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# tetrixboard.cpp Example File

widgets/tetrix/tetrixboard.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2015 The Qt Company Ltd.
     ** Contact: http://www.qt.io/licensing/
     **
     ** This file is part of the examples of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:BSD$
     ** You may use this file under the terms of the BSD license as follows:
     **
     ** "Redistribution and use in source and binary forms, with or without
     ** modification, are permitted provided that the following conditions are
     ** met:
     **   * Redistributions of source code must retain the above copyright
     **     notice, this list of conditions and the following disclaimer.
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     **     notice, this list of conditions and the following disclaimer in
     **     the documentation and/or other materials provided with the
     **     distribution.
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     **     contributors may be used to endorse or promote products derived
     **     from this software without specific prior written permission.
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     ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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     #include <QtGui>

     #include "tetrixboard.h"

     TetrixBoard::TetrixBoard(QWidget *parent)
         : QFrame(parent)
     {
         setFrameStyle(QFrame::Panel | QFrame::Sunken);
         setFocusPolicy(Qt::StrongFocus);
         isStarted = false;
         isPaused = false;
         clearBoard();

         nextPiece.setRandomShape();
     }

     void TetrixBoard::setNextPieceLabel(QLabel *label)
     {
         nextPieceLabel = label;
     }

     QSize TetrixBoard::sizeHint() const
     {
         return QSize(BoardWidth * 15 + frameWidth() * 2,
                      BoardHeight * 15 + frameWidth() * 2);
     }

     QSize TetrixBoard::minimumSizeHint() const
     {
         return QSize(BoardWidth * 5 + frameWidth() * 2,
                      BoardHeight * 5 + frameWidth() * 2);
     }

     void TetrixBoard::start()
     {
         if (isPaused)
             return;

         isStarted = true;
         isWaitingAfterLine = false;
         numLinesRemoved = 0;
         numPiecesDropped = 0;
         score = 0;
         level = 1;
         clearBoard();

         emit linesRemovedChanged(numLinesRemoved);
         emit scoreChanged(score);
         emit levelChanged(level);

         newPiece();
         timer.start(timeoutTime(), this);
     }

     void TetrixBoard::pause()
     {
         if (!isStarted)
             return;

         isPaused = !isPaused;
         if (isPaused) {
             timer.stop();
         } else {
             timer.start(timeoutTime(), this);
         }
         update();
     }

     void TetrixBoard::paintEvent(QPaintEvent *event)
     {
         QFrame::paintEvent(event);

         QPainter painter(this);
         QRect rect = contentsRect();

         if (isPaused) {
             painter.drawText(rect, Qt::AlignCenter, tr("Pause"));
             return;
         }

         int boardTop = rect.bottom() - BoardHeight*squareHeight();

         for (int i = 0; i < BoardHeight; ++i) {
             for (int j = 0; j < BoardWidth; ++j) {
                 TetrixShape shape = shapeAt(j, BoardHeight - i - 1);
                 if (shape != NoShape)
                     drawSquare(painter, rect.left() + j * squareWidth(),
                                boardTop + i * squareHeight(), shape);
             }
         }

         if (curPiece.shape() != NoShape) {
             for (int i = 0; i < 4; ++i) {
                 int x = curX + curPiece.x(i);
                 int y = curY - curPiece.y(i);
                 drawSquare(painter, rect.left() + x * squareWidth(),
                            boardTop + (BoardHeight - y - 1) * squareHeight(),
                            curPiece.shape());
             }
         }
     }

     void TetrixBoard::keyPressEvent(QKeyEvent *event)
     {
         if (!isStarted || isPaused || curPiece.shape() == NoShape) {
             QFrame::keyPressEvent(event);
             return;
         }

         switch (event->key()) {
         case Qt::Key_Left:
             tryMove(curPiece, curX - 1, curY);
             break;
         case Qt::Key_Right:
             tryMove(curPiece, curX + 1, curY);
             break;
         case Qt::Key_Down:
             tryMove(curPiece.rotatedRight(), curX, curY);
             break;
         case Qt::Key_Up:
             tryMove(curPiece.rotatedLeft(), curX, curY);
             break;
         case Qt::Key_Space:
             dropDown();
             break;
         case Qt::Key_D:
             oneLineDown();
             break;
         default:
             QFrame::keyPressEvent(event);
         }
     }

     void TetrixBoard::timerEvent(QTimerEvent *event)
     {
         if (event->timerId() == timer.timerId()) {
             if (isWaitingAfterLine) {
                 isWaitingAfterLine = false;
                 newPiece();
                 timer.start(timeoutTime(), this);
             } else {
                 oneLineDown();
             }
         } else {
             QFrame::timerEvent(event);
         }
     }

     void TetrixBoard::clearBoard()
     {
         for (int i = 0; i < BoardHeight * BoardWidth; ++i)
             board[i] = NoShape;
     }

     void TetrixBoard::dropDown()
     {
         int dropHeight = 0;
         int newY = curY;
         while (newY > 0) {
             if (!tryMove(curPiece, curX, newY - 1))
                 break;
             --newY;
             ++dropHeight;
         }
         pieceDropped(dropHeight);
     }

     void TetrixBoard::oneLineDown()
     {
         if (!tryMove(curPiece, curX, curY - 1))
             pieceDropped(0);
     }

     void TetrixBoard::pieceDropped(int dropHeight)
     {
         for (int i = 0; i < 4; ++i) {
             int x = curX + curPiece.x(i);
             int y = curY - curPiece.y(i);
             shapeAt(x, y) = curPiece.shape();
         }

