我有一个MVC应用程序,它使用Magick.NET上传PDF文件并将每个页面呈现为单个PNG图像。在大多数情况下转换很好,但在某些情况下,我得到一个空白图像,其中文本应该是和其他文本行在同一图像中正确显示。有谁知道这可能导致什么?
以下是我正在使用的代码。
public FileResult PNGPreview(Guid id, Int32 index)
{
MagickReadSettings settings = new MagickReadSettings();
// Settings the density to 300 dpi will create an image with a better quality
settings.FrameIndex = index;
settings.FrameCount = 1;
settings.Density = new PointD(300, 300);
settings.UseMonochrome = true;
using (MagickImageCollection images = new MagickImageCollection())
{
// Add all the pages of the pdf file to the collection
images.Read(CreateDocument(id), settings);
using (MemoryStream stream = new MemoryStream())
{
images[0].Write(stream, MagickFormat.Png24);
stream.Close();
byte[] result = stream.ToArray();
return File(result, "image/png");
}
}
}
private byte[] CreateDocument(Guid id)
{
PdfReader reader = new PdfReader(Server.MapPath(String.Format("~/documenttemplates/{0}.pdf", id)));
byte[] result = null;
using (MemoryStream ms = new MemoryStream())
{
PdfStamper stamper = new PdfStamper(reader, ms, '\0', false);
stamper.Close();
reader.Close();
result = ms.ToArray();
}
return result;
}
答案 0 :(得分:1)
导致此问题的PDF文件是通过电子邮件提供给我的,我被告知此文件是使用Word创建的,然后使用Foxit Pro进行编辑。
Magick.NET使用Ghostscript将PDF文件转换为图像。执行类似于下面的命令。
"c:\Program Files (x86)\gs\gs9.16\bin\gswin32c.exe" -q -dQUIET -dSAFER -dBATCH -dNOPAUSE
-dNOPROMPT -dMaxBitmap=500000000 -dAlignToPixels=0 -dGridFitTT=2 -sDEVICE=pnggray"
-dTextAlphaBits=4 -dGraphicsAlphaBits=4 "-r72x72" "-sOutputFile=Test.%d.png" "-fTest.pdf"
这将告诉我们创建的文件已损坏。
**** Error reading a content stream. The page may be incomplete.
**** File did not complete the page properly and may be damaged.
**** Error reading a content stream. The page may be incomplete.
**** File did not complete the page properly and may be damaged.
**** This file had errors that were repaired or ignored.
**** The file was produced by:
**** >>>> Microsoft? Word 2013 <<<<
**** Please notify the author of the software that produced this
**** file that it does not conform to Adobe's published PDF
**** specification.
这可以通过使用不同的程序创建输入文件来解决。