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JpegDevice类允许您将PDF页面转换为JPEG图像。这个类提供了一个叫Process的方法来执行这一转换操作。您首先需要创建一个文档类对象,从中获取您想要转换为JPEG的特定PDF页面。之后,你需要调用Process方法将页面转换为JPEG图像。

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下面是示例代码

C#

//open document
Document pdfDocument = new Document("input.pdf");


using (FileStream imageStream = new FileStream("image.jpg",FileMode.Create))
{
//create JPEG device with specified attributes
//Width, Height, Resolution, Quality
//Quality [0-100], 100 is Maximum
//create Resolution object
Resolution resolution = new Resolution(300);
//JpegDevice jpegDevice = new JpegDevice(500, 700, resolution, 
100);
JpegDevice jpegDevice = new JpegDevice(resolution, 100);

//convert a particular page and save the image to stream
jpegDevice.Process(pdfDocument.Pages[1], imageStream);

//close stream
imageStream.Close();

}
 

VB.NET

'open document
Dim pdfDocument As New Document("input.pdf")

Using imageStream As New FileStream("image.jpg",FileMode.Create)
'create JPEG device with specified attributes
'Width, Height, Resolution, Quality
'Quality [0-100], 100 is Maximum
'create Resolution object
Dim resolution As New Resolution(300)
'JpegDevice jpegDevice = new JpegDevice(500, 700, resolution, 
100);
Dim jpegDevice As New JpegDevice(resolution, 100)

'convert a particular page and save the image to stream
jpegDevice.Process(pdfDocument.Pages(1), imageStream)

'close stream
imageStream.Close()

End Using