| // Copyright 2019 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. |
| |
| #include "cc/layers/scrollbar_layer_impl_base.h" |
| |
| #include <algorithm> |
| |
| #include "base/cancelable_callback.h" |
| #include "cc/base/math_util.h" |
| #include "cc/input/scrollbar.h" |
| #include "cc/input/scrollbar_controller.h" |
| #include "cc/trees/layer_tree_impl.h" |
| #include "cc/trees/scroll_node.h" |
| |
| namespace cc { |
| ScrollbarController::~ScrollbarController() { |
| if (cancelable_autoscroll_task_) { |
| cancelable_autoscroll_task_->Cancel(); |
| cancelable_autoscroll_task_.reset(); |
| } |
| } |
| |
| ScrollbarController::ScrollbarController( |
| LayerTreeHostImpl* layer_tree_host_impl) |
| : layer_tree_host_impl_(layer_tree_host_impl), |
| scrollbar_scroll_is_active_(false), |
| currently_captured_scrollbar_(nullptr), |
| previous_pointer_position_(gfx::PointF(0, 0)), |
| drag_processed_for_current_frame_(false), |
| cancelable_autoscroll_task_(nullptr) {} |
| |
| void ScrollbarController::WillBeginImplFrame() { |
| drag_processed_for_current_frame_ = false; |
| if (!autoscroll_state_.has_value()) |
| return; |
| |
| // TODO(arakeri): Revisit this when addressing crbug.com/967004. The |
| // animations need to be aborted/restarted based on the pointer location (i.e |
| // leaving/entering the track/arrows, reaching the track end etc). The |
| // autoscroll_state_ however, needs to be reset on pointer changes. |
| if (ShouldCancelTrackAutoscroll()) |
| layer_tree_host_impl_->mutator_host()->ScrollAnimationAbort(); |
| |
| // When the scroller is autoscrolling forward, its dimensions need to be |
| // monitored. If the length of the scroller layer increases, the old one needs |
| // to be aborted and a new autoscroll animation needs to start. This needs to |
| // be done only for the "autoscroll forward" case. Autoscrolling backward |
| // always has a constant value to animate to (which is '0'. See the function |
| // ScrollbarController::StartAutoScrollAnimation). |
| if (autoscroll_state_->direction == AutoScrollDirection::AUTOSCROLL_FORWARD) { |
| const float scroll_layer_length = |
| currently_captured_scrollbar_->scroll_layer_length(); |
| if (autoscroll_state_->scroll_layer_length != scroll_layer_length) { |
| layer_tree_host_impl_->mutator_host()->ScrollAnimationAbort(); |
| StartAutoScrollAnimation( |
| autoscroll_state_->velocity, |
| currently_captured_scrollbar_->scroll_element_id()); |
| } |
| } |
| } |
| |
| gfx::Vector2dF ScrollbarController::GetThumbRelativePoint( |
| const gfx::PointF position_in_widget) { |
| bool clipped; |
| const gfx::PointF position_in_layer = |
| GetScrollbarRelativePosition(position_in_widget, &clipped); |
| |
| if (clipped) |
| return gfx::Vector2d(0, 0); |
| |
| const gfx::RectF thumb_rect( |
| currently_captured_scrollbar_->ComputeThumbQuadRect()); |
| DCHECK(thumb_rect.Contains(position_in_layer)); |
| return position_in_layer - gfx::PointF(thumb_rect.origin()); |
| } |
| |
| // Performs hit test and prepares scroll deltas that will be used by GSB and |
| // GSU. |
| InputHandlerPointerResult ScrollbarController::HandlePointerDown( |
| const gfx::PointF position_in_widget) { |
| InputHandlerPointerResult scroll_result; |
| LayerImpl* layer_impl = GetLayerHitByPoint(position_in_widget); |
| |
| // If a non-custom scrollbar layer was not found, we return early as there is |
| // no point in setting additional state in the ScrollbarController. |
| if (!(layer_impl && layer_impl->ToScrollbarLayer())) |
