Get legend as a separate picture in Matplotlib

Get legend as a separate picture in Matplotlib

In Matplotlib, you can create a legend as a separate picture by first creating the legend and then saving it as an image file. Here's how you can do it:

import matplotlib.pyplot as plt # Create a plot plt.plot([1, 2, 3], [4, 5, 6], label='Line A') plt.plot([1, 2, 3], [6, 5, 4], label='Line B') # Create a legend plt.legend() # Save the legend as a separate image legend_fig = plt.figure() legend_ax = legend_fig.add_subplot(111) legend_ax.legend(*plt.gca().get_legend_handles_labels()) legend_ax.axis('off') legend_fig.savefig('legend.png', bbox_inches='tight') # Close the legend figure plt.close(legend_fig) # Show the main plot plt.show()

In this example:

  1. We create a basic plot with two lines and labels using plt.plot().

  2. We create a legend using plt.legend().

  3. We create a separate figure and axis for the legend using legend_fig and legend_ax.

  4. We copy the legend from the main plot to the legend axis using legend_ax.legend(*plt.gca().get_legend_handles_labels()).

  5. We turn off the axis using legend_ax.axis('off').

  6. We save the legend as a separate image using legend_fig.savefig('legend.png', bbox_inches='tight'). You can specify the desired filename and format.

  7. We close the legend figure to release resources using plt.close(legend_fig).

  8. Finally, we display the main plot using plt.show().

After running this code, you'll have a separate image file named 'legend.png' that contains the legend. You can customize the legend's appearance and positioning as needed.

Examples

  1. Matplotlib separate legend image example:

    • Description: Demonstrates how to extract the legend from a Matplotlib plot as a separate image.
    import matplotlib.pyplot as plt from matplotlib.legend_handler import HandlerLine2D # Plotting data x = range(10) y1 = [i**2 for i in x] y2 = [i**1.5 for i in x] fig, ax = plt.subplots() ax.plot(x, y1, label='y = x^2') ax.plot(x, y2, label='y = x^1.5') # Getting legend as a separate image handles, labels = ax.get_legend_handles_labels() ax.legend(handles, labels, handler_map={str: HandlerLine2D(numpoints=1)}) legend = ax.legend_.legendHandles[0].figure # Displaying the legend image plt.show()

  2. Extract Matplotlib legend to image:

    • Description: Shows how to extract the legend from a Matplotlib plot and save it as a separate image file.
    import matplotlib.pyplot as plt # Plotting data x = range(10) y1 = [i**2 for i in x] y2 = [i**1.5 for i in x] fig, ax = plt.subplots() ax.plot(x, y1, label='y = x^2') ax.plot(x, y2, label='y = x^1.5') # Saving legend as a separate image ax.legend() legend = ax.legend_.legendHandles[0].figure legend.savefig('legend.png')

  3. Matplotlib save legend as image:

    • Description: Illustrates how to save the legend of a Matplotlib plot as a separate image file.
    import matplotlib.pyplot as plt # Plotting data x = range(10) y1 = [i**2 for i in x] y2 = [i**1.5 for i in x] fig, ax = plt.subplots() ax.plot(x, y1, label='y = x^2') ax.plot(x, y2, label='y = x^1.5') # Saving legend as an image ax.legend() legend = ax.legend_.legendHandles[0].figure legend.savefig('legend_image.png')

  4. Separate legend image Matplotlib:

    • Description: Provides code to create a Matplotlib plot and extract its legend as a separate image.
    import matplotlib.pyplot as plt # Plotting data x = range(10) y1 = [i**2 for i in x] y2 = [i**1.5 for i in x] fig, ax = plt.subplots() ax.plot(x, y1, label='y = x^2') ax.plot(x, y2, label='y = x^1.5') # Extracting legend as a separate image ax.legend() legend = ax.legend_.legendHandles[0].figure plt.figure() plt.imshow(legend) plt.axis('off') plt.show()

  5. Get legend as separate image in Matplotlib:

    • Description: Shows how to obtain the legend from a Matplotlib plot and display it as a separate image.
    import matplotlib.pyplot as plt # Plotting data x = range(10) y1 = [i**2 for i in x] y2 = [i**1.5 for i in x] fig, ax = plt.subplots() ax.plot(x, y1, label='y = x^2') ax.plot(x, y2, label='y = x^1.5') # Getting legend as a separate image ax.legend() legend = ax.legend_.legendHandles[0].figure plt.imshow(legend) plt.axis('off') plt.show()

  6. Extract legend image from Matplotlib plot:

    • Description: Demonstrates how to extract the legend from a Matplotlib plot and display it as a separate image.
    import matplotlib.pyplot as plt # Plotting data x = range(10) y1 = [i**2 for i in x] y2 = [i**1.5 for i in x] fig, ax = plt.subplots() ax.plot(x, y1, label='y = x^2') ax.plot(x, y2, label='y = x^1.5') # Extracting legend from the plot as an image ax.legend() legend = ax.legend_.legendHandles[0].figure plt.imshow(legend) plt.axis('off') plt.show()

  7. Save legend as image Matplotlib:

    • Description: Provides a method to save the legend of a Matplotlib plot as a separate image file.
    import matplotlib.pyplot as plt # Plotting data x = range(10) y1 = [i**2 for i in x] y2 = [i**1.5 for i in x] fig, ax = plt.subplots() ax.plot(x, y1, label='y = x^2') ax.plot(x, y2, label='y = x^1.5') # Saving legend as an image file ax.legend() legend = ax.legend_.legendHandles[0].figure legend.savefig('legend_image.png')

  8. Matplotlib extract legend to image:

    • Description: Demonstrates how to extract the legend from a Matplotlib plot and save it as a separate image.
    import matplotlib.pyplot as plt # Plotting data x = range(10) y1 = [i**2 for i in x] y2 = [i**1.5 for i in x] fig, ax = plt.subplots() ax.plot(x, y1, label='y = x^2') ax.plot(x, y2, label='y = x^1.5') # Extracting legend to an image file ax.legend() legend = ax.legend_.legendHandles[0].figure legend.savefig('legend_image.png')

  9. Get Matplotlib legend as image:

    • Description: Shows how to obtain the legend from a Matplotlib plot and display it as a separate image.
    import matplotlib.pyplot as plt # Plotting data x = range(10) y1 = [i**2 for i in x] y2 = [i**1.5 for i in x] fig, ax = plt.subplots() ax.plot(x, y1, label='y = x^2') ax.plot(x, y2, label='y = x^1.5') # Getting the legend as an image ax.legend() legend = ax.legend_.legendHandles[0].figure plt.imshow(legend) plt.axis('off') plt.show()

  10. Extract Matplotlib legend as image:

    • Description: Shows how to extract the legend from a Matplotlib plot and display it as a separate image.
    import matplotlib.pyplot as plt # Plotting data x = range(10) y1 = [i**2 for i in x] y2 = [i**1.5 for i in x] fig, ax = plt.subplots() ax.plot(x, y1, label='y = x^2') ax.plot(x, y2, label='y = x^1.5') # Extracting the legend to an image ax.legend() legend = ax.legend_.legendHandles[0].figure plt.imshow(legend) plt.axis('off') plt.show()

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