一起学习ArcEngine（3）缩小
继承自定义基类ToolBase，代码如下，比以前清爽多了！
1: /// <summary>
2: /// 地图缩小工具
3: /// </summary>
4: public class ZoomOut : ToolBase
5: {
6: private INewEnvelopeFeedback m_feedBack;
7: private IPoint m_point;
8: private Boolean m_isMouseDown;
9:
10: #region 实例化
11: public ZoomOut()
12: :base("ZoomOut")
13: {
14: if (m_cursor == null) m_cursor = getCursor(esriSystemMouseCursor.esriSystemMouseCursorZoomOut);
15: }
16:
17: public ZoomOut(AxMapControl mapCtl)
18: : base(mapCtl, "ZoomOut")
19: {
20: if (m_cursor == null) m_cursor = getCursor(esriSystemMouseCursor.esriSystemMouseCursorZoomOut);
21: }
22:
23: public ZoomOut(AxPageLayoutControl plCtl)
24: : base(plCtl, "ZoomOut")
25: {
26: if (m_cursor == null) m_cursor = getCursor(esriSystemMouseCursor.esriSystemMouseCursorZoomOut);
27: }
28: #endregion
29:
30: protected override void initContextMenu()
31: {
32: ContextMenu cmenu = new ContextMenu();
33: MenuItem m = new MenuItem();
34: m.Text = "结束";
35: m.Click += new EventHandler(m_Click);
36: cmenu.MenuItems.Add(m);
37: m_contextMenu = cmenu;
38:
39: }
40:
41: void m_Click(object sender, EventArgs e)
42: {
43: if (m_pControl is AxMapControl)
44: {
45: AxMapControl am = m_pControl as AxMapControl;
46: am.CurrentTool = null;
47: }
48: }
49:
50:
51: public override void OnMouseDown(int Button, int Shift, int X, int Y)
52: {
53: if (m_pActiveView == null) return;
54: if (Button == 2)
55: {
56: ShowContextMenu(X, Y);
57: return;
58: }
59:
60: m_point = m_pActiveView.ScreenDisplay.DisplayTransformation.ToMapPoint(X, Y);
61: m_cursor = getCursor(ESRI.ArcGIS.SystemUI.esriSystemMouseCursor.esriSystemMouseCursorZoomOut);
62: m_isMouseDown = true;
63:
64: }
65:
66: public override void OnMouseMove(int Button, int Shift, int X, int Y)
67: {
68: if (!m_isMouseDown) return;
69:
70: //Start an envelope feedback
71: if (m_feedBack == null)
72: {
73: m_feedBack = new NewEnvelopeFeedbackClass();
74: m_feedBack.Display = m_pActiveView.ScreenDisplay;
75: m_feedBack.Start(m_point);
76: }
77: //Move the envelope feedback
78: m_feedBack.MoveTo(m_pActiveView.ScreenDisplay.DisplayTransformation.ToMapPoint(X, Y));
79: }
80:
81: public override void OnMouseUp(int Button, int Shift, int X, int Y)
82: {
83: if (!m_isMouseDown) return;
84:
85: IEnvelope pEnvelope;
86: IEnvelope pFeedEnvelope;
87:
88: double newWidth, newHeight;
89:
90: //If an envelope has not been tracked
91: if (m_feedBack == null)
92: {
93: //Zoom out from the mouse click
94: pEnvelope = m_pActiveView.Extent;
95: pEnvelope.Expand(2, 2, true);
96: pEnvelope.CenterAt(m_point);
97: }
98: else
99: {
100: //Stop the envelope feedback
101: pFeedEnvelope = m_feedBack.Stop();
102:
103: //Exit if the envelope height or width is 0
104: if (pFeedEnvelope.Width == 0 || pFeedEnvelope.Height == 0)
105: {
106: m_feedBack = null;
107: m_isMouseDown = false;
108: }
109:
110: newWidth = m_pActiveView.Extent.Width * (m_pActiveView.Extent.Width / pFeedEnvelope.Width);
111: newHeight = m_pActiveView.Extent.Height * (m_pActiveView.Extent.Height / pFeedEnvelope.Height);
112:
113: //Set the new extent coordinates
114: pEnvelope = new EnvelopeClass();
115: pEnvelope.PutCoords(m_pActiveView.Extent.XMin - ((pFeedEnvelope.XMin - m_pActiveView.Extent.XMin) * (m_pActiveView.Extent.Width / pFeedEnvelope.Width)),
116: m_pActiveView.Extent.YMin - ((pFeedEnvelope.YMin - m_pActiveView.Extent.YMin) * (m_pActiveView.Extent.Height / pFeedEnvelope.Height)),
117: (m_pActiveView.Extent.XMin - ((pFeedEnvelope.XMin - m_pActiveView.Extent.XMin) * (m_pActiveView.Extent.Width / pFeedEnvelope.Width))) + newWidth,
118: (m_pActiveView.Extent.YMin - ((pFeedEnvelope.YMin - m_pActiveView.Extent.YMin) * (m_pActiveView.Extent.Height / pFeedEnvelope.Height))) + newHeight);
119: }
120:
121: //Set the new extent
122: m_pActiveView.Extent = pEnvelope;
123:
124: //Refresh the active view
125: m_pActiveView.Refresh();
126: m_feedBack = null;
127: m_isMouseDown = false;
128: }
129:
130: public void OnKeyDown(int keyCode, int shift)
131: {
132: if (m_isMouseDown)
133: {
134: if (keyCode == 27) //ESC key
135: {
136: m_feedBack = null;
137: m_isMouseDown = false;
138: m_pHookHelper.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewForeground, null, null);
139: }
140: }
141: }
142: }