How to make item view render rich (html) text in PyQt?

Question

I'm trying to translate code from this thread in python:

    import sys
from PyQt4.QtCore import *
from PyQt4.QtGui import *

__data__ = [
        "Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.",
        "Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.",
        "Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.",
        "Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."
    ]

def get_html_box(text):
    return '''<table border="0" width="100%"><tr width="100%" valign="top">
        <td width="1%"><img src="softwarecenter.png"/></td>
        <td><table border="0" width="100%" height="100%">
        <tr><td><b><a href="http://www.google.com"&gt;titolo&lt;/a&gt;&lt;/b&gt;&lt;/td&gt;&lt;/tr&gt;
        <tr><td>{0}</td></tr><tr><td align="right">88/88/8888, 88:88</td></tr>
        </table></td></tr></table>'''.format(text)

class HTMLDelegate(QStyledItemDelegate):

    def paint(self, painter, option, index):
        model = index.model()
        record = model.listdata[index.row()]
        doc = QTextDocument(self)
        doc.setHtml(get_html_box(record))
        doc.setTextWidth(option.rect.width())
        painter.save()
        ctx = QAbstractTextDocumentLayout.PaintContext()
        ctx.clip = QRectF(0, option.rect.top(), option.rect.width(), option.rect.height())
        dl = doc.documentLayout()
        dl.draw(painter, ctx)
        painter.restore()

    def sizeHint(self, option, index):
        model = index.model()
        record = model.listdata[index.row()]
        doc = QTextDocument(self)
        doc.setHtml(get_html_box(record))
        doc.setTextWidth(option.rect.width())
        return QSize(doc.idealWidth(), doc.size().height())

class MyListModel(QAbstractListModel):

    def __init__(self, parent=None, *args):
        super(MyListModel, self).__init__(parent, *args)
        self.listdata = __data__

    def rowCount(self, parent=QModelIndex()):
        return len(self.listdata)

    def data(self, index, role=Qt.DisplayRole):
        return index.isValid() and QVariant(self.listdata[index.row()]) or QVariant()

class MyWindow(QWidget):

    def __init__(self, *args):
        super(MyWindow, self).__init__(*args)
        # listview
        self.lv = QListView()
        self.lv.setModel(MyListModel(self))
        self.lv.setItemDelegate(HTMLDelegate(self))
        self.lv.setResizeMode(QListView.Adjust)
        # layout
        layout = QVBoxLayout()
        layout.addWidget(self.lv)
        self.setLayout(layout)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    w = MyWindow()
    w.show()
    sys.exit(app.exec_())

Element's size and position are not calculated correctly I guess, perhaps because I haven't understand at all the style related parts from original code. Can someone help me?

Answer 1

The code doesn't respect the desired target drawing area (option.rect):

ctx.clip = QRectF(0, option.rect.top(), option.rect.width(), option.rect.height())

The above clips the portion of the QTextDocument drawn to the specified region. You really want to translate the painter so that the it starts painting at the topLeft() of the rectangle and then extends for the specified width and height. Since documentLayout() assumes the painter is at the origin (i.e. in the position where it should draw), this is the fix:

def paint(self, painter, option, index):
    model = index.model()
    record = model.listdata[index.row()]
    doc = QTextDocument(self)
    doc.setHtml(get_html_box(record))
    doc.setTextWidth(option.rect.width())
    ctx = QAbstractTextDocumentLayout.PaintContext()

    painter.save()
    painter.translate(option.rect.topLeft());
    painter.setClipRect(option.rect.translated(-option.rect.topLeft()))
    dl = doc.documentLayout()
    dl.draw(painter, ctx)
    painter.restore()