touch_adjustment.cc | Explore in Territory

/*
 * Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies)
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/351564777): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif

#include "third_party/blink/renderer/core/page/touch_adjustment.h"

#include "third_party/blink/renderer/core/dom/container_node.h"
#include "third_party/blink/renderer/core/dom/node.h"
#include "third_party/blink/renderer/core/dom/node_computed_style.h"
#include "third_party/blink/renderer/core/dom/text.h"
#include "third_party/blink/renderer/core/editing/editing_behavior.h"
#include "third_party/blink/renderer/core/editing/editing_utilities.h"
#include "third_party/blink/renderer/core/editing/editor.h"
#include "third_party/blink/renderer/core/editing/frame_selection.h"
#include "third_party/blink/renderer/core/frame/local_frame.h"
#include "third_party/blink/renderer/core/frame/local_frame_view.h"
#include "third_party/blink/renderer/core/html/html_frame_owner_element.h"
#include "third_party/blink/renderer/core/html/html_iframe_element.h"
#include "third_party/blink/renderer/core/input/touch_action_util.h"
#include "third_party/blink/renderer/core/layout/layout_box.h"
#include "third_party/blink/renderer/core/layout/layout_object.h"
#include "third_party/blink/renderer/core/layout/layout_text.h"
#include "third_party/blink/renderer/core/page/chrome_client.h"
#include "third_party/blink/renderer/core/page/page.h"
#include "third_party/blink/renderer/core/style/computed_style.h"
#include "third_party/blink/renderer/platform/text/text_break_iterator.h"
#include "ui/display/screen_info.h"
#include "ui/gfx/geometry/point_conversions.h"
#include "ui/gfx/geometry/point_f.h"
#include "ui/gfx/geometry/quad_f.h"
#include "ui/gfx/geometry/rect_conversions.h"
#include "ui/gfx/geometry/size.h"

namespace blink {

namespace touch_adjustment {

const float kZeroTolerance = …;
// The touch adjustment range (diameters) in dip, using same as the value in
// gesture_configuration_android.cc
constexpr LayoutUnit kMaxAdjustmentSizeDip(32);
constexpr LayoutUnit kMinAdjustmentSizeDip(20);

// Class for remembering absolute quads of a target node and what node they
// represent.
class SubtargetGeometry { … };

}  // namespace touch_adjustment

}  // namespace blink

WTF_ALLOW_MOVE_INIT_AND_COMPARE_WITH_MEM_FUNCTIONS(…)

namespace blink {

namespace touch_adjustment {

SubtargetGeometryList;
NodeFilter;
AppendSubtargetsForNode;
DistanceFunction;

// Takes non-const |Node*| because |Node::WillRespondToMouseClickEvents()| is
// non-const.
bool NodeRespondsToTapGesture(Node* node) { … }

bool NodeIsZoomTarget(Node* node) { … }

bool ProvidesContextMenuItems(Node* node) { … }

bool NodeRespondsToTapOrMove(Node* node) { … }

static inline void AppendQuadsToSubtargetList(
    Vector<gfx::QuadF>& quads,
    Node* node,
    SubtargetGeometryList& subtargets) { … }

static inline void AppendBasicSubtargetsForNode(
    Node* node,
    SubtargetGeometryList& subtargets) { … }

static inline void AppendContextSubtargetsForNode(
    Node* node,
    SubtargetGeometryList& subtargets) { … }

static inline Node* ParentShadowHostOrOwner(const Node* node) { … }

// Compiles a list of subtargets of all the relevant target nodes.
void CompileSubtargetList(const HeapVector<Member<Node>>& intersected_nodes,
                          SubtargetGeometryList& subtargets,
                          NodeFilter node_filter,
                          AppendSubtargetsForNode append_subtargets_for_node) { … }

// This returns quotient of the target area and its intersection with the touch
// area.  This will prioritize largest intersection and smallest area, while
// balancing the two against each other.
float ZoomableIntersectionQuotient(const gfx::Point& touch_hotspot,
                                   const gfx::Rect& touch_area,
                                   const SubtargetGeometry& subtarget) { … }

// Uses a hybrid of distance to adjust and intersect ratio, normalizing each
// score between 0 and 1 and combining them. The distance to adjust works best
// for disambiguating clicks on targets such as links, where the width may be
// significantly larger than the touch width.  Using area of overlap in such
// cases can lead to a bias towards shorter links. Conversely, percentage of
// overlap can provide strong confidence in tapping on a small target, where the
// overlap is often quite high, and works well for tightly packed controls.
float HybridDistanceFunction(const gfx::Point& touch_hotspot,
                             const gfx::Rect& touch_rect,
                             const SubtargetGeometry& subtarget) { … }

gfx::PointF ConvertToRootFrame(LocalFrameView* view, gfx::PointF pt) { … }

// Adjusts 'point' to the nearest point inside rect, and leaves it unchanged if
// already inside.
void AdjustPointToRect(gfx::PointF& point, const gfx::Rect& rect) { … }

bool SnapTo(const SubtargetGeometry& geom,
            const gfx::Point& touch_point,
            const gfx::Rect& touch_area,
            gfx::Point& snapped_point) { … }

// A generic function for finding the target node with the lowest distance
// metric. A distance metric here is the result of a distance-like function,
// that computes how well the touch hits the node.  Distance functions could for
// instance be distance squared or area of intersection.
bool FindNodeWithLowestDistanceMetric(Node*& adjusted_node,
                                      gfx::Point& adjusted_point,
                                      const gfx::Point& touch_hotspot,
                                      const gfx::Rect& touch_area,
                                      SubtargetGeometryList& subtargets,
                                      DistanceFunction distance_function) { … }

bool FindBestCandidate(Node*& adjusted_node,
                       gfx::Point& adjusted_point,
                       const gfx::Point& touch_hotspot,
                       const gfx::Rect& touch_area,
                       const HeapVector<Member<Node>>& nodes,
                       NodeFilter node_filter,
                       AppendSubtargetsForNode append_subtargets_for_node) { … }

}  // namespace touch_adjustment

bool FindBestTouchAdjustmentCandidate(
    TouchAdjustmentCandidateType candidate_type,
    Node*& candidate_node,
    gfx::Point& candidate_point,
    const gfx::Point& touch_hotspot,
    const gfx::Rect& touch_area,
    const HeapVector<Member<Node>>& nodes) { … }

PhysicalSize GetHitTestRectForAdjustment(LocalFrame& frame,
                                         const PhysicalSize& touch_area) { … }

}  // namespace blink
chromium/third_party/blink/renderer/core/page/touch_adjustment.cc
