在滚动条中突出显示错误的日志查看器

我正在使用PySide6在Python 3.11中开发一个自定义记事本风格的日志查看器。

ui是用QtDesigner创建的,必须用pyuic命令编译成python,并用import“main_ui”导入到以下代码中。

应用程序将名为sample.log的文件加载到QPlainTextEdit字段中。 然后,用户可以单击按钮查找并突出显示包含“Error”子字符串的所有行。

每个突出显示的行的相对位置在自定义滚动条中用红线表示。

我的问题是如何正确计算滚动条中红线的位置? 我目前的逻辑是可行的,但立场并不准确。

这就是界面的样子:

本文提供了所有必要的代码,但也可以通过此zip文件下载 logtool.zip 其中包括这些文件:

1. logtool.py
2. main.ui
3. main_ui.py(使用Python6/Scripts/pyside6-uic.exe从main.ui构建)
4. sample.log

这是主程序logtool.py的样子:

import sys
import os
import os.path

from PySide6 import QtWidgets
from PySide6.QtCore import Qt, Slot
from PySide6.QtWidgets import QMainWindow, QScrollBar 
from PySide6.QtGui import QTextCursor, QTextCharFormat, QColor, QPainter, QPen 

import main_ui

substring_list = ["error", "exception", "fail"]     # Strings to look for in log file that indicate an error

class MyScroll(QScrollBar):

    def __init__(self, parent=None):
        super(MyScroll, self).__init__(parent)

    def paintEvent(self, event):
        super().paintEvent(event)  

        painter = QPainter(self)
        pen = QPen()
        pen.setWidth(3)
        pen.setColor(Qt.red)
        pen.setStyle(Qt.SolidLine)
        painter.setPen(pen)

        try: # return if values is not set
            self.values  
        except:
            return

        for value in self.values:
            painter.drawLine(0, value, 15, value)     

    def draw(self, values):
        self.values = values
        self.update()

class MainWindow(QMainWindow, main_ui.Ui_main):

    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)
        self.setupUi(self)   # setup the GUI --> function generated by pyuic4

        self.txtEdit.setCenterOnScroll(True)

        fullpath = "sample.log" # aos_diag log file
        self.readfile(fullpath)

        self.lines = []

        self.scroll = MyScroll()
        self.txtEdit.setVerticalScrollBar(self.scroll)

        self.show()

    def calc_drawline_pixel(self, lineno):

        widget = self.txtEdit.verticalScrollBar()

        total_lines = widget.maximum()
        scroll_pixel_height = widget.height()

        factor = lineno / total_lines
        uparrow_height = 15
        draw_at_pixel = int(factor * scroll_pixel_height) + uparrow_height

        return draw_at_pixel

    @Slot()
    def on_btnMarkErrors_clicked(self):

        self.lines = []  # lines is a list of line numbers which match search
        self.pos = 0

        string = self.txtEdit.toPlainText()

        reclist = string.split("\n")

        for lineno, line in enumerate(reclist):
            flag = any(substring.lower() in line.lower() for substring in substring_list)  # if any substring in list is in the line then return true
            if flag:
                self.markline(lineno)
                self.lines.append(lineno)

        self.lines = sorted(self.lines) 

        # fill values list and pass to draw method of scrollbar
        values = []
        for lineno in self.lines:
            pixel = self.calc_drawline_pixel(lineno)
            values.append(pixel)

        self.scroll.draw(values)

    def markline(self, line_number):
        """marks line with red highlighter"""

        widget = self.txtEdit
        cursor = QTextCursor(widget.document().findBlockByLineNumber(line_number))  # position cursor on the given line
        cursor.select(QTextCursor.LineUnderCursor)  # Select the line.
        fmt = QTextCharFormat()
        RED = QColor(228,191,190)
        fmt.setBackground(RED)
        cursor.mergeCharFormat(fmt) # Apply the format to the selected text

    def readfile(self, fullpath):

        fullpath = fullpath.replace("\\", "/")   # flip all backslashes to forward slashes because python prefers
        path,file = os.path.split(fullpath)     # extract path and file from fullpath
        fin = open(fullpath, encoding="utf8", errors='ignore')
        content = fin.read()
        fin.close()
            
        self.txtEdit.setPlainText(content)        

if __name__ == "__main__":

    app = QtWidgets.QApplication(sys.argv)
    app.setStyle("Fusion")
    myapp = MainWindow()      
    rc = app.exec()
    sys.exit(rc)   

这就是main_ui.py的样子:

from PySide6.QtCore import (QCoreApplication, QDate, QDateTime, QLocale,
    QMetaObject, QObject, QPoint, QRect,
    QSize, QTime, QUrl, Qt)
from PySide6.QtGui import (QBrush, QColor, QConicalGradient, QCursor,
    QFont, QFontDatabase, QGradient, QIcon,
    QImage, QKeySequence, QLinearGradient, QPainter,
    QPalette, QPixmap, QRadialGradient, QTransform)
from PySide6.QtWidgets import (QApplication, QFrame, QHBoxLayout, QMainWindow,
    QPlainTextEdit, QPushButton, QSizePolicy, QSpacerItem,
    QStatusBar, QVBoxLayout, QWidget)

class Ui_main(object):
    def setupUi(self, main):
        if not main.objectName():
            main.setObjectName(u"main")
        main.resize(602, 463)
        self.centralwidget = QWidget(main)
        self.centralwidget.setObjectName(u"centralwidget")
        self.verticalLayout = QVBoxLayout(self.centralwidget)
        self.verticalLayout.setObjectName(u"verticalLayout")
        self.frame = QFrame(self.centralwidget)
        self.frame.setObjectName(u"frame")
        self.frame.setFrameShape(QFrame.NoFrame)
        self.frame.setFrameShadow(QFrame.Raised)
        self.horizontalLayout = QHBoxLayout(self.frame)
        self.horizontalLayout.setObjectName(u"horizontalLayout")
        self.horizontalLayout.setContentsMargins(0, 0, 0, 0)
        self.btnMarkErrors = QPushButton(self.frame)
        self.btnMarkErrors.setObjectName(u"btnMarkErrors")

        self.horizontalLayout.addWidget(self.btnMarkErrors)

        self.horizontalSpacer_2 = QSpacerItem(40, 20, QSizePolicy.Expanding, QSizePolicy.Minimum)

        self.horizontalLayout.addItem(self.horizontalSpacer_2)


        self.verticalLayout.addWidget(self.frame)

        self.txtEdit = QPlainTextEdit(self.centralwidget)
        self.txtEdit.setObjectName(u"txtEdit")
        font = QFont()
        font.setFamilies([u"Consolas"])
        self.txtEdit.setFont(font)
        self.txtEdit.setLineWrapMode(QPlainTextEdit.NoWrap)

        self.verticalLayout.addWidget(self.txtEdit)

        main.setCentralWidget(self.centralwidget)
        self.statusbar = QStatusBar(main)
        self.statusbar.setObjectName(u"statusbar")
        main.setStatusBar(self.statusbar)

        self.retranslateUi(main)

        QMetaObject.connectSlotsByName(main)
    # setupUi

    def retranslateUi(self, main):
        main.setWindowTitle(QCoreApplication.translate("main", u"Log Viewer", None))
        self.btnMarkErrors.setText(QCoreApplication.translate("main", u"Mark Errors", None))