pyqtgraph限制缩放到轴的上/下界

Question

所以 Pyqtgraph 会自动计算轴并在缩放时重新缩放，这很好。然而我有两个轴，频率和小时。频率可以采用 0-100 之间的任何值，小时可以采用 0-39 之间的任何值。如何将轴限制为这些上限/下限，以便当用户缩放或平移时它们不能超出这些值？

我的代码如下（3行，我的实际代码会绘制更多）：

from pyqtgraph.Qt import QtGui, QtCore
import numpy as np
import pyqtgraph as pg

pg.setConfigOption('background', 'w')
pg.setConfigOption('foreground', 'k')

from random import randint

class CustomViewBox(pg.ViewBox):
    def __init__(self, *args, **kwds):
        pg.ViewBox.__init__(self, *args, **kwds)
        self.setMouseMode(self.RectMode)

    ## reimplement right-click to zoom out
    def mouseClickEvent(self, ev):
        if ev.button() == QtCore.Qt.RightButton:
            #self.autoRange()
            self.setXRange(0,5)
            self.setYRange(0,10)

    def mouseDragEvent(self, ev):
        if ev.button() == QtCore.Qt.RightButton:
            ev.ignore()
        else:
            pg.ViewBox.mouseDragEvent(self, ev)


app = pg.mkQApp()

vb = CustomViewBox()

graph = pg.PlotWidget(viewBox=vb, enableMenu=False)

colour = []

for i in range(0,3):
    colourvalue = [randint(0,255), randint(0,255), randint(0,255)]
    tuple(colourvalue)
    colour.append(colourvalue)

y_data = [ 
    [['a',0],['b',1],['c',None],['d',6],['e',7]],
    [['a',5],['b',2],['c',1],['d',None],['e',1]],
    [['a',3],['b',None],['c',4],['d',9],['e',None]],
    ]

x_data = [0, 1, 2, 3, 4]

for i in range(3):
    xv = []
    yv = []
    for j, v in enumerate(row[i][1] for row in y_data):
        if v is not None:
            xv.append(int(j))
            yv.append(float(v))
    graph.plot(xv, yv, pen = colour[i], name=y_data[0][i][0])

graph.show()
graph.setWindowTitle('Hourly Frequency Graph')
graph.setXRange(0,5)
graph.setYRange(0,10)

graph.setLabel('left', "Frequency", units='%')
graph.setLabel('bottom', "Hour")
graph.showGrid(x=True, y=True)

if __name__ == '__main__':
    import sys
    if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
        QtGui.QApplication.instance().exec_()

预先感谢您的任何帮助和建议！

Answer 1

我知道这是一个旧问题，但以防万一其他人需要解决方案。通过获取当前轴（假设为最大缩小）并将这些值设置为视图框的范围，可以阻止用户缩小超过轴限制。

例如

range_ = graph.getViewBox().viewRange() 
graph.getViewBox().setLimits(xMin=range_[0][0], xMax=range_[0][1],   
                             yMin=range_[1][0], yMax=range_[1][1])   

文档：https://pyqtgraph.readthedocs.io/en/latest/graphicsItems/viewbox.html