C# 调用 Google Earth Com API开发（三）

好久没有更新《C#调用Google Earth Com API开发》系列文章了，今天带给大家的是第三篇，本篇相对于第二篇主要改进了三个方面。

1) 实现GoogleEarth显示画面随窗口大小改变而改变

2) 截获GoogleEarth鼠标消息，实现单击、双击功能；鼠标滚轮缩放现在只能放大！O(∩_∩)O~

3) 实现GoogleEarth彩色截图（测试环境：Windows 2003 Server ，Vista与Win7中不可用，XP未测）

下面还是继续看代码：

1、GoogleEarth动态改变大小

/// <summary>
/// 重新改变GoogleEarth视图的大小
/// </summary>
private void ResizeGoogleControl()
{
    NativeMethods.SendMessage(GEHWnd, (uint)NativeMethods.WM_COMMAND, NativeMethods.WM_PAINT, 0);
    NativeMethods.PostMessage(GEHWnd, NativeMethods.WM_QT_PAINT, 0, 0);

    RECT mainRect = new RECT();
    NativeMethods.GetWindowRect(GEHWnd, out mainRect);
    clientRect = new RECT();
    NativeMethods.GetClientRect(GEHrender, out clientRect);

    int offsetW = mainRect.Width - clientRect.Width;
    int offsetH = mainRect.Height - clientRect.Height;

    int newWidth = this.Control.Width + (int)offsetW;
    int newHeight = this.Control.Height + (int)offsetH;

    NativeMethods.SetWindowPos(GEHWnd, NativeMethods.HWND_TOP,
        0, 0, newWidth, newHeight,
        NativeMethods.SWP_FRAMECHANGED);

    NativeMethods.SendMessage(GEHWnd, (uint)NativeMethods.WM_COMMAND, NativeMethods.WM_SIZE, 0);
}

2、鼠标消息

此例子中对于鼠标消息到处理使用了钩子，调用HookAPI.dll实现。

        /// <summary>
        /// 鼠标钩子
        /// </summary>
        private MouseHook mouseHook;

        // 设置鼠标钩子
        mouseHook = new MouseHook();
        mouseHook.MouseClick += new MouseEventHandler(mouseHook_MouseClick);
        mouseHook.MouseDbClick += new MouseEventHandler(mouseHook_MouseDbClick);
        mouseHook.MouseWheel += new MouseEventHandler(mouseHook_MouseWheel);
       // 启动鼠标钩子
        mouseHook.StartHook(HookType.WH_MOUSE_LL, 0);

单击事件：

/// <summary>
/// 鼠标钩子。鼠标单击事件
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
void mouseHook_MouseClick(object sender, MouseEventArgs e)
{
    IntPtr hWnd = NativeMethods.WindowFromPoint(e.Location);
    if (hWnd == this.GeRenderHWnd)
    {
        Point point = this.Control.PointToClient(e.Location);
        // 如果鼠标击点位置在控件内部，则说明鼠标点击了GoogleEarth视图
        if (this.Control.ClientRectangle.Contains(point))
        {
            Console.WriteLine("点击了GoogleEarth...");

            DoublePoint dp = ((GERenderPanel)Control).DetermineScreenCoordinates(point.X, point.Y);

            ParameterizedThreadStart pts = new ParameterizedThreadStart(ShowMouseClickPoint);

            Thread thread = new Thread(pts);
            thread.Start(dp);

        }
    }
}

protected void ShowMouseClickPoint(object obj)
{
    //Thread.Sleep(20);
    DoublePoint dp = (DoublePoint)obj;
    PointOnTerrainGE pGe = GeApp.GetPointOnTerrainFromScreenCoords(dp.X, dp.Y);
    Console.WriteLine("鼠标点击了：Lnt=" + pGe.Longitude.ToString()
        + ";Lat=" + pGe.Latitude.ToString());
}

双击事件：

/// <summary>
 /// 鼠标钩子。鼠标双击事件
 /// </summary>
 /// <param name="sender"></param>
 /// <param name="e"></param>
 void mouseHook_MouseDbClick(object sender, MouseEventArgs e)
 {
     IntPtr hWnd = NativeMethods.WindowFromPoint(e.Location);
     if (hWnd == this.GeRenderHWnd)
     {
         Point point = this.Control.PointToClient(e.Location);
         // 如果鼠标击点位置在控件内部，则说明鼠标点击了GoogleEarth视图
         if (this.Control.ClientRectangle.Contains(point))
         {
             Console.WriteLine("xx双击了GoogleEarth...");

