pil旋转图片水平翻转

可以使用PIL库中的transpose方法来实现图片的水平翻转，具体代码如下：

from PIL import Image

img = Image.open('image.jpg')
img_transposed = img.transpose(method=Image.FLIP_LEFT_RIGHT)
img_transposed.show()

这段代码可以将名为'image.jpg'的图片水平翻转并显示出来。

相关问题

jupyter lab中图像平移，旋转，基于变换矩阵的旋转，缩放，resize缩放，剪切y方向x方向同时进行，水平翻转，基于变换矩阵的水平翻转

在Jupyter Lab中，通常使用数据可视化库如Pandas的`matplotlib`或更专业的图像处理库`OpenCV`或`scikit-image`来进行图像操作，包括平移、旋转、缩放等。其中，基于变换矩阵的处理可以提供更高的灵活性。

1. 图像平移：`transform`模块的`Affine2D`可以创建二维仿射变换对象，通过设置平移的偏移量来实现图像移动。

2. 旋转：`rotate()`函数可以对图像进行旋转，比如使用`skimage.transform.rotate()`或`plt.imshow(transformed_image)`配合`Affine2D`对象。

3. 缩放：`scale()`或`zoom()`函数可以调整图像大小，例如` Affine2D(scale=(scale_factor, scale_factor))`。

4. Resize缩放：`resize()`函数在`PIL`（Python Imaging Library）中用于改变图像尺寸，例如`Image.resize(size, resample=Image.LANCZOS)`。

5. 剪切：需要先确定剪切区域，然后使用`crop()`函数，比如`cropped_image = image.crop((left, top, right, bottom))`。

6. 水平翻转：`flip_left_right()`或`horizontal_flip()`可以实现水平翻转，对于`numpy`数组，可以使用`np.fliplr(image)`；对于`OpenCV`，则有`cv2.flip()`

为了完成所有这些操作，首先你需要加载图片，然后创建并应用相应的变换矩阵，最后将变换后的图像显示出来：

import matplotlib.pyplot as plt
from skimage.transform import AffineTransform

# 加载图像
img = plt.imread('your_image.jpg')

# 创建变换对象
transformation = AffineTransform(translation=(dx, dy) if you want translation else None,
                                  rotation=np.radians(rotation_angle),
                                  scale=(scale_factor, scale_factor))

# 应用变换
transformed_img = transformation(img)

# 显示原图和变换后的图
fig, (ax1, ax2) = plt.subplots(nrows=1, ncols=2)
ax1.imshow(img)
ax2.imshow(transformed_img)

# 保存或展示
plt.show()

为pdf文件添加水印，要求： 1，可以文字水印，也可以上传图片作为水印 2，可以调节水印大小(0到100)，透明度(0到100)，旋转角度，翻转(无，水平翻转，垂直翻转)，和选择水印位置(九宫格或平铺) 3，使用python语言并显示完整代码 4，使用PyPDF4

模块

以下是实现以上要求的Python代码：

from PyPDF4 import PdfFileWriter, PdfFileReader
from reportlab.pdfgen import canvas
from reportlab.lib.units import mm
from PIL import Image
import io

def add_watermark(input_pdf, output_pdf, watermark_text=None, watermark_image=None, size=50, opacity=50, angle=0, flip=None, position='center'):
    # Open the input PDF file
    input_file = open(input_pdf, 'rb')
    pdf_reader = PdfFileReader(input_file)

    # Create a new PDF writer
    pdf_writer = PdfFileWriter()

    # If watermark text is provided, create a watermark PDF
    if watermark_text:
        # Create a canvas to draw the watermark text
        watermark_canvas = canvas.Canvas('watermark.pdf')

        # Set the font and font size for the watermark text
        watermark_canvas.setFont('Helvetica', size)

        # Draw the watermark text in the center of the canvas
        watermark_canvas.drawCentredString(105*mm, 148*mm, watermark_text)

        # Save the watermark PDF
        watermark_canvas.save()

        # Open the watermark PDF file
        watermark_file = open('watermark.pdf', 'rb')
        watermark_reader = PdfFileReader(watermark_file)

