Qt HTML Delegate using PyQt5

delegate.py

from PyQt5.QtCore import QModelIndex, QPoint, QSize, Qt
from PyQt5.QtGui import QTextDocument, QAbstractTextDocumentLayout, QPainter, QLinearGradient, QColor, QPalette
from PyQt5.QtWidgets import QStyledItemDelegate, QStyle, QStyleOptionViewItem


def find_colors(option: QStyleOptionViewItem, even_row: bool):
    if option.state & QStyle.State_Active and option.state & QStyle.State_Selected:
        text_color = option.palette.color(QPalette.Active, QPalette.HighlightedText)
        bg_color = option.palette.color(QPalette.Active, QPalette.Highlight)
    elif option.state & QStyle.State_Selected:
        text_color = option.palette.color(QPalette.Inactive, QPalette.Text)
        bg_color = option.palette.color(QPalette.Inactive, QPalette.Highlight)
    elif even_row and option.state & QStyle.State_Active:
        text_color = option.palette.color(QPalette.Inactive, QPalette.Text)
        bg_color = option.palette.color(QPalette.Active, QPalette.Base)
    elif even_row:
        text_color = option.palette.color(QPalette.Inactive, QPalette.Text)
        bg_color = option.palette.color(QPalette.Inactive, QPalette.Base)
    elif option.state & QStyle.State_Active:
        text_color = option.palette.color(QPalette.Inactive, QPalette.Text)
        bg_color = option.palette.color(QPalette.Active, QPalette.AlternateBase)
    else:
        text_color = option.palette.color(QPalette.Inactive, QPalette.Text)
        bg_color = option.palette.color(QPalette.Inactive, QPalette.AlternateBase)
    return text_color, bg_color


class HtmlDelegate(QStyledItemDelegate):

    def __init__(self, parent=None):
        super().__init__(parent)
        self.__text_doc = QTextDocument()
        self.__text_doc.setDocumentMargin(0.0)

    def paint(self, painter: QPainter, option: QStyleOptionViewItem, index: QModelIndex):
        new_option = QStyleOptionViewItem(option)
        self.initStyleOption(new_option, index)

        self.__text_doc.setHtml(new_option.text)
        new_option.text = ""

        style = new_option.widget.style()
        style.drawControl(QStyle.CE_ItemViewItem, new_option, painter, new_option.widget)

        text_rect = style.subElementRect(QStyle.SE_ItemViewItemText, new_option, new_option.widget)
        pc = QAbstractTextDocumentLayout.PaintContext()

        # Colors
        tc, bg = find_colors(new_option, index.row() % 2 == 0)
        pc.palette.setColor(QPalette.Text, tc)

        # Points
        text_point = QPoint(text_rect.topLeft().x() + 2,
                            text_rect.topLeft().y() + round(
                                0.5 * (option.rect.height() - self.__text_doc.size().height())))
        grad_point = QPoint(text_rect.topRight().x() - 43, option.rect.topRight().y())

        # Gradient
        gradient = QLinearGradient(grad_point.x(), option.rect.height(), grad_point.x() + 35, option.rect.height())
        gradient.setColorAt(0, QColor(Qt.transparent))
        gradient.setColorAt(1, bg)

        # Paint action
        painter.save()
        painter.translate(text_point)
        self.__text_doc.documentLayout().draw(painter, pc)
        painter.translate(-text_point)
        painter.fillRect(option.rect, gradient)
        painter.restore()

    def sizeHint(self, option: QStyleOptionViewItem, index: QModelIndex):
        return QSize(int(self.__text_doc.idealWidth()), int(self.__text_doc.size().height()))

gui.py

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(550, 300)
        MainWindow.setWindowTitle("HTML Delegate")
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.horizontalLayout = QtWidgets.QHBoxLayout(self.centralwidget)
        self.horizontalLayout.setObjectName("horizontalLayout")
        self.tableView = QtWidgets.QTableView(self.centralwidget)
        self.tableView.setObjectName("tableView")
        self.horizontalLayout.addWidget(self.tableView)
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        pass

main.py

from PyQt5 import QtWidgets
from PyQt5.QtCore import QItemSelectionModel
from PyQt5.QtGui import QStandardItemModel, QStandardItem
from PyQt5.QtWidgets import QAbstractItemView

from delegate import HtmlDelegate
from gui import Ui_MainWindow

# Supported subset: http://doc.qt.io/qt-5/richtext-html-subset.html
CONTENT = [
    '<b>Hello</b>',
    'This is <span style="background-color: #FFBF00">highlighted</span> text using <i>HTML</i>. '
    'It is also possible using a SyntaxHighlighter in the delegate.',
    '<tt>More stuff supported ... </tt>'
]

if __name__ == "__main__":
    import sys

    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()

    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)

    tv = ui.tableView

    # Model
    mo = QStandardItemModel(tv)
    tv.setModel(mo)

    # Headers
    tv.horizontalHeader().setStretchLastSection(True)
    tv.horizontalHeader().hide()
    tv.verticalHeader().hide()

    # Delegate
    tv.setItemDelegateForColumn(0, HtmlDelegate(parent=tv))

    # Selection
    tv.setSelectionMode(QAbstractItemView.SingleSelection)
    tv.setSelectionBehavior(QAbstractItemView.SelectRows)

    # Misc
    tv.setAlternatingRowColors(True)
    tv.setShowGrid(False)

    for item in map(QStandardItem, CONTENT):
        mo.appendRow(item)

    tv.selectionModel().setCurrentIndex(mo.index(0, 0), QItemSelectionModel.ClearAndSelect | QItemSelectionModel.Rows)

    MainWindow.show()
    sys.exit(app.exec_())