michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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: #ifndef mozilla_layers_APZCCallbackHelper_h
michael@0: #define mozilla_layers_APZCCallbackHelper_h
michael@0: 
michael@0: #include "FrameMetrics.h"
michael@0: #include "nsIContent.h"
michael@0: #include "nsIDocument.h"
michael@0: #include "nsIDOMWindowUtils.h"
michael@0: 
michael@0: namespace mozilla {
michael@0: namespace layers {
michael@0: 
michael@0: /* This class contains some helper methods that facilitate implementing the
michael@0:    GeckoContentController callback interface required by the AsyncPanZoomController.
michael@0:    Since different platforms need to implement this interface in similar-but-
michael@0:    not-quite-the-same ways, this utility class provides some helpful methods
michael@0:    to hold code that can be shared across the different platform implementations.
michael@0:  */
michael@0: class APZCCallbackHelper
michael@0: {
michael@0:     typedef mozilla::layers::FrameMetrics FrameMetrics;
michael@0:     typedef mozilla::layers::ScrollableLayerGuid ScrollableLayerGuid;
michael@0: 
michael@0: public:
michael@0:     /* Checks to see if the pres shell that the given FrameMetrics object refers
michael@0:        to is still the valid pres shell for the DOMWindowUtils. This can help
michael@0:        guard against apply stale updates (updates meant for a pres shell that has
michael@0:        since been torn down and replaced). */
michael@0:     static bool HasValidPresShellId(nsIDOMWindowUtils* aUtils,
michael@0:                                     const FrameMetrics& aMetrics);
michael@0: 
michael@0:     /* Applies the scroll and zoom parameters from the given FrameMetrics object to
michael@0:        the root frame corresponding to the given DOMWindowUtils. If tiled thebes
michael@0:        layers are enabled, this will align the displayport to tile boundaries.
michael@0:        Setting the scroll position can cause some small adjustments to be made
michael@0:        to the actual scroll position. aMetrics' display port and scroll position
michael@0:        will be updated with any modifications made. */
michael@0:     static void UpdateRootFrame(nsIDOMWindowUtils* aUtils,
michael@0:                                 FrameMetrics& aMetrics);
michael@0: 
michael@0:     /* Applies the scroll parameters from the given FrameMetrics object to the subframe
michael@0:        corresponding to the given content object. If tiled thebes
michael@0:        layers are enabled, this will align the displayport to tile boundaries.
michael@0:        Setting the scroll position can cause some small adjustments to be made
michael@0:        to the actual scroll position. aMetrics' display port and scroll position
michael@0:        will be updated with any modifications made. */
michael@0:     static void UpdateSubFrame(nsIContent* aContent,
michael@0:                                FrameMetrics& aMetrics);
michael@0: 
michael@0:     /* Get the DOMWindowUtils for the window corresponding to the given document. */
michael@0:     static already_AddRefed<nsIDOMWindowUtils> GetDOMWindowUtils(const nsIDocument* aDoc);
michael@0: 
michael@0:     /* Get the DOMWindowUtils for the window corresponding to the givent content
michael@0:        element. This might be an iframe inside the tab, for instance. */
michael@0:     static already_AddRefed<nsIDOMWindowUtils> GetDOMWindowUtils(const nsIContent* aContent);
michael@0: 
michael@0:     /* Get the presShellId and view ID for the given content element, if they can be
michael@0:        found. Returns false if the values could not be found, true if they could. */
michael@0:     static bool GetScrollIdentifiers(const nsIContent* aContent,
michael@0:                                      uint32_t* aPresShellIdOut,
michael@0:                                      FrameMetrics::ViewID* aViewIdOut);
michael@0: 
michael@0:     /* Tell layout that we received the scroll offset update for the given view ID, so
michael@0:        that it accepts future scroll offset updates from APZ. */
michael@0:     static void AcknowledgeScrollUpdate(const FrameMetrics::ViewID& aScrollId,
michael@0:                                         const uint32_t& aScrollGeneration);
michael@0: 
michael@0:     /* Save an "input transform" property on the content element corresponding to
michael@0:        the scrollable content. This is needed because in some cases when the APZ code
michael@0:        sends a paint request via the GeckoContentController interface, we don't always
michael@0:        apply the scroll offset that was requested. Since the APZ code doesn't know
michael@0:        that we didn't apply it, it will transform inputs assuming that we had applied
michael@0:        it, and so we need to apply a fixup to the input to account for the fact that
michael@0:        we didn't.
michael@0:        The |aApzcMetrics| argument are the metrics that the APZ sent us, and the
michael@0:        |aActualMetrics| argument are the metrics representing the gecko state after we
michael@0:        applied some or all of the APZ metrics. */
michael@0:     static void UpdateCallbackTransform(const FrameMetrics& aApzcMetrics,
michael@0:                                         const FrameMetrics& aActualMetrics);
michael@0: 
michael@0:     /* Apply an "input transform" to the given |aInput| and return the transformed value.
michael@0:        The input transform applied is the one for the content element corresponding to
michael@0:        |aGuid|; this is populated in a previous call to UpdateCallbackTransform. See that
michael@0:        method's documentations for details. */
michael@0:     static CSSPoint ApplyCallbackTransform(const CSSPoint& aInput,
michael@0:                                            const ScrollableLayerGuid& aGuid);
michael@0: 
michael@0:     /* Same as above, but operates on nsIntPoint that are assumed to be in LayoutDevice
michael@0:        pixel space. Requires an additonal |aScale| parameter to convert between CSS and
michael@0:        LayoutDevice space. */
michael@0:     static nsIntPoint ApplyCallbackTransform(const nsIntPoint& aPoint,
michael@0:                                              const ScrollableLayerGuid& aGuid,
michael@0:                                              const CSSToLayoutDeviceScale& aScale);
michael@0: };
michael@0: 
michael@0: }
michael@0: }
michael@0: 
michael@0: #endif /* mozilla_layers_APZCCallbackHelper_h */