| return scroll_result; |
| |
| currently_captured_scrollbar_ = layer_impl->ToScrollbarLayer(); |
| scroll_result.target_scroller = |
| currently_captured_scrollbar_->scroll_element_id(); |
| scroll_result.type = PointerResultType::kScrollbarScroll; |
| layer_tree_host_impl_->active_tree()->UpdateScrollbarGeometries(); |
| const ScrollbarPart scrollbar_part = |
| GetScrollbarPartFromPointerDown(position_in_widget); |
| scroll_result.scroll_offset = GetScrollOffsetForScrollbarPart( |
| scrollbar_part, currently_captured_scrollbar_->orientation()); |
| previous_pointer_position_ = position_in_widget; |
| scrollbar_scroll_is_active_ = true; |
| if (scrollbar_part == ScrollbarPart::THUMB) { |
| scroll_result.scroll_units = |
| ui::input_types::ScrollGranularity::kScrollByPrecisePixel; |
| drag_anchor_relative_to_thumb_ = GetThumbRelativePoint(position_in_widget); |
| } else { |
| // TODO(arakeri): This needs to be updated to kLine once cc implements |
| // handling it. crbug.com/959441 |
| scroll_result.scroll_units = |
| ui::input_types::ScrollGranularity::kScrollByPixel; |
| } |
| |
| if (!scroll_result.scroll_offset.IsZero()) { |
| // Thumb drag is the only scrollbar manipulation that cannot produce an |
| // autoscroll. All other interactions like clicking on arrows/trackparts |
| // have the potential of initiating an autoscroll (if held down for long |
| // enough). |
| DCHECK(scrollbar_part != ScrollbarPart::THUMB); |
| cancelable_autoscroll_task_ = |
| std::make_unique<base::CancelableClosure>(base::Bind( |
| &ScrollbarController::StartAutoScrollAnimation, |
| base::Unretained(this), |
| InitialDeltaToAutoscrollVelocity(scroll_result.scroll_offset), |
| currently_captured_scrollbar_->scroll_element_id())); |
| layer_tree_host_impl_->task_runner_provider() |
| ->ImplThreadTaskRunner() |
| ->PostDelayedTask(FROM_HERE, cancelable_autoscroll_task_->callback(), |
| kInitialAutoscrollTimerDelay); |
| } |
| return scroll_result; |
| } |
| |
| gfx::ScrollOffset ScrollbarController::GetScrollOffsetForDragPosition( |
| const gfx::PointF pointer_position_in_widget) { |
| layer_tree_host_impl_->active_tree()->UpdateScrollbarGeometries(); |
| |
| const gfx::Rect thumb_rect( |
| currently_captured_scrollbar_->ComputeThumbQuadRect()); |
| const gfx::PointF drag_position_relative_to_layer = |
| gfx::PointF(thumb_rect.origin()) + drag_anchor_relative_to_thumb_.value(); |
| |
| bool clipped = false; |
| const gfx::PointF pointer_position_in_layer = |
| GetScrollbarRelativePosition(pointer_position_in_widget, &clipped); |
| |
| if (clipped) |
| return gfx::ScrollOffset(0, 0); |
| |
| // Calculate the delta based on the previously known thumb drag point. |
| const gfx::Vector2dF pointer_delta = |
| pointer_position_in_layer - drag_position_relative_to_layer; |
| |
| gfx::ScrollOffset scaled_thumb_drag_delta; |
| const ScrollbarOrientation orientation = |
| currently_captured_scrollbar_->orientation(); |
| orientation == ScrollbarOrientation::VERTICAL |
| ? scaled_thumb_drag_delta.set_y(pointer_delta.y()) |
| : scaled_thumb_drag_delta.set_x(pointer_delta.x()); |
| |
| float scaled_scroller_to_scrollbar_ratio = GetScrollerToScrollbarRatio(); |
| scaled_thumb_drag_delta.Scale(scaled_scroller_to_scrollbar_ratio); |
| return scaled_thumb_drag_delta; |
| } |
| |
| // Performs hit test and prepares scroll deltas that will be used by GSU. |
| InputHandlerPointerResult ScrollbarController::HandleMouseMove( |
| const gfx::PointF position_in_widget) { |
