1、前言
在ArcEngine中，平行线的构造主要使用IConstructCurve接口实现，如果你想在生成平行线的同时对平行线的拐点进行一些特殊处理，那就需要使用IConstructCurve4接口，下面开始介绍。
2、构造一般平行线
构造一般平行线需要使用IConstructCurve接口的ConstructOffset方法，代码如下：
using ESRI.ArcGIS.ADF.BaseClasses;
using ESRI.ArcGIS.ADF.CATIDs;
using ESRI.ArcGIS.Carto;
using ESRI.ArcGIS.Controls;
using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS.Geometry;
using System;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;
namespace WindowsFormsApplication1.Command
{
/// <summary>
/// Summary description for ConstructParallelLinesCommand.
/// </summary>
[Guid("639b9a57-d595-4018-85d0-fb5e9350e53c")]
[ClassInterface(ClassInterfaceType.None)]
[ProgId("WindowsFormsApplication1.Command.ConstructParallelLinesCommand")]
public sealed class ConstructParallelLinesCommand : BaseCommand
{
#region COM Registration Function(s)
[ComRegisterFunction()]
[ComVisible(false)]
static void RegisterFunction(Type registerType)
{
// Required for ArcGIS Component Category Registrar support
ArcGISCategoryRegistration(registerType);
//
// TODO: Add any COM registration code here
//
}
[ComUnregisterFunction()]
[ComVisible(false)]
static void UnregisterFunction(Type registerType)
{
// Required for ArcGIS Component Category Registrar support
ArcGISCategoryUnregistration(registerType);
//
// TODO: Add any COM unregistration code here
//
}
#region ArcGIS Component Category Registrar generated code
/// <summary>
/// Required method for ArcGIS Component Category registration -
/// Do not modify the contents of this method with the code editor.
/// </summary>
private static void ArcGISCategoryRegistration(Type registerType)
{
string regKey = string.Format("HKEY_CLASSES_ROOT\\CLSID\\{{{0}}}", registerType.GUID);
ControlsCommands.Register(regKey);
}
/// <summary>
/// Required method for ArcGIS Component Category unregistration -
/// Do not modify the contents of this method with the code editor.
/// </summary>
private static void ArcGISCategoryUnregistration(Type registerType)
{
string regKey = string.Format("HKEY_CLASSES_ROOT\\CLSID\\{{{0}}}", registerType.GUID);
ControlsCommands.Unregister(regKey);
}
#endregion
#endregion
private IHookHelper m_hookHelper;
public ConstructParallelLinesCommand()
{
//
// TODO: Define values for the public properties
//
base.m_category = ""; //localizable text
base.m_caption = ""; //localizable text
base.m_message = ""; //localizable text
base.m_toolTip = ""; //localizable text
base.m_name = ""; //unique id, non-localizable (e.g. "MyCategory_MyCommand")
try
{
//
// TODO: change bitmap name if necessary
//
string bitmapResourceName = GetType().Name + ".bmp";
base.m_bitmap = new Bitmap(GetType(), bitmapResourceName);
}
catch (Exception ex)
{
System.Diagnostics.Trace.WriteLine(ex.Message, "Invalid Bitmap");
}
}
#region Overridden Class Methods
/// <summary>
/// Occurs when this command is created
/// </summary>
/// <param name="hook">Instance of the application</param>
public override void OnCreate(object hook)
{
if (hook == null)
return;
if (m_hookHelper == null)
m_hookHelper = new HookHelperClass();
m_hookHelper.Hook = hook;
}
/// <summary>
/// Occurs when this command is clicked
/// </summary>
public override void OnClick()
{
if (m_hookHelper.FocusMap.SelectionCount != 1)
{
MessageBox.Show("请选择1条线要素进行分割", "提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return;
}
// 获取被选择的要素
IEnumFeature pEnumFeature = m_hookHelper.FocusMap.FeatureSelection as IEnumFeature;
pEnumFeature.Reset();
IFeature pFeature = pEnumFeature.Next();
if (pFeature.Shape is IPoint || pFeature.Shape is IPolygon)
{
