百度地圖自定義圖層----BMapTileCutter(Java切圖工具網絡版）

最近做百度地圖API相關應用，需要將自己的地圖疊加到百度地圖上面，查看了百度官方的API說明Javascript部分，不沒有很好的解釋如何覆蓋接口。

在網上找了相關的文章看了下，（http://www.cnblogs.com/jz1108/archive/2011/10/08/2202239.html）這篇文章實現了這個切圖的功能，但是最新的百度最高縮放等級達到19級，項目需要，無奈只能自己寫個切圖工具。

參考了同樣作者的另一篇文章（http://www.cnblogs.com/jz1108/archive/2011/07/02/2095376.html），專門講百度坐標系統的。

程序是用Java Web實現, struts2文件標簽和簡單Js調用。

實現核心代碼

1.TileUtils.java

package com.xiefei.core;

import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.Transparency;
import java.awt.image.BufferedImage;
import java.awt.image.CropImageFilter;
import java.awt.image.FilteredImageSource;
import java.awt.image.ImageFilter;
import java.io.File;

import javax.imageio.ImageIO;

public class TileUtils {
    private int minLevel;
    private int maxLevel;
    private int picLevel;
    private double mercatorX;
    private double mercatorY;
    private String pic;
    private String savePath;

    public TileUtils(String pic, double mercatorX, double mercatorY,
            String savePath) {
        this.pic = pic;
        this.mercatorX = mercatorX;
        this.mercatorY = mercatorY;
        this.savePath = savePath;
    }

    public TileUtils(String pic, int minLevel, int maxLevel, int picLevel, double mercatorX,
            double mercatorY, String savePath) {
        this.pic = pic;
        this.minLevel = minLevel;
        this.maxLevel = maxLevel;
        this.mercatorX = mercatorX;
        this.mercatorY = mercatorY;
        this.savePath = savePath;
        this.picLevel = picLevel;
    }

    public void cutterAll() throws Exception {
        for (int i = minLevel; i <= maxLevel; i++) {
            cutterOne(i);
        }
    }

    public void cutterOne(int level) throws Exception {
        //圖片中心的像素坐標(pixelX,pixelY)，圖片中心的平面坐標即魔卡托坐標(mercatorX, mercatorY)
        //像素坐標  = 平面坐標 * Math.pow(2, level - 18)
        double pixelX = mercatorX * Math.pow(2, level - 18);
        double pixelY = mercatorY * Math.pow(2, level - 18);
        System.out.println("pixelX : " + pixelX);
        System.out.println("pixelY : " + pixelY);
        BufferedImage bi = ImageIO.read(new File(pic));
        int width = bi.getWidth();
        int height = bi.getHeight();
        //圖片遵循原則：當前圖片所屬級別picLevel不縮放即像素級別相等。
        //按照公式縮放：當前級別圖片長度 = 原圖片長度 * Math.pow(2, level - picLevel)
        //minX: 圖片左下角X坐標
        //minY: 圖片左下角Y坐標
        //maxX: 圖片右上角X坐標
        //maxY: 圖片右上角Y坐標
        double minX = pixelX - width * Math.pow(2, level - picLevel) / 2;
        double minY = pixelY - height * Math.pow(2, level - picLevel) / 2;
        double maxX = pixelX + width  * Math.pow(2, level - picLevel) / 2;
        double maxY = pixelY + height * Math.pow(2, level - picLevel)  / 2;
        System.out.println("(minX,minY) = (" + minX + ", " + minY + ")" );
        System.out.println("(maxX,maxY) = (" + maxX + ", " + maxY + ")" );
        int neatMinX = (int) minX / 256;
        int remMinX = (int) minX % 256;
        int neatMinY = (int) minY / 256;
        int remMinY = (int) minY % 256 ;
        
        int neatMaxX = (int) maxX / 256;
        int remMaxX = 256 - (int) maxX % 256;
        int neatMaxY = (int) maxY / 256;
        int remMaxY = 256 - (int) maxY % 256;
        //(neatMinX,neatMinY)為圖片左下角最近的整數圖塊坐標,neatMinX到neatMaxX即當前級別下切割圖塊的圖塊坐標x
        //(neatMaxX,neatMaxY)為圖片右上角最近的整數圖塊坐標,neatMinY到neatMaxY即當前級別下切割圖塊的圖塊坐標y
        System.out.println("neatMinX: " + neatMinX);
        System.out.println("neatMaxX: " + neatMaxX);
        System.out.println("neatMinY: " + neatMinY);
        System.out.println("neatMaxY: " + neatMaxY);
        System.out.println("remMinX width remMaxX : " + remMinX + " "+ width + " "+ remMaxX );
        System.out.println("remMinY height remMaxY : " + remMinY + " " +  height +" " + remMaxY );
        
        // 擴充原圖片為width * height --- > (remMinX + width + remMaxX ) * (remMinY +
        // height +remMaxY)
        int extendWidth = (neatMaxX - neatMinX + 1 ) * 256;
        int extendHeight = (neatMaxY - neatMinY + 1 ) * 256;
        System.out.println("extendWidth: " + extendWidth);
        System.out.println("extendHeight: " + extendHeight);
        
        BufferedImage outputImage = null;
        Graphics2D g = bi.createGraphics();
        BufferedImage extend = g.getDeviceConfiguration().createCompatibleImage(extendWidth, extendHeight, Transparency.TRANSLUCENT);
        g.dispose();
        g = extend.createGraphics();
        g.drawImage(extend, 0, 0, extendWidth, extendHeight, null);
        g.drawImage(bi, remMinX, remMaxY, (int) (width * Math.pow(2, level - picLevel)), (int)(height * Math.pow(2, level - picLevel)), null);
        outputImage = extend;
        
