[FIXED] Create shape using hlines, vlines with matplotlib so that the exterior corners are complete

Issue

Example code:

fig, ax = plt.subplots()

ax.vlines(x=0.6, ymin=0.2, ymax=0.8, linewidth=10)
ax.hlines(y=0.2, xmin=0.2, xmax=0.6, linewidth=10)
ax.hlines(y=0.8, xmin=.6, xmax=0.8, linewidth=10)
ax.vlines(x=0.8, ymin=0.8, ymax=1.1, linewidth=10)
ax.hlines(y=1.1, xmin=.5, xmax=0.8, linewidth=10)
ax.vlines(x=0.5, ymin=0.4, ymax=1.1, linewidth=10)
ax.hlines(y=.4, xmin=.2, xmax=0.5, linewidth=10)

Which produces:

In the corners are gaps though, whereas I would like these to be flush.

To be clear, the corners currently look like:

Whereas I would like them to look like:

# Edit

Side note - if there's just a rectangle to be created the following can be used:

import matplotlib.patches as pt 
fig, ax = plt.subplots() 
frame = pt.Rectangle((0.2,0.2),0.4,0.6, lw=10,facecolor='none', edgecolor='k') 
ax.add_patch(frame)

More info on the edit here:

• How to draw a rectangle over a specific region in a matplotlib graph
• matplotlib: how to draw a rectangle on image
• Drawing rectangle with border only in matplotlib

Solution

Apart from plotting the lines as one segmented curve, an idea is to put a scatter dot at the start and end of each line segment. The size of a scatter dot is measured quadratic; a line width of 10 corresponds to a scatter size of about 70. Matplotlib also supports capstyle='round', which starts and ends the lines with a rounded cap. (For ax.plot, the parameter is named solid_capstyle='round', while for ax.vlinesit is justcapstyle='round').`

Other allowed values for capstyle are 'projecting' (extending the line with half its thickness) and 'butt' (stops the lines at the end point).

import matplotlib.pyplot as plt

fig, axs = plt.subplots(ncols=3, figsize=(15, 4))
for ax, capstyle in zip(axs, ['round', 'projecting', 'butt']):
    ax.vlines(x=0.6, ymin=0.2, ymax=0.8, linewidth=10, capstyle=capstyle)
    ax.hlines(y=0.2, xmin=0.2, xmax=0.6, linewidth=10, capstyle=capstyle)
    ax.hlines(y=0.8, xmin=.6, xmax=0.8, linewidth=10, capstyle=capstyle)
    ax.vlines(x=0.8, ymin=0.8, ymax=1.1, linewidth=10, capstyle=capstyle)
    ax.hlines(y=1.1, xmin=.5, xmax=0.8, linewidth=10, capstyle=capstyle)
    ax.vlines(x=0.5, ymin=0.4, ymax=1.1, linewidth=10, capstyle=capstyle)
    ax.hlines(y=.4, xmin=.2, xmax=0.5, linewidth=10, capstyle=capstyle)
    ax.set_title(f"capstyle='{capstyle}'")
plt.show()

Answered By - JohanC