win8/metro_driver/display_properties.cc


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// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "stdafx.h"

#include <windows.h>
#include <wrl\implements.h>
#include <wrl\wrappers\corewrappers.h>
#include <windows.foundation.h>
#include <windows.graphics.display.h>
#include "base/win/scoped_com_initializer.h"
#include "winrt_utils.h"

#pragma comment(lib, "runtimeobject.lib")

extern "C" {

  __declspec(dllexport) float GetModernUIScale() {
  base::win::ScopedCOMInitializer com_init;
  Microsoft::WRL::ComPtr<
      ABI::Windows::Graphics::Display::IDisplayPropertiesStatics>
      display_properties;
  if (SUCCEEDED(winrt_utils::CreateActivationFactory(
      RuntimeClass_Windows_Graphics_Display_DisplayProperties,
      display_properties.GetAddressOf()))) {
    ABI::Windows::Graphics::Display::ResolutionScale resolution_scale;
    if (SUCCEEDED(display_properties->get_ResolutionScale(&resolution_scale)))
      return static_cast<float>(resolution_scale) / 100.0f;
  }
  return 1.0f;
}

}