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// Copyright 2011 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ui/views/controls/scrollbar/base_scroll_bar_thumb.h"
#include "base/i18n/rtl.h"
#include "ui/base/metadata/metadata_impl_macros.h"
#include "ui/gfx/canvas.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/views/controls/scrollbar/scroll_bar.h"
namespace {
// The distance the mouse can be dragged outside the bounds of the thumb during
// dragging before the scrollbar will snap back to its regular position.
static constexpr int kScrollThumbDragOutSnap = 100;
} // namespace
namespace views {
BaseScrollBarThumb::BaseScrollBarThumb(ScrollBar* scroll_bar)
: scroll_bar_(scroll_bar) {}
BaseScrollBarThumb::~BaseScrollBarThumb() = default;
void BaseScrollBarThumb::SetLength(int length) {
// Make sure the thumb is never sized smaller than its minimum possible
// display size.
gfx::Size size = GetPreferredSize({});
size.SetToMax(
gfx::Size(IsHorizontal() ? length : 0, IsHorizontal() ? 0 : length));
SetSize(size);
}
int BaseScrollBarThumb::GetLength() const {
if (IsHorizontal()) {
return width();
}
return height();
}
void BaseScrollBarThumb::SetPosition(int position) {
gfx::Rect thumb_bounds = bounds();
gfx::Rect track_bounds = scroll_bar_->GetTrackBounds();
if (IsHorizontal()) {
thumb_bounds.set_x(track_bounds.x() + position);
} else {
thumb_bounds.set_y(track_bounds.y() + position);
}
SetBoundsRect(thumb_bounds);
}
int BaseScrollBarThumb::GetPosition() const {
gfx::Rect track_bounds = scroll_bar_->GetTrackBounds();
if (IsHorizontal()) {
return x() - track_bounds.x();
}
return y() - track_bounds.y();
}
void BaseScrollBarThumb::SetSnapBackOnDragOutside(bool snap) {
snap_back_on_drag_outside_ = snap;
}
bool BaseScrollBarThumb::GetSnapBackOnDragOutside() const {
return snap_back_on_drag_outside_;
}
void BaseScrollBarThumb::OnMouseEntered(const ui::MouseEvent& event) {
SetState(Button::STATE_HOVERED);
}
void BaseScrollBarThumb::OnMouseExited(const ui::MouseEvent& event) {
SetState(Button::STATE_NORMAL);
}
bool BaseScrollBarThumb::OnMousePressed(const ui::MouseEvent& event) {
mouse_offset_ = IsHorizontal() ? event.x() : event.y();
drag_start_position_ = GetPosition();
SetState(Button::STATE_PRESSED);
return true;
}
bool BaseScrollBarThumb::OnMouseDragged(const ui::MouseEvent& event) {
if (snap_back_on_drag_outside_) {
// If the user moves the mouse more than |kScrollThumbDragOutSnap| outside
// the bounds of the thumb, the scrollbar will snap the scroll back to the
// point it was at before the drag began.
if (IsHorizontal()) {
if ((event.y() < y() - kScrollThumbDragOutSnap) ||
(event.y() > (y() + height() + kScrollThumbDragOutSnap))) {
scroll_bar_->ScrollToThumbPosition(drag_start_position_, false);
return true;
}
} else {
if ((event.x() < x() - kScrollThumbDragOutSnap) ||
(event.x() > (x() + width() + kScrollThumbDragOutSnap))) {
scroll_bar_->ScrollToThumbPosition(drag_start_position_, false);
return true;
}
}
}
if (IsHorizontal()) {
int thumb_x = event.x() - mouse_offset_;
if (base::i18n::IsRTL()) {
thumb_x *= -1;
}
scroll_bar_->ScrollToThumbPosition(GetPosition() + thumb_x, false);
} else {
int thumb_y = event.y() - mouse_offset_;
scroll_bar_->ScrollToThumbPosition(GetPosition() + thumb_y, false);
}
return true;
}
void BaseScrollBarThumb::OnMouseReleased(const ui::MouseEvent& event) {
SetState(HitTestPoint(event.location()) ? Button::STATE_HOVERED
: Button::STATE_NORMAL);
}
void BaseScrollBarThumb::OnMouseCaptureLost() {
SetState(Button::STATE_HOVERED);
}
Button::ButtonState BaseScrollBarThumb::GetState() const {
return state_;
}
void BaseScrollBarThumb::SetState(Button::ButtonState state) {
if (state_ == state) {
return;
}
state_ = state;
OnStateChanged();
}
void BaseScrollBarThumb::OnStateChanged() {
SchedulePaint();
}
bool BaseScrollBarThumb::IsHorizontal() const {
return scroll_bar_->GetOrientation() == ScrollBar::Orientation::kHorizontal;
}
BEGIN_METADATA(BaseScrollBarThumb)
ADD_PROPERTY_METADATA(bool, SnapBackOnDragOutside);
END_METADATA
} // namespace views
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