Update 俄罗斯方块游戏.md

Author: maicss

俄罗斯方块游戏.md

@@ -514,45 +514,53 @@ if __name__ == '__main__':
     sys.exit(app.exec_())
 ```
 The game is simplified a bit so that it is easier to understand. The game starts immediately after it is launched. We can pause the game by pressing the p key. The Space key will drop the tetris piece instantly to the bottom. The game goes at constant speed, no acceleration is implemented. The score is the number of lines that we have removed.
-
+```
 self.tboard = Board(self)
 self.setCentralWidget(self.tboard)
+```
 An instance of the Board class is created and set to be the central widget of the application.
-
+```
 self.statusbar = self.statusBar()        
 self.tboard.msg2Statusbar[str].connect(self.statusbar.showMessage)
+```
 We create a statusbar where we will display messages. We will display three possible messages: the number of lines already removed, the paused message, or the game over message. The msg2Statusbar is a custom signal that is implemented in the Board class. The showMessage() is a built-in method that displays a message on a statusbar.
-
+```
 self.tboard.start()
+```
 This line initiates the game.
-
+```
 class Board(QFrame):
     
     msg2Statusbar = pyqtSignal(str)
 ...    
+```
 A custom signal is created. The msg2Statusbar is a signal that is emitted when we want to write a message or the score to the statusbar.
-
+```
 BoardWidth = 10
 BoardHeight = 22
 Speed = 300
+```
 These are Board's class variables. The BoardWidth and the BoardHeight define the size of the board in blocks. The Speed defines the speed of the game. Each 300 ms a new game cycle will start.
-
+```
 ...
 self.curX = 0
 self.curY = 0
 self.numLinesRemoved = 0
 self.board = []
 ...
+```
 In the initBoard() method we initialize some important variables. The self.board variable is a list of numbers from 0 to 7. It represents the position of various shapes and remains of the shapes on the board.
-
+```
 def shapeAt(self, x, y):
     return self.board[(y * Board.BoardWidth) + x]
+```
 The shapeAt() method determines the type of a shape at a given block.
-
+```
 def squareWidth(self):
     return self.contentsRect().width() // Board.BoardWidth
+```
 The board can be dynamically resized. As a consequence, the size of a block may change. The squareWidth() calculates the width of the single square in pixels and returns it. The Board.BoardWidth is the size of the board in blocks.
-
+```
 for i in range(Board.BoardHeight):
     for j in range(Board.BoardWidth):
         shape = self.shapeAt(j, Board.BoardHeight - i - 1)
@@ -561,8 +569,9 @@ for i in range(Board.BoardHeight):
             self.drawSquare(painter,
                 rect.left() + j * self.squareWidth(),
                 boardTop + i * self.squareHeight(), shape)
+```
 The painting of the game is divided into two steps. In the first step, we draw all the shapes, or remains of the shapes that have been dropped to the bottom of the board. All the squares are remembered in the self.board list variable. The variable is accessed using the shapeAt() method.
-
+```
 if self.curPiece.shape() != Tetrominoe.NoShape:
     
     for i in range(4):
@@ -572,24 +581,29 @@ if self.curPiece.shape() != Tetrominoe.NoShape:
         self.drawSquare(painter, rect.left() + x * self.squareWidth(),
             boardTop + (Board.BoardHeight - y - 1) * self.squareHeight(),
             self.curPiece.shape())
+```
 The next step is the drawing of the actual piece that is falling down.
-
+```
 elif key == Qt.Key_Right:
     self.tryMove(self.curPiece, self.curX + 1, self.curY)
+```
 In the keyPressEvent() method we check for pressed keys. If we press the right arrow key, we try to move the piece to the right. We say try because the piece might not be able to move.
-
+```
 elif key == Qt.Key_Up:
     self.tryMove(self.curPiece.rotateLeft(), self.curX, self.curY)
+```
 The Up arrow key will rotate the falling piece to the left.
-
