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Matplotlib is a Python library that can be used to create beautiful charts and graphs. It can also be used to draw rectangles with various properties such as line color, edge color, line width, and fill color. To draw a rectangle, you’ll need to specify the coordinates of the top-left and bottom-right corners, and the line width and color of the rectangles. You can also add a fill color to the rectangle, which will fill the space inside it. Examples of how to draw rectangles with Matplotlib are included in this article.
To draw a rectangle in Matplotlib, you can use the matplotlib.patches.Rectangle function, which uses the following syntax:
matplotlib.patches.Rectangle(xy, width, height, angle=0.0)
where:
- xy: The (x, y) coordinates for the anchor point of the rectangle
- width: Rectangle width
- height: Rectangle height
- angle: Rotation in degrees counter-clockwise about xy (Default is 0)
This tutorial provides several examples of how to use this function in practice.
Example 1: Draw a Rectangle on a Plot
The following code shows how to draw a rectangle on a Matplotlib plot with a width of 2 and height of 6:
import matplotlib.pyplot as plt from matplotlib.patches import Rectangle #define Matplotlib figure and axis fig, ax = plt.subplots() #create simple line plot ax.plot([0, 10],[0, 10]) #add rectangle to plot ax.add_patch(Rectangle((1, 1), 2, 6)) #display plot plt.show()
Example 2: Style a Rectangle
The following code shows how to apply some styling to the rectangle:
import matplotlib.pyplot as plt from matplotlib.patches import Rectangle #define Matplotlib figure and axis fig, ax = plt.subplots() #create simple line plot ax.plot([0, 10],[0, 10]) #add rectangle to plot ax.add_patch(Rectangle((1, 1), 2, 6, edgecolor = 'pink', facecolor = 'blue', fill=True, lw=5)) #display plot plt.show()
You can find a complete list of styling properties that you can apply to a rectangle here.
Example 3: Draw a Rectangle on an Image
The following code shows how to draw a rectangle on an image in Matplotilb. Note that the image used in this example comes from this Matplotlib tutorial.
To replicate this example, just download the photo of the stinkbug from that tutorial and save it to your own computer.
import matplotlib.pyplot as plt from matplotlib.patches import Rectangle from PIL import Image #display the image plt.imshow(Image.open('stinkbug.png')) #add rectangle plt.gca().add_patch(Rectangle((50,100),40,80, edgecolor='red', facecolor='none', lw=4))
Note that we can use the angle argument to rotate the rectangle a certain number of degrees counter-clockwise:
import matplotlib.pyplot as plt from matplotlib.patches import Rectangle from PIL import Image #display the image plt.imshow(Image.open('stinkbug.png')) #add rectangle plt.gca().add_patch(Rectangle((50,100),40,80, angle=30, edgecolor='red', facecolor='none', lw=4))
