blob: ca9395880f4db9e21c1793664c116f4294b6d1c8 [file] [log] [blame]
// 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/display_util.h"
#include <stddef.h>
#include <algorithm>
#include <array>
#include <cmath>
#include "base/logging.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/stringprintf.h"
#include "ui/display/manager/managed_display_info.h"
#include "ui/display/types/display_snapshot.h"
namespace display {
namespace {
// The total number of display zoom factors to enumerate.
constexpr int kNumOfZoomFactors = 9;
// A pair representing the list of zoom values for a given minimum display
// resolution width.
using ZoomListBucket = std::pair<int, std::array<float, kNumOfZoomFactors>>;
// A pair representing the list of zoom values for a given minimum default dsf.
using ZoomListBucketDsf =
std::pair<float, std::array<float, kNumOfZoomFactors>>;
// For displays with a device scale factor of unity, we use a static list of
// initialized zoom values. For a given resolution width of a display, we can
// find its associated list of zoom values by simply finding the last bucket
// with a width less than the given resolution width.
// Ex. A resolution width of 1024, we will use the bucket with the width of 960.
constexpr std::array<ZoomListBucket, 8> kZoomListBuckets{{
{0, {0.60f, 0.65f, 0.70f, 0.75f, 0.80f, 0.85f, 0.90f, 0.95f, 1.f}},
{720, {0.70f, 0.75f, 0.80f, 0.85f, 0.90f, 0.95f, 1.f, 1.05f, 1.10f}},
{800, {0.75f, 0.80f, 0.85f, 0.90f, 0.95f, 1.f, 1.05f, 1.10f, 1.15f}},
{960, {0.90f, 0.95f, 1.f, 1.05f, 1.10f, 1.15f, 1.20f, 1.25f, 1.30f}},
{1280, {0.90f, 1.f, 1.05f, 1.10f, 1.15f, 1.20f, 1.25f, 1.30f, 1.50f}},
{1920, {1.f, 1.10f, 1.15f, 1.20f, 1.30f, 1.40f, 1.50f, 1.75f, 2.00f}},
{3840, {1.f, 1.10f, 1.20f, 1.40f, 1.60f, 1.80f, 2.00f, 2.20f, 2.40f}},
{5120, {1.f, 1.25f, 1.50f, 1.75f, 2.00f, 2.25f, 2.50f, 2.75f, 3.00f}},
// Displays with a default device scale factor have a static list of initialized
// zoom values that includes a zoom level to go to the native resolution of the
// display. Ensure that the list of DSFs are in sync with the list of default
// device scale factors in
constexpr std::array<ZoomListBucketDsf, 4> kZoomListBucketsForDsf{{
{1.25f, {0.7f, 1.f / 1.25f, 0.85f, 0.9f, 0.95f, 1.f, 1.1f, 1.2f, 1.3f}},
{1.6f, {1.f / 1.6f, 0.7f, 0.75f, 0.8f, 0.85f, 0.9f, 1.f, 1.15f, 1.3f}},
{2.f, {1.f / 2.f, 0.6f, 0.7f, 0.8f, 0.9f, 1.f, 1.1f, 1.25f, 1.5f}},
{2.25f, {1.f / 2.25f, 0.6f, 0.7f, 0.8f, 0.9f, 1.f, 1.15f, 1.3f, 1.5f}},
bool WithinEpsilon(float a, float b) {
return std::abs(a - b) < std::numeric_limits<float>::epsilon();
} // namespace
std::string DisplayPowerStateToString(chromeos::DisplayPowerState state) {
switch (state) {
case chromeos::DISPLAY_POWER_ALL_ON:
return "ALL_ON";
case chromeos::DISPLAY_POWER_ALL_OFF:
return "ALL_OFF";
return "unknown (" + base::IntToString(state) + ")";
std::string MultipleDisplayStateToString(MultipleDisplayState state) {
switch (state) {
return "INVALID";
return "HEADLESS";
return "SINGLE";
return "DUAL_MIRROR";
NOTREACHED() << "Unknown state " << state;
return "INVALID";
int GetDisplayPower(const std::vector<DisplaySnapshot*>& displays,
chromeos::DisplayPowerState state,
std::vector<bool>* display_power) {
int num_on_displays = 0;
if (display_power)
for (size_t i = 0; i < displays.size(); ++i) {
bool internal = displays[i]->type() == DISPLAY_CONNECTION_TYPE_INTERNAL;
bool on =
state == chromeos::DISPLAY_POWER_ALL_ON ||
!internal) ||
(state == chromeos::DISPLAY_POWER_INTERNAL_ON_EXTERNAL_OFF && internal);
if (display_power)
(*display_power)[i] = on;
if (on)
return num_on_displays;
bool IsPhysicalDisplayType(DisplayConnectionType type) {
std::vector<float> GetDisplayZoomFactors(const ManagedDisplayMode& mode) {
// Internal displays have an internal device scale factor greater than 1
// associated with them. This means that if we use the usual logic, we would
// end up with a list of zoom levels that the user may not find very useful.
