third_party/blink/renderer/core/scroll/scroll_animator_base.cc

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#include "third_party/blink/renderer/core/scroll/scroll_animator_base.h"

#include "base/callback_helpers.h"
#include "third_party/blink/renderer/core/scroll/scrollable_area.h"
#include "third_party/blink/renderer/platform/wtf/math_extras.h"

namespace blink {

ScrollAnimatorBase::ScrollAnimatorBase(ScrollableArea* scrollable_area)
    : scrollable_area_(scrollable_area) {}

ScrollAnimatorBase::~ScrollAnimatorBase() = default;

ScrollOffset ScrollAnimatorBase::ComputeDeltaToConsume(
    const ScrollOffset& delta) const {
  ScrollOffset new_pos =
      scrollable_area_->ClampScrollOffset(current_offset_ + delta);
  return new_pos - current_offset_;
}

ScrollResult ScrollAnimatorBase::UserScroll(
    ScrollGranularity,
    const ScrollOffset& delta,
    ScrollableArea::ScrollCallback on_finish) {
  // Run the callback for non-animation user scroll.
  base::ScopedClosureRunner run_on_return(std::move(on_finish));

  ScrollOffset consumed_delta = ComputeDeltaToConsume(delta);
  ScrollOffset new_pos = current_offset_ + consumed_delta;
  if (current_offset_ == new_pos)
    return ScrollResult(false, false, delta.Width(), delta.Height());

  current_offset_ = new_pos;

  NotifyOffsetChanged();

  return ScrollResult(consumed_delta.Width(), consumed_delta.Height(),
                      delta.Width() - consumed_delta.Width(),
                      delta.Height() - consumed_delta.Height());
}

void ScrollAnimatorBase::ScrollToOffsetWithoutAnimation(
    const ScrollOffset& offset) {
  current_offset_ = offset;
  NotifyOffsetChanged();
}

void ScrollAnimatorBase::SetCurrentOffset(const ScrollOffset& offset) {
  current_offset_ = offset;
}

ScrollOffset ScrollAnimatorBase::CurrentOffset() const {
  return current_offset_;
}

void ScrollAnimatorBase::NotifyOffsetChanged() {
  ScrollOffsetChanged(current_offset_, mojom::blink::ScrollType::kUser);
}

void ScrollAnimatorBase::Trace(Visitor* visitor) {
  visitor->Trace(scrollable_area_);
  ScrollAnimatorCompositorCoordinator::Trace(visitor);
}

}  // namespace blink