NamedWindow创建窗口

函数说明：创建一个窗口。通过窗口名称指向对应的窗口。如果对应名称窗口已经存在，则直接返回。

//函数原型
void NamedWindow(string winName,
    WindowFlags flags = WindowFlags.Normal)

WindowFlags.Normal可缩放拉伸

WindowFlags=AutoSize固定大小，不可拉伸

GetWindowProperty获取窗口属性

函数说明：获取指定窗口名称的相应属性值

//函数原型
double GetWindowProperty(string winName,
    WindowPropertyFlags propId)

SetWindowProperty设置窗口属性

函数说明：设置窗口各属性的值，不是所有的WindowPropertyFlags都可以设置，有些WindowPropertyFlags只是用来获取属性值

//函数原型
void SetWindowProperty(string winName,
    WindowPropertyFlags propId,
    double propValue)

除了窗口的WindowFlags为Normal下时，可以设置WindowPropertyFlags.Fullscreen属性，其它属性都是只读的？（查看源码可知，不同属性在不同平台下作用不同）

MoveWindow移动窗口

函数说明：移动窗口(左上角)到指定位置。

//函数原型
void MoveWindow(string winName,
    int x,
    int y)

ResizeWindow改变窗口大小

函数说明：改变窗口大小。如果窗口标记为AutoSize则，图像显示不随窗口缩放。非AutoSize时，图像显示随窗口缩放。设置的大小不包括滚动条。要先ImShow再ResizeWindow?

//函数原型1
void ResizeWindow(string winName,
    int width,
    int height)

//函数原型2
void ResizeWindow(string winName,
    Size size)

StartWindowThread

官方文档没有解释

参考

opencv中startWindowThread()的使用

What does cv::startwindowthread() do?

SetWindowTitle修改窗口标题

函数说明：修改窗口的标题。注意，窗口名称(即winName还是原来的)

//函数原型
void SetWindowTitle(string winName,
    string title)

GetWindowImageRect获取窗口中图像在屏幕中的位置

函数说明：获取指定窗口在当前屏幕中渲染的图像矩形（图像左上角坐标及宽高，不是窗口的大小，也不包括滚动条）

//函数原型
Rect GetWindowImageRect(string winName)

SelectROI从图像中选择感兴趣区域

函数说明：创建一个可以通过鼠标选择感兴趣区域(使用"空格键"或"回车键"完成选择，按"C"取消选择)的窗口，返回一个矩形(若取消，返回width和heigh为0)。点关闭时还会打开。

//函数原型1
Rect SelectROI(string windowName,
    InputArray img,
    bool showCrosshair = true,
    bool fromCenter = false)

//函数原型2
Rect SelectROI(InputArray img,
    bool showCrosshair = true,
    bool fromCenter = false)

SelectROIs从图像中选择多个感兴趣区域

函数说明：可从图像窗口中选择多个感兴趣区域，按"空格键"或"回车键"完成当次并新开一个，按"Esc"结束多选。

//函数原型
Rect[] SelectROIs(string windowName,
    InputArray img,
    bool showCrosshair = true,
    bool fromCenter = false) 

源码示例

public void Run() {
    using (var mat = Cv2.ImRead(ImagePath.LenaColor)) {
        //测试NamedWindow
        TestNamedWindow(mat);

        //测试GetWindowProperty
        TestGetWindowProperty(mat, WindowFlags.Normal);
        TestGetWindowProperty(mat, WindowFlags.AutoSize);

        //测试SetWindowProperty
        TestSetWindowProperty(mat, WindowFlags.Normal);
        TestSetWindowProperty(mat, WindowFlags.AutoSize);

        //测试ResizeWindow、MoveWindow
        TestResizeAndMoveWindow(mat, WindowFlags.Normal);
        TestResizeAndMoveWindow(mat, WindowFlags.AutoSize);

        //测试SelectROI、SelectROIs
        TestSelectROI(mat);
    }
}

/// <summary>
/// 选择区域
/// </summary>
/// <param name="mat"></param>
private void TestSelectROI(Mat mat) {
    var winName = "SelectROI ";

    //按Space\Enter选择，按"C"取消
    var rect = Cv2.SelectROI(winName, mat, true);

    if (rect != Rect.Empty) {
        Cv2.ImShow("Select Result", mat[rect]);
    }
    Cv2.WaitKey();
    Cv2.DestroyAllWindows();

    //按Space\Enter选择，按Esc结束选择
    var rects=Cv2.SelectROIs(winName, mat, true);
    int index = 0;
    foreach(var selectRect in rects) {
        Cv2.ImShow("Select Result"+ index, mat[selectRect]);
        index++;
    }
    Cv2.WaitKey();
    Cv2.DestroyAllWindows();
}

/// <summary>
/// 测试改变大小和移动窗口
/// </summary>
/// <param name="mat"></param>
/// <param name="windowFlag"></param>
private void TestResizeAndMoveWindow(Mat mat, WindowFlags windowFlag) {

    var winName = $"ResizeWindow WindowFlags={windowFlag}";

    //没解释
    Cv2.StartWindowThread();

