remoting/protocol/coordinate_converter.h

// Copyright 2025 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef REMOTING_PROTOCOL_COORDINATE_CONVERTER_H_
#define REMOTING_PROTOCOL_COORDINATE_CONVERTER_H_

#include <optional>

#include "remoting/proto/control.pb.h"
#include "third_party/webrtc/modules/desktop_capture/desktop_geometry.h"

namespace remoting::protocol {

// Class for converting fractional coordinates between [0, 1] to absolute
// coordinates. The converter is pixel-type-agnostic and whether the absolute
// coordinates are in DIPs or physical pixels depends on the pixel type of the
// provided VideoLayout.
class CoordinateConverter {
 public:
  CoordinateConverter();
  ~CoordinateConverter();

  CoordinateConverter(const CoordinateConverter&) = delete;
  CoordinateConverter& operator=(const CoordinateConverter&) = delete;

  // Sets the video layout to be used to convert fractional coordinates for
  // injection.
  void set_video_layout(const VideoLayout& layout);

  // Sets the fallback geometry to be used for fractional coordinates which
  // don't have `screen_id`. If no fallback is set (or has empty size), no
  // fallback will be used.
  // TODO: yuweih - The fallback geometry can be removed once multi-stream is
  // fully rolled out.
  void set_fallback_geometry(const webrtc::DesktopRect& geometry);

  // Converts the fractional coordinate to a global absolute coordinate. Returns
  // nullopt if conversion fails, usually because the screen ID is not found or
  // a fallback geometry is not provided.
  std::optional<webrtc::DesktopVector> ToGlobalAbsoluteCoordinate(
      const FractionalCoordinate& fractional) const;

 private:
  VideoLayout video_layout_;

  // webrtc::DesktopRect is a convenient choice because it uses 32-bit values
  // which match the proto definitions for VideoTrackLayout fields.
  webrtc::DesktopRect fallback_geometry_;
};

}  // namespace remoting::protocol

#endif  // REMOTING_PROTOCOL_COORDINATE_CONVERTER_H_