MessageBox.Show("请选择1条线要素进行分割", "提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return;
}
// 获取要素类
IFeatureLayer pFeatureLayer = m_hookHelper.FocusMap.get_Layer(0) as IFeatureLayer;
IFeatureClass pFeatureClass = pFeatureLayer.FeatureClass;
// 获取原始线段
IPolyline pPolyline = pFeature.ShapeCopy as IPolyline;
IConstructCurve pConstructCurve = new Polyline() as IConstructCurve;
pConstructCurve.ConstructOffset(pPolyline, 5);
// 创建左侧平行线要素
IFeature pNewFeature = pFeatureClass.CreateFeature();
pNewFeature.Shape = pConstructCurve as IPolyline;
pNewFeature.Store();
// 刷新地图
m_hookHelper.ActiveView.Refresh();
}
#endregion
}
}上面代码构造了一条间距为5米的平行线，运行结果如下图所示：
在构造平行线时，如果距离为正数，则在原始线段的右侧构建平行线，如果你想构建原始线段左侧的平行线，那么只需要把距离设置为负数即可：
IPolyline pPolyline = pFeature.ShapeCopy as IPolyline;
IConstructCurve pConstructCurve = new Polyline() as IConstructCurve;
pConstructCurve.ConstructOffset(pPolyline, -5);上面的代码就在原始线段左侧5米处生成了一条平行线，如下图所示：
同时生成左右两侧的平行线代码如下：
using ESRI.ArcGIS.ADF.BaseClasses;
using ESRI.ArcGIS.ADF.CATIDs;
using ESRI.ArcGIS.Carto;
using ESRI.ArcGIS.Controls;
using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS.Geometry;
using System;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;
namespace WindowsFormsApplication1.Command
{
/// <summary>
/// Summary description for ConstructParallelLinesCommand.
/// </summary>
[Guid("639b9a57-d595-4018-85d0-fb5e9350e53c")]
[ClassInterface(ClassInterfaceType.None)]
[ProgId("WindowsFormsApplication1.Command.ConstructParallelLinesCommand")]
public sealed class ConstructParallelLinesCommand : BaseCommand
{
#region COM Registration Function(s)
[ComRegisterFunction()]
[ComVisible(false)]
static void RegisterFunction(Type registerType)
{
// Required for ArcGIS Component Category Registrar support
ArcGISCategoryRegistration(registerType);
//
// TODO: Add any COM registration code here
//
}
[ComUnregisterFunction()]
[ComVisible(false)]
static void UnregisterFunction(Type registerType)
{
// Required for ArcGIS Component Category Registrar support
ArcGISCategoryUnregistration(registerType);
//
// TODO: Add any COM unregistration code here
//
}
#region ArcGIS Component Category Registrar generated code
/// <summary>
/// Required method for ArcGIS Component Category registration -
/// Do not modify the contents of this method with the code editor.
/// </summary>
private static void ArcGISCategoryRegistration(Type registerType)
{
string regKey = string.Format("HKEY_CLASSES_ROOT\\CLSID\\{{{0}}}", registerType.GUID);
ControlsCommands.Register(regKey);
}
/// <summary>
/// Required method for ArcGIS Component Category unregistration -
/// Do not modify the contents of this method with the code editor.
/// </summary>
private static void ArcGISCategoryUnregistration(Type registerType)
{
string regKey = string.Format("HKEY_CLASSES_ROOT\\CLSID\\{{{0}}}", registerType.GUID);
ControlsCommands.Unregister(regKey);
}
#endregion
#endregion
private IHookHelper m_hookHelper;
public ConstructParallelLinesCommand()
{
//
// TODO: Define values for the public properties
//
base.m_category = ""; //localizable text
base.m_caption = ""; //localizable text
base.m_message = ""; //localizable text
base.m_toolTip = ""; //localizable text
base.m_name = ""; //unique id, non-localizable (e.g. "MyCategory_MyCommand")
try
{
//
// TODO: change bitmap name if necessary
//
string bitmapResourceName = GetType().Name + ".bmp";
base.m_bitmap = new Bitmap(GetType(), bitmapResourceName);
}
catch (Exception ex)
{
System.Diagnostics.Trace.WriteLine(ex.Message, "Invalid Bitmap");
}
}
#region Overridden Class Methods
