《校园地图》的剖析

                                               《校园地图》的剖析
1.该项目小地图的功能
          该小地图的主要功能是从下拉列表中选择出发地和目的地，然后地图上可以显示路线。主要的显示方法是通过贴图来显示
2.实现该小地图软件的代码
          typedef struct road_dot{
        int i;   // 该节点的id
        int vistable; //该节点是否可访问
        cv::Point self; //该节点在地图上的位置
        std::vector<size_t> others_id; // 保存与该节点相连的节点的id
    }Road_node;
      该段代码用来记录所有的路网节点

void MainWindow::mousePressEvent(QMouseEvent *event)
{

if(0<x&&x<1480&&0<y&&y<800) // if on the pic
{

         Road_node new_node;
         new_node.self = Point(x,y);
         new_node.i = 200; // not a pos

         cv::circle(img,Point(x,y),6,cv::Scalar(255,0,255),-1);
         qimg = Mat2QImage(img);
         ui->pic->setPixmap(QPixmap::fromImage(qimg));

if(!first_node)
{start_node = new_node;start_set_flag = 1; first_node =2;pre_nodes_id = 0;}

         for(int i = 0;i<point.size();i++)
         {
             if((abs(x-point[i].x) <10 )&& (abs(y-point[i].y)<10)) // if at pos
               {
                 new_node.i = i;
                 qDebug()<<"this is pos "<<i;
                 break;
               }
         }

road.push_back(new_node);// record this new node ;

       for(int i = 0;i<road.size()-1;i++)
       {
           if((abs(x-road[i].self.x) <10 )&& (abs(y-road[i].self.y)<10)) // if at node
           { // yes

road.pop_back(); // drop this node

if(event->button() == Qt::LeftButton) // if leftButton
{

start_node = road[i]; // set start node
start_set_flag = 1;

pre_nodes_id = i;

                }
               else if(event->button() == Qt::RightButton)
               {

start_node = road[pre_nodes_id]; // this is start
start_set_flag = 1;

end_node = road[i];
end_set_flag = 1;

road[i].others_id.push_back(pre_nodes_id);
road[pre_nodes_id].others_id.push_back(i);

pre_nodes_id = i;
}

qDebug()<<"this node's others.size = "<<road[i].others_id.size();

               break;
            }
           else if(i == road.size() - 2)
           { // no

               if(!start_set_flag) // if have no start_node
               {
                   start_node = road[pre_nodes_id];
                   start_set_flag = 1;
               }
               if(!end_set_flag)
               {
                   end_node = road[road.size()-1];
                   end_set_flag = 1;
               }

               road[pre_nodes_id].others_id.push_back(road.size()-1); // push now node
               road[road.size()-1].others_id.push_back(pre_nodes_id);
               qDebug()<<"this node's others.size = "<<road[road.size()-1].others_id.size();
               pre_nodes_id = road.size()-1;
               break;

}
}

if(end_set_flag && start_set_flag)
{

           end_set_flag = 0;
           start_set_flag = 0;
           cv::line(img,start_node.self,end_node.self,cv::Scalar(0,0,0),3);
           qimg = Mat2QImage(img);
           ui->pic->setPixmap(QPixmap::fromImage(qimg)); // flush the pic

}

qDebug()<<"road.size"<<road.size();
}

} // :)
该段代码用来标记路网并自动储存，主要通过在地图上点击来标记，右键表示一个连续段的结束，每个节点会记录与之相连的其它节点的id号。

int start_id = ui->comboBox->currentIndex(); // get start and end node's id /
int end_id = ui->comboBox_2->currentIndex();

    for(int i = 0;i<road.size();i++)
    {
        road[i].vistable = 0; // set all nodes are visitable;
    }

// Road_node start_node_temp,end_node_temp; // temp node

int road_start_i,road_end_i;
int road_start_i_temp,road_end_i_temp;

    for(int i = 0;i<road.size();i++) // search which node is on the start/end point;
    {
        if(road[i].i == start_id)
        {
            qDebug()<<"start"<<i;
            start_node = road[i];
            road_start_i = i; // get the id of start roadnode;
            qDebug()<<"i = "<<start_node.i;
        }
        else if(road[i].i == end_id)
        {
            qDebug()<<"end"<<i;
            end_node = road[i];
            road_end_i = i; // get the id of end roadnode;
            qDebug()<<"i = "<<end_node.i;
        }

}

road_start_i_temp = road_start_i;
road_end_i_temp = road_start_i;

// start_node_temp = start_node;
//end_node_temp = start_node_temp;

std::vector<int> road_temp;

    int pre_distance = 9000000;
    while(road[road_end_i_temp].i!= end_id)
    //for(int xx = 0;xx<10;xx++)
    {

        int useable_flag = 0;
        for(int i = 0;i<road[road_end_i_temp].others_id.size();i++)   // if the current endpoint to have next point
        {
            if(road[road[road_end_i_temp].others_id[i]].vistable == 0)
                useable_flag = 1; // have useable point