// Take for example the pixelbook with device scale factor of 2. Based on the
// usual approach, we would get a zoom range of 90% to 150%. This means:
// 1. Users will not be able to go to the native resolution which is
// achieved at 50% zoom level.
// 2. Due to the device scale factor, the display already has a low DPI and
// users dont want to zoom in, they mostly want to zoom out and add more
// pixels to the screen. But we only provide a zoom list of 90% to 150%.
// This clearly shows we need a different logic to handle internal displays
// which have lower DPI due to the device scale factor associated with them.
// OTOH if we look at an external display with a device scale factor of 1 but
// the same resolution as the pixel book, the DPI would usually be very high
// and users mostly want to zoom in to reduce the number of pixels on the
// screen. So having a range of 90% to 130% makes sense.
// TODO(malaykeshav): Investigate if we can use DPI instead of resolution or
// device scale factor to decide the list of zoom levels.
if (mode.device_scale_factor() > 1.f)
return GetDisplayZoomFactorForDsf(mode.device_scale_factor());
// There may be cases where the device scale factor is less than 1. This can
// happen during testing or local linux builds.
const int effective_width = std::round(
static_cast<float>(mode.size().width()) / mode.device_scale_factor());
std::size_t index = kZoomListBuckets.size() - 1;
while (index > 0 && effective_width < kZoomListBuckets[index].first)
DCHECK_GE(effective_width, kZoomListBuckets[index].first);
const auto& zoom_array = kZoomListBuckets[index].second;
return std::vector<float>(zoom_array.begin(), zoom_array.end());
std::vector<float> GetDisplayZoomFactorForDsf(float dsf) {
DCHECK(!WithinEpsilon(dsf, 1.f));
DCHECK_GT(dsf, 1.f);
for (const auto& bucket : kZoomListBucketsForDsf) {
if (WithinEpsilon(bucket.first, dsf))
return std::vector<float>(bucket.second.begin(), bucket.second.end());
NOTREACHED() << "Received a DSF not on the list: " << dsf;
return {1.f / dsf, 1.f};
void InsertDsfIntoList(std::vector<float>* zoom_values, float dsf) {
// 1.0 is already in the list of |zoom_values|. We do not need to add it.
if (WithinEpsilon(dsf, 1.f))
if (dsf > 1.f && WithinEpsilon(*(zoom_values->rbegin()), 1.f)) {
// If the last element of the vector is 1 then |dsf|, which is greater than
// 1, will simply be inserted after that.
} else if (dsf < 1.f && WithinEpsilon(*(zoom_values->begin()), 1.f)) {
// If the first element in the list is 1 then |dsf|, which is less than 1,
// will simply be inseted before that.
zoom_values->insert(zoom_values->begin(), dsf);
// We dont need to add |dsf| to the list if it is already in the list.
auto it = std::lower_bound(zoom_values->begin(), zoom_values->end(), dsf);
if (it != zoom_values->end() && WithinEpsilon(*it, dsf))
if (it == zoom_values->begin()) {
DCHECK_LT(dsf, 1.f);
*(zoom_values->begin()) = dsf;
} else if (it == zoom_values->end()) {
DCHECK_GT(dsf, 1.f);
*(zoom_values->rbegin()) = dsf;
} else {
// There can only be 1 entry for 1.f value.
DCHECK(!(WithinEpsilon(*(it - 1), 1.f) && WithinEpsilon(*it, 1.f)));
// True if |dsf| is closer to |it| than it is to |it-1|.
const bool dsf_closer_to_it =
std::abs(*it - dsf) < std::abs(*(it - 1) - dsf);
if (WithinEpsilon(*(it - 1), 1.f) ||
(dsf_closer_to_it && !WithinEpsilon(*it, 1.f))) {
*it = dsf;
} else {
*(it - 1) = dsf;
} // namespace display