searchdemo 三.拖拽起始点

　　完成目标：让其实顶点可以随着鼠标拖动而改变位置

　　途中思路不清，忘记乘以BLOCKSIZE却无法察觉。

　　鼠标键按住不放，之后拖动，如果超出主界面会导致程序崩溃。检查之后发现，没有进行坐标范围限定，加入判定函数即ok。

main:

C++语言: Codee#26079

01 #include <QtGui>
02 #include <QtCore>
03 #include "pathfinding.h"
04
05 int main(int argc, char *argv[])
06 {
07     QApplication a(argc, argv);
08     Widget* window=new Widget;
09
10     QRect frect = window->frameGeometry();
11     frect.moveCenter(QDesktopWidget().availableGeometry().center());
12     window->move(frect.topLeft());
13     window->show();
14
15     return a.exec();
16 }

pathfinding.h

C++语言: Codee#26080

01 #ifndef PATHFINDING_H
02 #define PATHFINDING_H
03
04 #include <QtGui>
05 #include <QtCore>
06
07 class Widget : public QWidget
08 {
09     Q_OBJECT
10
11 public:
12     Widget(QWidget* parent = 0);
13     void paintEvent(QPaintEvent* event);
14     void mousePressEvent(QMouseEvent* event);
15     void mouseMoveEvent(QMouseEvent* event);
16     void setWindowPixel(const QPoint& pos, bool opaque);
17
18 private:
19     enum {LENGTH = 910};
20     enum {WIDTH = 700};
21     enum {BLOCKSIZE = 35};
22     bool blocks[LENGTH/BLOCKSIZE][WIDTH/BLOCKSIZE];
23     bool onDrag;
24     QPoint cursorpos;
25     QPoint startBlock;
26     QPoint endBlock;
27     bool checkPosition(const QPoint& pos);
28 };
29
30 #endif // PATHFINDING_H

 

pathfinding.cpp

C++语言: Codee#26081

001 #include "pathfinding.h"
002
003 Widget::Widget(QWidget* parent)
004     : QWidget(parent)
005 {
006     for (int i = 0; i < LENGTH / BLOCKSIZE; ++i)
007         for (int j = 0; j < WIDTH / BLOCKSIZE; ++j)
008             blocks[i][j] = true;
009     startBlock = QPoint(0, 0);
010     blocks[0][0] = false;
011
012     endBlock = QPoint(10, 10);
013     blocks[10][10] = false;
014     onDrag = false;
015
016     setAttribute(Qt::WA_StaticContents);
017     setSizePolicy(QSizePolicy::Minimum, QSizePolicy::Minimum);
018     this->setMouseTracking(true);
019     this->setFixedSize(LENGTH, WIDTH);
020 }
021
022 void Widget::paintEvent(QPaintEvent* event)
023 {
024     QPainter painter(this);
025     painter.setOpacity(0.5);
026     QColor color = Qt::red;
027
028     /* draw the start block */
029     /*
030     painter.fillRect(QRect(BLOCKSIZE*startBlock.x(), BLOCKSIZE*startBlock.y(),
031                            BLOCKSIZE, BLOCKSIZE), color);
032                            */
033
034     //qDebug("The startblock pos:%d,%d", startBlock.x(), startBlock.y());
035     /* draw the simple blocks */
036     for (int i = 0; i < LENGTH / BLOCKSIZE; ++i)
037         for (int j = 0; j < WIDTH / BLOCKSIZE; ++j)
038         {
039             QPoint cur(i, j);
040             if (cur == startBlock)
041                 color = Qt::red;
042             else if (cur == endBlock)
043                 color = Qt::green;
044
045             else if (!blocks[i][j])
046                 color = Qt::gray;
047             else
048                 color = Qt::white;
049             painter.fillRect(QRect(BLOCKSIZE * i, BLOCKSIZE * j,
050                                    BLOCKSIZE, BLOCKSIZE), color);
051         }
052
053     painter.setPen(QPen(Qt::gray));
054     /* draw the grids */
055     for (int i = 0; i < LENGTH; i += BLOCKSIZE)
056         painter.drawLine(i, 0,
057                          i, WIDTH);
058     for (int j = 0; j <= WIDTH; j += BLOCKSIZE)
059         painter.drawLine(0,  j,
060                          LENGTH, j);
061
062     painter.setFont(QFont("Arial", 50));
063     painter.drawText(rect(), Qt::AlignCenter, "path-finding demo");
064 }
065
066 /* 1. check the cursor's position,if on the start blocks,go to 2,
067 *    else go to 3;
068 * 2. drag the start block,set onDrag=true
069 * 3. just draw the current block
070 */
071 void Widget::mousePressEvent(QMouseEvent* event)
072 {
073     cursorpos = QPoint(event->pos().x() / BLOCKSIZE,
074                        event->pos().y() / BLOCKSIZE);
075     if (cursorpos == startBlock)
076         onDrag = true;
077     else
078     {
079         setWindowPixel(event->pos(), false);
080         onDrag = false;
081     }
082 }
083
084 void Widget::mouseMoveEvent(QMouseEvent* event)
085 {
086     /*
087      * check the cursor's position
088      * if out of the main window
089      * the application will faile
090      */
091     if (checkPosition(event->pos()))
092     {
093         QPoint tmppos = QPoint(event->pos().x() / BLOCKSIZE,
094                                event->pos().y() / BLOCKSIZE);
095         if (cursorpos != tmppos &&
096             (event->buttons() & Qt::LeftButton) ||
097             (event->buttons() & Qt::RightButton))
098             //       event->buttons() & Qt::RightButton)
099         {
100             //qDebug("Time elapsed: %d ms", time.msecsTo(curTime));
101             //setWindowPixel(event->pos(), true);
102             /* is on drag ,use this to change the start
103              * block's position,clear the old pos
104              * then take the new pos
105              */
106             if (onDrag)
107             {
108                 //qDebug("tmppos:%d,%d", tmppos.x(), tmppos.y());
109                 blocks[startBlock.x()][startBlock.y()] = true;
110                 startBlock = tmppos;
111                 blocks[tmppos.x()][tmppos.y()] = false;
112             }
113             setWindowPixel(event->pos(), onDrag);
114         }
115     }
116     //cursorpos=tmppos;
117 }
118
119 void Widget::setWindowPixel(const QPoint& pos, bool opaque)
120 {
121     int x = pos.x() / BLOCKSIZE;
122     int y = pos.y() / BLOCKSIZE;
123     cursorpos = QPoint(x, y);
124
125     if (!opaque)
126         blocks[x][y] = !blocks[x][y];
127     update();
128 }
129
130 bool Widget::checkPosition(const QPoint& pos)
131 {
132     QRect rect(0, 0, LENGTH, WIDTH);
133     return rect.contains(pos);
134 }