/// <summary>
/// Occurs when this command is created
/// </summary>
/// <param name="hook">Instance of the application</param>
public override void OnCreate(object hook)
{
if (hook == null)
return;
if (m_hookHelper == null)
m_hookHelper = new HookHelperClass();
m_hookHelper.Hook = hook;
}
/// <summary>
/// Occurs when this command is clicked
/// </summary>
public override void OnClick()
{
if (m_hookHelper.FocusMap.SelectionCount != 1)
{
MessageBox.Show("请选择1条线要素进行分割", "提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return;
}
// 获取被选择的要素
IEnumFeature pEnumFeature = m_hookHelper.FocusMap.FeatureSelection as IEnumFeature;
pEnumFeature.Reset();
IFeature pFeature = pEnumFeature.Next();
if (pFeature.Shape is IPoint || pFeature.Shape is IPolygon)
{
MessageBox.Show("请选择1条线要素进行分割", "提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return;
}
// 获取要素类
IFeatureLayer pFeatureLayer = m_hookHelper.FocusMap.get_Layer(0) as IFeatureLayer;
IFeatureClass pFeatureClass = pFeatureLayer.FeatureClass;
// 获取原始线段
IPolyline pPolyline = pFeature.ShapeCopy as IPolyline;
IConstructCurve pConstructCurve = new Polyline() as IConstructCurve;
// 构造左侧平行线
pConstructCurve.ConstructOffset(pPolyline, -5);
IPolyline pLeftPolyline = pConstructCurve as IPolyline;
// 创建左侧平行线要素
IFeature pLeftFeature = pFeatureClass.CreateFeature();
pLeftFeature.Shape = pLeftPolyline;
pLeftFeature.Store();
// 构造右侧平行线
pConstructCurve.ConstructOffset(pPolyline, 5);
IPolyline pRightPolyline = pConstructCurve as IPolyline;
// 创建右侧平行线要素
IFeature pRightFeature = pFeatureClass.CreateFeature();
pRightFeature.Shape = pRightPolyline;
pRightFeature.Store();
// 刷新地图
m_hookHelper.ActiveView.Refresh();
}
#endregion
}
}运行结果如下图所示：
3、构造特殊平行线
先来看看在ArcMap中构造平行线的过程：
可以发现，ArcMap在生成平行线的同时还对拐点进行了处理，第一次生成平行线采用钝角表示拐点，第二次则采用圆角表示拐点，如果你想实现类似的效果，那就需要使用IConstructCurve4接口，下面是生成圆角平行线的代码：
using ESRI.ArcGIS.ADF.BaseClasses;
using ESRI.ArcGIS.ADF.CATIDs;
using ESRI.ArcGIS.Carto;
using ESRI.ArcGIS.Controls;
using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS.Geometry;
using System;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;
namespace WindowsFormsApplication1.Command
{
/// <summary>
/// Summary description for ConstructParallelLinesCommand.
/// </summary>
[Guid("639b9a57-d595-4018-85d0-fb5e9350e53c")]
[ClassInterface(ClassInterfaceType.None)]
[ProgId("WindowsFormsApplication1.Command.ConstructParallelLinesCommand")]
public sealed class ConstructParallelLinesCommand : BaseCommand
{
#region COM Registration Function(s)
[ComRegisterFunction()]
[ComVisible(false)]
static void RegisterFunction(Type registerType)
{
// Required for ArcGIS Component Category Registrar support
ArcGISCategoryRegistration(registerType);
//
// TODO: Add any COM registration code here
//
}
[ComUnregisterFunction()]
[ComVisible(false)]
static void UnregisterFunction(Type registerType)
{
// Required for ArcGIS Component Category Registrar support
ArcGISCategoryUnregistration(registerType);
//
// TODO: Add any COM unregistration code here
//
}
#region ArcGIS Component Category Registrar generated code
/// <summary>
/// Required method for ArcGIS Component Category registration -
/// Do not modify the contents of this method with the code editor.
/// </summary>
private static void ArcGISCategoryRegistration(Type registerType)
{
string regKey = string.Format("HKEY_CLASSES_ROOT\\CLSID\\{{{0}}}", registerType.GUID);
ControlsCommands.Register(regKey);
}
/// <summary>
/// Required method for ArcGIS Component Category unregistration -
/// Do not modify the contents of this method with the code editor.
