| // Copyright 2016 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef CC_INPUT_MAIN_THREAD_SCROLLING_REASON_H_ |
| #define CC_INPUT_MAIN_THREAD_SCROLLING_REASON_H_ |
| |
| #include <memory> |
| #include <string> |
| #include "cc/cc_export.h" |
| |
| namespace base { |
| namespace trace_event { |
| class TracedValue; |
| } |
| } // namespace base |
| |
| namespace cc { |
| |
| // Ensure this stays in sync with MainThreadScrollingReason in histograms.xml. |
| // When adding a new MainThreadScrollingReason, make sure the corresponding |
| // [MainThread/Compositor]CanSetScrollReasons function is also updated. |
| struct CC_EXPORT MainThreadScrollingReason { |
| enum : uint32_t { |
| // Non-transient scrolling reasons. |
| kNotScrollingOnMain = 0, |
| kHasBackgroundAttachmentFixedObjects = 1 << 0, |
| kHasNonLayerViewportConstrainedObjects = 1 << 1, |
| kThreadedScrollingDisabled = 1 << 2, |
| kScrollbarScrolling = 1 << 3, |
| kFrameOverlay = 1 << 4, |
| |
| // This bit is set when any of the other main thread scrolling reasons cause |
| // an input event to be handled on the main thread, and the main thread |
| // blink::ScrollAnimator is in the middle of running a scroll offset |
| // animation. Note that a scroll handled by the main thread can result in an |
| // animation running on the main thread or on the compositor thread. |
| kHandlingScrollFromMainThread = 1 << 13, |
| kCustomScrollbarScrolling = 1 << 15, |
| |
| // Style-related scrolling on main reasons. |
| // These *AndLCDText reasons are due to subpixel text rendering which can |
| // only be applied by blending glyphs with the background at a specific |
| // screen position; transparency and transforms break this. |
| kNonCompositedReasonsFirst = 16, |
| kHasOpacityAndLCDText = 1 << 16, |
| kHasTransformAndLCDText = 1 << 17, |
| kBackgroundNotOpaqueInRectAndLCDText = 1 << 18, |
| kHasClipRelatedProperty = 1 << 20, |
| kHasBoxShadowFromNonRootLayer = 1 << 21, |
| kIsNotStackingContextAndLCDText = 1 << 22, |
| kNonCompositedReasonsLast = 22, |
| |
| // Transient scrolling reasons. These are computed for each scroll begin. |
| kNonFastScrollableRegion = 1 << 5, |
| kFailedHitTest = 1 << 7, |
| kNoScrollingLayer = 1 << 8, |
| kNotScrollable = 1 << 9, |
| kContinuingMainThreadScroll = 1 << 10, |
| kNonInvertibleTransform = 1 << 11, |
| kPageBasedScrolling = 1 << 12, |
| kWheelEventHandlerRegion = 1 << 23, |
| kTouchEventHandlerRegion = 1 << 24, |
| |
| // The maximum number of flags in this struct (excluding itself). |
| // New flags should increment this number but it should never be decremented |
| // because the values are used in UMA histograms. It should also be noted |
| // that it excludes the kNotScrollingOnMain value. |
| kMainThreadScrollingReasonCount = 25, |
| }; |
| |
| static const uint32_t kNonCompositedReasons = |
| kHasOpacityAndLCDText | kHasTransformAndLCDText | |
| kBackgroundNotOpaqueInRectAndLCDText | kHasClipRelatedProperty | |
| kHasBoxShadowFromNonRootLayer | kIsNotStackingContextAndLCDText; |
| |
| // Returns true if the given MainThreadScrollingReason can be set by the main |
| // thread. |
| static bool MainThreadCanSetScrollReasons(uint32_t reasons) { |
| uint32_t reasons_set_by_main_thread = |
| kNotScrollingOnMain | kHasBackgroundAttachmentFixedObjects | |
| kHasNonLayerViewportConstrainedObjects | kThreadedScrollingDisabled | |
| kScrollbarScrolling | kFrameOverlay | kHandlingScrollFromMainThread | |
| kCustomScrollbarScrolling; |
| return (reasons & reasons_set_by_main_thread) == reasons; |
| } |
| |
| // Returns true if the given MainThreadScrollingReason can be set by the |
| // compositor. |
| static bool CompositorCanSetScrollReasons(uint32_t reasons) { |
| uint32_t reasons_set_by_compositor = |
| kNonFastScrollableRegion | kFailedHitTest | kNoScrollingLayer | |
| kNotScrollable | kContinuingMainThreadScroll | kNonInvertibleTransform | |
| kPageBasedScrolling | kWheelEventHandlerRegion | |
| kTouchEventHandlerRegion; |
| return (reasons & reasons_set_by_compositor) == reasons; |
| } |
| |
| // Returns true if there are any reasons that prevented the scroller |
| // from being composited. |
| static bool HasNonCompositedScrollReasons(uint32_t reasons) { |
| return (reasons & kNonCompositedReasons) != 0; |
| } |
| |
| static std::string AsText(uint32_t reasons); |
| static void AddToTracedValue(uint32_t reasons, |
| base::trace_event::TracedValue&); |
| }; |
| |
| } // namespace cc |
| |
| #endif // CC_INPUT_MAIN_THREAD_SCROLLING_REASON_H_ |