如何在PyQt中使项目视图渲染富文本（HTML）？

Question

我正在尝试把这个讨论里的代码翻译成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">titolo</a></b></td></tr>
        <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_())

我觉得元素的大小和位置没有正确计算，可能是因为我完全不理解原始代码中与样式相关的部分。有人能帮我吗？

Answer 1

这段代码没有按照我们想要的绘图区域（option.rect）来工作：

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

上面的代码会把要绘制的QTextDocument的一部分裁剪掉，实际上你应该移动画笔的位置，让它从矩形的左上角（topLeft()）开始绘制，然后再按照指定的宽度和高度进行扩展。因为documentLayout()假设画笔是在原点（也就是应该绘制的位置），所以这里需要做这样的调整：

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()