/// </summary>
private static void ArcGISCategoryUnregistration(Type registerType)
{
string regKey = string.Format("HKEY_CLASSES_ROOT\\CLSID\\{{{0}}}", registerType.GUID);
ControlsCommands.Unregister(regKey);
}
#endregion
#endregion
private IHookHelper m_hookHelper;
public ConstructParallelLinesCommand()
{
//
// TODO: Define values for the public properties
//
base.m_category = ""; //localizable text
base.m_caption = ""; //localizable text
base.m_message = ""; //localizable text
base.m_toolTip = ""; //localizable text
base.m_name = ""; //unique id, non-localizable (e.g. "MyCategory_MyCommand")
try
{
//
// TODO: change bitmap name if necessary
//
string bitmapResourceName = GetType().Name + ".bmp";
base.m_bitmap = new Bitmap(GetType(), bitmapResourceName);
}
catch (Exception ex)
{
System.Diagnostics.Trace.WriteLine(ex.Message, "Invalid Bitmap");
}
}
#region Overridden Class Methods
/// <summary>
/// Occurs when this command is created
/// </summary>
/// <param name="hook">Instance of the application</param>
public override void OnCreate(object hook)
{
if (hook == null)
return;
if (m_hookHelper == null)
m_hookHelper = new HookHelperClass();
m_hookHelper.Hook = hook;
}
/// <summary>
/// Occurs when this command is clicked
/// </summary>
public override void OnClick()
{
if (m_hookHelper.FocusMap.SelectionCount != 1)
{
MessageBox.Show("请选择1条线要素进行分割", "提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return;
}
// 获取被选择的要素
IEnumFeature pEnumFeature = m_hookHelper.FocusMap.FeatureSelection as IEnumFeature;
pEnumFeature.Reset();
IFeature pFeature = pEnumFeature.Next();
if (pFeature.Shape is IPoint || pFeature.Shape is IPolygon)
{
MessageBox.Show("请选择1条线要素进行分割", "提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return;
}
// 获取要素类
IFeatureLayer pFeatureLayer = m_hookHelper.FocusMap.get_Layer(0) as IFeatureLayer;
IFeatureClass pFeatureClass = pFeatureLayer.FeatureClass;
// 获取原始线段
IPolyline pPolyline = pFeature.ShapeCopy as IPolyline;
IConstructCurve4 pConstructCurve = new Polyline() as IConstructCurve4;
// 构造左侧平行线
pConstructCurve.ConstructOffset(pPolyline, -5, 0, esriConstructOffsetEnum.esriConstructOffsetRounded, esriConstructOffsetSimplifyEnum.esriConstructOffsetFastSimplify, 0);
IPolyline pLeftPolyline = pConstructCurve as IPolyline;
// 创建左侧平行线要素
IFeature pLeftFeature = pFeatureClass.CreateFeature();
pLeftFeature.Shape = pLeftPolyline;
pLeftFeature.Store();
// 构造右侧平行线
pConstructCurve.ConstructOffset(pPolyline, 5, 0, esriConstructOffsetEnum.esriConstructOffsetRounded, esriConstructOffsetSimplifyEnum.esriConstructOffsetFastSimplify, 0);
IPolyline pRightPolyline = pConstructCurve as IPolyline;
// 创建右侧平行线要素
IFeature pRightFeature = pFeatureClass.CreateFeature();
pRightFeature.Shape = pRightPolyline;
pRightFeature.Store();
// 刷新地图
m_hookHelper.ActiveView.Refresh();
}
#endregion
}
}运行结果如下图所示：
如果要构造钝角平行线，则需要修改一下参数：
// 左侧平行线
pConstructCurve.ConstructOffset(pPolyline, -5, 0, esriConstructOffsetEnum.esriConstructOffsetBevelled, esriConstructOffsetSimplifyEnum.esriConstructOffsetFastSimplify, 1);
// 右侧平行线
pConstructCurve.ConstructOffset(pPolyline, 5, 0, esriConstructOffsetEnum.esriConstructOffsetBevelled, esriConstructOffsetSimplifyEnum.esriConstructOffsetFastSimplify, 1);运行结果如下图所示：
最后，IConstructCurve4接口也可以构造一般平行线，只需要修改一下参数即可：
// 左侧平行线
pConstructCurve.ConstructOffset(pPolyline, -5, 0, esriConstructOffsetEnum.esriConstructOffsetMitered, esriConstructOffsetSimplifyEnum.esriConstructOffsetFastSimplify, -5);
// 右侧平行线
pConstructCurve.ConstructOffset(pPolyline, 5, 0, esriConstructOffsetEnum.esriConstructOffsetMitered, esriConstructOffsetSimplifyEnum.esriConstructOffsetFastSimplify, 5);运行结果如下图所示：
