QStyledItemDelegate 绘画刷新问题

Question

我目前正在尝试围绕模型视图方法编写缩略图查看器应用程序。

在这个例子中，我只是尝试绘制 20 个方框，但我得到的似乎是一个随鼠标移动而更新的随机选择。滚动让事情变得更糟，有时只绘制框等。而且文本似乎根本没有呈现。

对我来说，这看起来像是 refresh/update 绘画方法的问题。我在这里遗漏了什么吗？

最终我需要展示很多项目。所有都包含一些标签和一个需要在运行时更新的像素图。所以我认为给它们上色是最快的解决办法。或者我尝试在 paint 方法中渲染我的小部件：

customWidget.render(painter, QtCore.QPoint(0,0), renderFlags=QtGui.QWidget.DrawChildren)

这似乎更慢，但至少可以工作。

这里有一个最小的工作示例来说明我的问题：

import sys
from PySide import QtCore
from PySide import QtGui

elements = range(20)

class ElementListModel(QtCore.QAbstractListModel):
    def __init__(self, elements = [], parent = None):
        super(ElementListModel, self).__init__()
        self.__elements = elements

    def rowCount(self, parent):
        return len(self.__elements)

    def data(self, index, role):
        if role == QtCore.Qt.DisplayRole:
            return str(self.__elements[index.row()])

class ElementThumbDelegate(QtGui.QStyledItemDelegate):
    def __init__(self, view, parent=None):
        super(ElementThumbDelegate, self).__init__(parent)

    def paint(self, painter, options, index):

        width = options.rect.width()
        height = options.rect.height()

        painter.setRenderHint(QtGui.QPainter.Antialiasing)
        painter.setPen(QtGui.QColor(255, 255, 255))
        painter.setBrush(QtGui.QColor(10, 10, 10))
        painter.drawRect(0, 0, width, height)
        painter.drawText(options.rect, QtCore.Qt.AlignHCenter | QtCore.Qt.AlignVCenter, str(index.data()))
        painter.translate(options.rect.topLeft())

    def sizeHint(self, options, index):
        return QtCore.QSize(50, 50)

def main():
    app = QtGui.QApplication(sys.argv)
    viewer = QtGui.QListView()

    viewModel = ElementListModel(elements)
    viewer.setModel(viewModel)
    viewer.setViewMode(QtGui.QListView.IconMode)
    viewer.setItemDelegate(ElementThumbDelegate(viewer))

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

if __name__ == '__main__':
    main()

提前致谢。非常感谢您提供任何帮助或指示下一步该去哪里！

Answer 1

事实证明，painter.translate() 与在查看器原点 (0,0) 处绘制框相结合会影响自动定位并导致问题。

委托到适当位置的转换由视图本身处理 - 无需手动执行。

工作代码：

import sys
from PySide import QtCore
from PySide import QtGui

elements = range(20)

class ElementListModel(QtCore.QAbstractListModel):
    def __init__(self, elements = [], parent = None):
        super(ElementListModel, self).__init__()
        self.__elements = elements

    def rowCount(self, parent):
        return len(self.__elements)

    def data(self, index, role):
        if role == QtCore.Qt.DisplayRole:
            return str(self.__elements[index.row()])

class ElementThumbDelegate(QtGui.QStyledItemDelegate):
    def __init__(self, view, parent=None):
        super(ElementThumbDelegate, self).__init__(parent)

    def paint(self, painter, options, index):
        painter.setRenderHint(QtGui.QPainter.Antialiasing)
        painter.setPen(QtGui.QColor(255, 255, 255))
        painter.setBrush(QtGui.QColor(10, 10, 10))
        painter.drawRect(options.rect)
        painter.drawText(options.rect, QtCore.Qt.AlignHCenter | QtCore.Qt.AlignVCenter, str(index.data()))

    def sizeHint(self, options, index):
        return QtCore.QSize(50, 50)

def main():
    app = QtGui.QApplication(sys.argv)
    viewer = QtGui.QListView()

    viewModel = ElementListModel(elements)
    viewer.setModel(viewModel)
    viewer.setViewMode(QtGui.QListView.IconMode)
    viewer.setItemDelegate(ElementThumbDelegate(viewer))

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

if __name__ == '__main__':
    main()

QStyledItemDelegate 绘画刷新问题

QStyledItemDelegate paint refresh issues

python

pyqt

pyside

paint

qstyleditemdelegate