             DoublePoint dp = ((GERenderPanel)Control).DetermineScreenCoordinates(point.X, point.Y);

             ParameterizedThreadStart pts = new ParameterizedThreadStart(ShowMouseDbClickPoint);

             Thread thread = new Thread(pts);
             thread.Start(dp);

         }
     }
 }

 protected void ShowMouseDbClickPoint(object obj)
 {
     //Thread.Sleep(20);
     DoublePoint dp = (DoublePoint)obj;
     PointOnTerrainGE pGe = GeApp.GetPointOnTerrainFromScreenCoords(dp.X, dp.Y);
     Console.WriteLine("xx鼠标双击了：Lnt=" + pGe.Longitude.ToString()
         + ";Lat=" + pGe.Latitude.ToString());

     MessageBox.Show("我还是出来一下吧！省得你不知道你已经双击了鼠标！");
 }

这两处代码还比较简陋，比如未添加主窗口焦点检测，相信读者可以自行添加。O(∩_∩)O~

3、截图

程序中有两种截图功能，一种是GoogleEarth自带的截图功能，只能截取黑白图片；另一种为彩色截图，但是Vista以上操作系统不支持，还未找到合适的方法实现Vista与Win7兼容。

1) GoogleEarth自带截图功能：

GEViewContent view = GetGEView();

if (view != null)
{
    ApplicationGE ge = view.GeApplication;
    if (ge != null && ge.IsInitialized() > 0)
    {
        using (SaveFileDialog sfd = new SaveFileDialog())
        {
            sfd.Filter = "jpg图片|*.jpg";
            sfd.AddExtension = true;
            sfd.CheckPathExists = true;
            sfd.Title = "保存Google Earth截图";

            if (sfd.ShowDialog() == DialogResult.OK)
            {
                ge.SaveScreenShot(sfd.FileName, 100);
            }
        }
    }
}

2) 彩色截图：

GEViewContent view = GetGEView();
if (view != null)
{
    int nWidth = view.Control.Width;
    int nHeight = view.Control.Height;
    Point pt = view.Control.PointToScreen(view.Control.Location);
    int nXSrc = pt.X;
    int nYSrc = pt.Y;

    IntPtr hRender = view.GeRenderHWnd;

    if (hRender != IntPtr.Zero)
    {
        // 取得Render DC
        IntPtr hRenderDC = NativeMethods.GetWindowDC(hRender);
        // 创建hBitmap
        IntPtr hBitmap = NativeMethods.CreateCompatibleBitmap(hRenderDC, nWidth, nHeight);
        // 创建MEM DC
        IntPtr hMemDC = NativeMethods.CreateCompatibleDC(hRenderDC);
        // 将Bitmap Select到MemDC
        NativeMethods.SelectObject(hMemDC, hBitmap);
        // 直接拷屏
        NativeMethods.BitBlt(hMemDC, 0, 0, nWidth, nHeight,
            hRenderDC, 0, 0, 13369376);

        using(Bitmap bmp = Bitmap.FromHbitmap(hBitmap))
        {
            using(SaveFileDialog sfd = new SaveFileDialog())
            {
                sfd.Filter = "JPG图片|*.jpg|PNG图片|*.png";
                sfd.AddExtension = true;
                sfd.CheckPathExists = true;
                sfd.Title = "保存Google Earth截图";

                if (sfd.ShowDialog() == DialogResult.OK)
                {
                    ImageFormat imgFormat = null;
                    // 默认选择JPG
                    if (sfd.FilterIndex == 0)
                    {
                        imgFormat = ImageFormat.Jpeg;
                    }
                    // 选择PNG
                    else
                    {
                        imgFormat = ImageFormat.Png;
                    }
                    bmp.Save(sfd.FileName, imgFormat);
                }
            }

            //销毁资源
            NativeMethods.DeleteDC(hRenderDC);
            NativeMethods.DeleteDC(hMemDC);
        }
    }

OK，这篇GE开发到此为止，请读者继续等待后面的精彩文章…

不好意思，刚才忘记上传源程序了！

https://files.cnblogs.com/wpwen/GEDemo_2009-05-22.rar