Question

我的目标是使用 PySide2 模块在 Python 3中创建具有刻度的自定义 QSlider 和刻度标签。为此，我在派生类中编辑QSlider类的默认paintEvent。但是，事实证明，可打印区域有限，并且裁切了我放置的顶部/底部标签（请参见屏幕截图）。我用来生成这些滑块的代码如下：

import sys
from PySide2.QtCore import *
from PySide2.QtWidgets import *
from PySide2.QtGui import *

slider_x = 150
slider_y = 450
slider_step = [0.01, 0.1, 1, 10, 100]  # in microns


class MySlider(QSlider):
    def __init__(self, type, parent=None):
        super(MySlider, self).__init__(parent)
        self.Type = type

    def paintEvent(self, event):
        super(MySlider, self).paintEvent(event)
        qp = QPainter(self)
        pen = QPen()
        pen.setWidth(2)
        pen.setColor(Qt.red)

        qp.setPen(pen)
        font = QFont('Times', 10)
        qp.setFont(font)
        self.setContentsMargins(50, 50, 50, 50)
        # size = self.size()
        # print(size)
        # print("margins", self.getContentsMargins())
        # print(self.getContentsMargins())
        # print(self.contentsRect())
        contents = self.contentsRect()
        self.setFixedSize(QSize(slider_x, slider_y))
        max_slider = self.maximum()
        y_inc = 0
        for i in range(max_slider):
            qp.drawText(contents.x() - font.pointSize(), y_inc + font.pointSize() / 2, '{0:2}'.format(slider_step[i]))
            qp.drawLine(contents.x() + font.pointSize(), y_inc, contents.x() + contents.width(), y_inc)
            y_inc += slider_y/4


class Window(QWidget):
    """ Inherits from QWidget """
    def __init__(self):
        super().__init__()
        self.title = 'Control Stages'
        self.left = 10
        self.top = 10
        self.width = 320
        self.height = 100
        self.AxesMapping = [0, 1, 2, 3]
        self.initUI()

    def initUI(self):
        """ Initializes the GUI either using the grid layout or the absolute position layout"""
        self.setWindowTitle(self.title)
        self.setGeometry(self.left, self.top, self.width, self.height)
        Comp4 = self.createSlider("step_size")
        Comp5 = self.createSlider("speed")
        windowLayout = QGridLayout()
        windowLayout.setContentsMargins(50, 50, 50, 50)
        HGroupBox = QGroupBox()
        layout = QGridLayout()
        layout.addWidget(Comp4, 0, 0)
        layout.addWidget(Comp5, 0, 1)
        HGroupBox.setLayout(layout)
        HGroupBox.setFixedSize(QSize(740, 480))
        windowLayout.addWidget(HGroupBox, 0, 0)
        self.setLayout(windowLayout)
        self.show()

    def createSlider(self, variant):
        Slider = MySlider(Qt.Vertical)
        Slider.Type = variant
        Slider.setMaximum(5)
        Slider.setMinimum(1)
        Slider.setSingleStep(1)
        Slider.setTickInterval(1)
        Slider.valueChanged.connect(lambda: self.sliderChanged(Slider))
        return Slider

    @staticmethod
    def sliderChanged(Slider):
        print("Slider value changed to ", Slider.value(), "slider type is ", Slider.Type)
        if Slider.Type == "step_size":
            print("this is a step size slider")
        elif Slider.Type == "speed":
            print("this is a speed slider")


if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = Window()
    sys.exit(app.exec_())

是否可以扩展QSlider周围的可绘制区域，如果可以，如何实现此效果？您可以在屏幕截图上看到，第一个和最后一个刻度线旁边的红色标签没有正确显示，并且被裁剪了（即，在第一个刻度线标签中，标记0.01缺少1和0的顶部）。

编辑：尝试了建议的解决方案后，顶部标签的一部分仍然被剪掉。下面的第二个版本在带有PySide2 5.12.0和Python 3.6.6的Windows 10 64位上仍然相似。

