一起学习ArcEngine（1）-放大工具
地图操作的工具，大部分ArcEngine都有现成的，但是这些工具不太好用，比如提示和名称都是英文，地图操作中没有右键，无法和vs提供的工具条控件或第三方工具条控件集成等，还是自己实现比较灵活方便。
我们就从最简单的放大工具开始来实现地图操作常用的工具吧！
废话少说，先上代码
using System;
using ESRI.ArcGIS.Carto;
using ESRI.ArcGIS.Geometry;
using ESRI.ArcGIS.Controls;
using ESRI.ArcGIS.Display;
using ESRI.ArcGIS.SystemUI;
using ESRI.ArcGIS.ADF.CATIDs;
using System.Runtime.InteropServices;
namespace TechFront.TPIS2.GisCommFun
{
public class ZoomIn : ICommand, ITool
{
[DllImport("gdi32.dll")]
static extern bool DeleteObject(IntPtr hObject);
private System.Drawing.Bitmap m_bitmap;
private IntPtr m_hBitmap;
private IHookHelper m_pHookHelper;
private INewEnvelopeFeedback m_feedBack;
private IPoint m_point;
private Boolean m_isMouseDown;
private System.Windows.Forms.Cursor m_zoomInCur;
private System.Windows.Forms.Cursor m_moveZoomInCur;
public ZoomIn()
{
//Load resources
string[] res = GetType().Assembly.GetManifestResourceNames();
if (res.GetLength(0) > 0)
{
m_bitmap = new System.Drawing.Bitmap(GetType().Assembly.GetManifestResourceStream(GetType(), "Bmp.ZoomIn.bmp"));
if (m_bitmap != null)
{
m_bitmap.MakeTransparent(m_bitmap.GetPixel(1, 1));
m_hBitmap = m_bitmap.GetHbitmap();
}
}
m_pHookHelper = new HookHelperClass();
}
~ZoomIn()
{
if (m_hBitmap.ToInt32() != 0)
DeleteObject(m_hBitmap);
m_pHookHelper = null;
m_zoomInCur = null;
m_moveZoomInCur = null;
}
#region ICommand Members
public void OnClick()
{
}
public string Message
{
get
{
return "放大地图";
}
}
public int Bitmap
{
get
{
return m_hBitmap.ToInt32();
}
}
public void OnCreate(object hook)
{
m_pHookHelper.Hook = hook;
m_zoomInCur = new System.Windows.Forms.Cursor(GetType().Assembly.GetManifestResourceStream(GetType(), "Cur.ZoomIn.cur"));
m_moveZoomInCur = new System.Windows.Forms.Cursor(GetType().Assembly.GetManifestResourceStream(GetType(), "Cur.MoveZoomIn.cur"));
}
public string Caption
{
get
{
return "放大";
}
}
public string Tooltip
{
get
{
return "放大";
}
}
public int HelpContextID
{
get
{
// TODO: Add ZoomIn.HelpContextID getter implementation
return 0;
}
}
public string Name
{
get
{
return "ZoomIn";
}
}
public bool Checked
{
get
{
return false;
}
}
public bool Enabled
{
get
{
if (m_pHookHelper.FocusMap == null) return false;
return true;
}
}
public string HelpFile
{
get
{
// TODO: Add ZoomIn.HelpFile getter implementation
return null;
}
}
public string Category
{
get
{
return "GisCommFun";
}
}
#endregion
#region ITool Members
public void OnMouseDown(int button, int shift, int x, int y)
{
if (m_pHookHelper.ActiveView == null) return;
//If the active view is a page layout
if (m_pHookHelper.ActiveView is IPageLayout)
{
//Create a point in map coordinates
IPoint pPoint = (IPoint)m_pHookHelper.ActiveView.ScreenDisplay.DisplayTransformation.ToMapPoint(x, y);
//Get the map if the point is within a data frame
IMap pMap = m_pHookHelper.ActiveView.HitTestMap(pPoint);
if (pMap == null) return;
//Set the map to be the page layout's focus map
if (pMap != m_pHookHelper.FocusMap)
{
m_pHookHelper.ActiveView.FocusMap = pMap;
m_pHookHelper.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);
}
}
//Create a point in map coordinates
IActiveView pActiveView = (IActiveView)m_pHookHelper.FocusMap;
m_point = pActiveView.ScreenDisplay.DisplayTransformation.ToMapPoint(x, y);
m_isMouseDown = true;
}
public void OnMouseMove(int button, int shift, int x, int y)
{
if (!m_isMouseDown) return;
//Get the focus map
IActiveView pActiveView = (IActiveView)m_pHookHelper.FocusMap;
//Start an envelope feedback
if (m_feedBack == null)
{
m_feedBack = new NewEnvelopeFeedbackClass();
m_feedBack.Display = pActiveView.ScreenDisplay;
m_feedBack.Start(m_point);
}
//Move the envelope feedback
m_feedBack.MoveTo(pActiveView.ScreenDisplay.DisplayTransformation.ToMapPoint(x, y));
}
public void OnMouseUp(int button, int shift, int x, int y)
{
if (!m_isMouseDown) return;
//Get the focus map
IActiveView pActiveView = (IActiveView)m_pHookHelper.FocusMap;
//If an envelope has not been tracked
IEnvelope pEnvelope;
if (m_feedBack == null)
{
//Zoom in from mouse click
pEnvelope = pActiveView.Extent;
pEnvelope.Expand(0.5, 0.5, true);
pEnvelope.CenterAt(m_point);
}
else
{
//Stop the envelope feedback
pEnvelope = m_feedBack.Stop();
//Exit if the envelope height or width is 0
if (pEnvelope.Width == 0 || pEnvelope.Height == 0)
{
m_feedBack = null;
m_isMouseDown = false;
}
}
//Set the new extent
pActiveView.Extent = pEnvelope;
//Refresh the active view
pActiveView.Refresh();
m_feedBack = null;
m_isMouseDown = false;
}
public void OnKeyDown(int keyCode, int shift)
{
if (m_isMouseDown)
{
if (keyCode == 27)
{
m_isMouseDown = false;
m_feedBack = null;
m_pHookHelper.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewForeground, null, null);
}
}
}
public void OnKeyUp(int keyCode, int shift)
{
// TODO: Add ZoomIn.OnKeyUp implementation
}
public int Cursor
{
get
{
if (m_isMouseDown)
return m_moveZoomInCur.Handle.ToInt32();
else
return m_zoomInCur.Handle.ToInt32();
}
}
public bool OnContextMenu(int x, int y)
{
// TODO: Add ZoomIn.OnContextMenu implementation
return false;
}
public bool Deactivate()
{
return true;
}
public void Refresh(int hdc)
{
// TODO: Add ZoomIn.Refresh implementation
}
public void OnDblClick()
{
// TODO: Add ZoomIn.OnDblClick implementation
}
#endregion
}
}
其实，放大工具 主要是实现Itool的OnMouseDown、OnMouseMove、OnMouseUp三个方法，设置ICommand的Caption，Tooltip、Message、Bitmap属性，实现OnCreate方法。
Itool的三个方法由名称就可以知道，三个方法分别是在鼠标按下左键时、按下左键移动时、鼠标弹起时执行。
Caption属性是设置工具显示的文本；Tooltip是设置鼠标移到工具上时，提示的信息；Bitmap是设置工具的图标信息