Stamp 类

Aspose.PDF for Python via .NET 提供了印章用于在 PDF 页面上放置可重复使用的可视内容的类。Stamp 可以基于文字、图像，甚至来自其他 PDF 的页面，并且可以定位、旋转、设置样式，并限制在特定页面上。

本文演示了几种常见的印章工作流：

为基于文本的印章创建可重复使用的文本资源。
添加图像和 PDF 页面印章。
添加样式化文本印章。
将印章限制在所选页面。
配置背景图像印章。

该示例使用两个辅助函数：一个用于创建基于文本的印章的格式化文本，另一个用于创建 TextState 用于设置文本印章样式的对象。

import sys
from os import path

import aspose.pdf as ap
import aspose.pdf.facades as pdf_facades
import aspose.pydrawing as drawing

from config import initialize_data_dir, set_license


def _create_text_logo(text: str) -> pdf_facades.FormattedText:
    """Create formatted text for text stamp examples."""
    return pdf_facades.FormattedText(
        text,
        drawing.Color.blue,
        drawing.Color.light_gray,
        pdf_facades.FontStyle.HELVETICA_BOLD,
        pdf_facades.EncodingType.WINANSI,
        True,
        14,
    )


def _create_text_state() -> ap.text.TextState:
    """Create a text state used to style text stamps."""
    text_state = ap.text.TextState()
    text_state.foreground_color = ap.Color.dark_blue
    text_state.font_size = 16
    text_state.font_style = ap.text.FontStyles.BOLD
    return text_state

添加图像印章

使用 bind_image() 当印章应显示图像（例如徽标、徽章或图标）时。绑定图像后，您可以在将其添加到文档之前设置印章 ID 和原点。

import sys
from os import path

import aspose.pdf as ap
import aspose.pdf.facades as pdf_facades
import aspose.pydrawing as drawing

from config import initialize_data_dir, set_license


def add_image_stamp(infile: str, image_file: str, outfile: str) -> None:
    """Add an image stamp to the PDF."""
    pdf_stamper = pdf_facades.PdfFileStamp()
    try:
        pdf_stamper.bind_pdf(infile)

        stamp = pdf_facades.Stamp()
        stamp.bind_image(image_file)
        stamp.stamp_id = 1
        stamp.set_origin(36, 520)

        pdf_stamper.add_stamp(stamp)
        pdf_stamper.save(outfile)
    finally:
        pdf_stamper.close()

将 PDF 页面添加为印章

使用 bind_pdf() 当您想要使用另一个 PDF 文件中的页面作为印章内容时。这对于覆盖层（例如批准、模板或存储在单独文档中的预构建视觉元素）非常有用。

import sys
from os import path

import aspose.pdf as ap
import aspose.pdf.facades as pdf_facades
import aspose.pydrawing as drawing

from config import initialize_data_dir, set_license


def add_pdf_page_as_stamp(infile: str, stamp_pdf: str, outfile: str) -> None:
    """Add the first page of another PDF as a stamp."""
    pdf_stamper = pdf_facades.PdfFileStamp()
    try:
        pdf_stamper.bind_pdf(infile)

        stamp = pdf_facades.Stamp()
        stamp.bind_pdf(stamp_pdf, 1)
        stamp.page_number = 1
        stamp.set_origin(36, 250)

        pdf_stamper.add_stamp(stamp)
        pdf_stamper.save(outfile)
    finally:
        pdf_stamper.close()

添加带文本状态的文字印章

使用 bind_logo() 以及 bind_text_state() 当您想要创建具有自定义字体样式的基于文本的印章时。此方法适用于审批标记、标签以及工作流特定的注释。

import sys
from os import path

import aspose.pdf as ap
import aspose.pdf.facades as pdf_facades
import aspose.pydrawing as drawing

from config import initialize_data_dir, set_license


def add_text_stamp_with_text_state(infile: str, outfile: str) -> None:
    """Add a text stamp and style it with a TextState object."""
    pdf_stamper = pdf_facades.PdfFileStamp()
    try:
        pdf_stamper.bind_pdf(infile)

        stamp = pdf_facades.Stamp()
        stamp.bind_logo(_create_text_logo("Approved by signing workflow"))
        stamp.bind_text_state(_create_text_state())
        stamp.set_origin(36, 700)
        stamp.rotation = 15.0

        pdf_stamper.add_stamp(stamp)
        pdf_stamper.save(outfile)
    finally:
        pdf_stamper.close()

在特定页面添加印章

如果印章不应出现在每一页上，请将目标页码分配给 pages 属性。此示例仅在首页添加图像印章。

import sys
from os import path

import aspose.pdf as ap
import aspose.pdf.facades as pdf_facades
import aspose.pydrawing as drawing

from config import initialize_data_dir, set_license


def add_stamp_to_specific_pages(infile: str, image_file: str, outfile: str) -> None:
    """Add an image stamp only to the selected pages."""
    pdf_stamper = pdf_facades.PdfFileStamp()
    try:
        pdf_stamper.bind_pdf(infile)

        stamp = pdf_facades.Stamp()
        stamp.bind_image(image_file)
        stamp.pages = [1]
        stamp.set_origin(400, 40)
        stamp.set_image_size(120, 60)

        pdf_stamper.add_stamp(stamp)
        pdf_stamper.save(outfile)
    finally:
        pdf_stamper.close()

添加背景图像印章

当图像应显示在页面内容后面时，使用背景印章。您还可以控制印章的不透明度、旋转、质量、大小和位置，以创建水印样式的效果。

import sys
from os import path

import aspose.pdf as ap
import aspose.pdf.facades as pdf_facades
import aspose.pydrawing as drawing

from config import initialize_data_dir, set_license


def add_background_image_stamp(infile: str, image_file: str, outfile: str) -> None:
    """Add a rotated background image stamp with opacity and quality settings."""
    pdf_stamper = pdf_facades.PdfFileStamp()
    try:
        pdf_stamper.bind_pdf(infile)

        stamp = pdf_facades.Stamp()
        stamp.bind_image(image_file)
        stamp.is_background = True
        stamp.opacity = 0.35
        stamp.quality = 90
        stamp.rotation = 45.0
        stamp.set_image_size(160, 80)
        stamp.set_origin(200, 300)

        pdf_stamper.add_stamp(stamp)
        pdf_stamper.save(outfile)
    finally:
        pdf_stamper.close()