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comparison: gfx/layers/apz/util/APZCCallbackHelper.h
gfx/layers/apz/util/APZCCallbackHelper.h
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| 1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ | |
| 2 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 3 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 5 | |
| 6 #ifndef mozilla_layers_APZCCallbackHelper_h | |
| 7 #define mozilla_layers_APZCCallbackHelper_h | |
| 8 | |
| 9 #include "FrameMetrics.h" | |
| 10 #include "nsIContent.h" | |
| 11 #include "nsIDocument.h" | |
| 12 #include "nsIDOMWindowUtils.h" | |
| 13 | |
| 14 namespace mozilla { | |
| 15 namespace layers { | |
| 16 | |
| 17 /* This class contains some helper methods that facilitate implementing the | |
| 18 GeckoContentController callback interface required by the AsyncPanZoomController. | |
| 19 Since different platforms need to implement this interface in similar-but- | |
| 20 not-quite-the-same ways, this utility class provides some helpful methods | |
| 21 to hold code that can be shared across the different platform implementations. | |
| 22 */ | |
| 23 class APZCCallbackHelper | |
| 24 { | |
| 25 typedef mozilla::layers::FrameMetrics FrameMetrics; | |
| 26 typedef mozilla::layers::ScrollableLayerGuid ScrollableLayerGuid; | |
| 27 | |
| 28 public: | |
| 29 /* Checks to see if the pres shell that the given FrameMetrics object refers | |
| 30 to is still the valid pres shell for the DOMWindowUtils. This can help | |
| 31 guard against apply stale updates (updates meant for a pres shell that has | |
| 32 since been torn down and replaced). */ | |
| 33 static bool HasValidPresShellId(nsIDOMWindowUtils* aUtils, | |
| 34 const FrameMetrics& aMetrics); | |
| 35 | |
| 36 /* Applies the scroll and zoom parameters from the given FrameMetrics object to | |
| 37 the root frame corresponding to the given DOMWindowUtils. If tiled thebes | |
| 38 layers are enabled, this will align the displayport to tile boundaries. | |
| 39 Setting the scroll position can cause some small adjustments to be made | |
| 40 to the actual scroll position. aMetrics' display port and scroll position | |
| 41 will be updated with any modifications made. */ | |
| 42 static void UpdateRootFrame(nsIDOMWindowUtils* aUtils, | |
| 43 FrameMetrics& aMetrics); | |
| 44 | |
| 45 /* Applies the scroll parameters from the given FrameMetrics object to the subframe | |
| 46 corresponding to the given content object. If tiled thebes | |
| 47 layers are enabled, this will align the displayport to tile boundaries. | |
| 48 Setting the scroll position can cause some small adjustments to be made | |
| 49 to the actual scroll position. aMetrics' display port and scroll position | |
| 50 will be updated with any modifications made. */ | |
| 51 static void UpdateSubFrame(nsIContent* aContent, | |
| 52 FrameMetrics& aMetrics); | |
| 53 | |
| 54 /* Get the DOMWindowUtils for the window corresponding to the given document. */ | |
| 55 static already_AddRefed<nsIDOMWindowUtils> GetDOMWindowUtils(const nsIDocument* aDoc); | |
| 56 | |
| 57 /* Get the DOMWindowUtils for the window corresponding to the givent content | |
| 58 element. This might be an iframe inside the tab, for instance. */ | |
| 59 static already_AddRefed<nsIDOMWindowUtils> GetDOMWindowUtils(const nsIContent* aContent); | |
| 60 | |
| 61 /* Get the presShellId and view ID for the given content element, if they can be | |
| 62 found. Returns false if the values could not be found, true if they could. */ | |
| 63 static bool GetScrollIdentifiers(const nsIContent* aContent, | |
| 64 uint32_t* aPresShellIdOut, | |
| 65 FrameMetrics::ViewID* aViewIdOut); | |
| 66 | |
| 67 /* Tell layout that we received the scroll offset update for the given view ID, so | |
| 68 that it accepts future scroll offset updates from APZ. */ | |
| 69 static void AcknowledgeScrollUpdate(const FrameMetrics::ViewID& aScrollId, | |
| 70 const uint32_t& aScrollGeneration); | |
| 71 | |
| 72 /* Save an "input transform" property on the content element corresponding to | |
| 73 the scrollable content. This is needed because in some cases when the APZ code | |
| 74 sends a paint request via the GeckoContentController interface, we don't always | |
| 75 apply the scroll offset that was requested. Since the APZ code doesn't know | |
| 76 that we didn't apply it, it will transform inputs assuming that we had applied | |
| 77 it, and so we need to apply a fixup to the input to account for the fact that | |
| 78 we didn't. | |
| 79 The |aApzcMetrics| argument are the metrics that the APZ sent us, and the | |
| 80 |aActualMetrics| argument are the metrics representing the gecko state after we | |
| 81 applied some or all of the APZ metrics. */ | |
| 82 static void UpdateCallbackTransform(const FrameMetrics& aApzcMetrics, | |
| 83 const FrameMetrics& aActualMetrics); | |
| 84 | |
| 85 /* Apply an "input transform" to the given |aInput| and return the transformed value. | |
| 86 The input transform applied is the one for the content element corresponding to | |
| 87 |aGuid|; this is populated in a previous call to UpdateCallbackTransform. See that | |
| 88 method's documentations for details. */ | |
| 89 static CSSPoint ApplyCallbackTransform(const CSSPoint& aInput, | |
| 90 const ScrollableLayerGuid& aGuid); | |
| 91 | |
| 92 /* Same as above, but operates on nsIntPoint that are assumed to be in LayoutDevice | |
| 93 pixel space. Requires an additonal |aScale| parameter to convert between CSS and | |
| 94 LayoutDevice space. */ | |
| 95 static nsIntPoint ApplyCallbackTransform(const nsIntPoint& aPoint, | |
| 96 const ScrollableLayerGuid& aGuid, | |
| 97 const CSSToLayoutDeviceScale& aScale); | |
| 98 }; | |
| 99 | |
| 100 } | |
| 101 } | |
| 102 | |
| 103 #endif /* mozilla_layers_APZCCallbackHelper_h */ |
