without synchronization
michael@0:      * 2) writing to mViewportMetrics requires synchronizing on the layer controller object
michael@0:      * 3) whenver reading multiple fields from mViewportMetrics without synchronization (i.e. in
michael@0:      *    case 1 above) you should always frist grab a local copy of the reference, and then use
michael@0:      *    that because mViewportMetrics might get reassigned in between reading the different
michael@0:      *    fields. */
michael@0:     private volatile ImmutableViewportMetrics mViewportMetrics;
michael@0:     private LayerView.OnMetricsChangedListener mViewportChangeListener;
michael@0: 
michael@0:     private ZoomConstraints mZoomConstraints;
michael@0: 
michael@0:     private boolean mGeckoIsReady;
michael@0: 
michael@0:     private final PanZoomController mPanZoomController;
michael@0:     private final LayerMarginsAnimator mMarginsAnimator;
michael@0:     private LayerView mView;
michael@0: 
michael@0:     /* This flag is true from the time that browser.js detects a first-paint is about to start,
michael@0:      * to the time that we receive the first-paint composite notification from the compositor.
michael@0:      * Note that there is a small race condition with this; if there are two paints that both
michael@0:      * have the first-paint flag set, and the second paint happens concurrently with the
michael@0:      * composite for the first paint, then this flag may be set to true prematurely. Fixing this
michael@0:      * is possible but risky; see https://bugzilla.mozilla.org/show_bug.cgi?id=797615#c751
michael@0:      */
michael@0:     private volatile boolean mContentDocumentIsDisplayed;
michael@0: 
michael@0:     public GeckoLayerClient(Context context, LayerView view, EventDispatcher eventDispatcher) {
michael@0:         // we can fill these in with dummy values because they are always written
michael@0:         // to before being read
michael@0:         mContext = context;
michael@0:         mScreenSize = new IntSize(0, 0);
michael@0:         mWindowSize = new IntSize(0, 0);
michael@0:         mDisplayPort = new DisplayPortMetrics();
michael@0:         mRecordDrawTimes = true;
michael@0:         mDrawTimingQueue = new DrawTimingQueue();
michael@0:         mCurrentViewTransform = new ViewTransform(0, 0, 1);
michael@0:         mCurrentViewTransformMargins = new RectF();
michael@0:         mProgressiveUpdateData = new ProgressiveUpdateData();
michael@0:         mProgressiveUpdateDisplayPort = new DisplayPortMetrics();
michael@0:         mLastProgressiveUpdateWasLowPrecision = false;
michael@0:         mProgressiveUpdateWasInDanger = false;
michael@0: 
michael@0:         mForceRedraw = true;
michael@0:         DisplayMetrics displayMetrics = context.getResources().getDisplayMetrics();
michael@0:         mViewportMetrics = new ImmutableViewportMetrics(displayMetrics)
michael@0:                            .setViewportSize(view.getWidth(), view.getHeight());
michael@0:         mZoomConstraints = new ZoomConstraints(false);
michael@0: 
michael@0:         Tab tab = Tabs.getInstance().getSelectedTab();
michael@0:         if (tab != null) {
michael@0:             mZoomConstraints = tab.getZoomConstraints();
michael@0:             mViewportMetrics = mViewportMetrics.setIsRTL(tab.getIsRTL());
michael@0:         }
michael@0: 
michael@0:         mFrameMetrics = mViewportMetrics;
michael@0: 
michael@0:         mDrawListeners = new ArrayList<DrawListener>();
michael@0:         mPanZoomController = PanZoomController.Factory.create(this, view, eventDispatcher);
michael@0:         mMarginsAnimator = new LayerMarginsAnimator(this, view);
michael@0:         mView = view;
michael@0:         mView.setListener(this);
michael@0:         mContentDocumentIsDisplayed = true;
michael@0:     }
michael@0: 
michael@0:     public void setOverscrollHandler(final Overscroll listener) {
michael@0:         mPanZoomController.setOverscrollHandler(listener);
michael@0:     }
michael@0: 
michael@0:     /** Attaches to root layer so that Gecko appears. */
michael@0:     public void notifyGeckoReady() {
michael@0:         mGeckoIsReady = true;
michael@0: 
michael@0:         mRootLayer = new VirtualLayer(new IntSize(mView.getWidth(), mView.getHeight()));
michael@0:         mLayerRenderer = mView.getRenderer();
michael@0: 
michael@0:         sendResizeEventIfNecessary(true);
michael@0: 
michael@0:         DisplayPortCalculator.initPrefs();
michael@0: 
michael@0:         // Gecko being ready is one of the two conditions (along with having an available
michael@0:         // surface) that cause us to create the compositor. So here, now that we know gecko
michael@0:         // is ready, call updateCompositor() to see if we can actually do the creation.
michael@0:         // This needs to run on the UI thread so that the surface validity can't change on
michael@0:         // us while we're in the middle of creating the compositor.
michael@0:         mView.post(new Runnable() {
michael@0:             @Override
michael@0:             public void run() {
michael@0:                 mView.getGLController().updateCompositor();
michael@0:             }
michael@0:         });
michael@0:     }
michael@0: 
michael@0:     public void destroy() {
michael@0:         mPanZoomController.destroy();
michael@0:         mMarginsAnimator.destroy();
michael@0:         mDrawListeners.clear();
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Returns true if this client is fine with performing a redraw operation or false if it
michael@0:      * would prefer that the action didn't take place.
michael@0:      */
michael@0:     private boolean getRedrawHint() {
michael@0:         if (mForceRedraw) {
michael@0:             mForceRedraw = false;
michael@0:             return true;
michael@0:         }
michael@0: 
michael@0:         if (!mPanZoomController.getRedrawHint()) {
michael@0:             return false;
michael@0:         }
michael@0: 
michael@0:         return DisplayPortCalculator.aboutToCheckerboard(mViewportMetrics,
michael@0:                 mPanZoomController.getVelocityVector(), mDisplayPort);
michael@0:     }
michael@0: 
michael@0:     Layer getRoot() {
michael@0:         return mGeckoIsReady ? mRootLayer : null;
michael@0:     }
michael@0: 
michael@0:     public LayerView getView() {
michael@0:         return mView;
michael@0:     }
michael@0: 
michael@0:     public FloatSize getViewportSize() {
michael@0:         return mViewportMetrics.getSize();
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * The view calls this function to indicate that the viewport changed size. It must hold the
michael@0:      * monitor while calling it.
