从 SVG 棋盘中获取被点击的棋子

Question

我正在 Python 3.6.3 使用 Windows 10 上的 PyQt5 5.9.1（GUI 框架）和 python-chess 0.21.1（国际象棋库）开发国际象棋 GUI。我想获取在 SVG 棋盘（由 python-chess 提供）上单击的棋子的值，以便我可以将该棋子移动到另一个方格。

第一次鼠标左键得到棋子后，我想得到用户第二次鼠标左键，得到用户点击的方块。然后我的国际象棋 GUI 必须将棋子从起始方格移动到目标方格。

所以，这是我到目前为止的完整工作代码。非常欢迎任何提示或实际代码添加。

#! /usr/bin/env python3

import chess
import chess.svg

from PyQt5.QtCore import pyqtSlot, Qt
from PyQt5.QtSvg import QSvgWidget
from PyQt5.QtWidgets import QApplication, QWidget


class MainWindow(QWidget):
    def __init__(self):
        super().__init__()

        self.setWindowTitle("Chess Titan")
        self.setGeometry(300, 300, 800, 800)

        self.widgetSvg = QSvgWidget(parent=self)
        self.widgetSvg.setGeometry(10, 10, 600, 600)

        self.chessboard = chess.Board()

    @pyqtSlot(QWidget)
    def mousePressEvent(self, event):
        if event.buttons() == Qt.LeftButton:
            ## How to get the clicked SVG chess piece?

            # Envoke the paint event.
            self.update()

    @pyqtSlot(QWidget)
    def paintEvent(self, event):
        self.chessboardSvg = chess.svg.board(self.chessboard).encode("UTF-8")
        self.widgetSvg.load(self.chessboardSvg)


if __name__ == "__main__":
    chessTitan = QApplication([])
    window = MainWindow()
    window.show()
    chessTitan.exec()

Answer 1

如果知道棋盘的大小，可以根据marginwidth和squaresize从event.pos() resp.event.x(), event.y()中找到鼠标点击的坐标，见chess.svg.py 第 129 行以后

编辑 11 月 25 日： event.pos() 在这个例子中是在 MainWindow 坐标中，要找到棋盘上的坐标都必须从左上角计算 self.svgX 和 self.svgY：

import chess
import chess.svg
from PyQt5.QtCore import pyqtSlot, Qt
from PyQt5.QtSvg import QSvgWidget
from PyQt5.QtWidgets import QApplication, QWidget


class MainWindow(QWidget):
    def __init__(self):
        super().__init__()

        self.setWindowTitle("Chess Titan")
        self.setGeometry(300, 300, 800, 800)

        self.widgetSvg = QSvgWidget(parent=self)
        self.svgX = 50                          # top left x-pos of chessboard
        self.svgY = 50                          # top left y-pos of chessboard
        self.cbSize = 600                       # size of chessboard
        self.widgetSvg.setGeometry(self.svgX,self.svgY, self.cbSize, self.cbSize)
        self.coordinates = True
        # see chess.svg.py line 129
        self.margin = 0.05*self.cbSize if self.coordinates == True else 0
        self.squareSize  = (self.cbSize - 2 * self.margin) / 8.0
        self.chessboard = chess.Board()
        self.pieceToMove = [None, None]

    @pyqtSlot(QWidget)
    def mousePressEvent(self, event):
        if self.svgX < event.x() <= self.svgX + self.cbSize and self.svgY < event.y() <= self.svgY + self.cbSize:   # mouse on chessboard
            if event.buttons() == Qt.LeftButton:
                # if the click is on chessBoard only
                if self.svgX + self.margin < event.x() < self.svgX + self.cbSize - self.margin and self.svgY + self.margin < event.y() < self.svgY + self.cbSize - self.margin:
                    file = int((event.x() - (self.svgX + self.margin))/self.squareSize)             
                    rank = 7 - int((event.y() - (self.svgY + self.margin))/self.squareSize) 
                    square = chess.square(file, rank)                       # chess.sqare.mirror() if white is on top
                    piece = self.chessboard.piece_at(square)
                    coordinates = '{}{}'.format(chr(file + 97), str(rank +1))       
                    if self.pieceToMove[0] is not None:
                        move = chess.Move.from_uci('{}{}'.format(self.pieceToMove[1], coordinates))
                        self.chessboard.push(move)
                        print(self.chessboard.fen())
                        piece = None
                        coordinates= None
                    self.pieceToMove = [piece, coordinates]                                           
                else:
                    print('coordinates clicked')
                # Envoke the paint event.
                self.update()
        else:
            QWidget.mousePressEvent(self, event)

