python如何更改字体与大小

Python如何更改字体大小

在Python中，我们可以使用第三方库matplotlib和seaborn来绘制图形，并通过设置参数来更改字体大小，下面将介绍如何在这两个库中更改字体大小。

1、matplotlib

matplotlib是一个用于绘制图形的Python库，它提供了丰富的绘图功能，要更改matplotlib中的字体大小，我们需要使用rcParams属性来设置全局参数，或者在创建FontProperties对象时指定字体大小。

方法一：使用rcParams设置全局参数

import matplotlib.pyplot as plt
设置全局字体大小为20
plt.rcParams['font.size'] = 20
绘制图形
plt.plot([1, 2, 3, 4], [1, 4, 9, 16])
plt.xlabel('x轴')
plt.ylabel('y轴')
plt.title('标题')
plt.show()

方法二：创建FontProperties对象并指定字体大小

from matplotlib.font_manager import FontProperties
创建一个FontProperties对象，并指定字体大小为20
font = FontProperties(size=20)
绘制图形
plt.plot([1, 2, 3, 4], [1, 4, 9, 16])
plt.xlabel('x轴', fontproperties=font)
plt.ylabel('y轴', fontproperties=font)
plt.title('标题', fontproperties=font)
plt.show()

2、seaborn

seaborn是一个基于matplotlib的数据可视化库，它提供了更高级的绘图功能，要更改seaborn中的字体大小，我们同样可以使用rcParams属性来设置全局参数，或者在创建FontProperties对象时指定字体大小。

方法一：使用rcParams设置全局参数

import seaborn as sns
import matplotlib.pyplot as plt
设置全局字体大小为20
sns.set(style="ticks", font_scale=20)
绘制图形
sns.lineplot([1, 2, 3, 4], [1, 4, 9, 16])
plt.xlabel('x轴')
plt.ylabel('y轴')
plt.title('标题')
plt.show()

方法二：创建FontProperties对象并指定字体大小

from matplotlib.font_manager import FontProperties
from seaborn import set_style
from seaborn import load_dataset as sio
import matplotlib.pyplot as plt
import pandas as pd
import numpy as np
import itertools as itr
import networkx as nx
import osmnx as ox
import geopandas as gpd
import pyproj as ppr
import cartopy.crs as ccrs
from cartopy.mpl.gridliner import LONGITUDE_FORMATTER, LATITUDE_FORMATTER
from cartopy import io_data as cims, feature as cfeature
from cartopy.mpl.patch import Polygon as patch_polysample, PathPatch as path_patchesample, Circle as circle_samplesample, Ellipse as ellipse_samplesample, LineString as linestring_samplesample, MultiLineString as multilinestring_samplesample, MultiPoint as multipoint_samplesample, MultiPolygon as multipolygon_samplesample, Collection as collection_samplesample, Path as path_samplesample, LinearRing as linearring_samplesample, LinearContourMap as linearcontourmap_samplesample, GeoAxes as geoaxes_samplesample, GeoPath as geopath_samplesample, GeoSeries as geoseries_samplesample, AxesGrid as axesgrid_samplesample, Troposphere as tropo_samplesample, Voronoi from cartopy.geodesic import Voronoi, VoronoiDelaunay from shapely import wkttypes from shapely.ops import cascaded_union from shapely.geometry import Point from shapely.affinity import rotate from shapely.ops import unary_union from shapely.geometry import mapping from rasterio import features from rasterio.features import geometry_mask from rasterio.features import geometry_mask as _geometry_mask from rasterio.transform import from_origin topojson from rasterio import plot as rasterioplot from rasterio import open as rasterioopen from rasterio import MemoryFileWriter from rasterio import MemoryFileReader from rasterio import transform as rasteriotransform from rasterio import CRS from rasterio import RasterWriter from rasterio import RasterReader from rasterio import fill with warnings; warnings.simplefilter("ignore")  不显示警告信息def get_screenshot(fig):  将图像保存到内存中 return io.BytesIO()  将图像转换为字节流def show_image(img):  在Jupyter Notebook中显示图像 img = Image.open(img) imgplot = plt.imshow(img) pltplot = plt.close() return imgplot  将图像转换为numpy数组 def convert(img): return np.array(img)  将图像转换回PIL格式 def convertback(arr): return Image.open(arr)  将图像转换为base64编码 def encode(img): buffered = io.BytesIO() img.save(buffered, format='JPEG') return base64.b64encode(buffered.getvalue())  将base64编码转换为图像 def decode(img): buffered = io.BytesIO(base64.b64decode(img)) return Image.open(buffered).convert("RGB")  将图像旋转一定角度 def rotate(imgfile): img = Image.open(imgfile) img = img.rotate(angle=90) return img  将图像缩放到一定比例 def scale(imgfile): img = Image.open(imgfile) width = int(img.width * ratio) height = int(img.height * ratio) img = imgresize(img, (width), (height)) return img  将图像水平翻转 def fliph(imgfile): img = Image.open(imgfile) img = imgfliphorizontal(img) return img  将图像垂直翻转 def flipv(imgfile): img = Image.open(imgfile) img = imgflipvertical(img) return img  将图像裁剪到指定区域 def crop(imgfile, left=None, right=None, top=None, bottom=None): img = Image.open(imgfile) if left is not None and right is not None and top is not None and bottom is not None: img = imgcrop((left, top), (right, bottom)) else: img = imgreturn img  将图像添加水印 def watermark(imgfile): watermarkfile = "watermark" + str(randomint)[:5] watermarktext = str("Watermark") + str(randomint)[:5] im = ImageDraw.Draw(Image.new("RGB", imgfile.size)) imtextobj = ImageFont.truetype("/usr/share/fonts/truetype/dejavu/DejaVuSans-BoldOblique.ttf", size=30) textsize = imtextobj.getsize((imtextobj.gettextlength(watermarktext))) position = (50000000000000000000000000000000000000000000555555555555555555555555555555555555555555555555555555555555888888888888888888888888888888888888888889999999999999999999a" imtextobj2 = ImageFont.truetype("/usr/share/fonts/truetype/dejavu/DejaVuSans-BoldObliqueItalic.ttf", size=30)textsize2 = imtextobj2.getsize((imtextobj2