On Tue, Mar 22, 2022 at 10:29 PM vpicouet ***@***.***> wrote: Bug summary I think xy[4] = .25, val[0] should be commented in /matplotlib/widgets. py", line 915, in set_val as it prevents to initialized value for RangeSlider Code for reproduction import numpy as npimport matplotlib.pyplot as pltfrom matplotlib.widgets import RangeSlider # generate a fake imagenp.random.seed(19680801)N = 128img = np.random.randn(N, N) fig, axs = plt.subplots(1, 2, figsize=(10, 5))fig.subplots_adjust(bottom=0.25) im = axs[0].imshow(img)axs[1].hist(img.flatten(), bins='auto')axs[1].set_title('Histogram of pixel intensities') # Create the RangeSliderslider_ax = fig.add_axes([0.20, 0.1, 0.60, 0.03])slider = RangeSlider(slider_ax, "Threshold", img.min(), img.max(),valinit=[0.0,0.0]) # Create the Vertical lines on the histogramlower_limit_line = axs[1].axvline(slider.val[0], color='k')upper_limit_line = axs[1].axvline(slider.val[1], color='k') def update(val): # The val passed to a callback by the RangeSlider will # be a tuple of (min, max) # Update the image's colormap im.norm.vmin = val[0] im.norm.vmax = val[1] # Update the position of the vertical lines lower_limit_line.set_xdata([val[0], val[0]]) upper_limit_line.set_xdata([val[1], val[1]]) # Redraw the figure to ensure it updates fig.canvas.draw_idle() slider.on_changed(update)plt.show() Actual outcome File "<ipython-input-52-b704c53e18d4>", line 19, in <module> slider = RangeSlider(slider_ax, "Threshold", img.min(), img.max(),valinit=[0.0,0.0]) File "/Users/Vincent/opt/anaconda3/envs/py38/lib/python3.8/site-packages/matplotlib/widgets.py", line 778, in __init__ self.set_val(valinit) File "/Users/Vincent/opt/anaconda3/envs/py38/lib/python3.8/site-packages/matplotlib/widgets.py", line 915, in set_val xy[4] = val[0], .25 IndexError: index 4 is out of bounds for axis 0 with size 4 Expected outcome range slider with user initial values Additional information error can be def set_val(self, val): """ Set slider value to *val*. Parameters ---------- val : tuple or array-like of float """ val = np.sort(np.asanyarray(val)) if val.shape != (2,): raise ValueError( f"val must have shape (2,) but has shape {val.shape}" ) val[0] = self._min_in_bounds(val[0]) val[1] = self._max_in_bounds(val[1]) xy = self.poly.xy if self.orientation == "vertical": xy[0] = .25, val[0] xy[1] = .25, val[1] xy[2] = .75, val[1] xy[3] = .75, val[0] # xy[4] = .25, val[0] else: xy[0] = val[0], .25 xy[1] = val[0], .75 xy[2] = val[1], .75 xy[3] = val[1], .25 # xy[4] = val[0], .25 self.poly.xy = xy self.valtext.set_text(self._format(val)) if self.drawon: self.ax.figure.canvas.draw_idle() self.val = val if self.eventson: self._observers.process("changed", val) Operating system OSX Matplotlib Version 3.5.1 Matplotlib Backend *No response* Python version 3.8 Jupyter version *No response* Installation pip — Reply to this email directly, view it on GitHub <#22686>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AACHF6CW2HVLKT5Q56BVZDLVBJ6X7ANCNFSM5RMUEIDQ> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>