Convert PDF To Image - library or command line - free

How can I convert each pages of a PDF's file in C#开发者_C百科, using free command line or free library?

Thank you

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Example commandlines for Ghostscript converting multipage PDF to images (1 image per page):

gswin32c ^
  -o gray_page_%03d.png ^
  -sDEVICE=pnggray ^
   input.pdf

.

gswin32c ^
  -o page_%03d.png ^
  -sDEVICE=png256 ^
   input.pdf

.

gswin32c ^
  -o page_with_alphachannel_%03d.png ^
  -sDEVICE=pngalpha ^
   input.pdf

.

gswin32c ^
  -o cmyk_page_%03d.jpeg ^
  -sDEVICE=jpegcmyk ^
  -dJPEGQ=80 ^
   input.pdf

.

gswin32c ^
  -o rgb_page_%03d.jpeg ^
  -sDEVICE=jpeg ^
  -dJPEGQ=100 ^
   input.pdf

.

gswin32c ^
  -o tiffg4_page_%03d.tiff ^
  -sDEVICE=tiffg4 ^
   input.pdf

.

gswin32c ^
  -o tiffg32nc_page_%03d.tiff ^
  -sDEVICE=tiff32nc ^
  -sCompression=lzw ^
   input.pdf

...and many more are possible....

If you need to control resolutions and page sizes (and not rely on Ghostscript's defaults) add these parameters:

-r600x600

gives you a horizontal and vertical resolution of 600 dpi.

-g5950x8420

applies a widths of 5950 "devicepoints" and a height of 8420 "devicepoints". Depending on the resolution used at the same time, the devicepoints will end up on paper in different sizes. In case of a resolution -r720x720 above example of -g5950x8420 will become the same as media size of DIN A4 ISO (which is in PostScript points 595 by 842.

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ImageMagick.NET, a .NET wrapper for the ImageMagick libraries, is your friend.

ImageMagick offers a variety of image manipulation and conversion tools. For converting PDF documents, it is using GhostScript under the hood.