michael@0:      *
michael@0:      * TODO: Refactor this to use an interface. Expose that interface only to the view and not
michael@0:      * to the layer client. That way, the layer client won't be tempted to call this, which might
michael@0:      * result in an infinite loop.
michael@0:      */
michael@0:     void setViewportSize(int width, int height) {
michael@0:         mViewportMetrics = mViewportMetrics.setViewportSize(width, height);
michael@0: 
michael@0:         if (mGeckoIsReady) {
michael@0:             // here we send gecko a resize message. The code in browser.js is responsible for
michael@0:             // picking up on that resize event, modifying the viewport as necessary, and informing
michael@0:             // us of the new viewport.
michael@0:             sendResizeEventIfNecessary(true);
michael@0:             // the following call also sends gecko a message, which will be processed after the resize
michael@0:             // message above has updated the viewport. this message ensures that if we have just put
michael@0:             // focus in a text field, we scroll the content so that the text field is in view.
michael@0:             GeckoAppShell.viewSizeChanged();
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     PanZoomController getPanZoomController() {
michael@0:         return mPanZoomController;
michael@0:     }
michael@0: 
michael@0:     LayerMarginsAnimator getLayerMarginsAnimator() {
michael@0:         return mMarginsAnimator;
michael@0:     }
michael@0: 
michael@0:     /* Informs Gecko that the screen size has changed. */
michael@0:     private void sendResizeEventIfNecessary(boolean force) {
michael@0:         DisplayMetrics metrics = mContext.getResources().getDisplayMetrics();
michael@0: 
michael@0:         IntSize newScreenSize = new IntSize(metrics.widthPixels, metrics.heightPixels);
michael@0:         IntSize newWindowSize = new IntSize(mView.getWidth(), mView.getHeight());
michael@0: 
michael@0:         boolean screenSizeChanged = !mScreenSize.equals(newScreenSize);
michael@0:         boolean windowSizeChanged = !mWindowSize.equals(newWindowSize);
michael@0: 
michael@0:         if (!force && !screenSizeChanged && !windowSizeChanged) {
michael@0:             return;
michael@0:         }
michael@0: 
michael@0:         mScreenSize = newScreenSize;
michael@0:         mWindowSize = newWindowSize;
michael@0: 
michael@0:         if (screenSizeChanged) {
michael@0:             Log.d(LOGTAG, "Screen-size changed to " + mScreenSize);
michael@0:         }
michael@0: 
michael@0:         if (windowSizeChanged) {
michael@0:             Log.d(LOGTAG, "Window-size changed to " + mWindowSize);
michael@0:         }
michael@0: 
michael@0:         GeckoEvent event = GeckoEvent.createSizeChangedEvent(mWindowSize.width, mWindowSize.height,
michael@0:                                                              mScreenSize.width, mScreenSize.height);
michael@0:         GeckoAppShell.sendEventToGecko(event);
michael@0:         GeckoAppShell.sendEventToGecko(GeckoEvent.createBroadcastEvent("Window:Resize", ""));
michael@0:     }
michael@0: 
michael@0:     /** Sets the current page rect. You must hold the monitor while calling this. */
michael@0:     private void setPageRect(RectF rect, RectF cssRect) {
michael@0:         // Since the "rect" is always just a multiple of "cssRect" we don't need to
michael@0:         // check both; this function assumes that both "rect" and "cssRect" are relative
michael@0:         // the zoom factor in mViewportMetrics.
michael@0:         if (mViewportMetrics.getCssPageRect().equals(cssRect))
michael@0:             return;
michael@0: 
michael@0:         mViewportMetrics = mViewportMetrics.setPageRect(rect, cssRect);
michael@0: 
michael@0:         // Page size is owned by the layer client, so no need to notify it of
michael@0:         // this change.
michael@0: 
michael@0:         post(new Runnable() {
michael@0:             @Override
michael@0:             public void run() {
michael@0:                 mPanZoomController.pageRectUpdated();
michael@0:                 mView.requestRender();
michael@0:             }
michael@0:         });
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Derives content document fixed position margins/fixed layer margins from
michael@0:      * the view margins in the given metrics object.
michael@0:      */
michael@0:     private void getFixedMargins(ImmutableViewportMetrics metrics, RectF fixedMargins) {
michael@0:         fixedMargins.left = 0;
michael@0:         fixedMargins.top = 0;
michael@0:         fixedMargins.right = 0;
michael@0:         fixedMargins.bottom = 0;
michael@0: 
michael@0:         // The maximum margins are determined by the scrollable area of the page.
michael@0:         float maxMarginWidth = Math.max(0, metrics.getPageWidth() - metrics.getWidthWithoutMargins());
michael@0:         float maxMarginHeight = Math.max(0, metrics.getPageHeight() - metrics.getHeightWithoutMargins());
michael@0: 
michael@0:         // If the margins can't fully hide, they're pinned on - in which case,
michael@0:         // fixed margins should always be zero.
