44#include " Win32Utils.h"
55#include " ThemeHelper.h"
66#include " XamlApp.h"
7+ #include < ShellScalingApi.h>
8+
9+ #pragma comment(lib, "Shcore.lib")
710
811namespace Magpie {
912
10- bool MainWindow::Create (HINSTANCE hInstance, const RECT& windowRect , bool isMaximized) noexcept {
13+ bool MainWindow::Create (HINSTANCE hInstance, winrt:: Point windowCenter, winrt:: Size windowSizeInDips , bool isMaximized) noexcept {
1114 static const int _ = [](HINSTANCE hInstance) {
1215 WNDCLASSEXW wcex{};
1316 wcex.cbSize = sizeof (wcex);
@@ -27,7 +30,7 @@ bool MainWindow::Create(HINSTANCE hInstance, const RECT& windowRect, bool isMaxi
2730 return 0 ;
2831 }(hInstance);
2932
30- _CreateWindow (hInstance, windowRect );
33+ const auto & [posToSet, sizeToSet] = _CreateWindow (hInstance, windowCenter, windowSizeInDips );
3134
3235 if (!_hWnd) {
3336 return false ;
@@ -46,8 +49,10 @@ bool MainWindow::Create(HINSTANCE hInstance, const RECT& windowRect, bool isMaxi
4649
4750 // 1. 设置初始 XAML Islands 窗口的尺寸
4851 // 2. 刷新窗口边框
49- // 3. 防止窗口显示时背景闪烁: https://stackoverflow.com/questions/69715610/how-to-initialize-the-background-color-of-win32-app-to-something-other-than-whit
50- SetWindowPos (_hWnd, NULL , 0 , 0 , 0 , 0 , SWP_NOMOVE | SWP_NOSIZE | SWP_FRAMECHANGED);
52+ // 3. 无法获知 DPI 的情况下 _CreateWindow 创建的窗口尺寸为零，在这里延后设置窗口位置
53+ // 4. 防止窗口显示时背景闪烁: https://stackoverflow.com/questions/69715610/how-to-initialize-the-background-color-of-win32-app-to-something-other-than-whit
54+ SetWindowPos (_hWnd, NULL , posToSet.x , posToSet.y , sizeToSet.cx , sizeToSet.cy ,
55+ (sizeToSet.cx == 0 ? (SWP_NOMOVE | SWP_NOSIZE) : 0 ) | SWP_FRAMECHANGED | SWP_NOACTIVATE | SWP_NOCOPYBITS);
5156
5257 // Xaml 控件加载完成后显示主窗口
5358 _content.Loaded ([this , isMaximized](winrt::IInspectable const &, winrt::RoutedEventArgs const &) {
@@ -155,8 +160,8 @@ LRESULT MainWindow::_MessageHandler(UINT msg, WPARAM wParam, LPARAM lParam) noex
155160 // 设置窗口最小尺寸
156161 MINMAXINFO* mmi = (MINMAXINFO*)lParam;
157162 mmi->ptMinTrackSize = {
158- std::lround (550 * _currentDpi / double (USER_DEFAULT_SCREEN_DPI)),
159- std::lround (300 * _currentDpi / double (USER_DEFAULT_SCREEN_DPI))
163+ std::lroundf (550 * _currentDpi / float (USER_DEFAULT_SCREEN_DPI)),
164+ std::lroundf (300 * _currentDpi / float (USER_DEFAULT_SCREEN_DPI))
160165 };
161166 return 0 ;
162167 }
@@ -217,31 +222,113 @@ LRESULT MainWindow::_MessageHandler(UINT msg, WPARAM wParam, LPARAM lParam) noex
217222 return base_type::_MessageHandler (msg, wParam, lParam);
218223}
219224
220- void MainWindow::_CreateWindow (HINSTANCE hInstance, const RECT& windowRect) noexcept {
221- // 防止窗口启动时不在可见区域，Windows 不会自动处理。
222- // 检查两个点的位置是否存在屏幕：窗口的中心点和上边框中心点。前者确保大部分窗口内容可见，后者确保大部分标题栏可见。
223- const POINT windowCenter{
224- (windowRect.left + windowRect.right ) / 2 ,
225- (windowRect.top + windowRect.bottom ) / 2
226- };
227- const bool isValidPosition = MonitorFromPoint (windowCenter, MONITOR_DEFAULTTONULL)
228- && MonitorFromPoint ({ windowCenter.x , windowRect.top }, MONITOR_DEFAULTTONULL);
225+ std::pair<POINT, SIZE> MainWindow::_CreateWindow (HINSTANCE hInstance, winrt::Point windowCenter, winrt::Size windowSizeInDips) noexcept {
226+ POINT windowPos = { CW_USEDEFAULT,CW_USEDEFAULT };
227+ SIZE windowSize{};
228+
229+ // windowSizeInDips 小于零表示默认位置和尺寸
230+ if (windowSizeInDips.Width > 0 ) {
231+ // 检查窗口中心点的 DPI，根据我的测试，创建窗口时 Windows 使用窗口中心点确定 DPI。
232+ // 如果窗口中心点不在任何屏幕上，则在默认位置启动，让调用者设置窗口尺寸。
233+ const HMONITOR hMon = MonitorFromPoint (
234+ { std::lroundf (windowCenter.X ),std::lroundf (windowCenter.Y ) },
235+ MONITOR_DEFAULTTONULL
236+ );
237+ if (hMon) {
238+ UINT dpi = USER_DEFAULT_SCREEN_DPI;
239+ GetDpiForMonitor (hMon, MDT_EFFECTIVE_DPI, &dpi, &dpi);
240+
