C#调用Google_Earth.doc

C#调用Google Earth COM API开发（一）
2009-07-18  来自：  字体大小：【大 中 小】
· 摘要：Google Earth提供了个人免费版、Plus版、Pro版，个人开发只安装个人免费版就可以了，如果需要更多的功能，那么只有每年上交$400购买专业版了。
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一、准备
Google Earth提供了个人免费版、Plus版、Pro版，个人开发只安装个人免费版就可以了，如果需要更多的功能，那么只有每年上交$400购买专业版了
到目前为止，GoogleEarth的二次开发接口还比较少，功能太弱，仅仅提供了1.0的类库。
GoogleEarth COM API参考文档可以在这里找到：
C#调用COM的参考资料多如牛毛，大家可以到网上搜一下
二、例子
这里提供一个利用VS2008 + Google Earth 5.0开发一个“Hello world”程序
首先，确保已经正确安装GE，打开VS2008 ，新建一个Windows应用程序项目，在“项目”菜单中选择“添加引用…”，切换到“COM”选项卡，选择“Google Earth 1.0 Type Library”，其实就是Google Earth的主程序
在项目的引用中你可以看到已经添加了一个EARTHLib的引用，然后我们就可以调用其中的接口进行开发了。
下面就是小例子的代码（功能很简单，只有三个，打开GE，然后让GE保存一张截图，然后可以打开这个截图看看。呵呵）
1: // 功能：GE实例
2: // 描述：GE COM API 网址：
3: // 作者：温伟鹏
4: // 日期：2008-01-20
5: 
6: using System;
7: using System.Collections.Generic;
8: using System.ComponentModel;
9: using System.Data;
10: using System.Drawing;
11: using System.Text;
12: using System.Windows.Forms;
13: using EARTHLib;
14: using System.Runtime.InteropServices;
15: using System.IO;
16: using System.Diagnostics;
17: 
18: namespace GEDemo
19: {
20: public partial class Form1 : Form
21: {
22: /// <summary>
23: /// 标记GE是否已经启动
24: /// </summary>
25: private bool isGeStarted = false;
26: /// <summary>
27: /// 定义GE应用程序类
28: /// </summary>
29: private ApplicationGEClass GeApp;
30: 
31: public Form1()
32: {
33: InitializeComponent();
34: }
35: 
36: private void button1_Click(object sender, EventArgs e)
37: {
38: StartGE();
39: }
40: 
41: /// <summary>
42: /// 启动GE
43: /// </summary>
44: private void StartGE()
45: {
46: if (isGeStarted)
47: {
48: return;
49: }
50: 
51: try
52: {
53: GeApp = (ApplicationGEClass)Marshal.GetActiveObject("GoogleEarth.Application");
54: 
55: isGeStarted = true;
56: }
57: catch
58: {
59: GeApp = new ApplicationGEClass();
60: 
61: isGeStarted = true;
62: }
63: }
64: 
65: private void button2_Click(object sender, EventArgs e)
66: {
67: string ssFile = Path.Combine(Application.StartupPath, "ScreenShot.jpg");
68: 
69: try
70: {
71: //quality的取值范围在(0,100)之间，质量越高，quality越大
72: GeApp.SaveScreenShot(ssFile, 100);
73: 
74: MessageBox.Show("成功保存截屏图像：" + ssFile);
75: }
76: catch(Exception ex)
77: {
78: MessageBox.Show("保存截屏图像时发生错误：" + ex.Message);
79: }
80: }
81: 
82: private void button3_Click(object sender, EventArgs e)
83: {
84: string ssFile = Path.Combine(Application.StartupPath, "ScreenShot.jpg");
85: 
86: if (!File.Exists(ssFile))
87: {
88: MessageBox.Show("未能找到保存的截屏图像！");
89: return;
90: }
91: 
92: Process.Start(ssFile);
93: }
94: 
95: private void button4_Click(object sender, EventArgs e)
96: {
97: this.Close();
98: Application.Exit();
99: }
100: 
101: }
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· C# 调用 Google Earth Com API开发（二）