EDIT2 我有一个双启动系统，所以我在带有Python 3.5.2 / PySide 5.12.0的Ubuntu 16.04.3 LTS上尝试了它，并且开箱即用。这是那里的屏幕截图，但不幸的是它必须在Windows上可以使用。

Answer 1

我的建议是调查QSlider继承的QAbstractSlider。它包含一个称为triggerAction（SliderToMaximum值为6）的方法，当set the Slider Position时可以用于action is triggered。

触发动作的语法是

 QAbstractSlider.triggerAction (self, SliderAction action)

SliderAction的值如下：

QAbstractSlider.SliderNoAction 0   QAbstractSlider.SliderSingleStepAdd 1

QAbstractSlider.SliderSingleStepSub 2

QAbstractSlider.SliderPageStepAdd 3

QAbstractSlider.SliderPageStepSub 4

QAbstractSlider.SliderToMinimum 5

QAbstractSlider.SliderToMaximum 6

QAbstractSlider.SliderMove 7

（source）

使用PySide2，您可以使用

调用这些方法

PySide2.QtWidgets.QAbstractSlider.maximum()  //returns the value of the maximum

或

PySide2.QtWidgets.QAbstractSlider.setMaximum(arg) // pass your own value

Answer 2

如果我做对了，您希望刻度线在顶部和底部都可见，因为由于边距，它们似乎被“割掉了”。我认为这是假设小部件边距正确设置为零或类似的结果，您可以尝试更改数字并看到这种效果。（我尝试移动页边距，但没有成功）

现在，在old post之后，我注意到实现类似的目标似乎很棘手，您可以基于{的minimum和maximum {1}}。

由于底部的勾号位于主窗口小部件的下方，因此您只需为其添加特殊条件即可使其可见。

不想粘贴整个代码，但是您只需要在循环之前声明QSlider和opt。计算内部的handle位置，并用它代替您的y。

y_inc

编辑：在Windows上似乎有一个大约10个单位的最高边距，这是IMHHO在Qt中的一个错误。一种解决方法是替换：

def paintEvent(self, event):                                                                                                                                                            
    super(MySlider, self).paintEvent(event)                                                     
    qp = QPainter(self)                                                                         
    pen = QPen()                                                                                
    pen.setWidth(2)                                                                             
    pen.setColor(Qt.red)                                                                        

    qp.setPen(pen)                                                                              
    font = QFont('Times', 10)                                                                   
    qp.setFont(font)                                                                            
    self.setContentsMargins(50, 50, 50, 50)                                                     
    # size = self.size()                                                                        
    # print(size)                                                                               
    # print("margins", self.getContentsMargins())                                               
    # print(self.getContentsMargins())                                                          
    # print(self.contentsRect())                                                                
    contents = self.contentsRect()                                                              
    self.setFixedSize(QSize(slider_x, slider_y))                                                

    # New code                                                                                  
    max_slider = self.maximum()                                                                 
    min_slider = self.minimum()                                                                 
    len_slider = max_slider - min_slider                                                        
    height = self.height()                                                                      

    opt = QStyleOptionSlider()                                                                  
    handle = self.style().subControlRect(QStyle.CC_Slider, opt, QStyle.SC_SliderHandle, self)   
    handle_height = handle.height() # Add +10 on windows (workarount)                                                            
    height_diff = height - handle_height                                                        
    point_size = font.pointSize()                                                               

    for i in range(max_slider):                                                                 
        y = round(((1 - i / len_slider) * height_diff + (handle_height / 2.0))) - 1             

        # Trick for the tick at the bottom                                                      
        if i == 0:                                                                              
            y = self.height() - handle_height/2.0 # To have the tick in the middle              
            #y = height_diff # to shift it a bit                                                

        qp.drawText(contents.x() - point_size, y + point_size / 2, '{0:2}'.format(slider_step[len_slider - i]))
        qp.drawLine(contents.x() + point_size, y, contents.x() + contents.width(), y)

使用

handle_height = handle.height()