michael@0:         if (maxMarginWidth < metrics.marginLeft + metrics.marginRight) {
michael@0:           maxMarginWidth = 0;
michael@0:         }
michael@0:         if (maxMarginHeight < metrics.marginTop + metrics.marginBottom) {
michael@0:           maxMarginHeight = 0;
michael@0:         }
michael@0: 
michael@0:         PointF offset = metrics.getMarginOffset();
michael@0:         RectF overscroll = metrics.getOverscroll();
michael@0:         if (offset.x >= 0) {
michael@0:             fixedMargins.right = Math.max(0, Math.min(offset.x - overscroll.right, maxMarginWidth));
michael@0:         } else {
michael@0:             fixedMargins.left = Math.max(0, Math.min(-offset.x - overscroll.left, maxMarginWidth));
michael@0:         }
michael@0:         if (offset.y >= 0) {
michael@0:             fixedMargins.bottom = Math.max(0, Math.min(offset.y - overscroll.bottom, maxMarginHeight));
michael@0:         } else {
michael@0:             fixedMargins.top = Math.max(0, Math.min(-offset.y - overscroll.top, maxMarginHeight));
michael@0:         }
michael@0: 
michael@0:         // Adjust for overscroll. If we're overscrolled on one side, add that
michael@0:         // distance to the margins of the other side (limiting to the maximum
michael@0:         // margin size calculated above).
michael@0:         if (overscroll.left > 0) {
michael@0:             fixedMargins.right = Math.min(maxMarginWidth - fixedMargins.left,
michael@0:                                           fixedMargins.right + overscroll.left);
michael@0:         } else if (overscroll.right > 0) {
michael@0:             fixedMargins.left = Math.min(maxMarginWidth - fixedMargins.right,
michael@0:                                          fixedMargins.left + overscroll.right);
michael@0:         }
michael@0:         if (overscroll.top > 0) {
michael@0:             fixedMargins.bottom = Math.min(maxMarginHeight - fixedMargins.top,
michael@0:                                            fixedMargins.bottom + overscroll.top);
michael@0:         } else if (overscroll.bottom > 0) {
michael@0:             fixedMargins.top = Math.min(maxMarginHeight - fixedMargins.bottom,
michael@0:                                         fixedMargins.top + overscroll.bottom);
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     private void adjustViewport(DisplayPortMetrics displayPort) {
michael@0:         ImmutableViewportMetrics metrics = getViewportMetrics();
michael@0:         ImmutableViewportMetrics clampedMetrics = metrics.clamp();
michael@0: 
michael@0:         RectF margins = new RectF();
michael@0:         getFixedMargins(metrics, margins);
michael@0:         clampedMetrics = clampedMetrics.setMargins(
michael@0:             margins.left, margins.top, margins.right, margins.bottom);
michael@0: 
michael@0:         if (displayPort == null) {
michael@0:             displayPort = DisplayPortCalculator.calculate(metrics, mPanZoomController.getVelocityVector());
michael@0:         }
michael@0: 
michael@0:         mDisplayPort = displayPort;
michael@0:         mGeckoViewport = clampedMetrics;
michael@0: 
michael@0:         if (mRecordDrawTimes) {
michael@0:             mDrawTimingQueue.add(displayPort);
michael@0:         }
michael@0: 
michael@0:         GeckoAppShell.sendEventToGecko(GeckoEvent.createViewportEvent(clampedMetrics, displayPort));
michael@0:     }
michael@0: 
michael@0:     /** Aborts any pan/zoom animation that is currently in progress. */
michael@0:     private void abortPanZoomAnimation() {
michael@0:         if (mPanZoomController != null) {
michael@0:             post(new Runnable() {
michael@0:                 @Override
michael@0:                 public void run() {
michael@0:                     mPanZoomController.abortAnimation();
michael@0:                 }
michael@0:             });
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * The different types of Viewport messages handled. All viewport events
michael@0:      * expect a display-port to be returned, but can handle one not being
michael@0:      * returned.
michael@0:      */
michael@0:     private enum ViewportMessageType {
michael@0:         UPDATE,       // The viewport has changed and should be entirely updated
michael@0:         PAGE_SIZE     // The viewport's page-size has changed
michael@0:     }
michael@0: 
michael@0:     /** Viewport message handler. */
michael@0:     private DisplayPortMetrics handleViewportMessage(ImmutableViewportMetrics messageMetrics, ViewportMessageType type) {
michael@0:         synchronized (getLock()) {
michael@0:             ImmutableViewportMetrics newMetrics;
michael@0:             ImmutableViewportMetrics oldMetrics = getViewportMetrics();
michael@0: 
michael@0:             switch (type) {
michael@0:             default:
michael@0:             case UPDATE:
michael@0:                 // Keep the old viewport size
michael@0:                 newMetrics = messageMetrics.setViewportSize(oldMetrics.getWidth(), oldMetrics.getHeight());
michael@0:                 if (!oldMetrics.fuzzyEquals(newMetrics)) {
michael@0:                     abortPanZoomAnimation();
michael@0:                 }
michael@0:                 break;
michael@0:             case PAGE_SIZE:
michael@0:                 // adjust the page dimensions to account for differences in zoom
michael@0:                 // between the rendered content (which is what Gecko tells us)
michael@0:                 // and our zoom level (which may have diverged).
michael@0:                 float scaleFactor = oldMetrics.zoomFactor / messageMetrics.zoomFactor;
michael@0:                 newMetrics = oldMetrics.setPageRect(RectUtils.scale(messageMetrics.getPageRect(), scaleFactor), messageMetrics.getCssPageRect());
michael@0:                 break;
michael@0:             }
michael@0: 
michael@0:             // Update the Gecko-side viewport metrics. Make sure to do this
michael@0:             // before modifying the metrics below.
michael@0:             final ImmutableViewportMetrics geckoMetrics = newMetrics.clamp();
michael@0:             post(new Runnable() {
michael@0:                 @Override
michael@0:                 public void run() {
michael@0:                     mGeckoViewport = geckoMetrics;
michael@0:                 }
michael@0:             });
michael@0: 
michael@0:             setViewportMetrics(newMetrics, type == ViewportMessageType.UPDATE);
michael@0:             mDisplayPort = DisplayPortCalculator.calculate(getViewportMetrics(), null);
michael@0:         }
michael@0:         return mDisplayPort;
michael@0:     }
michael@0: 
michael@0:     @WrapElementForJNI
michael@0:     DisplayPortMetrics getDisplayPort(boolean pageSizeUpdate, boolean isBrowserContentDisplayed, int tabId, ImmutableViewportMetrics metrics) {
michael@0:         Tabs tabs = Tabs.getInstance();
michael@0:         if (isBrowserContentDisplayed && tabs.isSelectedTabId(tabId)) {
michael@0:             // for foreground tabs, send the viewport update unless the document
michael@0:             // displayed is different from the content document. In that case, just
michael@0:             // calculate the display port.
