src/ui/input/drivers/virtio/input_touch.h

// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef SRC_UI_INPUT_DRIVERS_VIRTIO_INPUT_TOUCH_H_
#define SRC_UI_INPUT_DRIVERS_VIRTIO_INPUT_TOUCH_H_

#include <hid/paradise.h>

#include "input_device.h"

namespace virtio {

// The HidTouch class translates virtio touchscreen events into HID touchscreen
// events. It does this by making the virtio touchscreen appear exactly like
// a paradise touchscreen. There is no good reason to use the paradise
// touchscreen, other than it is a valid, tested report descriptor and it
// was easier to reuse it than building a new report descriptor from scratch.
class HidTouch : public HidDevice {
 public:
  HidTouch(virtio_input_absinfo_t x_info, virtio_input_absinfo_t y_info)
      : x_info_(x_info), y_info_(y_info) {
    report_.rpt_id = PARADISE_RPT_ID_TOUCH;
  }

  zx_status_t GetDescriptor(uint8_t desc_type, void* out_data_buffer, size_t data_size,
                            size_t* out_data_actual) override;
  void ReceiveEvent(virtio_input_event_t* event) override;
  const uint8_t* GetReport(size_t* size) override;

 private:
  static constexpr int MAX_TOUCH_POINTS = 5;
  virtio_input_absinfo_t x_info_;
  virtio_input_absinfo_t y_info_;
  int mt_slot_ = -1;
  paradise_touch_t report_ = {};
};

}  // namespace virtio

#endif  // SRC_UI_INPUT_DRIVERS_VIRTIO_INPUT_TOUCH_H_