CODEWITHSUNDEEP
pdfjpegghostscriptpostscript
radistao
radistao

Reputation: 15534

How to set PDF page size in PostScript from viewjpeg.ps file

I use Ghostscript to convert JPEG to PDF:

gs -sDEVICE=pdfwrite -o d.pdf viewjpeg.ps -c "(Imgp3826.Jpeg) viewJPEG showpage

This creates PDF with default page size and image, located on left bottom corner. I need to modify script to create page with correct dimensions.

in this note: https://stackoverflow.com/a/6508854/907576

they do this using ImageMagick, but I can't use it - I can use Ghostscript only.

Is is possible to get width-height values from viewjpeg.ps and set it to page size?

I see in viewjpeg.ps:

/height NextByte 8 bitshift NextByte add def
/width NextByte 8 bitshift NextByte add def

Looks like they use JPEG headers to read this info.

Can I then reuse it for <</PageSize [${dimension}]>> ?

Upvotes: 2

Views: 3679

Answers (3)

Yerlan
Yerlan

Reputation: 1

 gs -sDEVICE=pdfwrite -o /pathTo/newPdf.pdf "/pathTo/viewjpeg.ps" -c "(/pathTo/jpgToPdf.JPG) << /PageSize [400 300] >> setpagedevice  viewJPEG"
  • /pathTo/newPdf.pdf - file that'll be generated
  • /pathTo/jpgToPdf.JPG - input jpg file
  • << /PageSize [400 300] >> setpagedevice viewJPEG - viewjpeg.ps utility command line arguments
  • [400 300] - image size, width and height calculated by formula (width/resolution) * 72 and (height/resolution) * 72

Upvotes: 0

KenS
KenS

Reputation: 31199

You can't use those numbers directly as arguments to /PageSize, as those are the height and the width of the image (in image samples), while the arguments to PageSize are in PostScript units (1/72 inch).

You could, however, scale them by the current resolution and use the scaled numbers.

(width/resolution) * 72 and (height/resolution) * 72 should do the job.

So :

currentpagedevice /HWResolution get aload
height exch div 72 mul
exch width exch div 72 mul
exch 2 array 3 1 roll astore
<< /PageSize 3 -1 roll >> setpagedevice

Caveat: I haven't had time to actually try this....

Upvotes: 2

chrisl
chrisl

Reputation: 491

FWIW, the simple addition listed above won't work alone, due to how the viewJPEG procedure is written.

I suggest augmenting viewjpeg.ps with another procedure:

/viewJPEGgetsize {      % <file|string> ==> width height
    save
    JPEGdict begin
    /saved exch def
    /scratch 1 string def
    dup type /stringtype eq { (r) file } if
    /F exch def

    readJPEGmarkers begin
    width height
    saved end restore
} bind def

And then you can call it like this:

gs -I../lib -sDEVICE=pdfwrite \
   -o stuff.pdf viewjpeg.ps   \
   -c "(image.jpg) <</PageSize 2 index viewJPEGgetsize 2 array astore>> setpagedevice viewJPEG"

Upvotes: 2

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