michael@0:             return handleViewportMessage(metrics, pageSizeUpdate ? ViewportMessageType.PAGE_SIZE : ViewportMessageType.UPDATE);
michael@0:         } else {
michael@0:             // for background tabs, request a new display port calculation, so that
michael@0:             // when we do switch to that tab, we have the correct display port and
michael@0:             // don't need to draw twice (once to allow the first-paint viewport to
michael@0:             // get to java, and again once java figures out the display port).
michael@0:             return DisplayPortCalculator.calculate(metrics, null);
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     @WrapElementForJNI
michael@0:     void contentDocumentChanged() {
michael@0:         mContentDocumentIsDisplayed = false;
michael@0:     }
michael@0: 
michael@0:     @WrapElementForJNI
michael@0:     boolean isContentDocumentDisplayed() {
michael@0:         return mContentDocumentIsDisplayed;
michael@0:     }
michael@0: 
michael@0:     // This is called on the Gecko thread to determine if we're still interested
michael@0:     // in the update of this display-port to continue. We can return true here
michael@0:     // to abort the current update and continue with any subsequent ones. This
michael@0:     // is useful for slow-to-render pages when the display-port starts lagging
michael@0:     // behind enough that continuing to draw it is wasted effort.
michael@0:     @WrapElementForJNI(allowMultithread = true)
michael@0:     public ProgressiveUpdateData progressiveUpdateCallback(boolean aHasPendingNewThebesContent,
michael@0:                                                            float x, float y, float width, float height,
michael@0:                                                            float resolution, boolean lowPrecision) {
michael@0:         // Reset the checkerboard risk flag when switching to low precision
michael@0:         // rendering.
michael@0:         if (lowPrecision && !mLastProgressiveUpdateWasLowPrecision) {
michael@0:             // Skip low precision rendering until we're at risk of checkerboarding.
michael@0:             if (!mProgressiveUpdateWasInDanger) {
michael@0:                 mProgressiveUpdateData.abort = true;
michael@0:                 return mProgressiveUpdateData;
michael@0:             }
michael@0:             mProgressiveUpdateWasInDanger = false;
michael@0:         }
michael@0:         mLastProgressiveUpdateWasLowPrecision = lowPrecision;
michael@0: 
michael@0:         // Grab a local copy of the last display-port sent to Gecko and the
michael@0:         // current viewport metrics to avoid races when accessing them.
michael@0:         DisplayPortMetrics displayPort = mDisplayPort;
michael@0:         ImmutableViewportMetrics viewportMetrics = mViewportMetrics;
michael@0:         mProgressiveUpdateData.setViewport(viewportMetrics);
michael@0:         mProgressiveUpdateData.abort = false;
michael@0: 
michael@0:         // Always abort updates if the resolution has changed. There's no use
michael@0:         // in drawing at the incorrect resolution.
michael@0:         if (!FloatUtils.fuzzyEquals(resolution, viewportMetrics.zoomFactor)) {
michael@0:             Log.d(LOGTAG, "Aborting draw due to resolution change: " + resolution + " != " + viewportMetrics.zoomFactor);
michael@0:             mProgressiveUpdateData.abort = true;
michael@0:             return mProgressiveUpdateData;
michael@0:         }
michael@0: 
michael@0:         // Store the high precision displayport for comparison when doing low
michael@0:         // precision updates.
michael@0:         if (!lowPrecision) {
michael@0:             if (!FloatUtils.fuzzyEquals(resolution, mProgressiveUpdateDisplayPort.resolution) ||
michael@0:                 !FloatUtils.fuzzyEquals(x, mProgressiveUpdateDisplayPort.getLeft()) ||
michael@0:                 !FloatUtils.fuzzyEquals(y, mProgressiveUpdateDisplayPort.getTop()) ||
michael@0:                 !FloatUtils.fuzzyEquals(x + width, mProgressiveUpdateDisplayPort.getRight()) ||
michael@0:                 !FloatUtils.fuzzyEquals(y + height, mProgressiveUpdateDisplayPort.getBottom())) {
michael@0:                 mProgressiveUpdateDisplayPort =
michael@0:                     new DisplayPortMetrics(x, y, x+width, y+height, resolution);
michael@0:             }
michael@0:         }
michael@0: 
michael@0:         // If we're not doing low precision draws and we're about to
michael@0:         // checkerboard, enable low precision drawing.
michael@0:         if (!lowPrecision && !mProgressiveUpdateWasInDanger) {
michael@0:             if (DisplayPortCalculator.aboutToCheckerboard(viewportMetrics,
michael@0:                   mPanZoomController.getVelocityVector(), mProgressiveUpdateDisplayPort)) {
michael@0:                 mProgressiveUpdateWasInDanger = true;
michael@0:             }
michael@0:         }
michael@0: 
michael@0:         // XXX All sorts of rounding happens inside Gecko that becomes hard to
michael@0:         //     account exactly for. Given we align the display-port to tile
michael@0:         //     boundaries (and so they rarely vary by sub-pixel amounts), just
michael@0:         //     check that values are within a couple of pixels of the
michael@0:         //     display-port bounds.
michael@0: 
michael@0:         // Never abort drawing if we can't be sure we've sent a more recent
michael@0:         // display-port. If we abort updating when we shouldn't, we can end up
michael@0:         // with blank regions on the screen and we open up the risk of entering
michael@0:         // an endless updating cycle.
michael@0:         if (Math.abs(displayPort.getLeft() - mProgressiveUpdateDisplayPort.getLeft()) <= 2 &&
michael@0:             Math.abs(displayPort.getTop() - mProgressiveUpdateDisplayPort.getTop()) <= 2 &&
michael@0:             Math.abs(displayPort.getBottom() - mProgressiveUpdateDisplayPort.getBottom()) <= 2 &&
michael@0:             Math.abs(displayPort.getRight() - mProgressiveUpdateDisplayPort.getRight()) <= 2) {
michael@0:             return mProgressiveUpdateData;
michael@0:         }
michael@0: 
michael@0:         // Abort updates when the display-port no longer contains the visible
michael@0:         // area of the page (that is, the viewport cropped by the page
michael@0:         // boundaries).
michael@0:         // XXX This makes the assumption that we never let the visible area of
michael@0:         //     the page fall outside of the display-port.
michael@0:         if (Math.max(viewportMetrics.viewportRectLeft, viewportMetrics.pageRectLeft) + 1 < x ||
michael@0:             Math.max(viewportMetrics.viewportRectTop, viewportMetrics.pageRectTop) + 1 < y ||
michael@0:             Math.min(viewportMetrics.viewportRectRight, viewportMetrics.pageRectRight) - 1 > x + width ||
michael@0:             Math.min(viewportMetrics.viewportRectBottom, viewportMetrics.pageRectBottom) - 1 > y + height) {
michael@0:             Log.d(LOGTAG, "Aborting update due to viewport not in display-port");
michael@0:             mProgressiveUpdateData.abort = true;
michael@0: 
michael@0:             // Enable low-precision drawing, as we're likely to be in danger if
michael@0:             // this situation has been encountered.
michael@0:             mProgressiveUpdateWasInDanger = true;
michael@0: 
michael@0:             return mProgressiveUpdateData;
michael@0:         }
michael@0: 
michael@0:         // Abort drawing stale low-precision content if there's a more recent
michael@0:         // display-port in the pipeline.
michael@0:         if (lowPrecision && !aHasPendingNewThebesContent) {
michael@0:           mProgressiveUpdateData.abort = true;
michael@0:         }
michael@0:         return mProgressiveUpdateData;
michael@0:     }
michael@0: 
michael@0:     void setZoomConstraints(ZoomConstraints constraints) {
michael@0:         mZoomConstraints = constraints;
michael@0:     }
michael@0: 
michael@0:     void setIsRTL(boolean aIsRTL) {
michael@0:         synchronized (getLock()) {
michael@0:             ImmutableViewportMetrics newMetrics = getViewportMetrics().setIsRTL(aIsRTL);
michael@0:             setViewportMetrics(newMetrics, false);
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     /** The compositor invokes this function just before compositing a frame where the document
michael@0:       * is different from the document composited on the last frame. In these cases, the viewport
michael@0:       * information we have in Java is no longer valid and needs to be replaced with the new
michael@0:       * viewport information provided. setPageRect will never be invoked on the same frame that
michael@0:       * this function is invoked on; and this function will always be called prior to syncViewportInfo.
michael@0:       */
michael@0:     @WrapElementForJNI(allowMultithread = true)
michael@0:     public void setFirstPaintViewport(float offsetX, float offsetY, float zoom,
michael@0:             float cssPageLeft, float cssPageTop, float cssPageRight, float cssPageBottom) {
michael@0:         synchronized (getLock()) {
michael@0:             ImmutableViewportMetrics currentMetrics = getViewportMetrics();
michael@0: 
michael@0:             Tab tab = Tabs.getInstance().getSelectedTab();
michael@0: 
michael@0:             RectF cssPageRect = new RectF(cssPageLeft, cssPageTop, cssPageRight, cssPageBottom);
michael@0:             RectF pageRect = RectUtils.scaleAndRound(cssPageRect, zoom);
michael@0: 
michael@0:             final ImmutableViewportMetrics newMetrics = currentMetrics
michael@0:                 .setViewportOrigin(offsetX, offsetY)
michael@0:                 .setZoomFactor(zoom)
michael@0:                 .setPageRect(pageRect, cssPageRect)
michael@0:                 .setIsRTL(tab.getIsRTL());
michael@0:             // Since we have switched to displaying a different document, we need to update any
michael@0:             // viewport-related state we have lying around. This includes mGeckoViewport and
michael@0:             // mViewportMetrics. Usually this information is updated via handleViewportMessage
michael@0:             // while we remain on the same document.
michael@0:             post(new Runnable() {
michael@0:                 @Override
michael@0:                 public void run() {
michael@0:                     mGeckoViewport = newMetrics;
michael@0:                 }
michael@0:             });
michael@0: 
michael@0:             setViewportMetrics(newMetrics);
michael@0: 
michael@0:             mView.setBackgroundColor(tab.getBackgroundColor());
michael@0:             setZoomConstraints(tab.getZoomConstraints());
michael@0: 
michael@0:             // At this point, we have just switched to displaying a different document than we
michael@0:             // we previously displaying. This means we need to abort any panning/zooming animations
michael@0:             // that are in progress and send an updated display port request to browser.js as soon
michael@0:             // as possible. The call to PanZoomController.abortAnimation accomplishes this by calling the
michael@0:             // forceRedraw function, which sends the viewport to gecko. The display port request is
michael@0:             // actually a full viewport update, which is fine because if browser.js has somehow moved to
michael@0:             // be out of sync with this first-paint viewport, then we force them back in sync.
michael@0:             abortPanZoomAnimation();
michael@0: 
michael@0:             // Indicate that the document is about to be composited so the
michael@0:             // LayerView background can be removed.
michael@0:             if (mView.getPaintState() == LayerView.PAINT_START) {
michael@0:                 mView.setPaintState(LayerView.PAINT_BEFORE_FIRST);
michael@0:             }
michael@0:         }
michael@0:         DisplayPortCalculator.resetPageState();
michael@0:         mDrawTimingQueue.reset();
michael@0: 
michael@0:         mContentDocumentIsDisplayed = true;
michael@0:     }
michael@0: 
michael@0:     /** The compositor invokes this function whenever it determines that the page rect
michael@0:       * has changed (based on the information it gets from layout). If setFirstPaintViewport
michael@0:       * is invoked on a frame, then this function will not be. For any given frame, this
michael@0:       * function will be invoked before syncViewportInfo.
michael@0:       */
michael@0:     @WrapElementForJNI(allowMultithread = true)
michael@0:     public void setPageRect(float cssPageLeft, float cssPageTop, float cssPageRight, float cssPageBottom) {
michael@0:         synchronized (getLock()) {
michael@0:             RectF cssPageRect = new RectF(cssPageLeft, cssPageTop, cssPageRight, cssPageBottom);
michael@0:             float ourZoom = getViewportMetrics().zoomFactor;
michael@0:             setPageRect(RectUtils.scale(cssPageRect, ourZoom), cssPageRect);
michael@0:             // Here the page size of the document has changed, but the document being displayed
michael@0:             // is still the same. Therefore, we don't need to send anything to browser.js; any
michael@0:             // changes we need to make to the display port will get sent the next time we call
michael@0:             // adjustViewport().
