使用PyQtGraph绘制数据滚动图形（4）

app = pg.QtGui.QApplication([])
win = pg.GraphicsWindow(title="数据滚动")
win.resize(600,300)

p = win.addPlot()
# Use automatic downsampling and clipping to reduce the drawing load
p.setDownsampling(mode='peak')
p.setClipToView(True)
curve = p.plot()

data = np.empty(100)
ptr = 0

def update():
    global data, ptr
    data[ptr] = np.random.normal()
    ptr += 1

    if ptr >= data.shape[0]: #当ptr大于等于data的长度时，改变data的长度
        tmp = data
        data = np.empty(data.shape[0] * 2)
        data[:tmp.shape[0]] = tmp

    curve.setData(data[:ptr])

timer = QtCore.QTimer()
timer.timeout.connect(update)
timer.start(100)

app.exec_()

以上的图形中包含从“0”时刻开始的所有数据，随着数据的不断增加，坐标也随之变化。

app = pg.QtGui.QApplication([])
win = pg.GraphicsWindow(title="数据滚动")
win.resize(600,300)

p = win.addPlot()
# Use automatic downsampling and clipping to reduce the drawing load
p.setDownsampling(mode='peak')
p.setClipToView(True)
p.setRange(xRange=[-100,0])#将横坐标的范围限定为[-100,0]
p.setLimits(xMax=0)# 横坐标的最大值为0
curve = p.plot()

data = np.empty(100)
ptr = 0

def update():
    global data, ptr
    data[ptr] = np.random.normal()
    ptr += 1

    if ptr >= data.shape[0]:
        tmp = data
        data = np.empty(data.shape[0] * 2)
        data[:tmp.shape[0]] = tmp

    curve.setData(data[:ptr])
    curve.setPos(-ptr, 0)#

timer = QtCore.QTimer()
timer.timeout.connect(update)
timer.start(100)

app.exec_()