    @pyqtSlot(QWidget)
    def paintEvent(self, event):
        self.chessboardSvg = chess.svg.board(self.chessboard, size = self.cbSize, coordinates = self.coordinates).encode("UTF-8")
        self.widgetSvg.load(self.chessboardSvg)


if __name__ == "__main__":
    chessTitan = QApplication([])
    window = MainWindow()
    window.show()
    chessTitan.exec()

交替移动白色和黑色棋子，如果相同的颜色移动两次它们会改变颜色。

Answer 2

下面是 Python、PyQt5 和 python-chess 功能齐全的国际象棋 GUI 的代码，它内置了合法的走法检测，所以棋子的移动按照以下规则运行国际象棋.

#! /usr/bin/env python

"""
This module is the execution point of the chess GUI application.
"""

import sys

import chess

from PyQt5.QtCore import pyqtSlot, Qt
from PyQt5.QtSvg import QSvgWidget
from PyQt5.QtWidgets import QApplication, QWidget


class MainWindow(QWidget):
    """
    Create a surface for the chessboard.
    """
    def __init__(self):
        """
        Initialize the chessboard.
        """
        super().__init__()

        self.setWindowTitle("Chess GUI")
        self.setGeometry(300, 300, 800, 800)

        self.widgetSvg = QSvgWidget(parent=self)
        self.widgetSvg.setGeometry(10, 10, 600, 600)

        self.boardSize = min(self.widgetSvg.width(),
                             self.widgetSvg.height())
        self.coordinates = True
        self.margin = 0.05 * self.boardSize if self.coordinates else 0
        self.squareSize = (self.boardSize - 2 * self.margin) / 8.0
        self.pieceToMove = [None, None]

        self.board = chess.Board()
        self.drawBoard()

    @pyqtSlot(QWidget)
    def mousePressEvent(self, event):
        """
        Handle left mouse clicks and enable moving chess pieces by
        clicking on a chess piece and then the target square.

        Moves must be made according to the rules of chess because
        illegal moves are suppressed.
        """
        if event.x() <= self.boardSize and event.y() <= self.boardSize:
            if event.buttons() == Qt.LeftButton:
                if self.margin < event.x() < self.boardSize - self.margin and self.margin < event.y() < self.boardSize - self.margin:
                    file = int((event.x() - self.margin) / self.squareSize)
                    rank = 7 - int((event.y() - self.margin) / self.squareSize)
                    square = chess.square(file, rank)
                    piece = self.board.piece_at(square)
                    coordinates = "{}{}".format(chr(file + 97), str(rank + 1))
                    if self.pieceToMove[0] is not None:
                        move = chess.Move.from_uci("{}{}".format(self.pieceToMove[1], coordinates))
                        if move in self.board.legal_moves:
                            self.board.push(move)
                        piece = None
                        coordinates = None
                    self.pieceToMove = [piece, coordinates]
                    self.drawBoard()

    def drawBoard(self):
        """
        Draw a chessboard with the starting position and then redraw
        it for every new move.
        """
        self.boardSvg = self.board._repr_svg_().encode("UTF-8")
        self.drawBoardSvg = self.widgetSvg.load(self.boardSvg)

        return self.drawBoardSvg


if __name__ == "__main__":
    chessGui = QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(chessGui.exec_())

Answer 3

a_manthey_67 和 Boštjan Mejak，我结合了你们两个解决方案的功能： https://github.com/vtad4f/chess-ui/blob/master/board.py

完整版将 AI 播放器与您的棋盘集成 UI:

运行构建 https://github.com/vtad4f/chess-ai/
运行main.py玩游戏https://github.com/vtad4f/chess-ui/

从 SVG 棋盘中获取被点击的棋子

Get clicked chess piece from an SVG chessboard

svg

python-3.x

pyqt5

python-chess