在 Gtk# window 中刷新图像，一定时间后图像消失

Question

我正在使用 C#、.Net 4.5 和 Gtk# 编写一个简单的应用程序，它捕获屏幕的一部分并将其加载到 window 中的图像上。几秒钟后图像消失，我收到以下错误：

Glib-CRITICAL **：尝试删除时未找到源 ID xxxx。

相关代码：

Program.cs:

using System.Windows.Forms;

namespace Dota2Trainer
{
    class MainClass
    {
        public static void Main(string[] args)
        {
            Gtk.Application.Init();
            MiniMapOverlay myWin = new MiniMapOverlay();
            myWin.KeepAbove = true;
            //myWin.Decorated = false;
            myWin.Resize(200, 200);
            myWin.ShowAll();
            ScreenCapturer screenCap = new ScreenCapturer(30, Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height, myWin);
            screenCap.Start();
            Gtk.Application.Run();
        }
    }
}

MiniMapOverlay.cs:

using System;
using System.Drawing;
using System.IO;
using System.Timers;
using Gtk;

namespace Dota2Trainer
{
    public partial class MiniMapOverlay : Gtk.Window
    {
        Gtk.Image image = null;
        public MiniMapOverlay() : base(Gtk.WindowType.Toplevel)
        {
            image = new Gtk.Image();
            var buffer = System.IO.File.ReadAllBytes(".\image0.jpeg");
            var pixbuf = new Gdk.Pixbuf(buffer);
            image.Pixbuf = pixbuf;
            this.Add(image);
            this.Build();
        }

        public void RefreshImage(byte[] buffer)
        {
            try
            {
                var pixbuf = new Gdk.Pixbuf(buffer);
                image.Pixbuf = pixbuf;
            }
            catch (Exception exception)
            {
                Console.WriteLine(exception.Message);
            }
        }
    }
}

ScreenCapturer.cs:

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Timers;

namespace Dota2Trainer
{
    public delegate void OnSavedImage(byte[] screenCap);
    public class ScreenCapturer
    {
        public System.Timers.Timer aTimer;
        int interval= 30000;
        readonly int screenWidth;
        readonly int screenHeight;
        Rectangle bounds;
        const double miniMapWidthPercentage = 0.15;
        const double miniMapHeightPercentage = 0.25;
        Bitmap bitmap;
        bool Busy = false;
        ImageConverter converter = new ImageConverter();
        public OnSavedImage onSaveImage;

        public ScreenCapturer(int interval, int screenWidth, int screenHeight, MiniMapOverlay imageHolder)
        {
            this.screenHeight = screenHeight;
            this.screenWidth = screenWidth;
            this.interval = interval;
            aTimer = new System.Timers.Timer();
            aTimer.Elapsed += new ElapsedEventHandler(OnTimedEvent);
            aTimer.Interval = this.interval;
            int miniMapWidth = (int)(screenWidth * miniMapWidthPercentage);
            int miniMapHeight = (int)(screenHeight * miniMapHeightPercentage);
            int miniMapStartWidth = (screenWidth - miniMapWidth);
            int miniMapStartHeight = (screenHeight - miniMapHeight);

            bounds = new Rectangle(miniMapStartWidth, miniMapStartHeight, miniMapWidth, miniMapHeight);
            bitmap = new Bitmap(bounds.Width, bounds.Height);
            onSaveImage += imageHolder.RefreshImage;
        }

        public void Start()
        {
            aTimer.Enabled = true;
        }

        public void OnTimedEvent(object sender, ElapsedEventArgs e)
        {
            try
            {
                if (Busy)
                    return;
                Busy = true;
                using (Graphics g = Graphics.FromImage(bitmap))
                {
                    g.CopyFromScreen(new Point(bounds.Left, bounds.Top), Point.Empty, bounds.Size);
                    onSaveImage((byte[])converter.ConvertTo(bitmap, typeof(byte[])));
                }
                Busy = false;
            }
            catch (Exception exception)
            {
                Console.WriteLine(exception.Message);
            }
        }
    }
}

完整的源代码可以在这里找到：

https://github.com/oldtimerza/Dota2Trainer

它的工作原理是简单地创建一个计时器，在一定时间后运行s Screencapturer class 的 OnTimedEvent() 方法，它有一个委托将运行 MiniMapOverlay RefreshImage() 方法。目前的代码令人震惊，但我只是想在重构之前获得一个粗略且准备好的版本并运行ning。

我一直在寻找为什么会发生这种情况，有什么建议吗？

Answer 1

您应该使用 Glib.Timeout 而不是 System.Timers。 System.Timers 可能存在线程问题，计时器事件发生在与 GTK 应用程序不同的线程上。 Glib.Timeout 以特定间隔在主 GTK 应用程序循环中对事件进行排队，并在同一线程中运行。但是，它不适合时间敏感的功能，因为应用程序循环正在处理其他事件，例如鼠标单击。我见过大约半秒到一秒的延迟，但那是在旧计算机上调试时的情况。这对您的应用程序来说似乎不是问题；仅供将来参考。此外，Glib.Timeout 将继续调用更新事件，直到您 return false。

uint timerId;

public void Start(uint interval)
{
    timerId = GLib.Timeout.Add (interval, OnUpdateTimer);
}

protected bool OnUpdateTimer ()
{
    try
    {
        if (Busy)
            return;
        Busy = true;
        using (Graphics g = Graphics.FromImage(bitmap))
        {
            g.CopyFromScreen(new Point(bounds.Left, bounds.Top), Point.Empty, bounds.Size);
            onSaveImage((byte[])converter.ConvertTo(bitmap, typeof(byte[])));
        }
        Busy = false;
    }
    catch (Exception exception)
    {
        Console.WriteLine(exception.Message);
    }
    return true;
}

在 Gtk# window 中刷新图像，一定时间后图像消失

Refreshing an image in a Gtk# window, after a certain amount of time the image disappears

c#

.net

gtk#