QGraphicsView中选中QGraphicsPathItem使之不出现虚线框

最新推荐文章于 2023-09-02 16:44:47 发布

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最新推荐文章于 2023-09-02 16:44:47 发布

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CC 4.0 BY-SA版权

文章标签： c/c++

原文链接：http://www.cnblogs.com/jsben/p/4909885.html

本文介绍如何使用Qt绘制贝赛尔曲线，并在选中曲线时显示控制点及连接线，同时解决了选中时虚线框的问题。

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绘制一条贝赛尔曲线，当选中该曲线时，显示其控制点并把控制点和起始点连结起来，从而可以清晰的显示曲线的参数。

# -*- coding: utf-8 -*-
from PyQt4 import QtGui, QtCore

class PathItem(QtGui.QGraphicsPathItem):
def __init__(self, parent=None, scene=None):
QtGui.QGraphicsPathItem.__init__(self, parent=parent, scene=scene)
self.setFlag(QtGui.QGraphicsItem.ItemIsSelectable)
self.setFlag(QtGui.QGraphicsItem.ItemIsMovable)
path = QtGui.QPainterPath()
self.start_x, self.start_y = 20, 30
self.end_x, self.end_y = 80, 80
self.ctrl1_x, self.ctrl1_y = 80, 0
self.ctrl2_x, self.ctrl2_y = 50, 50
path.moveTo(self.start_x, self.start_y)
path.cubicTo(self.ctrl1_x, self.ctrl1_y, self.ctrl2_x, self.ctrl2_y, self.end_x, self.end_y)
self.setPath(path)

def paint(self, painter, options, widget):
if self.isSelected():
painter.drawEllipse(self.ctrl1_x - 3, self.ctrl1_y - 3, 6, 6)
painter.drawLine(self.start_x, self.start_y, self.ctrl1_x, self.ctrl1_y)

painter.drawEllipse(self.ctrl2_x - 3, self.ctrl2_y - 3, 6, 6)
painter.drawLine(self.end_x, self.end_y, self.ctrl2_x, self.ctrl2_y)

# 1

QtGui.QGraphicsPathItem.paint(self, painter, options, widget)

if __name__ == '__main__':
import sys
app = QtGui.QApplication(sys.argv)

view = QtGui.QGraphicsView()
scene = QtGui.QGraphicsScene(view)
view.setRenderHint(QtGui.QPainter.Antialiasing)
view.setScene(scene)
pathItem = PathItem(scene=scene)
view.show()

sys.exit(app.exec_())
效果如下所示：