ui/display/manager/configure_displays_task.cc

// Copyright 2014 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 "ui/display/manager/configure_displays_task.h"

#include "base/auto_reset.h"
#include "base/bind.h"
#include "base/containers/queue.h"
#include "base/logging.h"
#include "base/metrics/histogram_functions.h"
#include "base/stl_util.h"
#include "ui/display/manager/display_util.h"
#include "ui/display/types/display_configuration_params.h"
#include "ui/display/types/display_snapshot.h"
#include "ui/display/types/native_display_delegate.h"

namespace display {

namespace {

// Find the next best mode after |display_mode|. If none can be found return
// nullptr.
const DisplayMode* FindNextMode(const DisplaySnapshot& display_state,
                                const DisplayMode* display_mode) {
  if (!display_mode)
    return nullptr;

  int best_mode_pixels = 0;
  const DisplayMode* best_mode = nullptr;
  int current_mode_pixels = display_mode->size().GetArea();
  for (const std::unique_ptr<const DisplayMode>& mode : display_state.modes()) {
    int pixel_count = mode->size().GetArea();
    if (pixel_count < current_mode_pixels && pixel_count > best_mode_pixels) {
      best_mode = mode.get();
      best_mode_pixels = pixel_count;
    }
  }

  return best_mode;
}

// Samples used to define buckets used by DisplayResolution enum.
// The enum is used to record screen resolution statistics.
const int32_t kDisplayResolutionSamples[] = {1024, 1280, 1440, 1920,
                                             2560, 3840, 5120, 7680};

// Computes the index of the enum DisplayResolution.
// The index has to match the definition of the enum in enums.xml
int ComputeDisplayResolutionEnum(const DisplayMode* mode) {
  if (!mode)
    return 0;  // Display is powered off

  const gfx::Size size = mode->size();
  uint32_t width_idx = 0;
  uint32_t height_idx = 0;
  for (; width_idx < base::size(kDisplayResolutionSamples); width_idx++) {
    if (size.width() <= kDisplayResolutionSamples[width_idx])
      break;
  }
  for (; height_idx < base::size(kDisplayResolutionSamples); height_idx++) {
    if (size.height() <= kDisplayResolutionSamples[height_idx])
      break;
  }

  if (width_idx == base::size(kDisplayResolutionSamples) ||
      height_idx == base::size(kDisplayResolutionSamples))
    return base::size(kDisplayResolutionSamples) *
               base::size(kDisplayResolutionSamples) +
           1;  // Overflow bucket
  // Computes the index of DisplayResolution, starting from 1, since 0 is used
  // when powering off the display.
  return width_idx * base::size(kDisplayResolutionSamples) + height_idx + 1;
}

}  // namespace

DisplayConfigureRequest::DisplayConfigureRequest(DisplaySnapshot* display,
                                                 const DisplayMode* mode,
                                                 const gfx::Point& origin)
    : display(display), mode(mode), origin(origin) {}

ConfigureDisplaysTask::ConfigureDisplaysTask(
    NativeDisplayDelegate* delegate,
    const std::vector<DisplayConfigureRequest>& requests,
    ResponseCallback callback)
    : delegate_(delegate),