CODEWITHSUNDEEP
phpghostscriptimagick
Boognish100
Boognish100

Reputation: 35

Merging PDF's using Ghostscript outputs as grayscale / loses color

I have a script which takes a base64 string and converts it into a png image. I then use Imagick to to convert the png into a pdf which uses a AdobeRGB1998 icc profile. This all works as expected and creates a color pdf. 

$data = str_replace("data:image/png;base64,","",$_POST["rsa"]);
$save = $path.$_POST["pdfname"].".png";


$imagick = new Imagick();
$decoded = base64_decode($data);
$imagick->readimageblob($decoded);
$imagick->writeImage($save);
$imagick->clear();
$imagick->destroy(); 

    exec("convert $path.$_POST["pdfname"].".png -profile AdobeRGB1998.icc -density 300 ".$path.".$_POST["pdfname"].".pdf", $array);

However, when I then use Ghostscript to merge a bunch of these PDFs together using the below code it outputs in grayscale and I'm not sure why.

function getPDFs($e)
{
return $path.$e['pdffilename'].".pdf ";
}
$fileArray = array_map("getPDFs(", $_POST['item']);
$outputName = $path."LatestDispatch.pdf";
$cmd = "gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=$outputName ";
foreach($fileArray as $file) {
    $cmd .= $file." ";
}
$result = shell_exec($cmd);

I switched to using Ghostscript as opposed to imagick to merge pdfs. