New feature: Accept native parent window handle

This is necessary for platforms to present the dialog properly, e.g. ensuring that the dialog never goes behind the parent window.

src/include/nfd.h

@@ -93,19 +93,40 @@ typedef struct {
 typedef nfdu8filteritem_t nfdnfilteritem_t;
 #endif  // _WIN32
 
+// The native window handle type.
+enum {
+    NFD_WINDOW_HANDLE_TYPE_UNSET = 0,
+    // Windows: handle is HWND (the Windows API typedefs this to void*)
+    NFD_WINDOW_HANDLE_TYPE_WINDOWS = 1,
+    // Cocoa: handle is NSWindow*
+    NFD_WINDOW_HANDLE_TYPE_COCOA = 2,
+    // X11: handle is Window
+    NFD_WINDOW_HANDLE_TYPE_X11 = 3,
+    // Wayland: handle is wl_surface*
+    NFD_WINDOW_HANDLE_TYPE_WAYLAND = 4,
+};
+// The native window handle.  If using a platform abstraction framework (e.g. SDL), this should be
+// obtained using the corresponding NFD glue header (e.g. nfd_sdl.h).
+typedef struct {
+    size_t type;  // this is one of the values of the enum above
+    void* handle;
+} nfdwindowhandle_t;
+
 typedef size_t nfdversion_t;
 
 typedef struct {
     const nfdu8filteritem_t* filterList;
     nfdfiltersize_t filterCount;
     const nfdu8char_t* defaultPath;
+    nfdwindowhandle_t parentWindow;
 } nfdopendialogu8args_t;
 
 #ifdef _WIN32
 typedef struct {
     const nfdnfilteritem_t* filterList;
     nfdfiltersize_t filterCount;
     const nfdnchar_t* defaultPath;
+    nfdwindowhandle_t parentWindow;
 } nfdopendialognargs_t;
 #else
 typedef nfdopendialogu8args_t nfdopendialognargs_t;
@@ -116,6 +137,7 @@ typedef struct {
     nfdfiltersize_t filterCount;
     const nfdu8char_t* defaultPath;
     const nfdu8char_t* defaultName;
+    nfdwindowhandle_t parentWindow;
 } nfdsavedialogu8args_t;
 
 #ifdef _WIN32
@@ -124,18 +146,21 @@ typedef struct {
     nfdfiltersize_t filterCount;
     const nfdnchar_t* defaultPath;
     const nfdnchar_t* defaultName;
+    nfdwindowhandle_t parentWindow;
 } nfdsavedialognargs_t;
 #else
 typedef nfdsavedialogu8args_t nfdsavedialognargs_t;
 #endif  // _WIN32
 
 typedef struct {
     const nfdu8char_t* defaultPath;
+    nfdwindowhandle_t parentWindow;
 } nfdpickfolderu8args_t;
 
 #ifdef _WIN32
 typedef struct {
     const nfdnchar_t* defaultPath;
+    nfdwindowhandle_t parentWindow;
 } nfdpickfoldernargs_t;
 #else
 typedef nfdpickfolderu8args_t nfdpickfoldernargs_t;

src/nfd_win.cpp

@@ -284,6 +284,13 @@ nfdresult_t AddOptions(IFileDialog* dialog, FILEOPENDIALOGOPTIONS options) {
     }
     return NFD_OKAY;
 }
+
+HWND GetNativeWindowHandle(const nfdwindowhandle_t& nfd_handle) {
+    if (nfd_handle.type != NFD_WINDOW_HANDLE_TYPE_WINDOWS) {
+        return nullptr;
+    }
+    return static_cast<HWND>(nfd_handle.handle);
+}
 }  // namespace
 
 const char* NFD_GetError(void) {
@@ -382,7 +389,7 @@ nfdresult_t NFD_OpenDialogN_With_Impl(nfdversion_t version,
     }
 
     // Show the dialog.
-    result = fileOpenDialog->Show(nullptr);
+    result = fileOpenDialog->Show(GetNativeWindowHandle(args->parentWindow));
     if (SUCCEEDED(result)) {
         // Get the file name
         ::IShellItem* psiResult;
@@ -463,7 +470,7 @@ nfdresult_t NFD_OpenDialogMultipleN_With_Impl(nfdversion_t version,
     }
 
     // Show the dialog.
-    result = fileOpenDialog->Show(nullptr);
+    result = fileOpenDialog->Show(GetNativeWindowHandle(args->parentWindow));
     if (SUCCEEDED(result)) {
         ::IShellItemArray* shellItems;
         result = fileOpenDialog->GetResults(&shellItems);
@@ -542,7 +549,7 @@ nfdresult_t NFD_SaveDialogN_With_Impl(nfdversion_t version,
     }
 
