[Suggestion] [Windows] Use a Flutter widget for top resizing region overlay

[damywise]

If anything else fail, I suggest we make a widget that simulates the original behavior for the top region of the app in titleBarStyle hidden.
When said widget is hovered, change the cursor to SystemMouseCursors.resizeUp or resizeUpLeftDownRight or resizeUpRightDownLeft.
When said widget is clicked, call native event for resizing like in the now discontinued window_utils package, there exist a function startResize(DragPosition position).

[damywise]

Changed my mind. Now I think this is a stupid suggestion lol.
Might as well replace all borders with widgets.

[damywise]

I managed to do this btw except when double clicking the top border doesn't do anything when it should've maximised the window vertically.

[lijy91]

Can you share your code?

[damywise]

Here's the widget code,

import 'package:flutter/material.dart';
import 'package:window_manager/window_manager.dart';

class WindowsFrame extends StatefulWidget {
  final Widget child;
  final bool active;

  const WindowsFrame({
    Key? key,
    required this.child,
    required this.active,
  }) : super(key: key);

  @override
  State<WindowsFrame> createState() => _WindowsFrameState();
}

class _WindowsFrameState extends State<WindowsFrame> with WindowListener {
  final ValueNotifier<bool> isMaximised = ValueNotifier(false);

  @override
  void initState() {
    windowManager.addListener(this);
    super.initState();
  }

  @override
  void onWindowMaximize() {
    super.onWindowMaximize();
    setState(() {
      isMaximised.value = true;
    });
  }

  @override
  void onWindowUnmaximize() {
    super.onWindowUnmaximize();
    setState(() {
      isMaximised.value = false;
    });
  }

  @override
  Widget build(BuildContext context) {
    if (!widget.active) return widget.child;
    const width = 8.0;
    const height = 8.0;
    return Stack(
      children: [
        /// App
        ValueListenableBuilder(
          valueListenable: isMaximised,
          builder: (BuildContext context, bool value, Widget? child) =>
              Container(
            padding: value ? const EdgeInsets.only(top: 8) : null,
            decoration: BoxDecoration(
              border: Border(
                top: BorderSide(color: Colors.black.withOpacity(.56), width: 1),
              ),
            ),
            child: widget.child,
          ),
        ),

        /// Resizing widgets
        Stack(
          fit: StackFit.expand,
          children: <Widget>[
            Positioned(
              top: 0,
              left: 0,
              height: height,
              width: width,
              child: MouseRegion(
                cursor: !isMaximised.value
                    ? SystemMouseCursors.resizeUpLeft
                    : SystemMouseCursors.basic,
                child: GestureDetector(
                  onPanStart: (_) =>
                      windowManager.startResize(DragPosition.topLeft),
                ),
              ),
            ),
            Positioned(
              top: 0,
              left: width,
              right: width,
              height: height,
              child: MouseRegion(
                cursor: !isMaximised.value
                    ? SystemMouseCursors.resizeUpDown
                    : SystemMouseCursors.basic,
                child: GestureDetector(
                  //TODO: doubleTap Maximize Vertical
                  onPanStart: (_) =>
                      windowManager.startResize(DragPosition.top),
                ),
              ),
            ),
            Positioned(
              top: 0,
              right: 0,
              height: height,
              width: width,
              child: MouseRegion(
                cursor: !isMaximised.value
                    ? SystemMouseCursors.resizeUpRight
                    : SystemMouseCursors.basic,
                child: GestureDetector(
                  onPanStart: (_) =>
                      windowManager.startResize(DragPosition.topRight),
                ),
              ),
            ),
          ],
        ),
      ],
    );
  }
}

[damywise]

I added this to window_manager.dart

  Future<void> startResize(DragPosition position) {
    return _channel.invokeMethod<bool>(
      'startResize',
      {
        "top": position == DragPosition.top ||
            position == DragPosition.topLeft ||
            position == DragPosition.topRight,
        "bottom": position == DragPosition.bottom ||
            position == DragPosition.bottomLeft ||
            position == DragPosition.bottomRight,
        "right": position == DragPosition.right ||
            position == DragPosition.topRight ||
            position == DragPosition.bottomRight,
        "left": position == DragPosition.left ||
            position == DragPosition.topLeft ||
            position == DragPosition.bottomLeft,
      },
    );
  }

enum DragPosition {
  top,
  left,
  right,
  bottom,
  topLeft,
  bottomLeft,
  topRight,
  bottomRight
}

[damywise]

In window_manager_plugin.cpp

	else if (method_name.compare("startResize") == 0)
	{
        const flutter::EncodableMap &args = std::get<flutter::EncodableMap>(*method_call.arguments());
        window_manager->StartResize(args);
        result->Success(flutter::EncodableValue(true));
	}

[damywise]

In window_manager.cpp

    void WindowManager::StartResize(const flutter::EncodableMap &args);

void WindowManager::StartResize(const flutter::EncodableMap &args)
{
	bool top = std::get<bool>(args.at(flutter::EncodableValue("top")));
	bool bottom = std::get<bool>(args.at(flutter::EncodableValue("bottom")));
	bool left = std::get<bool>(args.at(flutter::EncodableValue("left")));
	bool right = std::get<bool>(args.at(flutter::EncodableValue("right")));
	HWND hWnd = GetMainWindow();
	ReleaseCapture();
	LONG command = SC_SIZE;
	if (top && !bottom && !right && !left)
	{
	  command |= WMSZ_TOP;
	}
	else if (top && left && !bottom && !right)
	{
	  command |= WMSZ_TOPLEFT;
	}
	else if (left && !top && !bottom && !right)
	{
	  command |= WMSZ_LEFT;
	}
	else if (right && !top && !left && !bottom)
	{
	  command |= WMSZ_RIGHT;
	}
	else if (top && right && !left && !bottom)
	{
	  command |= WMSZ_TOPRIGHT;
	}
	else if (bottom && !top && !right && !left)
	{
	  command |= WMSZ_BOTTOM;
	}
	else if (bottom && left && !top && !right)
	{
	  command |= WMSZ_BOTTOMLEFT;
	}
	else if (bottom && right && !top && !left)
	{
	  command |= WMSZ_BOTTOMRIGHT;
	}
	SendMessage(hWnd, WM_SYSCOMMAND, command, 0);
}

[damywise]

Should I make a PR for the startResize() function?

[lijy91]

Merged pr and added DragToResizeArea example in main branch