         ++numPiecesDropped;
         if (numPiecesDropped % 25 == 0) {
             ++level;
             timer.start(timeoutTime(), this);
             emit levelChanged(level);
         }

         score += dropHeight + 7;
         emit scoreChanged(score);
         removeFullLines();

         if (!isWaitingAfterLine)
             newPiece();
     }

     void TetrixBoard::removeFullLines()
     {
         int numFullLines = 0;

         for (int i = BoardHeight - 1; i >= 0; --i) {
             bool lineIsFull = true;

             for (int j = 0; j < BoardWidth; ++j) {
                 if (shapeAt(j, i) == NoShape) {
                     lineIsFull = false;
                     break;
                 }
             }

             if (lineIsFull) {
                 ++numFullLines;
                 for (int k = i; k < BoardHeight - 1; ++k) {
                     for (int j = 0; j < BoardWidth; ++j)
                         shapeAt(j, k) = shapeAt(j, k + 1);
                 }
                 for (int j = 0; j < BoardWidth; ++j)
                     shapeAt(j, BoardHeight - 1) = NoShape;
             }
         }

         if (numFullLines > 0) {
             numLinesRemoved += numFullLines;
             score += 10 * numFullLines;
             emit linesRemovedChanged(numLinesRemoved);
             emit scoreChanged(score);

             timer.start(500, this);
             isWaitingAfterLine = true;
             curPiece.setShape(NoShape);
             update();
         }
     }

     void TetrixBoard::newPiece()
     {
         curPiece = nextPiece;
         nextPiece.setRandomShape();
         showNextPiece();
         curX = BoardWidth / 2 + 1;
         curY = BoardHeight - 1 + curPiece.minY();

         if (!tryMove(curPiece, curX, curY)) {
             curPiece.setShape(NoShape);
             timer.stop();
             isStarted = false;
         }
     }

     void TetrixBoard::showNextPiece()
     {
         if (!nextPieceLabel)
             return;

         int dx = nextPiece.maxX() - nextPiece.minX() + 1;
         int dy = nextPiece.maxY() - nextPiece.minY() + 1;

         QPixmap pixmap(dx * squareWidth(), dy * squareHeight());
         QPainter painter(&pixmap);
         painter.fillRect(pixmap.rect(), nextPieceLabel->palette().background());

         for (int i = 0; i < 4; ++i) {
             int x = nextPiece.x(i) - nextPiece.minX();
             int y = nextPiece.y(i) - nextPiece.minY();
             drawSquare(painter, x * squareWidth(), y * squareHeight(),
                        nextPiece.shape());
         }
         nextPieceLabel->setPixmap(pixmap);
     }

     bool TetrixBoard::tryMove(const TetrixPiece &newPiece, int newX, int newY)
     {
         for (int i = 0; i < 4; ++i) {
             int x = newX + newPiece.x(i);
             int y = newY - newPiece.y(i);
             if (x < 0 || x >= BoardWidth || y < 0 || y >= BoardHeight)
                 return false;
             if (shapeAt(x, y) != NoShape)
                 return false;
         }

         curPiece = newPiece;
         curX = newX;
         curY = newY;
         update();
         return true;
     }

     void TetrixBoard::drawSquare(QPainter &painter, int x, int y, TetrixShape shape)
     {
         static const QRgb colorTable[8] = {
             0x000000, 0xCC6666, 0x66CC66, 0x6666CC,
             0xCCCC66, 0xCC66CC, 0x66CCCC, 0xDAAA00
         };

         QColor color = colorTable[int(shape)];
         painter.fillRect(x + 1, y + 1, squareWidth() - 2, squareHeight() - 2,
                          color);

         painter.setPen(color.light());
         painter.drawLine(x, y + squareHeight() - 1, x, y);
         painter.drawLine(x, y, x + squareWidth() - 1, y);

         painter.setPen(color.dark());
         painter.drawLine(x + 1, y + squareHeight() - 1,
                          x + squareWidth() - 1, y + squareHeight() - 1);
         painter.drawLine(x + squareWidth() - 1, y + squareHeight() - 1,
                          x + squareWidth() - 1, y + 1);
     }