+```
 elif key == Qt.Key_Space:
     self.dropDown()
+```
 The Space key will drop the falling piece instantly to the bottom.
-
+```
 elif key == Qt.Key_D:
     self.oneLineDown()
+```
 Pressing the d key, the piece will go one block down. It can be used to accellerate the falling of a piece a bit.
-
+```
 def tryMove(self, newPiece, newX, newY):
     
     for i in range(4):
@@ -608,8 +622,9 @@ def tryMove(self, newPiece, newX, newY):
     self.curY = newY
     self.update()
     return True
+```
 In the tryMove() method we try to move our shapes. If the shape is at the edge of the board or is adjacent to some other piece, we return False. Otherwise we place the current falling piece to a new position.
-
+```
 def timerEvent(self, event):
     
     if event.timerId() == self.timer.timerId():
@@ -622,14 +637,16 @@ def timerEvent(self, event):
             
     else:
         super(Board, self).timerEvent(event)
+```
 In the timer event, we either create a new piece after the previous one was dropped to the bottom or we move a falling piece one line down.
-
+```
 def clearBoard(self):
     
     for i in range(Board.BoardHeight * Board.BoardWidth):
         self.board.append(Tetrominoe.NoShape)
+```
 The clearBoard() method clears the board by setting Tetrominoe.NoShape at each block of the board.
-
+```
 def removeFullLines(self):
     
     numFullLines = 0
@@ -656,8 +673,9 @@ def removeFullLines(self):
 
     numFullLines = numFullLines + len(rowsToRemove)
  ...
+```
 If the piece hits the bottom, we call the removeFullLines() method. We find out all full lines and remove them. We do it by moving all lines above the current full line to be removed one line down. Notice that we reverse the order of the lines to be removed. Otherwise, it would not work correctly. In our case we use a naive gravity. This means that the pieces may be floating above empty gaps.
-
+```
 def newPiece(self):
     
     self.curPiece = Shape()
@@ -671,8 +689,9 @@ def newPiece(self):
         self.timer.stop()
         self.isStarted = False
         self.msg2Statusbar.emit("Game over")
+```
 The newPiece() method creates randomly a new tetris piece. If the piece cannot go into its initial position, the game is over.
-
+```
 class Tetrominoe(object):
     
     NoShape = 0
@@ -683,10 +702,11 @@ class Tetrominoe(object):
     SquareShape = 5
     LShape = 6
     MirroredLShape = 7
+```
 The Tetrominoe class holds names of all possible shapes. We have also a NoShape for an empty space.
 
 The Shape class saves information about a tetris piece.
-
+```
 class Shape(object):
     
     coordsTable = (
@@ -695,15 +715,19 @@ class Shape(object):
         ...
     )
 ...    
+```
 The coordsTable tuple holds all possible coordinate values of our tetris pieces. This is a template from which all pieces take their coordinate values.
-
+```
 self.coords = [[0,0] for i in range(4)]
+```
 Upon creation we create an empty coordinates list. The list will save the coordinates of the tetris piece.
 
-Coordinates
-Figure: Coordinates
-The above image will help understand the coordinate values a bit more. For example, the tuples (0, -1), (0, 0), (-1, 0), (-1, -1) represent a Z-shape. The diagram illustrates the shape.
+坐标系示意图：
 
+![coordinates](./images/11-coordinates.png)
+
+The above image will help understand the coordinate values a bit more. For example, the tuples (0, -1), (0, 0), (-1, 0), (-1, -1) represent a Z-shape. The diagram illustrates the shape.
+```
 def rotateLeft(self):
     
     if self.pieceShape == Tetrominoe.SquareShape:
@@ -718,6 +742,7 @@ def rotateLeft(self):
         result.setY(i, -self.x(i))
 
     return result
+```
 The rotateLeft() method rotates a piece to the left. The square does not have to be rotated. That is why we simply return the reference to the current object. A new piece is created and its coordinates are set to the ones of the rotated piece.
 
 ![Tetris](./images/11-tetris.png)