        # Get the first page of the input PDF file
        input_page = pdf_reader.getPage(0)

        # Get the first page of the watermark PDF file
        watermark_page = watermark_reader.getPage(0)

        # Merge the pages
        input_page.mergePage(watermark_page)

        # Add the merged page to the output PDF writer
        pdf_writer.addPage(input_page)

        # Close the watermark PDF file
        watermark_file.close()

    # If watermark image is provided, create a watermark PDF
    if watermark_image:
        # Open the watermark image file
        with Image.open(watermark_image) as img:
            # Create a buffer to hold the PDF data
            img_buffer = io.BytesIO()

            # Convert the image to PDF and save it to the buffer
            img.save(img_buffer, 'PDF', resolution=100.0)

            # Set the buffer position to the beginning
            img_buffer.seek(0)

            # Open the PDF data as a reader
            watermark_reader = PdfFileReader(img_buffer)

            # Get the first page of the input PDF file
            input_page = pdf_reader.getPage(0)

            # Get the first page of the watermark PDF file
            watermark_page = watermark_reader.getPage(0)

            # Merge the pages
            input_page.mergePage(watermark_page)

            # Add the merged page to the output PDF writer
            pdf_writer.addPage(input_page)

    # If neither watermark text nor watermark image is provided, simply copy the input PDF file to the output PDF file
    if not watermark_text and not watermark_image:
        for page in pdf_reader.pages:
            pdf_writer.addPage(page)

    # Set the opacity of the watermark
    opacity_percent = opacity / 100.0
    pdf_writer.encrypt(user_pwd=None, owner_pwd=None, use_128bit=True)
    pdf_writer._encrypt_metadata=False

    # Get the output PDF file object
    output_file = open(output_pdf, 'wb')

    # Set the watermark position
    if position == 'center':
        x = 0.5
        y = 0.5
    elif position == 'top_left':
        x = 0.1
        y = 0.9
    elif position == 'top_center':
        x = 0.5
        y = 0.9
    elif position == 'top_right':
        x = 0.9
        y = 0.9
    elif position == 'center_left':
        x = 0.1
        y = 0.5
    elif position == 'center_right':
        x = 0.9
        y = 0.5
    elif position == 'bottom_left':
        x = 0.1
        y = 0.1
    elif position == 'bottom_center':
        x = 0.5
        y = 0.1
    elif position == 'bottom_right':
        x = 0.9
        y = 0.1

    # Loop through all pages of the output PDF writer
    for page in pdf_writer.pages:
        # Get the page width and height
        width = page.mediaBox.getWidth()
        height = page.mediaBox.getHeight()

        # Create a new content stream for the watermark
        watermark_content = PdfFileWriter().addBlankPage(width, height)

        # Set the opacity of the watermark
        watermark_content.getPage(0).gfx.setAlpha(opacity_percent)

        # Rotate the watermark
        if angle != 0:
            watermark_content.getPage(0).rotateClockwise(angle)

        # Flip the watermark
        if flip == 'horizontal':
            watermark_content.getPage(0).scale(-1, 1)
            watermark_content.getPage(0).translate(-width, 0)
        elif flip == 'vertical':
            watermark_content.getPage(0).scale(1, -1)
            watermark_content.getPage(0).translate(0, -height)

        # Draw the watermark on the content stream
        if watermark_text:
            watermark_content.mergePage(watermark_reader.getPage(0))
        elif watermark_image:
            watermark_content.mergePage(watermark_reader.getPage(0))

        # Add the content stream to the output page
        page.mergePage(watermark_content.getPage(0))

        # Set the position of the watermark on the output page
        page.mergeTranslatedPage(watermark_content.getPage(0), x*width, y*height)

        # Add the modified page to the output PDF file
        output_page = page
        pdf_writer.addPage(output_page)

    # Write the output PDF file
    pdf_writer.write(output_file)

    # Close the input and output PDF files
    input_file.close()
    output_file.close()

# Example usage
add_watermark('input.pdf', 'output.pdf', watermark_text='CONFIDENTIAL', size=50, opacity=50, angle=45, flip='horizontal', position='center')
add_watermark('input.pdf', 'output.pdf', watermark_image='watermark.png', size=50, opacity=50, angle=45, flip='horizontal', position='center')