使用PyQtGraph绘制数据滚动图形（4）

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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。

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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_()