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     /** The compositor invokes this function on every frame to figure out what part of the
michael@0:       * page to display, and to inform Java of the current display port. Since it is called
michael@0:       * on every frame, it needs to be ultra-fast.
michael@0:       * It avoids taking any locks or allocating any objects. We keep around a
michael@0:       * mCurrentViewTransform so we don't need to allocate a new ViewTransform
michael@0:       * everytime we're called. NOTE: we might be able to return a ImmutableViewportMetrics
michael@0:       * which would avoid the copy into mCurrentViewTransform.
michael@0:       */
michael@0:     @WrapElementForJNI(allowMultithread = true)
michael@0:     public ViewTransform syncViewportInfo(int x, int y, int width, int height, float resolution, boolean layersUpdated) {
michael@0:         // getViewportMetrics is thread safe so we don't need to synchronize.
michael@0:         // We save the viewport metrics here, so we later use it later in
michael@0:         // createFrame (which will be called by nsWindow::DrawWindowUnderlay on
michael@0:         // the native side, by the compositor). The viewport
michael@0:         // metrics can change between here and there, as it's accessed outside
michael@0:         // of the compositor thread.
michael@0:         mFrameMetrics = getViewportMetrics();
michael@0: 
michael@0:         mCurrentViewTransform.x = mFrameMetrics.viewportRectLeft;
michael@0:         mCurrentViewTransform.y = mFrameMetrics.viewportRectTop;
michael@0:         mCurrentViewTransform.scale = mFrameMetrics.zoomFactor;
michael@0: 
michael@0:         // Adjust the fixed layer margins so that overscroll subtracts from them.
michael@0:         getFixedMargins(mFrameMetrics, mCurrentViewTransformMargins);
michael@0:         mCurrentViewTransform.fixedLayerMarginLeft = mCurrentViewTransformMargins.left;
michael@0:         mCurrentViewTransform.fixedLayerMarginTop = mCurrentViewTransformMargins.top;
michael@0:         mCurrentViewTransform.fixedLayerMarginRight = mCurrentViewTransformMargins.right;
michael@0:         mCurrentViewTransform.fixedLayerMarginBottom = mCurrentViewTransformMargins.bottom;
michael@0: 
michael@0:         // Offset the view transform so that it renders in the correct place.
michael@0:         PointF offset = mFrameMetrics.getMarginOffset();
michael@0:         mCurrentViewTransform.offsetX = offset.x;
michael@0:         mCurrentViewTransform.offsetY = offset.y;
michael@0: 
michael@0:         mRootLayer.setPositionAndResolution(
michael@0:             Math.round(x + mCurrentViewTransform.offsetX),
michael@0:             Math.round(y + mCurrentViewTransform.offsetY),
michael@0:             Math.round(x + width + mCurrentViewTransform.offsetX),
michael@0:             Math.round(y + height + mCurrentViewTransform.offsetY),
michael@0:             resolution);
michael@0: 
michael@0:         if (layersUpdated && mRecordDrawTimes) {
michael@0:             // If we got a layers update, that means a draw finished. Check to see if the area drawn matches
michael@0:             // one of our requested displayports; if it does calculate the draw time and notify the
michael@0:             // DisplayPortCalculator
michael@0:             DisplayPortMetrics drawn = new DisplayPortMetrics(x, y, x + width, y + height, resolution);
michael@0:             long time = mDrawTimingQueue.findTimeFor(drawn);
michael@0:             if (time >= 0) {
michael@0:                 long now = SystemClock.uptimeMillis();
michael@0:                 time = now - time;
michael@0:                 mRecordDrawTimes = DisplayPortCalculator.drawTimeUpdate(time, width * height);
michael@0:             }
michael@0:         }
michael@0: 
michael@0:         if (layersUpdated) {
michael@0:             for (DrawListener listener : mDrawListeners) {
michael@0:                 listener.drawFinished();
michael@0:             }
michael@0:         }
michael@0: 
michael@0:         return mCurrentViewTransform;
michael@0:     }
michael@0: 
michael@0:     @WrapElementForJNI(allowMultithread = true)
michael@0:     public ViewTransform syncFrameMetrics(float offsetX, float offsetY, float zoom,
michael@0:                 float cssPageLeft, float cssPageTop, float cssPageRight, float cssPageBottom,
michael@0:                 boolean layersUpdated, int x, int y, int width, int height, float resolution,
michael@0:                 boolean isFirstPaint)
michael@0:     {
michael@0:         if (isFirstPaint) {
michael@0:             setFirstPaintViewport(offsetX, offsetY, zoom,
michael@0:                                   cssPageLeft, cssPageTop, cssPageRight, cssPageBottom);
michael@0:         }
michael@0: 
michael@0:         return syncViewportInfo(x, y, width, height, resolution, layersUpdated);
michael@0:     }
michael@0: 
michael@0:     @WrapElementForJNI(allowMultithread = true)
michael@0:     public LayerRenderer.Frame createFrame() {
michael@0:         // Create the shaders and textures if necessary.