| previous_pointer_position_ = position_in_widget; |
| InputHandlerPointerResult scroll_result; |
| |
| // If a thumb drag is not in progress or if a GSU was already produced for a |
| // thumb drag in this frame, there's no point in continuing on. Please see the |
| // header file for details. |
| if (!drag_anchor_relative_to_thumb_.has_value() || |
| drag_processed_for_current_frame_) |
| return scroll_result; |
| |
| const ScrollNode* currently_scrolling_node = |
| layer_tree_host_impl_->CurrentlyScrollingNode(); |
| |
| // Thumb drag needs a scroll_node. Clear the thumb drag state and exit if it |
| // is unset. |
| if (currently_scrolling_node == nullptr) { |
| drag_anchor_relative_to_thumb_ = base::nullopt; |
| return scroll_result; |
| } |
| |
| // If scroll_offset can't be consumed, there's no point in continuing on. |
| const gfx::ScrollOffset scroll_offset( |
| GetScrollOffsetForDragPosition(position_in_widget)); |
| const gfx::Vector2dF clamped_scroll_offset( |
| layer_tree_host_impl_->ComputeScrollDelta( |
| *currently_scrolling_node, ScrollOffsetToVector2dF(scroll_offset))); |
| |
| if (clamped_scroll_offset.IsZero()) |
| return scroll_result; |
| |
| // Thumb drags have more granularity and are purely dependent on the pointer |
| // movement. Hence we use kPrecisePixel when dragging the thumb. |
| scroll_result.scroll_units = |
| ui::input_types::ScrollGranularity::kScrollByPrecisePixel; |
| scroll_result.type = PointerResultType::kScrollbarScroll; |
| scroll_result.scroll_offset = gfx::ScrollOffset(clamped_scroll_offset); |
| drag_processed_for_current_frame_ = true; |
| |
| return scroll_result; |
| } |
| |
| float ScrollbarController::GetScrollerToScrollbarRatio() { |
| // Calculating the delta by which the scroller layer should move when |
| // dragging the thumb depends on the following factors: |
| // - scrollbar_track_length |
| // - scrollbar_thumb_length |
| // - scroll_layer_length |
| // - viewport_length |
| // - device_scale_factor |
| // - position_in_widget |
| // |
| // When a thumb drag is in progress, for every pixel that the pointer moves, |
| // the delta for the corresponding scroll_layer needs to be scaled by the |
| // following ratio: |
| // scaled_scroller_to_scrollbar_ratio = |
| // (scroll_layer_length - viewport_length) / |
| // (scrollbar_track_length - scrollbar_thumb_length) |
| // |
| // |<--------------------- scroll_layer_length -------------------------->| |
| // |
| // +------------------------------------------------+...................... |
| // | | . |
| // |<-------------- viewport_length --------------->| . |
| // | | . |
| // | | . |
| // | | . |
| // | | . |
| // | | . |
| // | | . |
| // | | . |
| // | | . |
| // | | . |
| // | |<------- scrollbar_track_length --------->| | . |
| // | | . |
| // +--+-----+----------------------------+-------+--+...................... |
| // |<|| |############################| ||>| |
| // +--+-----+----------------------------+-------+--+ |
| // |
| // |<- scrollbar_thumb_length ->| |
| // |
| layer_tree_host_impl_->active_tree()->UpdateScrollbarGeometries(); |
| float scroll_layer_length = |
| currently_captured_scrollbar_->scroll_layer_length(); |
| float scrollbar_track_length = currently_captured_scrollbar_->TrackLength(); |
| gfx::Rect thumb_rect(currently_captured_scrollbar_->ComputeThumbQuadRect()); |
| const ScrollbarOrientation orientation = |
| currently_captured_scrollbar_->orientation(); |
| float scrollbar_thumb_length = orientation == ScrollbarOrientation::VERTICAL |