    //不通过NamedWindow创建，而直接ImShow的窗口，AutoSize=1
    Cv2.NamedWindow(winName, windowFlag);
    Console.WriteLine($"AutoSize={Cv2.GetWindowProperty(winName, WindowPropertyFlags.AutoSize)}");
    //测试ResizeWindow的大小不含滚动条
    Cv2.CreateTrackbar("bar1", winName, 100);
    Cv2.CreateTrackbar("bar2", winName, 100);
    Cv2.ImShow(winName, mat);
    Console.WriteLine($"AutoSize={Cv2.GetWindowProperty(winName, WindowPropertyFlags.AutoSize)}");
    //改变窗口大小，先ImShow再ResizeWindow
    Cv2.ResizeWindow(winName, 300, 300);
    Cv2.WaitKey();
    
    Console.WriteLine($"AutoSize={Cv2.GetWindowProperty(winName, WindowPropertyFlags.AutoSize)}");
    Cv2.ImShow(winName, mat);
    Cv2.ResizeWindow(winName, 600, 600);
    Cv2.WaitKey();

    //移动窗口
    Cv2.MoveWindow(winName, 50, 100);
    Cv2.WaitKey();

    //只是修改窗口标题，不修改winName
    Cv2.SetWindowTitle(winName, "New Title");
    Cv2.WaitKey();

    //还是用winName找窗口，而不是"New Title"
    //指定窗口中渲染的图像的位置及宽高
    var winImageRect = Cv2.GetWindowImageRect(winName);
    Console.WriteLine($"WindowImageRect={winImageRect}");
    Cv2.WaitKey();

    Cv2.DestroyAllWindows();
}



/// <summary>
/// 测试SetWindowProperty函数
/// </summary>
/// <param name="mat"></param>
/// <param name="winFlag"></param>
private void TestSetWindowProperty(Mat mat, WindowFlags winFlag) {
    var winName = "TestGetWindowProperty," + winFlag;
    Cv2.NamedWindow(winName, winFlag);

    Console.WriteLine(winName);
    foreach (WindowPropertyFlags propertyFlag in Enum.GetValues(typeof(WindowPropertyFlags))) {
        try {
            Cv2.SetWindowProperty(winName, propertyFlag, 1);
            Console.WriteLine($"WindowFlags={winFlag},Set {propertyFlag} = 1 ,Get {propertyFlag} = {Cv2.GetWindowProperty(winName, propertyFlag)}");
            Cv2.ImShow(winName, mat);
            Cv2.WaitKey();
            Cv2.SetWindowProperty(winName, propertyFlag, 0);
            Console.WriteLine($"WindowFlags={winFlag},Set {propertyFlag} = 0 ,Get {propertyFlag} = {Cv2.GetWindowProperty(winName, propertyFlag)}");
            Cv2.ImShow(winName, mat);
            Cv2.WaitKey();
        }
        catch (Exception ex) {
            Console.WriteLine($"{propertyFlag},Exception:{ex.Message}");
        }
    }
    Cv2.WaitKey();
    Cv2.DestroyAllWindows();
}

/// <summary>
/// 测试GetWindowProperty各参数值
/// </summary>
/// <param name="mat"></param>
private void TestGetWindowProperty(Mat mat, WindowFlags winFlag) {
    var winName = "TestGetWindowProperty," + winFlag;
    Cv2.NamedWindow(winName, winFlag);
    Cv2.ImShow(winName, mat);
    //Cv2.DestroyAllWindows();
    Console.WriteLine(winName);
    foreach (WindowPropertyFlags propertyFlag in Enum.GetValues(typeof(WindowPropertyFlags))) {
        try {
            Console.WriteLine($"{propertyFlag}={Cv2.GetWindowProperty(winName, propertyFlag)}");
        }
        catch (Exception ex) {
            Console.WriteLine($"{propertyFlag},Exception:{ex.Message}");
        }

    }
    Cv2.WaitKey();
    Cv2.DestroyAllWindows();
}

/// <summary>
/// 测试NamedWindows函数
/// </summary>
/// <param name="mat"></param>
private void TestNamedWindow(Mat mat) {
    //测试WindowFlags各值
    NamedWindowShowWaitDestory("Normal", mat, WindowFlags.Normal);
    NamedWindowShowWaitDestory("AutoSize", mat, WindowFlags.AutoSize);
    NamedWindowShowWaitDestory("OpenGL", mat, WindowFlags.OpenGL);
    NamedWindowShowWaitDestory("FullScreen", mat, WindowFlags.FullScreen);
    NamedWindowShowWaitDestory("FreeRatio", mat, WindowFlags.FreeRatio);
    NamedWindowShowWaitDestory("KeepRatio", mat, WindowFlags.KeepRatio);
    NamedWindowShowWaitDestory("GuiExpanded", mat, WindowFlags.GuiExpanded);
    NamedWindowShowWaitDestory("GuiNormal", mat, WindowFlags.GuiNormal);
}

private void NamedWindowShowWaitDestory(string winName, Mat mat, WindowFlags flags) {
    try {
        winName = "WindowFlags=" + winName;
        Cv2.NamedWindow(winName, flags);
        Cv2.ImShow(winName, mat);
        Cv2.WaitKey();
        Cv2.DestroyAllWindows();
    }
    catch (Exception ex) {//没开启OpenGL的话，会报错
        Console.WriteLine(ex.Message);
    }
}

OpenCvSharp函数示例(目录)

参考

https://docs.opencv.org/