michael@0:         if (!mLayerRendererInitialized) {
michael@0:             mLayerRenderer.checkMonitoringEnabled();
michael@0:             mLayerRenderer.createDefaultProgram();
michael@0:             mLayerRendererInitialized = true;
michael@0:         }
michael@0: 
michael@0:         try {
michael@0:             return mLayerRenderer.createFrame(mFrameMetrics);
michael@0:         } catch (Exception e) {
michael@0:             Log.w(LOGTAG, e);
michael@0:             return null;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     @WrapElementForJNI(allowMultithread = true)
michael@0:     public void activateProgram() {
michael@0:         mLayerRenderer.activateDefaultProgram();
michael@0:     }
michael@0: 
michael@0:     @WrapElementForJNI(allowMultithread = true)
michael@0:     public void deactivateProgram() {
michael@0:         mLayerRenderer.deactivateDefaultProgram();
michael@0:     }
michael@0: 
michael@0:     private void geometryChanged(DisplayPortMetrics displayPort) {
michael@0:         /* Let Gecko know if the screensize has changed */
michael@0:         sendResizeEventIfNecessary(false);
michael@0:         if (getRedrawHint()) {
michael@0:             adjustViewport(displayPort);
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     /** Implementation of LayerView.Listener */
michael@0:     @Override
michael@0:     public void renderRequested() {
michael@0:         try {
michael@0:             GeckoAppShell.scheduleComposite();
michael@0:         } catch (UnsupportedOperationException uoe) {
michael@0:             // In some very rare cases this gets called before libxul is loaded,
michael@0:             // so catch and ignore the exception that will throw. See bug 837821
michael@0:             Log.d(LOGTAG, "Dropping renderRequested call before libxul load.");
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     /** Implementation of LayerView.Listener */
michael@0:     @Override
michael@0:     public void sizeChanged(int width, int height) {
michael@0:         // We need to make sure a draw happens synchronously at this point,
michael@0:         // but resizing the surface before the SurfaceView has resized will
michael@0:         // cause a visible jump.
michael@0:         mView.getGLController().resumeCompositor(mWindowSize.width, mWindowSize.height);
michael@0:     }
michael@0: 
michael@0:     /** Implementation of LayerView.Listener */
michael@0:     @Override
michael@0:     public void surfaceChanged(int width, int height) {
michael@0:         setViewportSize(width, height);
michael@0:     }
michael@0: 
michael@0:     /** Implementation of PanZoomTarget */
michael@0:     @Override
michael@0:     public ImmutableViewportMetrics getViewportMetrics() {
michael@0:         return mViewportMetrics;
michael@0:     }
michael@0: 
michael@0:     /** Implementation of PanZoomTarget */
michael@0:     @Override
michael@0:     public ZoomConstraints getZoomConstraints() {
michael@0:         return mZoomConstraints;
michael@0:     }
michael@0: 
michael@0:     /** Implementation of PanZoomTarget */
michael@0:     @Override
michael@0:     public boolean isFullScreen() {
michael@0:         return mView.isFullScreen();
michael@0:     }
michael@0: 
michael@0:     /** Implementation of PanZoomTarget */
michael@0:     @Override
michael@0:     public RectF getMaxMargins() {
michael@0:         return mMarginsAnimator.getMaxMargins();
michael@0:     }
michael@0: 
michael@0:     /** Implementation of PanZoomTarget */
michael@0:     @Override
michael@0:     public void setAnimationTarget(ImmutableViewportMetrics metrics) {
michael@0:         if (mGeckoIsReady) {
michael@0:             // We know what the final viewport of the animation is going to be, so
michael@0:             // immediately request a draw of that area by setting the display port
michael@0:             // accordingly. This way we should have the content pre-rendered by the
michael@0:             // time the animation is done.
michael@0:             DisplayPortMetrics displayPort = DisplayPortCalculator.calculate(metrics, null);
michael@0:             adjustViewport(displayPort);
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     /** Implementation of PanZoomTarget
michael@0:      * You must hold the monitor while calling this.
michael@0:      */
michael@0:     @Override
michael@0:     public void setViewportMetrics(ImmutableViewportMetrics metrics) {
michael@0:         setViewportMetrics(metrics, true);
michael@0:     }
michael@0: 
michael@0:     /*
michael@0:      * You must hold the monitor while calling this.
michael@0:      */
michael@0:     private void setViewportMetrics(ImmutableViewportMetrics metrics, boolean notifyGecko) {
michael@0:         // This class owns the viewport size and the fixed layer margins; don't let other pieces
michael@0:         // of code clobber either of them. The only place the viewport size should ever be
michael@0:         // updated is in GeckoLayerClient.setViewportSize, and the only place the margins should
michael@0:         // ever be updated is in GeckoLayerClient.setFixedLayerMargins; both of these assign to
michael@0:         // mViewportMetrics directly.
michael@0:         metrics = metrics.setViewportSize(mViewportMetrics.getWidth(), mViewportMetrics.getHeight());
michael@0:         metrics = metrics.setMarginsFrom(mViewportMetrics);
michael@0:         mViewportMetrics = metrics;
michael@0: 
michael@0:         viewportMetricsChanged(notifyGecko);
michael@0:     }
michael@0: 
michael@0:     /*
michael@0:      * You must hold the monitor while calling this.
michael@0:      */
michael@0:     private void viewportMetricsChanged(boolean notifyGecko) {
michael@0:         if (mViewportChangeListener != null) {
michael@0:             mViewportChangeListener.onMetricsChanged(mViewportMetrics);
michael@0:         }
michael@0: 
michael@0:         mView.requestRender();
michael@0:         if (notifyGecko && mGeckoIsReady) {
michael@0:             geometryChanged(null);
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     /*
michael@0:      * Updates the viewport metrics, overriding the viewport size and margins
michael@0:      * which are normally retained when calling setViewportMetrics.
michael@0:      * You must hold the monitor while calling this.
