问题描述
我使用了以下来源并对其进行了一些修改,以获得以下小示例:
I used the following source and modified it a bit, to get the following mini example:
import sys
from PyQt5 import QtCore, QtWidgets
class GraphicsScene(QtWidgets.QGraphicsScene):
def __init__(self):
super(GraphicsScene, self).__init__()
self.setSceneRect(0, 0, 600, 400)
def mousePressEvent(self, event):
if event.buttons() == QtCore.Qt.LeftButton:
x = event.scenePos().x()
y = event.scenePos().y()
self.addRect(x, y, 100, 100)
elif event.buttons() == QtCore.Qt.RightButton:
for elem in self.items():
print(elem.x())
super(GraphicsScene, self).mousePressEvent(event)
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
scene = GraphicsScene()
w = QtWidgets.QGraphicsView(scene)
w.resize(610, 410)
w.show()
sys.exit(app.exec_())
这个想法是,通过点击鼠标左键来创建新的矩形(这已经有效了)并通过点击鼠标右键删除最近的矩形.我知道,如何找到最近的矩形,但为此我需要现有矩形的坐标.如果我们向场景中添加一个新矩形,我们会执行以下操作:
The idea is, to create new rectangles by making left mouse clicks (this works already) and delete the nearest rectangle by making a right mouse click. I know, how I can find the nearest rectangle, but for this I need the coordinates of the existing rectangles. If we add a new rectangle to the scene, we do the following:
self.addRect(x, y, 100, 100)
但是如果我遍历场景中的所有元素,并尝试使用此方法获取元素的 x 坐标:
But if I iterate over all elements in the scene, and try to get the x-coordinate of the elements using this:
for elem in self.items():
print(elem.x())
print(elem.pos().x())
print(elem.scenePos().x())
那么所有的打印输出都是零.我已经看过docu,但正如我理解它,我正在按照文档的建议做.你知道我做错了什么吗?
then all the print-outputs are zero. I had already a look at the docu, but as I understand it I am doing exactly what the docu recommends. Do you know what I am doing wrong?
当然,我可以将所有坐标保存在一个附加列表中,使用该列表中的值计算最近的矩形,使用以下方法删除每个矩形:
Of course, I could save all the coordinates in an additional list, compute the nearest rectangle with the values in that list, delete each rectangle by using:
for elem in self.items():
self.removeItem(elem)
并绘制剩余的矩形.但是,我希望有一个更干净的版本.:)
and plot the remaining rectangles. However, I hope there is a cleaner version for this. :)
推荐答案
作为 文档说明:
请注意,item 的几何图形是在 item 坐标中提供的,并且它的位置被初始化为 (0, 0).例如,如果添加了 QRect(50, 50, 100, 100),其左上角将位于相对于项目坐标系中的原点的 (50, 50) 处.
所以有两种选择:
- 在位置 (0, 0) 添加一个指定大小的矩形,然后将其移动到所需位置:
rectItem = self.addRect(0, 0, 100, 100)
rectItem.setPos(x, y)
- 使用 addRect 中的坐标并根据矩形的左上角获取实际位置:
for elem in self.items():
pos = elem.pos()
if isinstance(elem, QtWidgets.QGraphicsRectItem):
pos += elem.rect().topLeft()
这篇关于PyQt5:GraphicsScene 的所有项的坐标为 0.0的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!