| ? thumb_rect.height() |
| : thumb_rect.width(); |
| |
| const LayerImpl* owner_scroll_layer = |
| layer_tree_host_impl_->active_tree()->ScrollableLayerByElementId( |
| currently_captured_scrollbar_->scroll_element_id()); |
| float viewport_length = |
| orientation == ScrollbarOrientation::VERTICAL |
| ? owner_scroll_layer->scroll_container_bounds().height() |
| : (owner_scroll_layer->scroll_container_bounds().width()); |
| float scaled_scroller_to_scrollbar_ratio = |
| ((scroll_layer_length - viewport_length) / |
| (scrollbar_track_length - scrollbar_thumb_length)) * |
| layer_tree_host_impl_->active_tree()->device_scale_factor(); |
| |
| // Avoid precision loss later on by rounding up 3 decimal places here. |
| // TODO(arakeri): Revisit this while fixing crbug.com/986174. There is a |
| // precision loss that is happening somewhere which affects root scrollbars |
| // only. Even though it is not visible to the end user, without rounding up, |
| // the scrolling tests will fail due to this precision loss. |
| DCHECK_GT(scaled_scroller_to_scrollbar_ratio, 0); |
| scaled_scroller_to_scrollbar_ratio = |
| ceil(scaled_scroller_to_scrollbar_ratio * 1000.0) / 1000.0; |
| |
| return scaled_scroller_to_scrollbar_ratio; |
| } |
| |
| bool ScrollbarController::ShouldCancelTrackAutoscroll() { |
| // This function should only ever be called if an autoscroll is in progress. |
| DCHECK(autoscroll_state_.has_value()); |
| |
| layer_tree_host_impl_->active_tree()->UpdateScrollbarGeometries(); |
| const ScrollbarOrientation orientation = |
| currently_captured_scrollbar_->orientation(); |
| const gfx::Rect thumb_quad = |
| currently_captured_scrollbar_->ComputeThumbQuadRect(); |
| |
| bool clipped; |
| gfx::PointF scroller_relative_position( |
| GetScrollbarRelativePosition(previous_pointer_position_, &clipped)); |
| |
| if (clipped) |
| return false; |
| |
| // Based on the orientation of the scrollbar and the direction of the |
| // autoscroll, the code below makes a decision of whether the track autoscroll |
| // should be canceled or not. |
| int thumb_start = 0; |
| int thumb_end = 0; |
| int pointer_position = 0; |
| if (orientation == ScrollbarOrientation::VERTICAL) { |
| thumb_start = thumb_quad.y(); |
| thumb_end = thumb_quad.y() + thumb_quad.height(); |
| pointer_position = scroller_relative_position.y(); |
| } else { |
| thumb_start = thumb_quad.x(); |
| thumb_end = thumb_quad.x() + thumb_quad.width(); |
| pointer_position = scroller_relative_position.x(); |
| } |
| |
| if ((autoscroll_state_->direction == |
| AutoScrollDirection::AUTOSCROLL_FORWARD && |
| thumb_end > pointer_position) || |
| (autoscroll_state_->direction == |
| AutoScrollDirection::AUTOSCROLL_BACKWARD && |
| thumb_start < pointer_position)) |
| return true; |
| |
| return false; |
| } |
| |
| // Helper to calculate the autoscroll velocity. |
| float ScrollbarController::InitialDeltaToAutoscrollVelocity( |
| gfx::ScrollOffset scroll_offset) const { |
| const float scroll_delta = currently_captured_scrollbar_->orientation() == |
| ScrollbarOrientation::VERTICAL |
| ? scroll_offset.y() |
| : scroll_offset.x(); |
| return scroll_delta * kAutoscrollMultiplier; |
| } |
| |
| void ScrollbarController::StartAutoScrollAnimation(const float velocity, |
| ElementId element_id) { |
| // Autoscroll and thumb drag are mutually exclusive. Both can't be active at |
| // the same time. |
| DCHECK(!drag_anchor_relative_to_thumb_.has_value()); |
| DCHECK_NE(velocity, 0); |