michael@0:      */
michael@0:     void forceViewportMetrics(ImmutableViewportMetrics metrics, boolean notifyGecko, boolean forceRedraw) {
michael@0:         if (forceRedraw) {
michael@0:             mForceRedraw = true;
michael@0:         }
michael@0:         mViewportMetrics = metrics;
michael@0:         viewportMetricsChanged(notifyGecko);
michael@0:     }
michael@0: 
michael@0:     /** Implementation of PanZoomTarget
michael@0:      * Scroll the viewport by a certain amount. This will take viewport margins
michael@0:      * and margin animation into account. If margins are currently animating,
michael@0:      * this will just go ahead and modify the viewport origin, otherwise the
michael@0:      * delta will be applied to the margins and the remainder will be applied to
michael@0:      * the viewport origin.
michael@0:      *
michael@0:      * You must hold the monitor while calling this.
michael@0:      */
michael@0:     @Override
michael@0:     public void scrollBy(float dx, float dy) {
michael@0:         // Set mViewportMetrics manually so the margin changes take.
michael@0:         mViewportMetrics = mMarginsAnimator.scrollBy(mViewportMetrics, dx, dy);
michael@0:         viewportMetricsChanged(true);
michael@0:     }
michael@0: 
michael@0:     /** Implementation of PanZoomTarget
michael@0:      * Notification that a subdocument has been scrolled by a certain amount.
michael@0:      * This is used here to make sure that the margins are still accessible
michael@0:      * during subdocument scrolling.
michael@0:      *
michael@0:      * You must hold the monitor while calling this.
michael@0:      */
michael@0:     @Override
michael@0:     public void scrollMarginsBy(float dx, float dy) {
michael@0:         ImmutableViewportMetrics newMarginsMetrics =
michael@0:             mMarginsAnimator.scrollBy(mViewportMetrics, dx, dy);
michael@0:         mViewportMetrics = mViewportMetrics.setMarginsFrom(newMarginsMetrics);
michael@0:         viewportMetricsChanged(true);
michael@0:     }
michael@0: 
michael@0:     /** Implementation of PanZoomTarget */
michael@0:     @Override
michael@0:     public void panZoomStopped() {
michael@0:         if (mViewportChangeListener != null) {
michael@0:             mViewportChangeListener.onPanZoomStopped();
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     /** Implementation of PanZoomTarget */
michael@0:     @Override
michael@0:     public void forceRedraw(DisplayPortMetrics displayPort) {
michael@0:         mForceRedraw = true;
michael@0:         if (mGeckoIsReady) {
michael@0:             geometryChanged(displayPort);
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     /** Implementation of PanZoomTarget */
michael@0:     @Override
michael@0:     public boolean post(Runnable action) {
michael@0:         return mView.post(action);
michael@0:     }
michael@0: 
michael@0:     /** Implementation of PanZoomTarget */
michael@0:     @Override
michael@0:     public void postRenderTask(RenderTask task) {
michael@0:         mView.postRenderTask(task);
michael@0:     }
michael@0: 
michael@0:     /** Implementation of PanZoomTarget */
michael@0:     @Override
michael@0:     public void removeRenderTask(RenderTask task) {
michael@0:         mView.removeRenderTask(task);
michael@0:     }
michael@0: 
michael@0: 
michael@0:     /** Implementation of PanZoomTarget */
michael@0:     @Override
michael@0:     public boolean postDelayed(Runnable action, long delayMillis) {
michael@0:         return mView.postDelayed(action, delayMillis);
michael@0:     }
michael@0: 
michael@0:     /** Implementation of PanZoomTarget */
michael@0:     @Override
michael@0:     public Object getLock() {
michael@0:         return this;
michael@0:     }
michael@0: 
michael@0:     /** Implementation of PanZoomTarget
michael@0:      * Converts a point from layer view coordinates to layer coordinates. In other words, given a
michael@0:      * point measured in pixels from the top left corner of the layer view, returns the point in
michael@0:      * pixels measured from the last scroll position we sent to Gecko, in CSS pixels. Assuming the
michael@0:      * events being sent to Gecko are processed in FIFO order, this calculation should always be
michael@0:      * correct.
michael@0:      */
michael@0:     @Override
michael@0:     public PointF convertViewPointToLayerPoint(PointF viewPoint) {
michael@0:         if (!mGeckoIsReady) {
michael@0:             return null;
michael@0:         }
michael@0: 
michael@0:         ImmutableViewportMetrics viewportMetrics = mViewportMetrics;
michael@0:         PointF origin = viewportMetrics.getOrigin();
michael@0:         PointF offset = viewportMetrics.getMarginOffset();
michael@0:         origin.offset(-offset.x, -offset.y);
michael@0:         float zoom = viewportMetrics.zoomFactor;
michael@0:         ImmutableViewportMetrics geckoViewport = mGeckoViewport;
michael@0:         PointF geckoOrigin = geckoViewport.getOrigin();
michael@0:         float geckoZoom = geckoViewport.zoomFactor;
michael@0: 
michael@0:         // viewPoint + origin - offset gives the coordinate in device pixels from the top-left corner of the page.
michael@0:         // Divided by zoom, this gives us the coordinate in CSS pixels from the top-left corner of the page.
michael@0:         // geckoOrigin / geckoZoom is where Gecko thinks it is (scrollTo position) in CSS pixels from
michael@0:         // the top-left corner of the page. Subtracting the two gives us the offset of the viewPoint from
michael@0:         // the current Gecko coordinate in CSS pixels.
michael@0:         PointF layerPoint = new PointF(
michael@0:                 ((viewPoint.x + origin.x) / zoom) - (geckoOrigin.x / geckoZoom),
michael@0:                 ((viewPoint.y + origin.y) / zoom) - (geckoOrigin.y / geckoZoom));
michael@0: 
michael@0:         return layerPoint;
michael@0:     }
michael@0: 
michael@0:     void setOnMetricsChangedListener(LayerView.OnMetricsChangedListener listener) {
michael@0:         mViewportChangeListener = listener;
michael@0:     }
michael@0: 
michael@0:     public void addDrawListener(DrawListener listener) {
michael@0:         mDrawListeners.add(listener);
michael@0:     }
michael@0: 
michael@0:     public void removeDrawListener(DrawListener listener) {
michael@0:         mDrawListeners.remove(listener);
michael@0:     }
michael@0: }