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display_manager.cc
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1 // Copyright 2013 The Flutter Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "display_manager.h"
6
7 #include <windows.h>
8
9 #include "flutter/shell/platform/windows/dpi_utils.h"
10 #include "flutter/shell/platform/windows/flutter_windows_engine.h"
11
12 namespace flutter {
13
14 namespace {
15
16 // Data structure to pass to the display enumeration callback.
17 struct MonitorEnumState {
18 const DisplayManagerWin32* display_manager;
19 std::vector<FlutterEngineDisplay>* displays;
20 };
21
22 } // namespace
23
24 DisplayManagerWin32::DisplayManagerWin32(FlutterWindowsEngine* engine)
25 : engine_(engine), win32_(engine->windows_proc_table()) {}
26
27 DisplayManagerWin32::~DisplayManagerWin32() = default;
28
29 std::optional<FlutterEngineDisplay> DisplayManagerWin32::FromMonitor(
30 HMONITOR monitor) const {
31 MONITORINFOEXW monitor_info = {};
32 monitor_info.cbSize = sizeof(monitor_info);
33 if (win32_->GetMonitorInfoW(monitor, &monitor_info) == 0) {
34 return std::nullopt;
35 }
36
37 DEVMODEW dev_mode = {};
38 dev_mode.dmSize = sizeof(dev_mode);
39 if (!win32_->EnumDisplaySettingsW(monitor_info.szDevice,
40 ENUM_CURRENT_SETTINGS, &dev_mode)) {
41 return std::nullopt;
42 }
43
44 UINT dpi = GetDpiForMonitor(monitor);
45
46 FlutterEngineDisplay display = {};
47 display.struct_size = sizeof(FlutterEngineDisplay);
48 display.display_id = reinterpret_cast<FlutterEngineDisplayId>(monitor);
49 display.single_display = false;
50 display.refresh_rate = dev_mode.dmDisplayFrequency;
51 display.width = monitor_info.rcMonitor.right - monitor_info.rcMonitor.left;
52 display.height = monitor_info.rcMonitor.bottom - monitor_info.rcMonitor.top;
53 display.device_pixel_ratio =
54 static_cast<double>(dpi) / static_cast<double>(kDefaultDpi);
55 return display;
56 }
57
58 BOOL CALLBACK DisplayManagerWin32::EnumMonitorCallback(HMONITOR monitor,
59 HDC hdc,
60 LPRECT rect,
61 LPARAM data) {
62 MonitorEnumState* state = reinterpret_cast<MonitorEnumState*>(data);
63 const DisplayManagerWin32* self = state->display_manager;
64 std::vector<FlutterEngineDisplay>* displays = state->displays;
65 const std::optional<FlutterEngineDisplay> display =
66 self->FromMonitor(monitor);
67 if (!display) {
68 // Return TRUE to continue enumeration and skip this monitor.
69 // Returning FALSE would stop the entire enumeration process,
70 // potentially missing other valid monitors.
71 return TRUE;
72 }
73 displays->push_back(*display);
74 return TRUE;
75 }
76
77 void DisplayManagerWin32::UpdateDisplays() {
78 auto displays = GetDisplays();
79 engine_->UpdateDisplay(displays);
80 }
81
82 bool DisplayManagerWin32::HandleWindowMessage(HWND hwnd,
83 UINT message,
84 WPARAM wparam,
85 LPARAM lparam,
86 LRESULT* result) {
87 switch (message) {
88 case WM_DISPLAYCHANGE:
89 case WM_DPICHANGED:
90 UpdateDisplays();
91 break;
92 }
93 return false;
94 }
95
96 std::optional<FlutterEngineDisplay> DisplayManagerWin32::FindById(
97 FlutterEngineDisplayId id) {
98 for (auto const& display : GetDisplays()) {
99 if (display.display_id == id) {
100 return display;
101 }
102 }
103
104 return std::nullopt;
105 }
106
107 std::vector<FlutterEngineDisplay> DisplayManagerWin32::GetDisplays() const {
108 std::vector<FlutterEngineDisplay> displays;
109 MonitorEnumState state = {this, &displays};
110 win32_->EnumDisplayMonitors(nullptr, nullptr, EnumMonitorCallback,
111 reinterpret_cast<LPARAM>(&state));
112
113 if (displays.size() == 1) {
114 displays[0].single_display = true;
115 }
116
117 return displays;
118 }
119
120 } // namespace flutter
flutter::DisplayManagerWin32::~DisplayManagerWin32
~DisplayManagerWin32()
flutter::DisplayManagerWin32::FindById
std::optional< FlutterEngineDisplay > FindById(FlutterEngineDisplayId id)
Definition: display_manager.cc:96
flutter::DisplayManagerWin32::UpdateDisplays
void UpdateDisplays()
Definition: display_manager.cc:77
flutter::DisplayManagerWin32::HandleWindowMessage
bool HandleWindowMessage(HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam, LRESULT *result)
Definition: display_manager.cc:82
flutter::DisplayManagerWin32::DisplayManagerWin32
DisplayManagerWin32(FlutterWindowsEngine *engine)
Definition: display_manager.cc:24
flutter::DisplayManagerWin32::GetDisplays
std::vector< FlutterEngineDisplay > GetDisplays() const
Definition: display_manager.cc:107
flutter::FlutterWindowsEngine
Definition: flutter_windows_engine.h:92
flutter::FlutterWindowsEngine::UpdateDisplay
void UpdateDisplay(const std::vector< FlutterEngineDisplay > &displays)
Definition: flutter_windows_engine.cc:710
displays
std::vector< FlutterEngineDisplay > * displays
Definition: display_manager.cc:19
display_manager
const DisplayManagerWin32 * display_manager
Definition: display_manager.cc:18
display_manager.h
dpi_utils.h
flutter_windows_engine.h
message
Win32Message message
Definition: keyboard_unittests.cc:137
flutter
Definition: accessibility_bridge_windows.cc:11
flutter::GetDpiForMonitor
UINT GetDpiForMonitor(HMONITOR monitor)
Definition: dpi_utils.cc:132
flutter::kDefaultDpi
constexpr UINT kDefaultDpi
Definition: dpi_utils.h:12