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// Copyright 2016 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ui/gfx/win/physical_size.h"
#include <windows.h>
#include <setupapi.h>
#include <iostream>
#include <memory>
#include "base/check_op.h"
#include "base/compiler_specific.h"
#include "base/memory/free_deleter.h"
#include "base/scoped_generic.h"
#include "base/strings/utf_string_conversions.h"
#include "base/win/registry.h"
// This GUID {E6F07B5F-EE97-4A90-B076-33F57BF4EAA7} was taken from
// https://msdn.microsoft.com/en-us/library/windows/hardware/ff545901.aspx
const GUID GUID_DEVICEINTERFACE_MONITOR = {
0xE6F07B5F,
0xEE97,
0x4A90,
{0xB0, 0x76, 0x33, 0xF5, 0x7B, 0xF4, 0xEA, 0xA7}};
namespace {
struct DeviceInfoListScopedTraits {
static HDEVINFO InvalidValue() { return INVALID_HANDLE_VALUE; }
static void Free(HDEVINFO h) { SetupDiDestroyDeviceInfoList(h); }
};
bool GetSizeFromRegistry(HDEVINFO device_info_list,
SP_DEVINFO_DATA* device_info,
int* width_mm,
int* height_mm) {
base::win::RegKey reg_key(SetupDiOpenDevRegKey(
device_info_list, device_info, DICS_FLAG_GLOBAL, 0, DIREG_DEV, KEY_READ));
if (!reg_key.Valid())
return false;
BYTE data[128]; // EDID block is exactly 128 bytes long.
UNSAFE_TODO(ZeroMemory(&data[0], sizeof(data)));
DWORD data_length = sizeof(data);
LONG return_value =
reg_key.ReadValue(L"EDID", &data[0], &data_length, nullptr);
if (return_value != ERROR_SUCCESS)
return false;
// Byte 54 is the start of the first descriptor block, which contains the
// required timing information with the highest preference, and 12 bytes
// into that block is the size information.
// 66: width least significant bits
// 67: height least significant bits
// 68: 4 bits for each of width and height most significant bits
if (data[54] == 0)
return false;
const int w = ((data[68] & 0xF0) << 4) + data[66];
const int h = ((data[68] & 0x0F) << 8) + data[67];
if (w <= 0 || h <= 0)
return false;
*width_mm = w;
*height_mm = h;
return true;
}
bool GetInterfaceDetailAndDeviceInfo(
HDEVINFO device_info_list,
SP_DEVICE_INTERFACE_DATA* interface_data,
std::unique_ptr<SP_DEVICE_INTERFACE_DETAIL_DATA, base::FreeDeleter>*
interface_detail,
SP_DEVINFO_DATA* device_info) {
DCHECK_EQ(sizeof(*device_info), device_info->cbSize);
DWORD buffer_size;
// This call populates device_info. It will also fail, but if the error is
// "insufficient buffer" then it will set buffer_size and we can call again
// with an allocated buffer.
SetupDiGetDeviceInterfaceDetail(device_info_list, interface_data, nullptr, 0,
&buffer_size, device_info);
if (GetLastError() != ERROR_INSUFFICIENT_BUFFER)
return false;
interface_detail->reset(
reinterpret_cast<SP_DEVICE_INTERFACE_DETAIL_DATA*>(malloc(buffer_size)));
(*interface_detail)->cbSize = sizeof(SP_DEVICE_INTERFACE_DETAIL_DATA);
return SetupDiGetDeviceInterfaceDetail(device_info_list, interface_data,
interface_detail->get(), buffer_size,
nullptr, nullptr) != 0;
}
} // namespace
namespace gfx {
// The physical size information is only available by looking in the EDID block
// via setup. However setup has the device path and not the device name that we
// use to identify displays. Therefore after looking up a device via setup we
// need to find the display again via EnumDisplayDevices (matching device path
// to the device ID of the display's interface) so we can return the device name
// (available from the interface's attached monitor).
std::vector<PhysicalDisplaySize> GetPhysicalSizeForDisplays() {
std::vector<PhysicalDisplaySize> out;
base::ScopedGeneric<HDEVINFO, DeviceInfoListScopedTraits> device_info_list(
SetupDiGetClassDevs(&GUID_DEVICEINTERFACE_MONITOR, nullptr, nullptr,
DIGCF_PRESENT | DIGCF_DEVICEINTERFACE));
if (!device_info_list.is_valid())
return out;
SP_DEVICE_INTERFACE_DATA interface_data = {};
interface_data.cbSize = sizeof(interface_data);
int interface_index = 0;
while (SetupDiEnumDeviceInterfaces(device_info_list.get(), nullptr,
&GUID_DEVICEINTERFACE_MONITOR,
interface_index++, &interface_data)) {
std::unique_ptr<SP_DEVICE_INTERFACE_DETAIL_DATA, base::FreeDeleter>
interface_detail;
SP_DEVINFO_DATA device_info = {};
device_info.cbSize = sizeof(device_info);
bool get_info_succeeded =
GetInterfaceDetailAndDeviceInfo(device_info_list.get(), &interface_data,
&interface_detail, &device_info);
if (!get_info_succeeded)
continue;
DISPLAY_DEVICE display_device = {};
display_device.cb = sizeof(display_device);
int display_index = 0;
while (EnumDisplayDevices(nullptr, display_index++, &display_device,
EDD_GET_DEVICE_INTERFACE_NAME)) {
DISPLAY_DEVICE attached_device = {};
attached_device.cb = sizeof(attached_device);
int attached_index = 0;
while (EnumDisplayDevices(display_device.DeviceName, attached_index++,
&attached_device,
EDD_GET_DEVICE_INTERFACE_NAME)) {
wchar_t* attached_device_id = attached_device.DeviceID;
wchar_t* setup_device_path = interface_detail->DevicePath;
if (UNSAFE_TODO(wcsicmp(attached_device_id, setup_device_path)) == 0) {
int width_mm;
int height_mm;
bool found = GetSizeFromRegistry(device_info_list.get(), &device_info,
&width_mm, &height_mm);
if (found) {
out.push_back(
PhysicalDisplaySize(base::WideToUTF8(display_device.DeviceName),
width_mm, height_mm));
}
break;
}
}
}
}
return out;
}
} // namespace gfx
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