GMap.Net開發之自定義Marker

時間 2019-11-19

標籤 gmap.net gmap 開發自定義 marker 简体版

原文原文鏈接

上一篇文章介紹瞭如何在WinForm和WPF中使用GMap控件，這篇介紹下GMap中Marker的使用。html

自定義Marker，能夠理解爲在地圖上自定義圖標（Custom Marker），先看看GMap的地圖和圖標的顯示方式：緩存

Map控件上能夠添加Overlay（圖層），能夠添加多個圖層，先添加的圖層在下面顯示。ide

圖層上能夠添加GMapMarker，固然也能夠添加GMapPolygon和GMapRoute，後續介紹。this

在地圖的使用中常要求的功能就是添加自定義圖標，能夠點擊圖標、刪除圖標、拖動圖標、高亮圖標等。google

下面介紹這些功能的實現（主要是基於WinForm的，WPF的能夠參考官方Demo實現）：spa

一、自定義圖標，使用官方的Marker：code

Bitmap bitmap = Bitmap.FromFile("F:\\Projects\\GMapDemo\\GMapDemo\\Image\\A.png") as Bitmap;
GMapMarker marker = new GMarkerGoogle(point, bitmap);

直接使用GMap.NET.WindowsForms.Markers中的GMarkerGoogle，傳入一個Bitmap，就能夠使用自定義的圖片來作圖標。orm

二、繼承GMapMarker，自定義Marker：htm

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using GMap.NET;
using GMap.NET.WindowsForms;
using System.Drawing;

namespace GMapWinFormDemo
{
    class GMapMarkerImage : GMapMarker
    {
        private Image image;
        public Image Image
        {
            get
            {
                return image;
            }
            set
            {
                image = value;
                if (image != null)
                {
                    this.Size = new Size(image.Width, image.Height);
                }
            }
        }

        public Pen Pen
        {
            get;
            set;
        }

        public Pen OutPen
        {
            get;
            set;
        }

        public GMapMarkerImage(GMap.NET.PointLatLng p, Image image)
            : base(p)
        {
            Size = new System.Drawing.Size(image.Width, image.Height);
            Offset = new System.Drawing.Point(-Size.Width / 2, -Size.Height / 2);
            this.image = image;
            Pen = null;
            OutPen = null;
        }

        public override void OnRender(Graphics g)
        {
            if (image == null)
                return;

            Rectangle rect = new Rectangle(LocalPosition.X, LocalPosition.Y, Size.Width, Size.Height);
            g.DrawImage(image, rect);

            if (Pen != null)
            {
                g.DrawRectangle(Pen, rect);
            }

            if (OutPen != null)
            {
                g.DrawEllipse(OutPen, rect);
            }
        }

        public override void Dispose()
        {
            if (Pen != null)
            {
                Pen.Dispose();
                Pen = null;
            }

            if (OutPen != null)
            {
                OutPen.Dispose();
                OutPen = null;
            }

            base.Dispose();
        }
    }
}

介紹下GMapMarkerImage三個屬性的做用：blog

Image：保存圖標的圖片。

Pen：在圖片外圍畫DrawRectangle的Pen，當其不爲null的時候，會在圖片的外圍畫一個矩形，實現高亮（highlight）的效果。

OutPen：在圖片外圍畫DrawEllipse的Pen，當其不爲null的時候，會在圖片外圍畫一個一個橢圓，設置這個值能夠實現閃動。

三、移動圖標（Move Marker）的實現：

在MapControl中添加以下事件的響應：

mapControl.MouseDown += new MouseEventHandler(mapControl_MouseDown);
mapControl.MouseUp += new MouseEventHandler(mapControl_MouseUp);
mapControl.MouseMove += new MouseEventHandler(mapControl_MouseMove);

mapControl.OnMarkerClick += new MarkerClick(mapControl_OnMarkerClick);
mapControl.OnMarkerEnter += new MarkerEnter(mapControl_OnMarkerEnter);
mapControl.OnMarkerLeave += new MarkerLeave(mapControl_OnMarkerLeave);

MouseDown和MouseUp中判斷左鍵是否按下（用左鍵來移動圖標）。

OnMarkerEnter中設置選中的Marker，同時設置Pen的值，實現高亮。

OnMarkerLeave中取消選中的Marker，取消Pen的值，取消高亮。

MouseMove中更新選中選中Marker的Position就能夠了。

四、圖標閃動的實現：

須要一個定時器：使用的是Form下的Timer，定時器響應的事件：

        void blinkTimer_Tick(object sender, EventArgs e)
        {
            foreach (GMapMarker m in objects.Markers)
            {
                if (m is GMapMarkerImage)
                {
                    GMapMarkerImage marker = m as GMapMarkerImage;
                    if (marker.OutPen == null)
                        marker.OutPen = new Pen(Brushes.Red, 2);
                    else
                    {
                        marker.OutPen.Dispose();
                        marker.OutPen = null;
                    }
                }
            }
            mapControl.Refresh();
        }

更新全部Marker的OutPen的值（固然你也能夠只更新某個Marker），經過在圖標上畫圈圈來實現閃動，固然你也能夠經過設置Marker的IsVisible屬性來實現本身想要的效果。。。

