我正在嘗試旋轉(zhuǎn) QGraphicsView 對象的背景，但遇到了麻煩。紅筆描述了我遇到的問題。我想要的是：我想讓箭頭保持在屏幕中間的中心位置。我希望背景圖像以屏幕中心為參考旋轉(zhuǎn)我想在 QGraphicsView 中定義一個(gè)矩形。這將被定義為界定顯示內(nèi)容的區(qū)域。因此，每次我旋轉(zhuǎn)屏幕時(shí)。圖像“未覆蓋”的區(qū)域始終位于矩形邊界之外。我想在屏幕中間定義旋轉(zhuǎn)參考點(diǎn)（x=VIEW_WIDTH/2，y=VIEW_HEIGHT/2）這是我的代碼：首先，我將顯示箭頭類：from PyQt5 import QtCore, QtGui, QtWidgets # importation of some libraries # Construnction of an arrow item, it'll be used in the QGraphicsView class ArrowItem(QtWidgets.QGraphicsPathItem): # it inherit QgraphicsPathItem, which allows to handle it # in the QgraphicsView def __init__(self, parent=None): # The init method super().__init__(parent) self._length = -1 self._angle = 0 self._points = QtCore.QPointF(), QtCore.QPointF(), QtCore.QPointF() # with three points we # construct a triangle. self.length = 40.0 # the basic triangle length self.rotate(180) # the triangle was built upside down, though I've just ran the function 'rotate' @property def angle(self): """ angle of the arrow :return: """ return self._angle @angle.setter def angle(self, angle): self._angle = angle @property def length(self): return self._length @length.setter def length(self, l): self._length = l pos_top = QtCore.QPointF(0, l * 4 / 5) pos_left = QtCore.QPointF(-l * 3 / 5, -l / 5) pos_right = QtCore.QPointF( l * 3 / 5, -l / 5, ) path = QtGui.QPainterPath() path.moveTo(pos_top) path.lineTo(pos_right) path.lineTo(pos_left) self.setPath(path) self._points = pos_top, pos_left, pos_right def paint(self, painter, option, widget): pos_top, pos_left, pos_right = self._points left_color = QtGui.QColor("#cc0000") right_color = QtGui.QColor("#ff0000") bottom_color = QtGui.QColor("#661900")
1 回答
慕姐4208626
TA貢獻(xiàn)1852條經(jīng)驗(yàn) 獲得超7個(gè)贊
如果你想旋轉(zhuǎn)一個(gè)QGraphicsItem，沒有必要使用QTransform，只需使用setRotation方法即可。另一方面，必須對圖像進(jìn)行縮放，以便與可見區(qū)域相交的旋轉(zhuǎn)區(qū)域與可見區(qū)域相同，并且最小區(qū)域計(jì)算如下：sqrt(2) x max(width, height)。綜合以上情況，解決方案是：
from PyQt5 import QtCore, QtGui, QtWidgets
class ArrowItem(QtWidgets.QGraphicsPathItem):
def __init__(self, parent=None):
super().__init__(parent)
self._length = -1
self._points = (
QtCore.QPointF(),
QtCore.QPointF(),
QtCore.QPointF(),
)
self.length = 40.0
@property
def length(self):
return self._length
@length.setter
def length(self, l):
self._length = l
pos_top = QtCore.QPointF(0, l * 4 / 5)
pos_left = QtCore.QPointF(-l * 3 / 5, -l / 5)
pos_right = QtCore.QPointF(
l * 3 / 5,
-l / 5,
)
path = QtGui.QPainterPath()
path.moveTo(pos_top)
path.lineTo(pos_right)
path.lineTo(pos_left)
self.setPath(path)
self._points = pos_top, pos_left, pos_right
def paint(self, painter, option, widget):
pos_top, pos_left, pos_right = self._points
left_color = QtGui.QColor("#cc0000")
right_color = QtGui.QColor("#ff0000")
bottom_color = QtGui.QColor("#661900")
path_left = QtGui.QPainterPath()
path_left.lineTo(pos_top)
path_left.lineTo(pos_left)
path_right = QtGui.QPainterPath()
path_right.lineTo(pos_top)
path_right.lineTo(pos_right)
path_bottom = QtGui.QPainterPath()
path_bottom.lineTo(pos_left)
path_bottom.lineTo(pos_right)
painter.setPen(QtGui.QColor("black"))
painter.setBrush(left_color)
painter.drawPath(path_left)
painter.setBrush(right_color)
painter.drawPath(path_right)
painter.setBrush(bottom_color)
painter.drawPath(path_bottom)
def moveTo(self, next_position, duration=100):
self._animation = QtCore.QVariantAnimation()
self._animation.setStartValue(self.pos())
self._animation.setEndValue(next_position)
self._animation.setDuration(duration)
self._animation.start(QtCore.QAbstractAnimation.DeleteWhenStopped)
self._animation.valueChanged.connect(self.setPos)
class MainWindow(QtWidgets.QMainWindow):
VIEW_HEIGHT = 600
VIEW_WIDTH = 900
def __init__(self, parent=None):
super().__init__(parent)
self.scene = QtWidgets.QGraphicsScene(self)
self.view = QtWidgets.QGraphicsView(self.scene)
self.status_btn = QtWidgets.QPushButton("Status")
self.settings_btn = QtWidgets.QPushButton("Settings")
self.analyze_btn = QtWidgets.QPushButton("Analyze")
self.field_btn = QtWidgets.QPushButton("Field")
self.guide_btn = QtWidgets.QPushButton("Guide")
self.mapping_btn = QtWidgets.QPushButton("Mapping")
central_widget = QtWidgets.QWidget()
self.setCentralWidget(central_widget)
vlayl = QtWidgets.QVBoxLayout()
vlayl.addWidget(self.status_btn)
vlayl.addWidget(self.settings_btn)
vlayl.addWidget(self.analyze_btn)
vlayr = QtWidgets.QVBoxLayout()
vlayr.addWidget(self.field_btn)
vlayr.addWidget(self.guide_btn)
vlayr.addWidget(self.mapping_btn)
hlay = QtWidgets.QHBoxLayout(central_widget)
hlay.addLayout(vlayl)
hlay.addWidget(self.view)
hlay.addLayout(vlayr)
self.status_btn.clicked.connect(self.rotate_arrow)
self.guide_btn.clicked.connect(self.rotate_pixmap)
self.view.setFixedSize(self.VIEW_WIDTH, self.VIEW_HEIGHT)
r = self.view.mapToScene(self.view.viewport().rect()).boundingRect()
self.view.setSceneRect(r)
factor = 1.5 * max(self.VIEW_WIDTH, self.VIEW_HEIGHT)
pixmap = QtGui.QPixmap("ola.png").scaled(factor, factor)
self.pixmap_item = self.scene.addPixmap(pixmap)
center = self.pixmap_item.boundingRect().center()
self.pixmap_item.setPos(-center)
self.pixmap_item.setTransformOriginPoint(center)
self.arrow_item = ArrowItem()
self.scene.addItem(self.arrow_item)
def rotate_arrow(self):
delta = 30.0
self.arrow_item.setRotation(self.arrow_item.rotation() + delta)
def rotate_pixmap(self):
delta = 15.0
self.pixmap_item.setRotation(self.pixmap_item.rotation() + delta)
self.arrow_item.setRotation(self.arrow_item.rotation() + delta)
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
w = MainWindow()
w.show()
sys.exit(app.exec_())
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