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// Copyright (C) 2023 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#include "qwincapturablewindows_p.h"
#include "private/qcapturablewindow_p.h"
#include <QtGui/qwindow.h>
#include <qt_windows.h>
#include <dwmapi.h>
QT_BEGIN_NAMESPACE
static bool isTopLevelWindow(HWND hwnd)
{
return hwnd && ::GetAncestor(hwnd, GA_ROOT) == hwnd;
}
static bool canCaptureWindow(HWND hwnd)
{
Q_ASSERT(hwnd);
if (!::IsWindowVisible(hwnd))
return false;
// Minimized windows are not rendered, so capturing them never delivers a frame
if (::IsIconic(hwnd))
return false;
// The desktop is not a window that can be captured
if (hwnd == ::GetShellWindow())
return false;
// Windows without a class name are not real windows
wchar_t className[2] = {};
if (::GetClassNameW(hwnd, className, 2) == 0)
return false;
if (::GetWindowLongPtrW(hwnd, GWL_STYLE) & WS_DISABLED)
return false;
// Tool windows are helpers like the taskbar, tooltips and message windows
if (::GetWindowLongPtrW(hwnd, GWL_EXSTYLE) & WS_EX_TOOLWINDOW)
return false;
// Cloaked windows are visible according to IsWindowVisible, but are not shown on screen
// (e.g. suspended UWP apps, windows on other virtual desktops, or system helper windows)
DWORD cloaked = 0;
if (SUCCEEDED(::DwmGetWindowAttribute(hwnd, DWMWA_CLOAKED, &cloaked, sizeof(cloaked)))
&& cloaked != 0)
return false;
RECT rect{};
if (!::GetWindowRect(hwnd, &rect))
return false;
if (rect.left >= rect.right || rect.top >= rect.bottom)
return false;
return true;
}
static QString windowTitle(HWND hwnd) {
// QTBUG-114890
// TODO: investigate the case when hwnd is inner and belows to another thread.
// It might causes deadlocks in specific cases.
auto titleLength = ::GetWindowTextLengthW(hwnd);
std::wstring buffer(titleLength + 1, L'\0');
titleLength = ::GetWindowTextW(hwnd, buffer.data(), titleLength + 1);
buffer.resize(titleLength);
return QString::fromStdWString(buffer);
}
static BOOL CALLBACK windowHandler(HWND hwnd, LPARAM lParam) {
if (!canCaptureWindow(hwnd))
return TRUE; // Ignore window and continue enumerating
auto &windows = *reinterpret_cast<QList<QCapturableWindow> *>(lParam);
windows.push_back(QCapturableWindowPrivate::create(
reinterpret_cast<QCapturableWindowPrivate::Id>(hwnd),
windowTitle(hwnd)));
return TRUE;
}
QList<QCapturableWindow> QWinCapturableWindows::windows() const
{
QList<QCapturableWindow> result;
::EnumWindows(windowHandler, reinterpret_cast<LPARAM>(&result));
return result;
}
bool QWinCapturableWindows::isWindowValid(const QCapturableWindowPrivate &window) const
{
const auto hwnd = reinterpret_cast<HWND>(window.id);
return isTopLevelWindow(hwnd) && canCaptureWindow(hwnd);
}
q23::expected<QCapturableWindow, QString> QWinCapturableWindows::fromQWindow(QWindow *window) const
{
const auto hwnd = reinterpret_cast<HWND>(window->winId());
return QCapturableWindowPrivate::create(
reinterpret_cast<QCapturableWindowPrivate::Id>(hwnd),
windowTitle(hwnd));
}
QT_END_NAMESPACE