241+ const float dpiFactor = dpi / float (USER_DEFAULT_SCREEN_DPI);
242+ const winrt::Size windowSizeInPixels = {
243+ windowSizeInDips.Width * dpiFactor,
244+ windowSizeInDips.Height * dpiFactor
245+ };
246+
247+ windowSize.cx = std::lroundf (windowSizeInPixels.Width );
248+ windowSize.cy = std::lroundf (windowSizeInPixels.Height );
249+
250+ MONITORINFO mi{ sizeof (mi) };
251+ GetMonitorInfo (hMon, &mi);
252+
253+ // 确保启动位置在屏幕工作区内。不允许启动时跨越多个屏幕。
254+ if (windowSize.cx <= mi.rcWork .right - mi.rcWork .left && windowSize.cy <= mi.rcWork .bottom - mi.rcWork .top ) {
255+ windowPos.x = std::lroundf (windowCenter.X - windowSizeInPixels.Width / 2 );
256+ windowPos.x = std::clamp (windowPos.x , mi.rcWork .left , mi.rcWork .right - windowSize.cx );
257+
258+ windowPos.y = std::lroundf (windowCenter.Y - windowSizeInPixels.Height / 2 );
259+ windowPos.y = std::clamp (windowPos.y , mi.rcWork .top , mi.rcWork .bottom - windowSize.cy );
260+ } else {
261+ // 屏幕工作区无法容纳窗口则使用默认窗口尺寸
262+ windowSize = {};
263+ windowSizeInDips.Width = -1 .0f ;
264+ }
265+ }
266+ }
229267
230268 // Win11 22H2 中为了使用 Mica 背景需指定 WS_EX_NOREDIRECTIONBITMAP
269+ // windowSize 可能为零，并返回窗口尺寸给调用者
231270 CreateWindowEx (
232271 Win32Utils::GetOSVersion ().Is22H2OrNewer () ? WS_EX_NOREDIRECTIONBITMAP : 0 ,
233272 CommonSharedConstants::MAIN_WINDOW_CLASS_NAME,
234273 L" Magpie"
235274 WS_OVERLAPPEDWINDOW,
236- isValidPosition ? windowRect. left : CW_USEDEFAULT ,
237- isValidPosition ? windowRect. top : CW_USEDEFAULT ,
238- windowRect. right - windowRect. left ,
239- windowRect. bottom - windowRect. top ,
275+ windowPos. x ,
276+ windowPos. y ,
277+ windowSize. cx ,
278+ windowSize. cy ,
240279 NULL ,
241280 NULL ,
242281 hInstance,
243282 this
244283 );
284+
285+ if (windowSize.cx == 0 ) {
286+ const HMONITOR hMon = MonitorFromWindow (_hWnd, MONITOR_DEFAULTTONEAREST);
287+
288+ MONITORINFO mi{ sizeof (mi) };
289+ GetMonitorInfo (hMon, &mi);
290+
291+ const float dpiFactor = _currentDpi / float (USER_DEFAULT_SCREEN_DPI);
292+ const winrt::Size workingAreaSizeInDips = {
293+ (mi.rcWork .right - mi.rcWork .left ) / dpiFactor,
294+ (mi.rcWork .bottom - mi.rcWork .top ) / dpiFactor
295+ };
296+
297+ // 确保启动尺寸小于屏幕工作区
298+ if (windowSizeInDips.Width <= 0 ||
299+ windowSizeInDips.Width > workingAreaSizeInDips.Width ||
300+ windowSizeInDips.Height > workingAreaSizeInDips.Height ) {
301+ // 默认尺寸
302+ static constexpr winrt::Size DEFAULT_SIZE{ 980 .0f , 690 .0f };
303+
304+ windowSizeInDips = DEFAULT_SIZE;
305+
306+ if (windowSizeInDips.Width > workingAreaSizeInDips.Width ||
307+ windowSizeInDips.Height > workingAreaSizeInDips.Height ) {
308+ // 屏幕太小无法容纳默认尺寸
309+ windowSizeInDips.Width = workingAreaSizeInDips.Width * 0 .8f ;
310+ windowSizeInDips.Height = windowSizeInDips.Width * DEFAULT_SIZE.Height / DEFAULT_SIZE.Width ;
311+
312+ if (windowSizeInDips.Height > workingAreaSizeInDips.Height ) {
313+ windowSizeInDips.Height = workingAreaSizeInDips.Height * 0 .8f ;
314+ windowSizeInDips.Width = windowSizeInDips.Height * DEFAULT_SIZE.Width / DEFAULT_SIZE.Height ;
315+ }
316+ }
317+ }
318+
319+ windowSize.cx = std::lroundf (windowSizeInDips.Width * dpiFactor);
320+ windowSize.cy = std::lroundf (windowSizeInDips.Height * dpiFactor);
321+
322+ // 确保启动位置在屏幕工作区内
323+ RECT targetRect;
324+ GetWindowRect (_hWnd, &targetRect);
325+ windowPos.x = std::clamp (targetRect.left , mi.rcWork .left , mi.rcWork .right - windowSize.cx );
326+ windowPos.y = std::clamp (targetRect.top , mi.rcWork .top , mi.rcWork .bottom - windowSize.cy );
327+
328+ return std::make_pair (windowPos, windowSize);
329+ } else {
330+ return {};
331+ }
245332}
246333
247334void MainWindow::_UpdateTheme () {
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