本文通过Python3+PyQt5实现自定义部件–分数滑块。它既能支持键盘也支持鼠标，使用物理（视口）坐标通过绘制方式显示。
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#!/usr/bin/env python3
import platform
from PyQt5.QtCore import (QPointF, QRectF, QSize, Qt,pyqtSignal)
from PyQt5.QtWidgets import (QApplication, QDialog,QSizePolicy,
QGridLayout, QLCDNumber, QLabel,
QSpinBox, QWidget)
from PyQt5.QtGui import QColor,QFont,QPainter,QFontMetricsF,QPalette, QPolygonF
X11 = True
try:
from PyQt5.QtGui import qt_x11_wait_for_window_manager
except ImportError:
X11 = False
class FractionSlider(QWidget):
XMARGIN = 12.0
YMARGIN = 5.0
WSTRING = "999"
valueChanged = pyqtSignal(int,int)
def __init__(self, numerator=0, denominator=10, parent=None):
super(FractionSlider, self).__init__(parent)
self.__numerator = numerator
self.__denominator = denominator
self.setFocusPolicy(Qt.WheelFocus)
self.setSizePolicy(QSizePolicy(QSizePolicy.MinimumExpanding,
QSizePolicy.Fixed))
def decimal(self):
return self.__numerator / float(self.__denominator)
def fraction(self):
return self.__numerator, self.__denominator
def sizeHint(self):
return self.minimumSizeHint()
def minimumSizeHint(self):
font = QFont(self.font())
font.setPointSize(font.pointSize() - 1)
fm = QFontMetricsF(font)
return QSize(fm.width(FractionSlider.WSTRING) *
self.__denominator,
(fm.height() * 4) + FractionSlider.YMARGIN)
def setFraction(self, numerator, denominator=None):
if denominator is not None:
if 3 <= denominator <= 60:
self.__denominator = denominator
else:
raise ValueError("denominator out of range")
if 0 <= numerator <= self.__denominator:
self.__numerator = numerator
else:
raise ValueError("numerator out of range")
self.update()
self.updateGeometry()
def mousePressEvent(self, event):
if event.button() == Qt.LeftButton:
self.moveSlider(event.x())
event.accept()
else:
QWidget.mousePressEvent(self, event)
def mouseMoveEvent(self, event):
self.moveSlider(event.x())
def moveSlider(self, x):
span = self.width() - (FractionSlider.XMARGIN * 2)
offset = span - x + FractionSlider.XMARGIN
numerator = int(round(self.__denominator *
(1.0 - (offset / span))))
numerator = max(0, min(numerator, self.__denominator))
if numerator != self.__numerator:
self.__numerator = numerator
#self.emit(SIGNAL("valueChanged(int,int)"),
# self.__numerator, self.__denominator)
self.valueChanged.emit(self.__numerator, self.__denominator)
self.update()
def keyPressEvent(self, event):
change = 0
if event.key() == Qt.Key_Home:
change = -self.__denominator
elif event.key() in (Qt.Key_Up, Qt.Key_Right):
change = 1
elif event.key() == Qt.Key_PageUp:
change = (self.__denominator // 10) + 1
elif event.key() in (Qt.Key_Down, Qt.Key_Left):
change = -1
elif event.key() == Qt.Key_PageDown:
change = -((self.__denominator // 10) + 1)
elif event.key() == Qt.Key_End:
change = self.__denominator
if change:
numerator = self.__numerator
numerator += change
numerator = max(0, min(numerator, self.__denominator))
if numerator != self.__numerator:
self.__numerator = numerator
#self.emit(SIGNAL("valueChanged(int,int)"),
# self.__numerator, self.__denominator)
self.valueChanged.emit(self.__numerator, self.__denominator)
self.update()
event.accept()
else:
QWidget.keyPressEvent(self, event)
def paintEvent(self, event=None):
font = QFont(self.font())
font.setPointSize(font.pointSize() - 1)
fm = QFontMetricsF(font)