在handle_height = handle.height() + 10方法内部。

Answer 3

摆弄更多东西后，我终于找到了解决方案。它包括样式表，我之前曾尝试过。但是，那时我无法正确实现它。 II使小部件尺寸保持恒定，但减小了凹槽长度，以便能够将标签适合可打印区域内。完整的代码如下：

import sys
from PySide2.QtCore import *
from PySide2.QtWidgets import *
from PySide2.QtGui import *

slider_x = 150
slider_y = 450
slider_step = [0.01, 0.1, 1, 10, 100]  # in microns
groove_y = 400
handle_height = 10


class MySlider(QSlider):
    def __init__(self, type, parent=None):
        # super(MySlider, self).__init__(parent)
        super().__init__()
        self.parent = parent
        self.Type = type
        # self.setFixedHeight(115)
        self.setStyleSheet("""QSlider::groove:vertical {
    border: 1px solid black;
    height: """ + str(groove_y) + """ px;
    width: 10px;
    border-radius: 2px;
    }

    QSlider::handle:vertical {
        background: red;
        border: 1px solid red;
        height: """ + str(handle_height) + """ px;
        margin: 2px 0;
        border-radius: 1px;
    }

    QSlider::add-page:vertical {
        background: blue;
    }
    QSlider::sub-page:vertical {
        background: red;
""")

    def paintEvent(self, event):
        super(MySlider, self).paintEvent(event)
        qp = QPainter(self)
        pen = QPen()
        pen.setWidth(2)
        pen.setColor(Qt.black)

        qp.setPen(pen)
        font = QFont('Times', 10)
        qp.setFont(font)
        self.setContentsMargins(50, 50, 50, 50)
        self.setFixedSize(QSize(slider_x, slider_y))
        contents = self.contentsRect()
        max = self.maximum()
        min = self.minimum()

        y_inc = slider_y - (slider_y - groove_y) / 2
        for i in range(len(slider_step)):
            qp.drawText(contents.x() - 2 * font.pointSize(), y_inc + font.pointSize() / 2, '{0:3}'.format(slider_step[i]))
            qp.drawLine(contents.x() + 2 * font.pointSize(), y_inc, contents.x() + contents.width(), y_inc)
            y_inc -= groove_y / (max - min)



class Window(QWidget):
    """ Inherits from QWidget """
    def __init__(self):
        super().__init__()
        self.title = 'Control Stages'
        self.left = 10
        self.top = 10
        self.width = 320
        self.height = 100
        self.AxesMapping = [0, 1, 2, 3]
        self.initUI()

    def initUI(self):
        """ Initializes the GUI either using the grid layout or the absolute position layout"""
        self.setWindowTitle(self.title)
        self.setGeometry(self.left, self.top, self.width, self.height)
        Comp4 = self.createSlider("step_size")
        Comp5 = self.createSlider("speed")
        windowLayout = QGridLayout()
        windowLayout.setContentsMargins(50, 50, 50, 50)
        HGroupBox = QGroupBox()
        layout = QGridLayout()
        layout.addWidget(Comp4, 0, 0)
        layout.addWidget(Comp5, 0, 1)
        HGroupBox.setLayout(layout)
        HGroupBox.setFixedSize(QSize(740, 480))
        windowLayout.addWidget(HGroupBox, 0, 0)
        self.setLayout(windowLayout)
        self.show()

    def createSlider(self, variant):
        Slider = MySlider(Qt.Vertical)
        Slider.Type = variant
        Slider.setMaximum(len(slider_step))
        Slider.setMinimum(1)
        Slider.setSingleStep(1)
        Slider.setTickInterval(1)
        Slider.valueChanged.connect(lambda: self.sliderChanged(Slider))
        return Slider

    @staticmethod
    def sliderChanged(Slider):
        print("Slider value changed to ", Slider.value(), "slider type is ", Slider.Type)
        if Slider.Type == "step_size":
            print("this is a step size slider")
        elif Slider.Type == "speed":
            print("this is a speed slider")


if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = Window()
    sys.exit(app.exec_())

是否可以扩大QSlider周围的可绘制区域

3 个答案: