1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/layers/apz/util/APZCCallbackHelper.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,103 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#ifndef mozilla_layers_APZCCallbackHelper_h
1.10 +#define mozilla_layers_APZCCallbackHelper_h
1.11 +
1.12 +#include "FrameMetrics.h"
1.13 +#include "nsIContent.h"
1.14 +#include "nsIDocument.h"
1.15 +#include "nsIDOMWindowUtils.h"
1.16 +
1.17 +namespace mozilla {
1.18 +namespace layers {
1.19 +
1.20 +/* This class contains some helper methods that facilitate implementing the
1.21 + GeckoContentController callback interface required by the AsyncPanZoomController.
1.22 + Since different platforms need to implement this interface in similar-but-
1.23 + not-quite-the-same ways, this utility class provides some helpful methods
1.24 + to hold code that can be shared across the different platform implementations.
1.25 + */
1.26 +class APZCCallbackHelper
1.27 +{
1.28 + typedef mozilla::layers::FrameMetrics FrameMetrics;
1.29 + typedef mozilla::layers::ScrollableLayerGuid ScrollableLayerGuid;
1.30 +
1.31 +public:
1.32 + /* Checks to see if the pres shell that the given FrameMetrics object refers
1.33 + to is still the valid pres shell for the DOMWindowUtils. This can help
1.34 + guard against apply stale updates (updates meant for a pres shell that has
1.35 + since been torn down and replaced). */
1.36 + static bool HasValidPresShellId(nsIDOMWindowUtils* aUtils,
1.37 + const FrameMetrics& aMetrics);
1.38 +
1.39 + /* Applies the scroll and zoom parameters from the given FrameMetrics object to
1.40 + the root frame corresponding to the given DOMWindowUtils. If tiled thebes
1.41 + layers are enabled, this will align the displayport to tile boundaries.
1.42 + Setting the scroll position can cause some small adjustments to be made
1.43 + to the actual scroll position. aMetrics' display port and scroll position
1.44 + will be updated with any modifications made. */
1.45 + static void UpdateRootFrame(nsIDOMWindowUtils* aUtils,
1.46 + FrameMetrics& aMetrics);
1.47 +
1.48 + /* Applies the scroll parameters from the given FrameMetrics object to the subframe
1.49 + corresponding to the given content object. If tiled thebes
1.50 + layers are enabled, this will align the displayport to tile boundaries.
1.51 + Setting the scroll position can cause some small adjustments to be made
1.52 + to the actual scroll position. aMetrics' display port and scroll position
1.53 + will be updated with any modifications made. */
1.54 + static void UpdateSubFrame(nsIContent* aContent,
1.55 + FrameMetrics& aMetrics);
1.56 +
1.57 + /* Get the DOMWindowUtils for the window corresponding to the given document. */
1.58 + static already_AddRefed<nsIDOMWindowUtils> GetDOMWindowUtils(const nsIDocument* aDoc);
1.59 +
1.60 + /* Get the DOMWindowUtils for the window corresponding to the givent content
1.61 + element. This might be an iframe inside the tab, for instance. */
1.62 + static already_AddRefed<nsIDOMWindowUtils> GetDOMWindowUtils(const nsIContent* aContent);
1.63 +
1.64 + /* Get the presShellId and view ID for the given content element, if they can be
1.65 + found. Returns false if the values could not be found, true if they could. */
1.66 + static bool GetScrollIdentifiers(const nsIContent* aContent,
1.67 + uint32_t* aPresShellIdOut,
1.68 + FrameMetrics::ViewID* aViewIdOut);
1.69 +
1.70 + /* Tell layout that we received the scroll offset update for the given view ID, so
1.71 + that it accepts future scroll offset updates from APZ. */
1.72 + static void AcknowledgeScrollUpdate(const FrameMetrics::ViewID& aScrollId,
1.73 + const uint32_t& aScrollGeneration);
1.74 +
1.75 + /* Save an "input transform" property on the content element corresponding to
1.76 + the scrollable content. This is needed because in some cases when the APZ code
1.77 + sends a paint request via the GeckoContentController interface, we don't always
1.78 + apply the scroll offset that was requested. Since the APZ code doesn't know
1.79 + that we didn't apply it, it will transform inputs assuming that we had applied
1.80 + it, and so we need to apply a fixup to the input to account for the fact that
1.81 + we didn't.
1.82 + The |aApzcMetrics| argument are the metrics that the APZ sent us, and the
1.83 + |aActualMetrics| argument are the metrics representing the gecko state after we
1.84 + applied some or all of the APZ metrics. */
1.85 + static void UpdateCallbackTransform(const FrameMetrics& aApzcMetrics,
1.86 + const FrameMetrics& aActualMetrics);
1.87 +
1.88 + /* Apply an "input transform" to the given |aInput| and return the transformed value.
1.89 + The input transform applied is the one for the content element corresponding to
1.90 + |aGuid|; this is populated in a previous call to UpdateCallbackTransform. See that
1.91 + method's documentations for details. */
1.92 + static CSSPoint ApplyCallbackTransform(const CSSPoint& aInput,
1.93 + const ScrollableLayerGuid& aGuid);
1.94 +
1.95 + /* Same as above, but operates on nsIntPoint that are assumed to be in LayoutDevice
1.96 + pixel space. Requires an additonal |aScale| parameter to convert between CSS and
1.97 + LayoutDevice space. */
1.98 + static nsIntPoint ApplyCallbackTransform(const nsIntPoint& aPoint,
1.99 + const ScrollableLayerGuid& aGuid,
1.100 + const CSSToLayoutDeviceScale& aScale);
1.101 +};
1.102 +
1.103 +}
1.104 +}
1.105 +
1.106 +#endif /* mozilla_layers_APZCCallbackHelper_h */