| |
| // scroll_node is set up while handling GSB. If there's no node to scroll, we |
| // don't need to create any animation for it. |
| ScrollTree& scroll_tree = |
| layer_tree_host_impl_->active_tree()->property_trees()->scroll_tree; |
| ScrollNode* scroll_node = scroll_tree.FindNodeFromElementId(element_id); |
| |
| if (!(scroll_node && scrollbar_scroll_is_active_)) |
| return; |
| |
| layer_tree_host_impl_->active_tree()->UpdateScrollbarGeometries(); |
| |
| // TODO(arakeri): The animation needs to be readjusted if the scroller length |
| // changes. Tracked here: crbug.com/972485 |
| float scroll_layer_length = |
| currently_captured_scrollbar_->scroll_layer_length(); |
| |
| gfx::ScrollOffset current_offset = |
| scroll_tree.current_scroll_offset(scroll_node->element_id); |
| |
| // Determine the max offset for the scroll based on the scrolling direction. |
| // Negative scroll velocity indicates backwards scrolling whereas a positive |
| // value indicates forwards scrolling. |
| const float target_offset = velocity < 0 ? 0 : scroll_layer_length; |
| const gfx::Vector2dF target_offset_vector = |
| currently_captured_scrollbar_->orientation() == |
| ScrollbarOrientation::VERTICAL |
| ? gfx::Vector2dF(current_offset.x(), target_offset) |
| : gfx::Vector2dF(target_offset, current_offset.y()); |
| |
| autoscroll_state_ = AutoScrollState(); |
| autoscroll_state_->velocity = velocity; |
| autoscroll_state_->scroll_layer_length = scroll_layer_length; |
| autoscroll_state_->direction = velocity < 0 |
| ? AutoScrollDirection::AUTOSCROLL_BACKWARD |
| : AutoScrollDirection::AUTOSCROLL_FORWARD; |
| |
| layer_tree_host_impl_->AutoScrollAnimationCreate( |
| scroll_node, target_offset_vector, std::abs(velocity)); |
| } |
| |
| // Performs hit test and prepares scroll deltas that will be used by GSE. |
| InputHandlerPointerResult ScrollbarController::HandlePointerUp( |
| const gfx::PointF position_in_widget) { |
| InputHandlerPointerResult scroll_result; |
| if (scrollbar_scroll_is_active_) { |
| scrollbar_scroll_is_active_ = false; |
| scroll_result.type = PointerResultType::kScrollbarScroll; |
| } |
| |
| // TODO(arakeri): This needs to be moved to ScrollOffsetAnimationsImpl as it |
| // has knowledge about what type of animation is running. crbug.com/976353 |
| // Only abort the animation if it is an "autoscroll" animation. |
| if (autoscroll_state_.has_value()) |
| layer_tree_host_impl_->mutator_host()->ScrollAnimationAbort(); |
| |
| if (cancelable_autoscroll_task_) { |
| cancelable_autoscroll_task_->Cancel(); |
| cancelable_autoscroll_task_.reset(); |
| } |
| |
| drag_anchor_relative_to_thumb_ = base::nullopt; |
| autoscroll_state_ = base::nullopt; |
| return scroll_result; |
| } |
| |
| // Returns the layer that is hit by the position_in_widget. |
| LayerImpl* ScrollbarController::GetLayerHitByPoint( |
| const gfx::PointF position_in_widget) { |
| LayerTreeImpl* active_tree = layer_tree_host_impl_->active_tree(); |
| gfx::Point viewport_point(position_in_widget.x(), position_in_widget.y()); |
| |
| gfx::PointF device_viewport_point = gfx::ScalePoint( |
| gfx::PointF(viewport_point), active_tree->device_scale_factor()); |
| LayerImpl* layer_impl = |
| active_tree->FindFirstScrollingLayerOrScrollbarThatIsHitByPoint( |
| device_viewport_point); |
| |
| return layer_impl; |
| } |
| |
| int ScrollbarController::GetScrollDeltaForScrollbarPart( |
| ScrollbarPart scrollbar_part) { |
| int scroll_delta = 0; |
| int viewport_length = 0; |
