用程序来处理图像和办公文档经常出现在实际开发中,Python的标准库中虽然没有直接支持这些操作的模块,但我们可以通过Python生态圈中的第三方模块来完成这些操作。
Pillow是由从著名的Python图像处理库PIL发展出来的一个分支,通过Pillow可以实现图像压缩和图像处理等各种操作。可以使用下面的命令来安装Pillow。
pip install pillow
Pillow中最为重要的是Image类,读取和处理图像都要通过这个类来完成。
>>> from PIL import Image
>>>
>>> image = Image.open('./res/guido.jpg')
>>> image.format, image.size, image.mode
('JPEG', (500, 750), 'RGB')
>>> image.show()
剪裁图像
>>> image = Image.open('./res/guido.jpg')
>>> rect = 80, 20, 310, 360
>>> image.crop(rect).show()
生成缩略图
>>> image = Image.open('./res/guido.jpg')
>>> size = 128, 128
>>> image.thumbnail(size)
>>> image.show()
缩放和黏贴图像
>>> image1 = Image.open('./res/luohao.png')
>>> image2 = Image.open('./res/guido.jpg')
>>> rect = 80, 20, 310, 360
>>> guido_head = image2.crop(rect)
>>> width, height = guido_head.size
>>> image1.paste(guido_head.resize((int(width / 1.5), int(height / 1.5))), (172, 40))
旋转和翻转
>>> image = Image.open('./res/guido.png')
>>> image.rotate(180).show()
>>> image.transpose(Image.FLIP_LEFT_RIGHT).show()
操作像素
>>> image = Image.open('./res/guido.jpg')
>>> for x in range(80, 310):
... for y in range(20, 360):
... image.putpixel((x, y), (128, 128, 128))
...
>>> image.show()
滤镜效果
>>> from PIL import Image, ImageFilter
>>>
>>> image = Image.open('./res/guido.jpg')
>>> image.filter(ImageFilter.CONTOUR).show()
Python的openpyxl模块让我们可以在Python程序中读取和修改Excel电子表格,由于微软从Office 2007开始使用了新的文件格式,这使得Office Excel和LibreOffice Calc、OpenOffice Calc是完全兼容的,这就意味着openpyxl模块也能处理来自这些软件生成的电子表格。
import datetime
from openpyxl import Workbook
wb = Workbook()
ws = wb.active
ws['A1'] = 42
ws.append([1, 2, 3])
ws['A2'] = datetime.datetime.now()
wb.save("sample.xlsx")
利用python-docx模块,Python可以创建和修改Word文档,当然这里的Word文档不仅仅是指通过微软的Office软件创建的扩展名为docx的文档,LibreOffice Writer和OpenOffice Writer都是免费的字处理软件。
from docx import Document
from docx.shared import Inches
document = Document()
document.add_heading('Document Title', 0)
p = document.add_paragraph('A plain paragraph having some ')
p.add_run('bold').bold = True
p.add_run(' and some ')
p.add_run('italic.').italic = True
document.add_heading('Heading, level 1', level=1)
document.add_paragraph('Intense quote', style='Intense Quote')
document.add_paragraph(
'first item in unordered list', style='List Bullet'
)
document.add_paragraph(
'first item in ordered list', style='List Number'
)
document.add_picture('monty-truth.png', width=Inches(1.25))
records = (
(3, '101', 'Spam'),
(7, '422', 'Eggs'),
(4, '631', 'Spam, spam, eggs, and spam')
)
table = document.add_table(rows=1, cols=3)
hdr_cells = table.rows[0].cells
hdr_cells[0].text = 'Qty'
hdr_cells[1].text = 'Id'
hdr_cells[2].text = 'Desc'
for qty, id, desc in records:
row_cells = table.add_row().cells
row_cells[0].text = str(qty)
row_cells[1].text = id
row_cells[2].text = desc
document.add_page_break()
document.save('demo.docx')