PyQtGraphピクセルの色を取得する

Question

以下のPyQtGraphの例と非常によく似たコードがいくつかあります。また、マウスオーバーしている正確なピクセルの色（十字線のピクセル）をラベルに追加したいと思います。どうすればいい？

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

#generate layout 
app = QtGui.QApplication([]) 
win = pg.GraphicsWindow() 
win.setWindowTitle('pyqtgraph example: crosshair') 
label = pg.LabelItem(justify='right') 
win.addItem(label) 
p1 = win.addPlot(row=1, col=0) 
p2 = win.addPlot(row=2, col=0) 

region = pg.LinearRegionItem() 
region.setZValue(10) 
# Add the LinearRegionItem to the ViewBox, but tell the ViewBox to exclude this 
# item when doing auto-range calculations. 
p2.addItem(region, ignoreBounds=True) 

#pg.dbg() 
p1.setAutoVisible(y=True) 


#create numpy arrays 
#make the numbers large to show that the xrange shows data from 10000 to all the way 0 
data1 = 10000 + 15000 * pg.gaussianFilter(np.random.random(size=10000), 10) + 3000 * np.random.random(size=10000) 
data2 = 15000 + 15000 * pg.gaussianFilter(np.random.random(size=10000), 10) + 3000 * np.random.random(size=10000) 

p1.plot(data1, pen="r") 
p1.plot(data2, pen="g") 

p2.plot(data1, pen="w") 

def update(): 
    region.setZValue(10) 
    minX, maxX = region.getRegion() 
    p1.setXRange(minX, maxX, padding=0)  

region.sigRegionChanged.connect(update) 

def updateRegion(window, viewRange): 
    rgn = viewRange[0] 
    region.setRegion(rgn) 

p1.sigRangeChanged.connect(updateRegion) 

region.setRegion([1000, 2000]) 

#cross hair 
vLine = pg.InfiniteLine(angle=90, movable=False) 
hLine = pg.InfiniteLine(angle=0, movable=False) 
p1.addItem(vLine, ignoreBounds=True) 
p1.addItem(hLine, ignoreBounds=True) 


vb = p1.vb 

def mouseMoved(evt): 
    pos = evt[0] ## using signal proxy turns original arguments into a tuple 
    if p1.sceneBoundingRect().contains(pos): 
     mousePoint = vb.mapSceneToView(pos) 
     index = int(mousePoint.x()) 

     ####### 
     GET THE PIXEL COLOR AND ADD TO LABEL??? HOW? 
     ####### 

     if index > 0 and index < len(data1): 
      label.setText("<span style='font-size: 12pt'>x=%0.1f, <span style='color: red'>y1=%0.1f</span>, <span style='color: green'>y2=%0.1f</span>" % (mousePoint.x(), data1[index], data2[index])) 
     vLine.setPos(mousePoint.x()) 
     hLine.setPos(mousePoint.y()) 


proxy = pg.SignalProxy(p1.scene().sigMouseMoved, rateLimit=60, slot=mouseMoved) 
#p1.scene().sigMouseMoved.connect(mouseMoved) 


## Start Qt event loop unless running in interactive mode or using pyside. 
if __name__ == '__main__': 
    import sys 
    if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'): 
     QtGui.QApplication.instance().exec_() 

Answer 1

mouseMoveEventメソッドをオーバーライドし、ウィジェットを記録してピクセルを取得する必要があります。

class MyGraphicsWindow(pg.GraphicsWindow): 
    def __init__(self, parent=None): 
     pg.GraphicsWindow.__init__(self, parent=parent) 
     self.setMouseTracking(True) 

    def mouseMoveEvent(self, e): 
     image = QtGui.QPixmap.grabWidget(self).toImage() 
     color = QtGui.QColor(image.pixel(e.pos())) 
     print(color.name()) 
     print("red:{}, green:{}, blue:{}".format(color.red(), color.green(), color.blue())) 
     pg.GraphicsWindow.mouseMoveEvent(self, e) 

はその後、我々はwin = MyGraphicsWindow()

完全なコードでwin = pg.GraphicsWindow()を置き換えます：

class MyGraphicsWindow(pg.GraphicsWindow): 
    def __init__(self, parent=None): 
     pg.GraphicsWindow.__init__(self, parent=parent) 
     self.setMouseTracking(True) 

    def mouseMoveEvent(self, e): 
     image = QtGui.QPixmap.grabWidget(self).toImage() 
     color = QtGui.QColor(image.pixel(e.pos())) 
     print(color.name()) 
     print("{}, {}, {}".format(color.red(), color.green(), color.blue())) 
     pg.GraphicsWindow.mouseMoveEvent(self, e) 


#generate layout 
app = QtGui.QApplication(sys.argv) 
win = MyGraphicsWindow() 
win.setWindowTitle('pyqtgraph example: crosshair') 
label = pg.LabelItem(justify='right') 
win.addItem(label) 
p1 = win.addPlot(row=1, col=0) 
p2 = win.addPlot(row=2, col=0) 

region = pg.LinearRegionItem() 
region.setZValue(10) 
# Add the LinearRegionItem to the ViewBox, but tell the ViewBox to exclude this 
# item when doing auto-range calculations. 
p2.addItem(region, ignoreBounds=True) 

#pg.dbg() 
p1.setAutoVisible(y=True) 


#create numpy arrays 
#make the numbers large to show that the xrange shows data from 10000 to all the way 0 
data1 = 10000 + 15000 * pg.gaussianFilter(np.random.random(size=10000), 10) + 3000 * np.random.random(size=10000) 
data2 = 15000 + 15000 * pg.gaussianFilter(np.random.random(size=10000), 10) + 3000 * np.random.random(size=10000) 

p1.plot(data1, pen="r") 
p1.plot(data2, pen="g") 

p2.plot(data1, pen="w") 

def update(): 
    region.setZValue(10) 
    minX, maxX = region.getRegion() 

sys.exit(app.exec_()) 

我々は pg.GraphicsWindowから継承するクラスを作成します。このため