如何在 PyQt5 中在屏幕上移动一个点? [英] How to move a point across the screen in PyQt5?

问题描述

我正在尝试使用 PyQt5 在屏幕上移动一个点.我希望这个点总是在移动.我不确定在哪里放置代码来改变它的速度.有没有代码不断执行的方法?

I'm trying to make a point move around the screen using PyQt5. I want the point to always be moving. I'm not sure where to place the code to change it's velocity. Is there some method whose code is executed constantly?

这是我的代码:

import sys
from PyQt5.QtWidgets import (QApplication, QLabel, QWidget)
from PyQt5.QtGui import QPainter, QColor, QPen
from PyQt5.QtCore import Qt

class MouseTracker(QWidget):
    distance_from_target = 0
    mouse_x_pos = 0
    mouse_y_pos = 0
    target_x_pos = 500
    target_y_pos = 250

    def __init__(self):
        super().__init__()
        self.initUI()
        self.setMouseTracking(True)

    def initUI(self):
        self.setGeometry(200, 200, 1000, 500)
        self.setWindowTitle('Mouse Tracker')
        self.label = QLabel(self)
        self.label.resize(500, 40)
        self.show()

    def mouseMoveEvent(self, event):
        distance_from_target = round(((event.y() - self.target_y_pos)**2 + (event.x() - self.target_x_pos)**2)**0.5)
        self.label.setText('Coordinates: (%d : %d)' % (event.x(), event.y()) + "   Distance from target: " + str(distance_from_target))       
        self.mouse_x_pos = event.x()
        self.mouse_y_pos = event.y()
        self.update()

    def mousePressEvent(self, event):
        self.target_x_pos = event.x()
        self.target_y_pos = event.y()
        self.update()

    def paintEvent(self, event):
        q = QPainter()
        q.begin(self)
        q.drawLine(self.mouse_x_pos, self.mouse_y_pos, self.target_x_pos, self.target_y_pos)

app = QApplication(sys.argv)
ex = MouseTracker()
sys.exit(app.exec_())

我想要做的是让 target_x_pos 不断增加，不管鼠标是移动还是点击.我该怎么做?

What I want to do is make target_x_pos constantly increment, regardless of whether the mouse is moving or clicked. How do I do this?

我无法实现循环，因为这样就没有其他响应了.这是线程的用武之地吗?

I can't implement a loop because then nothing else would be responsive. Is this where threading comes in?

推荐答案

你只需要实现一个QTimer，每次触发你必须更新想要的位置，除了使用self.update() 更新绘图.

You only have to implement a QTimer, every time it is triggered you must update the desired position, in addition to using self.update() to update the drawing.

import sys

from PyQt5.QtCore import QTimer
from PyQt5.QtWidgets import (QApplication, QLabel, QWidget)
from PyQt5.QtGui import QPainter


class MouseTracker(QWidget):
    distance_from_target = 0
    mouse_x_pos = 0
    mouse_y_pos = 0
    target_x_pos = 500
    target_y_pos = 250
    vel = 60  # pixels per second

    def __init__(self, parent=None):
        super(MouseTracker, self).__init__(parent=parent)
        self.initUI()
        self.setMouseTracking(True)
        self.timer = QTimer(self)
        self.timer.timeout.connect(self.changePosition)
        self.timer.start(1000 / self.vel)

    def changePosition(self):
        self.target_x_pos += 1
        self.update()

    def initUI(self):
        self.setGeometry(200, 200, 1000, 500)
        self.setWindowTitle('Mouse Tracker')
        self.label = QLabel(self)
        self.label.resize(500, 40)
        self.show()

    def mouseMoveEvent(self, event):
        distance_from_target = round(
            ((event.y() - self.target_y_pos) ** 2 + (event.x() - self.target_x_pos) ** 2) ** 0.5)
        self.label.setText(
            'Coordinates: (%d : %d)' % (event.x(), event.y()) + "   Distance from target: " + str(distance_from_target))
        self.mouse_x_pos = event.x()
        self.mouse_y_pos = event.y()
        self.update()

    def mousePressEvent(self, event):
        self.target_x_pos = event.x()
        self.target_y_pos = event.y()
        self.update()

    def paintEvent(self, event):
        q = QPainter()
        q.begin(self)
        q.drawLine(self.mouse_x_pos, self.mouse_y_pos, self.target_x_pos, self.target_y_pos)


app = QApplication(sys.argv)
w = MouseTracker()
sys.exit(app.exec_())

如果您想使用 Thread 进行测试，我会向您展示以下代码，我在刷新值时没有遇到任何问题.

If you want to test with Thread I show you the following code, I have not had problems in refreshing the values.

import sys
import time
from PyQt5.QtCore import QThread
from PyQt5.QtCore import QTimer
from PyQt5.QtCore import pyqtSignal
from PyQt5.QtWidgets import (QApplication, QLabel, QWidget)
from PyQt5.QtGui import QPainter


class MyThread(QThread):
    signal = pyqtSignal(int)

    def __init__(self, parent=None):
        super(MyThread, self).__init__(parent=parent)
        self.value = None
        self.vel = None

    def setValue(self, value):
        self.value = value

    def setVelocity(self, vel):
        self.vel = vel

    def run(self):
        while True:
            self.value += 1
            self.signal.emit(self.value)
            time.sleep(1/self.vel)


class MouseTracker(QWidget):
    distance_from_target = 0
    mouse_x_pos = 0
    mouse_y_pos = 0
    target_x_pos = 500
    target_y_pos = 250
    vel = 60  # pixels per second

    def __init__(self, parent=None):
        super(MouseTracker, self).__init__(parent=parent)
        self.initUI()
        self.setMouseTracking(True)
        self.thread = MyThread(self)
        self.thread.setValue(self.target_x_pos)
        self.thread.setVelocity(self.vel)
        self.thread.signal.connect(self.updatePosition)
        self.thread.start()

    def updatePosition(self, val):
        self.target_x_pos = val
        self.update()

    def initUI(self):
        self.setGeometry(200, 200, 1000, 500)
        self.setWindowTitle('Mouse Tracker')
        self.label = QLabel(self)
        self.label.resize(500, 40)
        self.show()

    def mouseMoveEvent(self, event):
        distance_from_target = round(
            ((event.y() - self.target_y_pos) ** 2 + (event.x() - self.target_x_pos) ** 2) ** 0.5)
        self.label.setText(
            'Coordinates: (%d : %d)' % (event.x(), event.y()) + "   Distance from target: " + str(distance_from_target))
        self.mouse_x_pos = event.x()
        self.mouse_y_pos = event.y()
        self.update()

    def mousePressEvent(self, event):
        self.target_x_pos = event.x()
        self.thread.setValue(self.target_x_pos)
        self.target_y_pos = event.y()
        self.update()

    def paintEvent(self, event):
        q = QPainter()
        q.begin(self)
        q.drawLine(self.mouse_x_pos, self.mouse_y_pos, self.target_x_pos, self.target_y_pos)


app = QApplication(sys.argv)
w = MouseTracker()
sys.exit(app.exec_())

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