pyqtgraph 鼠标交互：使用鼠标右键或中键缩放到所选框

Question

在 pyqtgraph examples -> View Box Freatures 中，我们可以通过设置 v2.setMouseMode(v2.RectMode)

使用鼠标交互“左拖动缩放到框”

但此交互仅在鼠标一键模式下可用。我如何修改交互，以便我可以在标准的三键鼠标模式下使用鼠标右键或鼠标中键 缩放到所选框？

谢谢大家！

Answer 1

pyqtgraph的ViewBoxclass只有两种“鼠标模式”：

PanMode：鼠标左键和中键用于拖动。鼠标右键拖动缩放in/out。
RectMode: 鼠标左键和中键用于缩放框。鼠标右键拖动缩放in/out。

左键和中键的作用相同的原因在于ViewBox class 的源代码。您希望鼠标左键拖动图片，鼠标中键缩放框，鼠标中键缩放框以通过拖动缩放 in/out。我的解决方案可能很激进，但它确实有效。我修改了class，使用源代码作为模型（来源：Pyqtgraph's ViewBox class）：

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

class ViewBox(pg.ViewBox):
    MyMode = 2
    def __init__(self):
        pg.ViewBox.__init__(self)
        
    def setMouseMode(self, mode):
        ## First we change this method to accept our new configuration
        if mode not in [ViewBox.PanMode, ViewBox.RectMode, ViewBox.MyMode]:
            raise Exception("Mode must be ViewBox.PanMode, ViewBox.RectMode or ViewBox.MyMode")
        self.state['mouseMode'] = mode
        self.sigStateChanged.emit(self)

    def mouseDragEvent(self, ev, axis=None):
        ev.accept()
        pos = ev.pos()
        lastPos = ev.lastPos()
        dif = pos - lastPos
        dif = dif * -1
        mouseEnabled = np.array(self.state['mouseEnabled'], dtype=np.float)
        mask = mouseEnabled.copy()
        if axis is not None:
            mask[1-axis] = 0.0

        ## Here is the main change for it to work    
        if ev.button() & QtCore.Qt.LeftButton:
            if self.state['mouseMode'] == ViewBox.RectMode and axis is None:
                if ev.isFinish():  ## This is the final move in the drag; change the view scale now
                    #print "finish"
                    self.rbScaleBox.hide()
                    ax = QtCore.QRectF(QtCore.QPointF(ev.buttonDownPos(ev.button())), QtCore.QPointF(pos))
                    ax = self.childGroup.mapRectFromParent(ax)
                    self.showAxRect(ax)
                    self.axHistoryPointer += 1
                    self.axHistory = self.axHistory[:self.axHistoryPointer] + [ax]
                else:
                    ## update shape of scale box
                    self.updateScaleBox(ev.buttonDownPos(), ev.pos())
            else:
                tr = self.childGroup.transform()
                tr = pg.functions.invertQTransform(tr)
                tr = tr.map(dif*mask) - tr.map(QtCore.QPointF(0,0))
                x = tr.x() if mask[0] == 1 else None
                y = tr.y() if mask[1] == 1 else None
                self._resetTarget()
                if x is not None or y is not None:
                    self.translateBy(x=x, y=y)
                self.sigRangeChangedManually.emit(self.state['mouseEnabled'])
        elif ev.button() & QtCore.Qt.MidButton:
            if self.state['mouseMode'] in {ViewBox.RectMode,ViewBox.MyMode} and axis is None:
                if ev.isFinish():  ## This is the final move in the drag; change the view scale now
                    #print "finish"
                    self.rbScaleBox.hide()
                    ax = QtCore.QRectF(QtCore.QPointF(ev.buttonDownPos(ev.button())), QtCore.QPointF(pos))
                    ax = self.childGroup.mapRectFromParent(ax)
                    self.showAxRect(ax)
                    self.axHistoryPointer += 1
                    self.axHistory = self.axHistory[:self.axHistoryPointer] + [ax]
                else:
                    ## update shape of scale box
                    self.updateScaleBox(ev.buttonDownPos(), ev.pos())
            else:
                tr = self.childGroup.transform()
                tr = pg.functions.invertQTransform(tr)
                tr = tr.map(dif*mask) - tr.map(QtCore.QPointF(0,0))
                x = tr.x() if mask[0] == 1 else None
                y = tr.y() if mask[1] == 1 else None
                self._resetTarget()
                if x is not None or y is not None:
                    self.translateBy(x=x, y=y)
                self.sigRangeChangedManually.emit(self.state['mouseEnabled'])
        elif ev.button() & QtCore.Qt.RightButton:
            if self.state['aspectLocked'] is not False:
                mask[0] = 0
            dif = ev.screenPos() - ev.lastScreenPos()
            dif = np.array([dif.x(), dif.y()])
            dif[0] *= -1
            s = ((mask * 0.02) + 1) ** dif
            tr = self.childGroup.transform()
            tr = pg.functions.invertQTransform(tr)
            x = s[0] if mouseEnabled[0] == 1 else None
            y = s[1] if mouseEnabled[1] == 1 else None
            center = QtCore.QPointF(tr.map(ev.buttonDownPos(QtCore.Qt.RightButton)))
            self._resetTarget()
            self.scaleBy(x=x, y=y, center=center)
            self.sigRangeChangedManually.emit(self.state['mouseEnabled'])

我们继承Pyqtgraph的ViewBoxclass，然后改两个方法：

setMouseMode() 兼容性
mouseDragEvent 3次点击的不同功能

在上面的 class 中，您保持其他两种鼠标模式不变，但添加了一种新模式：MyMode.

然后不要像这样添加 ViewBox :

sub2 = win.addLayout()
sub2.addLabel("<b>One-button mouse interaction:</b><br>left-drag zoom to box, wheel to zoom out.")
sub2.nextRow()
v2 = sub2.addViewBox()
v2.setMouseMode(v2.RectMode)
l2 = pg.PlotDataItem(y)
v2.addItem(l2)

你应该这样做：

sub2 = win.addLayout()
sub2.addLabel("<b>One-button mouse interaction:</b><br>left-drag zoom to box, wheel to zoom out.")
sub2.nextRow()
v2 = ViewBox() ## This is our new class
sub2.addItem(v2)
v2.setMouseMode(v2.MyMode) ## Seting the new Mouse Mode
l2 = pg.PlotDataItem(y)
v2.addItem(l2)

我测试了代码并没有发现任何问题，但我不得不承认这个解决方案有点夸张。希望有更简单的方法。

Edit: 例子取自Pyqtgraph的例子 (ViewBox Features) (Here)

pyqtgraph 鼠标交互：使用鼠标右键或中键缩放到所选框

pyqtgraph mouse interaction: using mouse right or middle button to zoom to the selected box

python

pyqt

pyqt5

pyside2

pyqtgraph