        //切割圖片，共( neatMaxX - neatMinX + 1) * (neatMaxY - neatMinY + 1)份 256*256圖片
        String dirName = savePath.substring(0, savePath.lastIndexOf("\\")) + "\\tiles\\" + level;
        System.out.println("dirName : " + dirName);
        
        
        File dir = new File(dirName);
        Image image = extend.getScaledInstance(extendWidth, extendHeight, Image.SCALE_DEFAULT);
        if(dir.exists()) {
            System.out.println("創建目錄失敗！, 目錄已存在！");
        } else {
            if(dir.mkdirs()) {
                ImageIO.write(extend, "png", new File(dirName + savePath.substring(savePath.lastIndexOf("\\"))));
                System.out.println("savePath : " + dirName + savePath.substring(savePath.lastIndexOf("\\")));
                System.out.println("Extend success!");
                int w = neatMaxX - neatMinX + 1;
                int h = neatMaxY - neatMinY + 1;
                for(int i = 0; i < w; i++) {
                    for(int j = 1; j <= h; j++) {
                        ImageFilter cropFilter = new CropImageFilter(256 * i, 256* (h - j), 256, 256);
                        Image img = Toolkit.getDefaultToolkit().createImage(new FilteredImageSource(image.getSource(),cropFilter));
                        BufferedImage tag = new BufferedImage(256, 256 , BufferedImage.TYPE_INT_BGR);
                        Graphics2D gs = tag.createGraphics();
                        tag = gs.getDeviceConfiguration().createCompatibleImage(256, 256, Transparency.TRANSLUCENT);
                        gs.dispose();
                        gs = tag.createGraphics();
                        gs.drawImage(img, 0, 0, null);
                        g.dispose();
                        String cropPicName = dirName + "\\tile" + (neatMinX + i) + "_" + (neatMinY + j - 1) + ".png"; 
                        ImageIO.write(tag, "png", new File(cropPicName));
                    }
                }
                System.out.println("切割圖片成功！");
            } else {
                System.out.println("創建目錄失敗！");
            }
        }
    }

}

代碼的核心思想是將原圖片外圍拓展成256整數倍長度（最小包圍），即源代碼中的extendWidth * extendHeight圖片長度，然后再橫豎切割成多個256*256的瓦片圖塊。

2.index.jsp(切割圖片主頁)

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<%@ taglib prefix="s" uri="/struts-tags" %> 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>百度地圖切圖工具</title>
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <script type="text/javascript" src="http://api.map.baidu.com/api?v=1.3"></script>
    <script type="text/javascript">
        function getData(){
            //var map = new BMap.Map("baiduMap");
            var centerX = document.form1.centerX.value;
            var centerY = document.form1.centerY.value;
            //alert(centerX);
            //alert(centerY);
            var center = new BMap.Point(centerX, centerY);
            /*獲取中心點的魔卡托坐標*/
            var projection = new BMap.MercatorProjection();
            var mercatorPoint = projection.lngLatToPoint(center);
            document.form1.mercatorX.value = mercatorPoint.x;
            document.form1.mercatorY.value = mercatorPoint.y;
            document.form1.submit();
            //alert(mercatorPoint.x+","+mercatorPoint.y);
        }
        function chooseDir(){
            var savePath;
            var objSrc = new ActiveXObject("Shell.Application").BrowseForFolder(0,"請選擇輸出文件夾路徑",0,"");
            if(objSrc!=null){
                savePath = objSrc.Items().Item().Path;
                document.form1.savePath.value = savePath;
                //alert(savePath);
            }
        }
    </script>
  </head>
  
  <body>
      <!--  
      <div id="baiduMap" style="width:600px,height:800px"></div>
    -->
    
    <form action="cutter" method="post" name="form1" id="form1" enctype="multipart/form-data">
        請選擇需要切圖的圖片來源<s:file name="pic" label="Picture"/><br/>
        圖片中心的經度坐標<input type="text" name="centerX" id="centerX" value="120.27628"/><br>
        圖片中心的緯度坐標<input type="text" name="centerY"/ id="centerY" value="30.27554"><br>
        <input type="text" name="mercatorX" id="mercatorX" value="" style="display:none"/>
        <input type="text" name="mercatorY"/ id="mercatorY" value="" style="display:none">
        最小級別
        <select name="minLevel">
            <option selected>16</option>
            <option>17</option>
            <option>18</option>
            <option>19</option>
        </select><br>
        最大級別
        <select name="maxLevel">
            <option>16</option>
            <option>17</option>
            <option>18</option>
            <option selected>19</option>
        </select><br>
        圖片所在級別
        <select name="picLevel">
            <option>16</option>
            <option>17</option>
            <option>18</option>
            <option selected>19</option>
        </select><br>
        請選擇輸出目錄
        <input type="text" name="savePath"/>
        <input type="button" name="selectDir" onClick="chooseDir()" value="瀏覽"/><br/>
        <input type="button" value="提交" onClick="getData()"/>
    </form>
  </body>
</html>

3.實現截圖

4.選擇輸出目錄，是查看本地目錄，用javascript調用ActiveX實現，只能在IE下運行，且需要把IE-->Internet選項-->安全中運行ActiveX控件運行才可以查看本地文件夾目錄。

源碼下載鏈接：http://files.cnblogs.com/thly1990/BaiduMapTileCutter.rar