fracWidth = fm.width(FractionSlider.WSTRING)
indent = fm.boundingRect("9").width() / 2.0
if not X11:
fracWidth *= 1.5
span = self.width() - (FractionSlider.XMARGIN * 2)
value = self.__numerator / float(self.__denominator)
painter = QPainter(self)
painter.setRenderHint(QPainter.Antialiasing)
painter.setRenderHint(QPainter.TextAntialiasing)
painter.setPen(self.palette().color(QPalette.Mid))
painter.setBrush(self.palette().brush(
QPalette.AlternateBase))
painter.drawRect(self.rect())
segColor = QColor(Qt.green).darker(120)
segLineColor = segColor.darker()
painter.setPen(segLineColor)
painter.setBrush(segColor)
painter.drawRect(FractionSlider.XMARGIN,
FractionSlider.YMARGIN, span, fm.height())
textColor = self.palette().color(QPalette.Text)
segWidth = span / self.__denominator
segHeight = fm.height() * 2
nRect = fm.boundingRect(FractionSlider.WSTRING)
x = FractionSlider.XMARGIN
yOffset = segHeight + fm.height()
for i in range(self.__denominator + 1):
painter.setPen(segLineColor)
painter.drawLine(x, FractionSlider.YMARGIN, x, segHeight)
painter.setPen(textColor)
y = segHeight
rect = QRectF(nRect)
rect.moveCenter(QPointF(x, y + fm.height() / 2.0))
#painter.drawText(rect, Qt.AlignCenter,
#QString.number(i))
painter.drawText(rect, Qt.AlignCenter,str(i))
y = yOffset
rect.moveCenter(QPointF(x, y + fm.height() / 2.0))
painter.drawText(rect, Qt.AlignCenter,
str(self.__denominator))
painter.drawLine(QPointF(rect.left() + indent, y),
QPointF(rect.right() - indent, y))
x += segWidth
span = int(span)
y = FractionSlider.YMARGIN - 0.5
triangle = [QPointF(value * span, y),
QPointF((value * span) +
(2 * FractionSlider.XMARGIN), y),
QPointF((value * span) +
FractionSlider.XMARGIN, fm.height())]
painter.setPen(Qt.yellow)
painter.setBrush(Qt.darkYellow)
painter.drawPolygon(QPolygonF(triangle))
if __name__ == "__main__":
import sys
app = QApplication(sys.argv)
form = QDialog()
sliderLabel = QLabel("&Fraction")
slider = FractionSlider(denominator=12)
sliderLabel.setBuddy(slider)
denominatorLabel = QLabel("&Denominator")
denominatorSpinBox = QSpinBox()
denominatorLabel.setBuddy(denominatorSpinBox)
denominatorSpinBox.setRange(3, 60)
denominatorSpinBox.setValue(slider.fraction()[1])
denominatorSpinBox.setAlignment(Qt.AlignRight|Qt.AlignVCenter)
numeratorLabel = QLabel("Numerator")
numeratorLCD = QLCDNumber()
numeratorLCD.setSegmentStyle(QLCDNumber.Flat)
layout = QGridLayout()
layout.addWidget(sliderLabel, 0, 0)
layout.addWidget(slider, 0, 1, 1, 5)
layout.addWidget(numeratorLabel, 1, 0)
layout.addWidget(numeratorLCD, 1, 1)
layout.addWidget(denominatorLabel, 1, 2)
layout.addWidget(denominatorSpinBox, 1, 3)
form.setLayout(layout)
def valueChanged(denominator):
numerator = int(slider.decimal() * denominator)
slider.setFraction(numerator, denominator)
numeratorLCD.display(numerator)
#form.connect(slider, SIGNAL("valueChanged(int,int)"),
#numeratorLCD, SLOT("display(int)"))
slider.valueChanged[int,int].connect(numeratorLCD.display)
#form.connect(denominatorSpinBox, SIGNAL("valueChanged(int)"),
#valueChanged)
denominatorSpinBox.valueChanged[int].connect(valueChanged)
form.setWindowTitle("Fraction Slider")
form.show()
app.exec_()
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运行结果：
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：https://blog.csdn.net/xiaoyangyang20/article/details/55253667