继《C#调用GoogleEarth Com API开发（一）》，我Neil又带给大家第二篇文章。这一篇文章在第一篇的基础上，展示如何调用Windows API将GoogleEarth的界面隐藏掉，并将GoogleEarth的地图显示在自定义的窗体上。废话少说，直接上代码。
1、主窗口代码：
1: // 功能：GE实例(二)
2: // 描述：GE COM API 网址：
3: // 作者：温伟鹏
4: // 日期：2009-02-08
5: 
6: using System;
7: using System.Collections.Generic;
8: using System.ComponentModel;
9: using System.Data;
10: using System.Drawing;
11: using System.Text;
12: using System.Windows.Forms;
13: using EARTHLib;
14: 
15: namespace GEDemo
16: {
17: public partial class Form2 : Form
18: {
19: /// <summary>
20: /// 用来关闭GoogleEarth的消息定义
21: /// </summary>
22: static readonly Int32 WM_QUIT = 0x0012;
23: 
24: private IntPtr GEHWnd = (IntPtr)5;
25: private IntPtr GEHrender = (IntPtr)5;
26: private IntPtr GEParentHrender = (IntPtr)5;
27: /// <summary>
28: /// 定义GE应用程序类
29: /// </summary>
30: private ApplicationGEClass GeApp;
31: 
32: public Form2()
33: {
34: InitializeComponent();
35: }
36: 
37: protected override void OnLoad(EventArgs e)
38: {
39: base.OnLoad(e);
40: 
41: if (!this.DesignMode)
42: {
43: GeApp = new ApplicationGEClass();
44: 
45: GEHWnd = (IntPtr)GeApp.GetMainHwnd();
46: 
47: NativeMethods.SetWindowPos(GEHWnd, NativeMethods.HWND_BOTTOM, 0, 0, 0, 0,
48: NativeMethods.SWP_NOSIZE + NativeMethods.SWP_HIDEWINDOW);
49: 
50: GEHrender = (IntPtr)GeApp.GetRenderHwnd();
51: GEParentHrender = (IntPtr)NativeMethods.GetParent(GEHrender);
52: 
53: NativeMethods.MoveWindow(GEHrender, 0, 0, this.Width, this.Height, true);
54: 
55: NativeMethods.SetParent(GEHrender, this.Handle);
56: }
57: }
58: 
59: protected override void OnClosing(CancelEventArgs e)
60: {
61: base.OnClosing(e);
62: 
63: NativeMethods.PostMessage(GeApp.GetMainHwnd(), WM_QUIT, 0, 0);
64: }
65: }
66: }

2、NativeMethods类定义：
1: // 功能：Windows API调用
2: // 描述：大家可以参照MSDN
3: // 作者：温伟鹏
4: // 日期：2009-02-08
5: 
6: using System;
7: using System.Collections.Generic;
8: using System.Text;
9: using System.Runtime.InteropServices;
10: 
11: namespace GEDemo
12: {
13: public class NativeMethods
14: {
15: [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
16: public static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int x, int y, int cx, int cy, UInt32 uflags);
17: 
18: [DllImport("user32.dll", CharSet = CharSet.Auto)]
19: public static extern IntPtr PostMessage(int hWnd, int msg, int wParam, int lParam);
20: 
21: #region 预定义
22: 
23: public static readonly IntPtr HWND_BOTTOM = new IntPtr(1);
24: public static readonly IntPtr HWND_NOTOPMOST = new IntPtr(-2);
25: public static readonly IntPtr HWND_TOP = new IntPtr(0);
26: public static readonly IntPtr HWND_TOPMOST = new IntPtr(-1);
27: public static readonly UInt32 SWP_NOSIZE = 1;
28: public static readonly UInt32 SWP_NOMOVE = 2;
29: public static readonly UInt32 SWP_NOZORDER = 4;
30: public static readonly UInt32 SWP_NOREDRAW = 8;
31: public static readonly UInt32 SWP_NOACTIVATE = 16;
32: public static readonly UInt32 SWP_FRAMECHANGED = 32;
33: public static readonly UInt32 SWP_SHOWWINDOW = 64;
34: public static readonly UInt32 SWP_HIDEWINDOW = 128;
35: public static readonly UInt32 SWP_NOCOPYBITS = 256;
36: public static readonly UInt32 SWP_NOOWNERZORDER = 512;
37: public static readonly UInt32 SWP_NOSENDCHANGING = 1024;
38: 
39: #endregion
40: 
41: public delegate int EnumWindowsProc(IntPtr hwnd, int lParam);
42: 
43: [DllImport("user32", CharSet = CharSet.Auto)]
44: public extern static IntPtr GetParent(IntPtr hWnd);
45: 
46: [DllImport("user32", CharSet = CharSet.Auto)]
47: public extern static bool MoveWindow(IntPtr hWnd, int X, int Y, int nWidth, int nHeight, bool bRepaint);
48: 
49: [DllImport("user32", CharSet = CharSet.Auto)]
50: public extern static IntPtr SetParent(IntPtr hWndChild, IntPtr hWndNewParent);
51: 
52: [DllImport("user32.dll", ExactSpelling = true, CharSet = CharSet.Auto)]
53: public static extern IntPtr GetWindow(IntPtr hWnd, int uCmd);
54: 
55: public static int GW_CHILD = 5;
56: public static int GW_HWNDNEXT = 2;
57: }
58: }
3、执行效果：

· 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
1: /// <summary>
2: /// 重新改变GoogleEarth视图的大小
3: /// </summary>
4: private void ResizeGoogleControl()
5: {
6: NativeMethods.SendMessage(GEHWnd, (uint)NativeMethods.WM_COMMAND, NativeMethods.WM_PAINT, 0);
7: NativeMethods.PostMessage(GEHWnd, NativeMethods.WM_QT_PAINT, 0, 0);
8: 
9: RECT mainRect = new RECT();
10: NativeMethods.GetWindowRect(GEHWnd, out mainRect);
11: clientRect = new RECT();
12: NativeMethods.GetClientRect(GEHrender, out clientRect);
13: 
14: int offsetW = mainRect.Width - clientRect.Width;
15: int offsetH = mainRect.Height - clientRect.Height;
16: 
17: int newWidth = this.Control.Width + (int)offsetW;
18: int newHeight = this.Control.Height + (int)offsetH;
19: 
20: NativeMethods.SetWindowPos(GEHWnd, NativeMethods.HWND_TOP,
21: 0, 0, newWidth, newHeight,
22: NativeMethods.SWP_FRAMECHANGED);
23: 
24: NativeMethods.SendMessage(GEHWnd, (uint)NativeMethods.WM_COMMAND, NativeMethods.WM_SIZE, 0);
25: }
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。
1: /// <summary>
2: /// 鼠标钩子
3: /// </summary>
4: private MouseHook mouseHook;
5:  
6: // 设置鼠标钩子
7: mouseHook = new MouseHook();
8: mouseHook.MouseClick += new MouseEventHandler(mouseHook_MouseClick);
9: mouseHook.MouseDbClick += new MouseEventHandler(mouseHook_MouseDbClick);
10: mouseHook.MouseWheel += new MouseEventHandler(mouseHook_MouseWheel);
11: // 启动鼠标钩子
12: mouseHook.StartHook(HookType.WH_MOUSE_LL, 0);
单击事件：
1: /// <summary>
2: /// 鼠标钩子。鼠标单击事件
3: /// </summary>
4: /// <param name="sender"></param>
5: /// <param name="e"></param>
6: void mouseHook_MouseClick(object sender, MouseEventArgs e)
7: {
8: IntPtr hWnd = NativeMethods.WindowFromPoint(e.Location);
9: if (hWnd == this.GeRenderHWnd)
10: {
