// Copyright (c) 2011 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 "chrome/browser/metrics/display_utils.h"

#include <ApplicationServices/ApplicationServices.h>

// static
void DisplayUtils::GetPrimaryDisplayDimensions(int* width, int* height) {
  CGDirectDisplayID main_display = CGMainDisplayID();
  if (width)
    *width = CGDisplayPixelsWide(main_display);
  if (height)
    *height = CGDisplayPixelsHigh(main_display);
}

// static
int DisplayUtils::GetDisplayCount() {
  // Don't just return the number of online displays.  It includes displays
  // that mirror other displays, which are not desired in the count.  It's
  // tempting to use the count returned by CGGetActiveDisplayList, but active
  // displays exclude sleeping displays, and those are desired in the count.

  // It would be ridiculous to have this many displays connected, but
  // CGDirectDisplayID is just an integer, so supporting up to this many
  // doesn't hurt.
  CGDirectDisplayID online_displays[128];
  CGDisplayCount online_display_count = 0;
  if (CGGetOnlineDisplayList(arraysize(online_displays),
                             online_displays,
                             &online_display_count) != kCGErrorSuccess) {
    // 1 is a reasonable assumption.
    return 1;
  }

  int display_count = 0;
  for (CGDisplayCount online_display_index = 0;
       online_display_index < online_display_count;
       ++online_display_index) {
    CGDirectDisplayID online_display = online_displays[online_display_index];
    if (CGDisplayMirrorsDisplay(online_display) == kCGNullDirectDisplay) {
      // If this display doesn't mirror any other, include it in the count.
      // The primary display in a mirrored set will be counted, but those that
      // mirror it will not be.
      ++display_count;
    }
  }

  return display_count;
}