peridot/lib/fidl/view_host.h

// Copyright 2017 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 PERIDOT_LIB_FIDL_VIEW_HOST_H_
#define PERIDOT_LIB_FIDL_VIEW_HOST_H_

#include <fuchsia/ui/gfx/cpp/fidl.h>
#include <fuchsia/ui/views/cpp/fidl.h>
#include <lib/ui/base_view/cpp/base_view.h>
#include <lib/ui/scenic/cpp/resources.h>
#include <lib/ui/scenic/cpp/session.h>
#include <src/lib/fxl/logging.h>
#include <src/lib/fxl/macros.h>
#include <map>
#include <memory>

namespace modular {

// A class that allows modules to display the UI of their child
// modules, without displaying any UI on their own. Used for modules
// that play the role of a view controller (aka quarterback, recipe).
// It supports to embed views of *multiple* children, which are laid
// out horizontally.
class ViewHost : public scenic::BaseView {
 public:
  explicit ViewHost(scenic::ViewContext view_context);
  ~ViewHost() override = default;

  // Connects one more view. Calling this method multiple times adds
  // multiple views and lays them out horizontally next to each other.
  // This is experimental to establish data flow patterns in toy
  // applications and can be changed or extended as needed.
  void ConnectView(fuchsia::ui::views::ViewHolderToken view_holder_token);

 private:
  struct ViewData {
    explicit ViewData(scenic::Session* session,
                      fuchsia::ui::views::ViewHolderToken view_holder_token)
        : host_node(session),
          host_view_holder(session, std::move(view_holder_token),
                           "modular::ViewHost") {
      host_node.Attach(host_view_holder);
    }

    scenic::EntityNode host_node;
    scenic::ViewHolder host_view_holder;
  };

  // |scenic::SessionListener|
  void OnScenicError(std::string error) override {
    FXL_LOG(ERROR) << "Scenic Error " << error;
  }

  // |scenic::BaseView|
  void OnPropertiesChanged(
      fuchsia::ui::gfx::ViewProperties old_properties) override;
  void OnScenicEvent(fuchsia::ui::scenic::Event event) override;

  void UpdateScene();

  std::map<uint32_t, std::unique_ptr<ViewData>> views_;

  FXL_DISALLOW_COPY_AND_ASSIGN(ViewHost);
};

}  // namespace modular

#endif  // PERIDOT_LIB_FIDL_VIEW_HOST_H_