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36f7f3ca82
Add copyright headers in a few files where they were missing. Trim trailing blank comment line where present, for consistency with other engine code. Use the standard libtxt copyright header in one file where it differed (extra (C) and comma compared to other files in libtxt). This also amends tools/const_finder/test/const_finder_test.dart to look for a const an additional four lines down to account for the copyright header added to the test fixture.
134 lines
4.1 KiB
C++
134 lines
4.1 KiB
C++
// Copyright 2013 The Flutter Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "win32_dpi_utils.h"
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namespace flutter {
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namespace {
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constexpr UINT kDefaultDpi = 96;
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// This is the MDT_EFFECTIVE_DPI value from MONITOR_DPI_TYPE, an enum declared
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// in ShellScalingApi.h. Replicating here to avoid importing the library
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// directly.
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constexpr UINT kEffectiveDpiMonitorType = 0;
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template <typename T>
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/// Retrieves a function |name| from a given |comBaseModule| into |outProc|.
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/// Returns a bool indicating whether the function was found.
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bool AssignProcAddress(HMODULE comBaseModule, const char* name, T*& outProc) {
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outProc = reinterpret_cast<T*>(GetProcAddress(comBaseModule, name));
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return *outProc != nullptr;
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}
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/// A helper class for abstracting various Windows DPI related functions across
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/// Windows OS versions.
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class Win32DpiHelper {
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public:
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Win32DpiHelper();
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~Win32DpiHelper();
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/// Returns the DPI for |hwnd|. Supports all DPI awareness modes, and is
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/// backward compatible down to Windows Vista. If |hwnd| is nullptr, returns
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/// the DPI for the primary monitor. If Per-Monitor DPI awareness is not
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/// available, returns the system's DPI.
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UINT GetDpiForWindow(HWND);
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/// Returns the DPI of a given monitor. Defaults to 96 if the API is not
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/// available.
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UINT GetDpiForMonitor(HMONITOR);
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private:
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using GetDpiForWindow_ = UINT __stdcall(HWND);
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using GetDpiForMonitor_ = HRESULT __stdcall(HMONITOR hmonitor,
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UINT dpiType,
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UINT* dpiX,
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UINT* dpiY);
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using EnableNonClientDpiScaling_ = BOOL __stdcall(HWND hwnd);
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GetDpiForWindow_* get_dpi_for_window_ = nullptr;
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GetDpiForMonitor_* get_dpi_for_monitor_ = nullptr;
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EnableNonClientDpiScaling_* enable_non_client_dpi_scaling_ = nullptr;
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HMODULE user32_module_ = nullptr;
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HMODULE shlib_module_ = nullptr;
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bool dpi_for_window_supported_ = false;
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bool dpi_for_monitor_supported_ = false;
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};
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Win32DpiHelper::Win32DpiHelper() {
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if ((user32_module_ = LoadLibraryA("User32.dll")) != nullptr) {
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dpi_for_window_supported_ = (AssignProcAddress(
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user32_module_, "GetDpiForWindow", get_dpi_for_window_));
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}
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if ((shlib_module_ = LoadLibraryA("Shcore.dll")) != nullptr) {
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dpi_for_monitor_supported_ = AssignProcAddress(
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shlib_module_, "GetDpiForMonitor", get_dpi_for_monitor_);
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}
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}
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Win32DpiHelper::~Win32DpiHelper() {
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if (user32_module_ != nullptr) {
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FreeLibrary(user32_module_);
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}
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if (shlib_module_ != nullptr) {
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FreeLibrary(shlib_module_);
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}
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}
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UINT Win32DpiHelper::GetDpiForWindow(HWND hwnd) {
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// GetDpiForWindow returns the DPI for any awareness mode. If not available,
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// or no |hwnd| is provided, fallback to a per monitor, system, or default
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// DPI.
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if (dpi_for_window_supported_ && hwnd != nullptr) {
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return get_dpi_for_window_(hwnd);
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}
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if (dpi_for_monitor_supported_) {
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HMONITOR monitor = nullptr;
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if (hwnd != nullptr) {
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monitor = MonitorFromWindow(hwnd, MONITOR_DEFAULTTOPRIMARY);
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}
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return GetDpiForMonitor(monitor);
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}
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HDC hdc = GetDC(hwnd);
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UINT dpi = GetDeviceCaps(hdc, LOGPIXELSX);
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ReleaseDC(hwnd, hdc);
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return dpi;
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}
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UINT Win32DpiHelper::GetDpiForMonitor(HMONITOR monitor) {
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if (dpi_for_monitor_supported_) {
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if (monitor == nullptr) {
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const POINT target_point = {0, 0};
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monitor = MonitorFromPoint(target_point, MONITOR_DEFAULTTOPRIMARY);
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}
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UINT dpi_x = 0, dpi_y = 0;
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HRESULT result =
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get_dpi_for_monitor_(monitor, kEffectiveDpiMonitorType, &dpi_x, &dpi_y);
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if (SUCCEEDED(result)) {
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return dpi_x;
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}
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}
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return kDefaultDpi;
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} // namespace
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Win32DpiHelper* GetHelper() {
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static Win32DpiHelper* dpi_helper = new Win32DpiHelper();
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return dpi_helper;
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}
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} // namespace
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UINT GetDpiForHWND(HWND hwnd) {
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return GetHelper()->GetDpiForWindow(hwnd);
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}
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UINT GetDpiForMonitor(HMONITOR monitor) {
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return GetHelper()->GetDpiForMonitor(monitor);
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}
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} // namespace flutter
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