我的 matplotlib 标题被裁剪

Question

已解决 - 请参阅下面关于结合 wraptext.wrap 和 plt.tightlayout 的评论。

问题： 代码如下：

import matplotlib.pyplot as plt
plt.bar([1,2],[5,4])
plt.title('this is a very long title and therefore it gets cropped which is an unthinkable behaviour as it loses the information in the title')
plt.show()

这会创建一个看起来像的图形

标题被裁剪，如何让它显示整个标题？

更新：我正在寻找一种使图形大小与标题和轴标签中的文本相匹配的解决方案，而不是一种用换行符剪切标题的解决方案，因为那种解决方案并不总是有帮助：

from textwrap import wrap
import matplotlib.pyplot as plt
title = 'this is a very long title and therefore it gets cropped which is an unthinkable behaviour as it loses the information in the title'*5
plt.bar([1,2],[5,4])
plt.title('\n'.join(wrap(title,60)))
plt.show()` 

查看结果：

Answer 1

您可以尝试找到here 的解决方案。

这是相当多的代码，但它似乎可以处理情节上任何类型文本的文本换行。

这是解决方案中的代码，经过修改以适合您的示例：

import matplotlib.pyplot as plt

def main():
    fig = plt.figure()
    plt.subplots_adjust(top=0.85) # use a lower number to make more vertical space
    plt.bar([1,2],[5,4])
    fig.canvas.mpl_connect('draw_event', on_draw)
    plt.title('this is a very long title and therefore it gets cropped which is an unthinkable behaviour as it loses the information in the title')
    plt.savefig('./test.png')

def on_draw(event):
    """Auto-wraps all text objects in a figure at draw-time"""
    import matplotlib as mpl
    fig = event.canvas.figure

    # Cycle through all artists in all the axes in the figure
    for ax in fig.axes:
        for artist in ax.get_children():
            # If it's a text artist, wrap it...
            if isinstance(artist, mpl.text.Text):
                autowrap_text(artist, event.renderer)

    # Temporarily disconnect any callbacks to the draw event...
    # (To avoid recursion)
    func_handles = fig.canvas.callbacks.callbacks[event.name]
    fig.canvas.callbacks.callbacks[event.name] = {}
    # Re-draw the figure..
    fig.canvas.draw()
    # Reset the draw event callbacks
    fig.canvas.callbacks.callbacks[event.name] = func_handles

def autowrap_text(textobj, renderer):
    """Wraps the given matplotlib text object so that it exceed the boundaries
    of the axis it is plotted in."""
    import textwrap
    # Get the starting position of the text in pixels...
    x0, y0 = textobj.get_transform().transform(textobj.get_position())
    # Get the extents of the current axis in pixels...
    clip = textobj.get_axes().get_window_extent()
    # Set the text to rotate about the left edge (doesn't make sense otherwise)
    textobj.set_rotation_mode('anchor')

    # Get the amount of space in the direction of rotation to the left and 
    # right of x0, y0 (left and right are relative to the rotation, as well)
    rotation = textobj.get_rotation()
    right_space = min_dist_inside((x0, y0), rotation, clip)
    left_space = min_dist_inside((x0, y0), rotation - 180, clip)

    # Use either the left or right distance depending on the horiz alignment.
    alignment = textobj.get_horizontalalignment()
    if alignment is 'left':
        new_width = right_space 
    elif alignment is 'right':
        new_width = left_space
    else:
        new_width = 2 * min(left_space, right_space)

    # Estimate the width of the new size in characters...
    aspect_ratio = 0.5 # This varies with the font!! 
    fontsize = textobj.get_size()
    pixels_per_char = aspect_ratio * renderer.points_to_pixels(fontsize)

    # If wrap_width is < 1, just make it 1 character
    wrap_width = max(1, new_width // pixels_per_char)
    try:
        wrapped_text = textwrap.fill(textobj.get_text(), wrap_width)
    except TypeError:
        # This appears to be a single word
        wrapped_text = textobj.get_text()
    textobj.set_text(wrapped_text)

def min_dist_inside(point, rotation, box):
    """Gets the space in a given direction from "point" to the boundaries of
    "box" (where box is an object with x0, y0, x1, & y1 attributes, point is a
    tuple of x,y, and rotation is the angle in degrees)"""
    from math import sin, cos, radians
    x0, y0 = point
    rotation = radians(rotation)
    distances = []
    threshold = 0.0001 
    if cos(rotation) > threshold: 
        # Intersects the right axis
        distances.append((box.x1 - x0) / cos(rotation))
    if cos(rotation) < -threshold: 
        # Intersects the left axis
        distances.append((box.x0 - x0) / cos(rotation))
    if sin(rotation) > threshold: 
        # Intersects the top axis
        distances.append((box.y1 - y0) / sin(rotation))
    if sin(rotation) < -threshold: 
        # Intersects the bottom axis
        distances.append((box.y0 - y0) / sin(rotation))
    return min(distances)

if __name__ == '__main__':
    main()

这会产生以下情节：

更新：

使用以下行在图形顶部和实际绘图顶部之间创建更多空间：

plt.subplots_adjust(top=0.85) # use a lower number to make more vertical space

例如，如果您使用：

plt.subplots_adjust(top=0.5)

输出将如下所示：

Answer 2

您可以使用 textwrap 自动用换行符 (\n) 换行文本：

>>> longstring = "this is a very long title and therefore it gets cropped which is an unthinkable behaviour as it loses the information in the title"
>>> "\n".join(textwrap.wrap(longstring, 100))
'this is a very long title and therefore it gets cropped which is an unthinkable behaviour as it\nloses the information in the title'

在这种情况下，100 是每行的字符数（到最近的空格 - textwrap 尽量不分解单词）

---

另一种选择是减小字体的大小：

matplotlib.rcParams.update({'font.size': 12})

Answer 3

您可以在标题中包含换行符 \n 以将标题分隔多行。