Update.

Signed-off-by: Yuhang Zhao <2546789017@qq.com>

examples/Win32Demo/widget.cpp

@@ -73,6 +73,7 @@ Widget::Widget(QWidget *parent) : QWidget(parent), ui(new Ui::Widget)
 
     connect(ui->customizeTitleBarCB, &QCheckBox::stateChanged, this, [this](int state) {
         const bool enable = state == Qt::Checked;
+        ui->windowFrameCB->setEnabled(enable);
         WinNativeEventFilter::updateQtFrame(windowHandle(),
                                             enable ? WinNativeEventFilter::getSystemMetric(
                                                 getRawHandle(this),
@@ -81,7 +82,7 @@ Widget::Widget(QWidget *parent) : QWidget(parent), ui(new Ui::Widget)
         ui->titleBarWidget->setVisible(enable);
         if (enable) {
             qunsetenv(useNativeTitleBar);
-        } else if (state == Qt::Unchecked) {
+        } else {
             qputenv(useNativeTitleBar, "1");
         }
         updateWindow(this);
@@ -89,7 +90,7 @@ Widget::Widget(QWidget *parent) : QWidget(parent), ui(new Ui::Widget)
     connect(ui->windowFrameCB, &QCheckBox::stateChanged, this, [this](int state) {
         if (state == Qt::Checked) {
             qunsetenv(preserveWindowFrame);
-        } else if (state == Qt::Unchecked) {
+        } else {
             qputenv(preserveWindowFrame, "1");
         }
         updateWindow(this);
@@ -98,17 +99,28 @@ Widget::Widget(QWidget *parent) : QWidget(parent), ui(new Ui::Widget)
         const bool enable = state == Qt::Checked;
         QPalette palette = {};
         // Choose the gradient color you like.
-        palette.setColor(QPalette::Window, QColor(255, 255, 255, 235));
+        palette.setColor(QPalette::Window, QColor(255, 255, 255, 220));
         setPalette(enable ? palette : QPalette());
         WinNativeEventFilter::setBlurEffectEnabled(getRawHandle(this), enable);
         updateWindow(this);
     });
     connect(ui->resizableCB, &QCheckBox::stateChanged, this, [this](int state) {
+        const bool enable = state == Qt::Checked;
+        ui->maximizeButton->setEnabled(enable);
         const auto data = WinNativeEventFilter::windowData(this);
         if (data) {
-            data->fixedSize = state == Qt::Unchecked;
+            data->fixedSize = !enable;
             updateWindow(this);
         }
+        if (!ui->customizeTitleBarCB->isChecked()) {
+            if (enable) {
+                setWindowFlags(windowFlags() | Qt::WindowMaximizeButtonHint);
+            } else {
+                setWindowFlags(windowFlags() & ~Qt::WindowMaximizeButtonHint);
+            }
+            show();
+            WinNativeEventFilter::setWindowResizable(getRawHandle(this), enable);
+        }
     });
 
     QStyleOption option;

winnativeeventfilter.cpp

@@ -2397,3 +2397,20 @@ void WinNativeEventFilter::updateFrameMargins(void *handle)
         UpdateFrameMarginsForWindow(hwnd);
     }
 }
+
+void WinNativeEventFilter::setWindowResizable(void *handle, const bool resizable)
+{
+    Q_ASSERT(handle);
+    const auto hwnd = reinterpret_cast<HWND>(handle);
+    if (WNEF_EXECUTE_WINAPI_RETURN(IsWindow, FALSE, hwnd)) {
+        const auto originalStyle = WNEF_EXECUTE_WINAPI_RETURN(GetWindowLongPtrW, 0, hwnd, GWL_STYLE);
+        const auto diffStyle = WS_MAXIMIZEBOX | WS_THICKFRAME;
+        const auto resizableStyle = originalStyle | diffStyle;
+        const auto fixedSizeStyle = originalStyle & ~diffStyle;
+        WNEF_EXECUTE_WINAPI(SetWindowLongPtrW,
+                            hwnd,
+                            GWL_STYLE,
+                            resizable ? resizableStyle : fixedSizeStyle)
+        updateWindow(hwnd, true, false);
+    }
+}

winnativeeventfilter.h

@@ -146,6 +146,9 @@ public:
     // Thin wrapper of DwmExtendFrameIntoClientArea().
     static void updateFrameMargins(void *handle /* HWND */);
 
+    // Helper function.
+    static void setWindowResizable(void *handle /* HWND */, const bool resizable = true);
+
     ///////////////////////////////////////////////
     ///   CORE FUNCTION - THE SOUL OF THIS CODE
     ///////////////////////////////////////////////