11: Point point = this.Control.PointToClient(e.Location);
12: // 如果鼠标击点位置在控件内部，则说明鼠标点击了GoogleEarth视图
13: if (this.Control.ClientRectangle.Contains(point))
14: {
15: Console.WriteLine("点击了GoogleEarth...");
16: 
17: DoublePoint dp = ((GERenderPanel)Control).DetermineScreenCoordinates(point.X, point.Y);
18: 
19: ParameterizedThreadStart pts = new ParameterizedThreadStart(ShowMouseClickPoint);
20: 
21: Thread thread = new Thread(pts);
22: thread.Start(dp);
23: 
24: }
25: }
26: }
27: 
28: protected void ShowMouseClickPoint(object obj)
29: {
30: //Thread.Sleep(20);
31: DoublePoint dp = (DoublePoint)obj;
32: PointOnTerrainGE pGe = GeApp.GetPointOnTerrainFromScreenCoords(dp.X, dp.Y);
33: Console.WriteLine("鼠标点击了：Lnt=" + pGe.Longitude.ToString()
34: + ";Lat=" + pGe.Latitude.ToString());
35: }

双击事件：
1: /// <summary>
2: /// 鼠标钩子。鼠标双击事件
3: /// </summary>
4: /// <param name="sender"></param>
5: /// <param name="e"></param>
6: void mouseHook_MouseDbClick(object sender, MouseEventArgs e)
7: {
8: IntPtr hWnd = NativeMethods.WindowFromPoint(e.Location);
9: if (hWnd == this.GeRenderHWnd)
10: {
11: Point point = this.Control.PointToClient(e.Location);
12: // 如果鼠标击点位置在控件内部，则说明鼠标点击了GoogleEarth视图
13: if (this.Control.ClientRectangle.Contains(point))
14: {
15: Console.WriteLine("xx双击了GoogleEarth...");
16: 
17: DoublePoint dp = ((GERenderPanel)Control).DetermineScreenCoordinates(point.X, point.Y);
18: 
19: ParameterizedThreadStart pts = new ParameterizedThreadStart(ShowMouseDbClickPoint);
20: 
21: Thread thread = new Thread(pts);
22: thread.Start(dp);
23: 
24: }
25: }
26: }
27: 
28: protected void ShowMouseDbClickPoint(object obj)
29: {
30: //Thread.Sleep(20);
31: DoublePoint dp = (DoublePoint)obj;
32: PointOnTerrainGE pGe = GeApp.GetPointOnTerrainFromScreenCoords(dp.X, dp.Y);
33: Console.WriteLine("xx鼠标双击了：Lnt=" + pGe.Longitude.ToString()
34: + ";Lat=" + pGe.Latitude.ToString());
35: 
36: MessageBox.Show("我还是出来一下吧！省得你不知道你已经双击了鼠标！");
37: }

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：
1: GEViewContent view = GetGEView();
2: 
3: if (view != null)
4: {
5: ApplicationGE ge = view.GeApplication;
6: if (ge != null && ge.IsInitialized() > 0)
7: {
8: using (SaveFileDialog sfd = new SaveFileDialog())
9: {
10: sfd.Filter = "jpg图片|*.jpg";
11: sfd.AddExtension = true;
12: sfd.CheckPathExists = true;
13: sfd.Title = "保存Google Earth截图";
14: 
15: if (sfd.ShowDialog() == DialogResult.OK)
16: {
17: ge.SaveScreenShot(sfd.FileName, 100);
18: }
19: }
20: }
21: }
2) 彩色截图：
1: GEViewContent view = GetGEView();
2: if (view != null)
3: {
4: int nWidth = view.Control.Width;
5: int nHeight = view.Control.Height;
6: Point pt = view.Control.PointToScreen(view.Control.Location);
7: int nXSrc = pt.X;
8: int nYSrc = pt.Y;
9: 
10: IntPtr hRender = view.GeRenderHWnd;
11: 
12: if (hRender != IntPtr.Zero)
13: {
14: // 取得Rend