效果圖以下：

所有代碼以下：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using GMap.NET;
using GMap.NET.WindowsForms;
using GMap.NET.MapProviders;
using GMap.NET.WindowsForms.Markers;

namespace GMapWinFormDemo
{
    public partial class MainForm : Form
    {
        private GMapOverlay objects = new GMapOverlay("objects"); //放置marker的圖層
        private GMapMarkerImage currentMarker;
        private bool isLeftButtonDown = false;

        private Timer blinkTimer = new Timer();

        public MainForm()
        {
            InitializeComponent();

            try
            {
                System.Net.IPHostEntry e = System.Net.Dns.GetHostEntry("ditu.google.cn");
            }
            catch
            {
                mapControl.Manager.Mode = AccessMode.CacheOnly;
                MessageBox.Show("No internet connection avaible, going to CacheOnly mode.", "GMap.NET Demo", MessageBoxButtons.OK, MessageBoxIcon.Warning);
            }

            mapControl.CacheLocation = Environment.CurrentDirectory + "\\GMapCache\\"; //緩存位置
            mapControl.MapProvider = GMapProviders.GoogleChinaMap; //google china 地圖
            mapControl.MinZoom = 2;  //最小比例
            mapControl.MaxZoom = 17; //最大比例
            mapControl.Zoom = 5;     //當前比例
            mapControl.ShowCenter = false; //不顯示中心十字點
            mapControl.DragButton = System.Windows.Forms.MouseButtons.Left; //左鍵拖拽地圖
            mapControl.Position = new PointLatLng(32.064,118.704); //地圖中心位置：南京

            mapControl.OnMapZoomChanged += new MapZoomChanged(mapControl_OnMapZoomChanged);
            mapControl.MouseClick += new MouseEventHandler(mapControl_MouseClick);
            mapControl.MouseDown += new MouseEventHandler(mapControl_MouseDown);
            mapControl.MouseUp += new MouseEventHandler(mapControl_MouseUp);
            mapControl.MouseMove += new MouseEventHandler(mapControl_MouseMove);

            mapControl.OnMarkerClick += new MarkerClick(mapControl_OnMarkerClick);
            mapControl.OnMarkerEnter += new MarkerEnter(mapControl_OnMarkerEnter);
            mapControl.OnMarkerLeave += new MarkerLeave(mapControl_OnMarkerLeave);

            mapControl.Overlays.Add(objects);
        }

        void mapControl_MouseMove(object sender, MouseEventArgs e)
        {
            if (e.Button == System.Windows.Forms.MouseButtons.Left && isLeftButtonDown)
            {
                if (currentMarker != null)
                {
                    PointLatLng point = mapControl.FromLocalToLatLng(e.X, e.Y);
                    currentMarker.Position = point;
                    currentMarker.ToolTipText = string.Format("{0},{1}", point.Lat, point.Lng);
                }
            }
        }

        void mapControl_MouseUp(object sender, MouseEventArgs e)
        {
            if (e.Button == System.Windows.Forms.MouseButtons.Left)
            {
                isLeftButtonDown = false;
            }
        }

        void mapControl_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == System.Windows.Forms.MouseButtons.Left)
            {
                isLeftButtonDown = true;
            }
        }

        void mapControl_OnMarkerLeave(GMapMarker item)
        {
            if (item is GMapMarkerImage)
            {
                currentMarker = null;
                GMapMarkerImage m = item as GMapMarkerImage;
                m.Pen.Dispose();
                m.Pen = null;
            }
        }

        void mapControl_OnMarkerEnter(GMapMarker item)
        {
            if (item is GMapMarkerImage)
            {
                currentMarker = item as GMapMarkerImage;
                currentMarker.Pen = new Pen(Brushes.Red, 2);
            }
        }

        void mapControl_OnMarkerClick(GMapMarker item, MouseEventArgs e)
        {
        }

        void mapControl_MouseClick(object sender, MouseEventArgs e)
        {
            if(e.Button == System.Windows.Forms.MouseButtons.Right)
            {
                //objects.Markers.Clear();
                PointLatLng point = mapControl.FromLocalToLatLng(e.X,e.Y);
                //GMapMarker marker = new GMarkerGoogle(point, GMarkerGoogleType.green);
                Bitmap bitmap = Bitmap.FromFile("F:\\Projects\\GMapDemo\\GMapDemo\\Image\\A.png") as Bitmap;
                //GMapMarker marker = new GMarkerGoogle(point, bitmap);
                GMapMarker marker = new GMapMarkerImage(point, bitmap);
                marker.ToolTipMode = MarkerTooltipMode.OnMouseOver;
                marker.ToolTipText = string.Format("{0},{1}", point.Lat, point.Lng);
                objects.Markers.Add(marker);
            }
        }

        void mapControl_OnMapZoomChanged()
        {
        }

        private void buttonBeginBlink_Click(object sender, EventArgs e)
        {
            blinkTimer.Interval = 1000;
            blinkTimer.Tick += new EventHandler(blinkTimer_Tick);
            blinkTimer.Start();
        }

        void blinkTimer_Tick(object sender, EventArgs e)
        {
            foreach (GMapMarker m in objects.Markers)
            {
                if (m is GMapMarkerImage)
                {
                    GMapMarkerImage marker = m as GMapMarkerImage;
                    if (marker.OutPen == null)
                        marker.OutPen = new Pen(Brushes.Red, 2);
                    else
                    {
                        marker.OutPen.Dispose();
                        marker.OutPen = null;
                    }
                }
            }
            mapControl.Refresh();
        }

        private void buttonStopBlink_Click(object sender, EventArgs e)
        {
            blinkTimer.Stop();
            foreach (GMapMarker m in objects.Markers)
            {
                if (m is GMapMarkerImage)
                {
                    GMapMarkerImage marker = m as GMapMarkerImage;
                    marker.OutPen.Dispose();
                    marker.OutPen = null;
                }
            }
            mapControl.Refresh();
        }
    }
}

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