     // Show the dialog.
-    result = fileSaveDialog->Show(nullptr);
+    result = fileSaveDialog->Show(GetNativeWindowHandle(args->parentWindow));
     if (SUCCEEDED(result)) {
         // Get the file name
         ::IShellItem* psiResult;
@@ -607,7 +614,7 @@ nfdresult_t NFD_PickFolderN_With_Impl(nfdversion_t version,
     }
 
     // Show the dialog to the user
-    const HRESULT result = fileOpenDialog->Show(nullptr);
+    const HRESULT result = fileOpenDialog->Show(GetNativeWindowHandle(args->parentWindow));
     if (result == HRESULT_FROM_WIN32(ERROR_CANCELLED)) {
         return NFD_CANCEL;
     } else if (!SUCCEEDED(result)) {
@@ -673,7 +680,7 @@ nfdresult_t NFD_PickFolderMultipleN_With_Impl(nfdversion_t version,
     }
 
     // Show the dialog.
-    const HRESULT result = fileOpenDialog->Show(nullptr);
+    const HRESULT result = fileOpenDialog->Show(GetNativeWindowHandle(args->parentWindow));
     if (SUCCEEDED(result)) {
         ::IShellItemArray* shellItems;
         if (!SUCCEEDED(fileOpenDialog->GetResults(&shellItems))) {
@@ -933,7 +940,7 @@ nfdresult_t NFD_OpenDialogU8_With_Impl(nfdversion_t version,
     // call the native function
     nfdnchar_t* outPathN;
     const nfdopendialognargs_t argsN{
-        filterItemsNGuard.data, args->filterCount, defaultPathNGuard.data};
+        filterItemsNGuard.data, args->filterCount, defaultPathNGuard.data, args->parentWindow};
     nfdresult_t res = NFD_OpenDialogN_With_Impl(NFD_INTERFACE_VERSION, &outPathN, &argsN);
 
     if (res != NFD_OKAY) {
@@ -978,7 +985,7 @@ nfdresult_t NFD_OpenDialogMultipleU8_With_Impl(nfdversion_t version,
 
     // call the native function
     const nfdopendialognargs_t argsN{
-        filterItemsNGuard.data, args->filterCount, defaultPathNGuard.data};
+        filterItemsNGuard.data, args->filterCount, defaultPathNGuard.data, args->parentWindow};
     return NFD_OpenDialogMultipleN_With_Impl(NFD_INTERFACE_VERSION, outPaths, &argsN);
 }
 
@@ -1017,8 +1024,11 @@ nfdresult_t NFD_SaveDialogU8_With_Impl(nfdversion_t version,
 
     // call the native function
     nfdnchar_t* outPathN;
-    const nfdsavedialognargs_t argsN{
-        filterItemsNGuard.data, args->filterCount, defaultPathNGuard.data, defaultNameNGuard.data};
+    const nfdsavedialognargs_t argsN{filterItemsNGuard.data,
+                                     args->filterCount,
+                                     defaultPathNGuard.data,
+                                     defaultNameNGuard.data,
+                                     args->parentWindow};
     nfdresult_t res = NFD_SaveDialogN_With_Impl(NFD_INTERFACE_VERSION, &outPathN, &argsN);
 
     if (res != NFD_OKAY) {
@@ -1054,7 +1064,7 @@ nfdresult_t NFD_PickFolderU8_With_Impl(nfdversion_t version,
 
     // call the native function
     nfdnchar_t* outPathN;
-    const nfdpickfoldernargs_t argsN{defaultPathNGuard.data};
+    const nfdpickfoldernargs_t argsN{defaultPathNGuard.data, args->parentWindow};
     nfdresult_t res = NFD_PickFolderN_With_Impl(NFD_INTERFACE_VERSION, &outPathN, &argsN);
 
     if (res != NFD_OKAY) {
@@ -1090,7 +1100,7 @@ nfdresult_t NFD_PickFolderMultipleU8_With_Impl(nfdversion_t version,
     NormalizePathSeparator(defaultPathNGuard.data);
 
     // call the native function
-    const nfdpickfoldernargs_t argsN{defaultPathNGuard.data};
+    const nfdpickfoldernargs_t argsN{defaultPathNGuard.data, args->parentWindow};
     return NFD_PickFolderMultipleN_With_Impl(NFD_INTERFACE_VERSION, outPaths, &argsN);
 }