        }
        if(useable_flag)   // have useable next node
        {
           // start_node_temp = end_node_temp;
            road_start_i_temp = road_end_i_temp;
            road[road_start_i_temp].vistable = 1; // have visited it;

//start_node_temp.vistable = 1; // have visited it;

road_temp.push_back(road_start_i_temp); // record the walked node

            int temp_min_id;
            for(int i = 0;i<road[road_start_i_temp].others_id.size();i++) // find the min dis node   // int these next points
            {
                if(road[road[road_start_i_temp].others_id[i]].vistable == 0 ) // if this node have not visited;
                {

int tempx,tempy;

             tempx = (road[road[road_start_i_temp].others_id[i]].self.x- end_node.self.x)*(road[road[road_start_i_temp].others_id[i]].self.x - end_node.self.x);
             tempy = (road[road[road_start_i_temp].others_id[i]].self.y- end_node.self.y)*(road[road[road_start_i_temp].others_id[i]].self.y - end_node.self.y);
             if(pre_distance<(tempx+tempy))
                {

                 qDebug()<<"pre_distance = "<<pre_distance;
                 qDebug()<<"now distance = "<<tempx+tempy;
                  // end_node_temp = road[road[road_start_i_temp].others_id[i-1]];
                    road_end_i_temp = road[road_start_i_temp].others_id[temp_min_id];

                }
             else {
                    //end_node_temp = road[start_node_temp.others_id[i]];
                    road_end_i_temp = road[road_start_i_temp].others_id[i];
                    temp_min_id = i;

                    pre_distance = tempx+tempy;
                   }
                }

}

pre_distance = 9000000;

        }
   else // have no useable next node
        {
            road[road_end_i_temp].vistable = 1;
          loop:    for(int i = 0;i<road[road_start_i_temp].others_id.size();i++) // if have other useable nodes
            {
                if(road[road[road_start_i_temp].others_id[i]].vistable == 0)
                    useable_flag = 1; // have useable point

}

            if(useable_flag)
            {
                int temp_min_id;
                for(int i = 0;i<road[road_start_i_temp].others_id.size();i++) // fine the min dis node
                {
                    if(road[road[road_start_i_temp].others_id[i]].vistable == 0 ) // if this node have not visited;
                    {

int tempx,tempy;

                 tempx = (road[road[road_start_i_temp].others_id[i]].self.x- end_node.self.x)*(road[road[road_start_i_temp].others_id[i]].self.x - end_node.self.x);
                 tempy = (road[road[road_start_i_temp].others_id[i]].self.y- end_node.self.y)*(road[road[road_start_i_temp].others_id[i]].self.y - end_node.self.y);
                 if(pre_distance<(tempx+tempy))
                    {

//end_node_temp = road[road[road_start_i_temp].others_id[i-1]];
road_end_i_temp = road[road_start_i_temp].others_id[temp_min_id];

                    }
                 else {
                        //end_node_temp = road[start_node_temp.others_id[i]];
                        road_end_i_temp = road[road_start_i_temp].others_id[i];

                        temp_min_id = i;
                        pre_distance = tempx+tempy;
                       }
                    }

}
pre_distance = 9000000;

            }
            else
            {

                road_temp.pop_back(); // drop this start_temp node
                road_start_i_temp = road_temp[road_temp.size()-1];
                goto loop;
            }
        }
road_temp.push_back(road_end_i_temp);
    for(int i = 0;i<road_temp.size()-1;i++)
    {

        cv::line(img,road[road_temp[i]].self,road[road_temp[i+1]].self,cv::Scalar(0,0,0),3);
        qimg = Mat2QImage(img);
        ui->pic->setPixmap(QPixmap::fromImage(qimg)); // flush the pic
    }
    qDebug()<<road_temp.size();

}

该代码为寻路算法，通过设立两个哨兵，一个在当前出发节点(哨兵A)，另一个在下一个目标出发点(哨兵 B)，下一个目标出发点由所有子节点中距离目的地最近的节点确定。当B所在的节点具有可走子节点（不是死胡同）并且还未达到目的地时，A走到B（所有走过的路压栈，方便后退），B继续探路，若走到死胡同就后退，走其他的最近子节点。

3.优缺点
      优点：
           （1）有利于新生和学生父母便于在学校行走，不居于在学校乱走
           （2）能显示学校具体地点的具体信息，有利于了解学校概况
      缺点：
            （1）涉众不多，一旦新生适应了就不会用了，则客户群不稳定
            （2）功能较少，没新鲜点和创新点
4.增加点
             可以和学校的社团，美食街，校团委合作，在校园地图的软件上用图片展示学校的社团的活动，美食，团委消息，赛事等等

5.代码来源
作者：whlook
来源：CSDN
原文：https://blog.csdn.net/whlook/article/details/77076395
版权声明：本文为博主原创文章，转载请附上博文链接！

《校园地图》的剖析

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