| LayerImpl* owner_scroll_layer = nullptr; |
| |
| switch (scrollbar_part) { |
| case ScrollbarPart::BACK_BUTTON: |
| case ScrollbarPart::FORWARD_BUTTON: |
| scroll_delta = kPixelsPerLineStep; |
| break; |
| case ScrollbarPart::BACK_TRACK: |
| case ScrollbarPart::FORWARD_TRACK: |
| owner_scroll_layer = |
| layer_tree_host_impl_->active_tree()->ScrollableLayerByElementId( |
| currently_captured_scrollbar_->scroll_element_id()); |
| viewport_length = |
| currently_captured_scrollbar_->orientation() == |
| ScrollbarOrientation::VERTICAL |
| ? owner_scroll_layer->scroll_container_bounds().height() |
| : (owner_scroll_layer->scroll_container_bounds().width()); |
| scroll_delta = viewport_length * kMinFractionToStepWhenPaging; |
| break; |
| default: |
| scroll_delta = 0; |
| } |
| return scroll_delta * |
| layer_tree_host_impl_->active_tree()->device_scale_factor(); |
| } |
| |
| gfx::PointF ScrollbarController::GetScrollbarRelativePosition( |
| const gfx::PointF position_in_widget, |
| bool* clipped) { |
| gfx::Transform inverse_screen_space_transform( |
| gfx::Transform::kSkipInitialization); |
| if (!currently_captured_scrollbar_->ScreenSpaceTransform().GetInverse( |
| &inverse_screen_space_transform)) |
| return gfx::PointF(0, 0); |
| |
| return gfx::PointF(MathUtil::ProjectPoint(inverse_screen_space_transform, |
| position_in_widget, clipped)); |
| } |
| |
| // Determines the ScrollbarPart based on the position_in_widget. |
| ScrollbarPart ScrollbarController::GetScrollbarPartFromPointerDown( |
| const gfx::PointF position_in_widget) { |
| // position_in_widget needs to be transformed and made relative to the |
| // scrollbar layer because hit testing assumes layer relative coordinates. |
| bool clipped = false; |
| |
| const gfx::PointF scroller_relative_position( |
| GetScrollbarRelativePosition(position_in_widget, &clipped)); |
| |
| if (clipped) |
| return ScrollbarPart::NO_PART; |
| |
| return currently_captured_scrollbar_->IdentifyScrollbarPart( |
| scroller_relative_position); |
| } |
| |
| // Determines the scroll offsets based on the ScrollbarPart and the scrollbar |
| // orientation. |
| gfx::ScrollOffset ScrollbarController::GetScrollOffsetForScrollbarPart( |
| const ScrollbarPart scrollbar_part, |
| const ScrollbarOrientation orientation) { |
| float scroll_delta = GetScrollDeltaForScrollbarPart(scrollbar_part); |
| |
| // See CreateScrollStateForGesture for more information on how these values |
| // will be interpreted. |
| if (scrollbar_part == ScrollbarPart::BACK_BUTTON) { |
| return orientation == ScrollbarOrientation::VERTICAL |
| ? gfx::ScrollOffset(0, -scroll_delta) // Up arrow |
| : gfx::ScrollOffset(-scroll_delta, 0); // Left arrow |
| } else if (scrollbar_part == ScrollbarPart::FORWARD_BUTTON) { |
| return orientation == ScrollbarOrientation::VERTICAL |
| ? gfx::ScrollOffset(0, scroll_delta) // Down arrow |
| : gfx::ScrollOffset(scroll_delta, 0); // Right arrow |
| } else if (scrollbar_part == ScrollbarPart::BACK_TRACK) { |
| return orientation == ScrollbarOrientation::VERTICAL |
| ? gfx::ScrollOffset(0, -scroll_delta) // Track click up |
| : gfx::ScrollOffset(-scroll_delta, 0); // Track click left |
| } else if (scrollbar_part == ScrollbarPart::FORWARD_TRACK) { |
| return orientation == ScrollbarOrientation::VERTICAL |
| ? gfx::ScrollOffset(0, scroll_delta) // Track click down |
| : gfx::ScrollOffset(scroll_delta, 0); // Track click right |
| } |
| |
| return gfx::ScrollOffset(0, 0); |
| } |
| |
| } // namespace cc |
