【发布时间】：2019-04-03 21:42:58
【问题描述】：
我想用QPainter 画一些线，然后将线的起点(x1,y1) 坐标移动到centerpoint 和其他一些想要从中心偏移的线。这些线应该基于椭圆的值或其他值以编程方式运行。我已经尝试过不同的方法来解决它，但不起作用。
到QRect可以使用
moveCenter, moveTopLeft, etc...
但是对于Qline，没有这样的方法。根据PyQt doc，可以这样画一条线：
QLine(int x1, int y1, int x2, int y2)
QLine(const QPoint &p1, const QPoint &p2)
也许应该使用这条线来抵消它。但不知道怎么做。
translated(const QPoint &offset)
另一方面想绘制一些文本并以与Qline类似的方式偏移它们。
看看下面的图，看看我到底想做什么？
可视化
到目前为止我所取得的成就。
我想要达到的目标。
代码：
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
class Foo(QtWidgets.QWidget):
def __init__(self, parent=None):
super(Foo, self).__init__(parent)
self.setGeometry(QtCore.QRect(200, 100, 700, 600))
self.paint = Paint()
self.sizeHint()
self.lay = QtWidgets.QVBoxLayout()
self.lay.addWidget(self.paint)
self.setLayout(self.lay)
class Paint(QtWidgets.QWidget):
def __init__(self, parent=None):
super(Paint, self).__init__(parent)
self.setBackgroundRole(QtGui.QPalette.Base)
self.setAutoFillBackground(True)
xl = self.rect().center().x()
yl = self.rect().center().y()
self.e = QtCore.QRect(QtCore.QPoint(), QtCore.QSize(250, 250))
self.l = QtCore.QLine(QtCore.QPoint(xl, yl) , QtCore.QPoint(self.width(), self.height()/2))
def paintEvent(self, event):
pen = QtGui.QPen()
brush = QtGui.QBrush( QtCore.Qt.darkCyan, QtCore.Qt.Dense7Pattern)
painter = QtGui.QPainter(self)
painter.setBrush(brush)
painter.setPen(pen)
painter.setRenderHint(QtGui.QPainter.Antialiasing)
self.e.moveCenter(self.rect().center())
painter.drawEllipse(self.e)
painter.drawLine(self.l)
# painter.drawText('D')
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
w = Foo()
w.show()
sys.exit(app.exec_())
更新问题：
我已经更新了代码，我设法画出我想要的东西。但面临另一个挑战。如下图所示。
代码运行和显示时
Widget最小化或最大化时，有些线条消失了？
更新代码：
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
class Foo(QtWidgets.QWidget):
def __init__(self, parent=None):
super(Foo, self).__init__(parent)
self.setGeometry(QtCore.QRect(200, 100, 700, 600))
self.paint = Paint()
self.sizeHint()
self.lay = QtWidgets.QVBoxLayout()
self.lay.addWidget(self.paint)
self.setLayout(self.lay)
class Paint(QtWidgets.QWidget):
def __init__(self, parent=None):
super(Paint, self).__init__(parent)
self.setBackgroundRole(QtGui.QPalette.Base)
self.setAutoFillBackground(True)
self.e = QtCore.QRect(QtCore.QPoint(), QtCore.QSize(250, 250))
self.l1 = QtCore.QLine(QtCore.QPoint(), QtCore.QPoint(200, 0))
self.l2 = QtCore.QLine(QtCore.QPoint(), QtCore.QPoint(0, -200))
self.vl = QtCore.QLine(QtCore.QPoint(), QtCore.QPoint(0, -125))
delta = QtCore.QPoint(20, 0)
self.hl = QtCore.QLine(-delta, self.e.topRight() + delta)
self.al = QtCore.QLine(QtCore.QPoint(), QtCore.QPoint(-20, -20))
self.a2 = QtCore.QLine(QtCore.QPoint(), QtCore.QPoint(-20, 20))
self.a3 = QtCore.QLine(QtCore.QPoint(), QtCore.QPoint(20, 20))
self.a4 = QtCore.QLine(QtCore.QPoint(), QtCore.QPoint(-20, 20))
self._factor = 1.0
def paintEvent(self, event):
pen = QtGui.QPen()
brush = QtGui.QBrush( QtCore.Qt.darkCyan, QtCore.Qt.Dense7Pattern)
painter = QtGui.QPainter(self)
painter.setBrush(brush)
painter.setPen(pen)
painter.setRenderHint(QtGui.QPainter.Antialiasing)
self.e.moveCenter(self.rect().center())
self.l1.translate(self.rect().center() - self.l1.p1())
self.l2.translate(self.rect().center() - self.l2.p1())
self.al.translate(self.l1.p2())
self.a2.translate(self.l1.p2())
painter.translate(self.rect().center())
painter.scale(self._factor, self._factor)
painter.translate(-self.rect().center())
painter.drawEllipse(self.e)
painter.drawLine(self.l1)
painter.drawLine(self.l2)
fnt = painter.font()
fnt.setPointSize(20)
painter.setFont(fnt)
h = QtGui.QFontMetrics(painter.font()).height()
p = QtCore.QPoint(self.rect().center().x(), self.e.top() - 3*h)
u = QtCore.QPoint(self.e.right() + 3*h, self.rect().center().y())
painter.drawText(p, "y")
painter.drawText(u, "x")
r = QtCore.QRect(QtCore.QPoint(self.e.x(), self.e.bottom()), QtCore.QSize(self.e.width(), h))
painter.drawText(r, QtCore.Qt.AlignCenter, "D = 350mm")
offset = QtCore.QPoint(0, 1.5*h)
self.vl.translate(self.e.bottomLeft() - self.vl.p1() + offset)
painter.drawLine(self.vl)
self.vl.translate(self.e.width(), 0)
painter.drawLine(self.vl)
self.hl.translate(self.e.bottomLeft() + offset - QtCore.QPoint(0, 0.4*h))
self.a3.translate(self.l2.p2())
self.a4.translate(self.l2.p2())
painter.drawLine(self.hl)
painter.drawLine(self.al)
painter.drawLine(self.a2)
painter.drawLine(self.a3)
painter.drawLine(self.a4)
def wheelEvent(self, event):
self._factor *= 1.01**(event.angleDelta().y()/15.0)
self.update()
super(Paint, self).wheelEvent(event)
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
w = Foo()
w.show()
sys.exit(app.exec_())
我不知道它为什么会这样？任何评论或帮助我都非常感谢。
【问题讨论】：
标签： python python-3.x pyqt pyqt5 qpainter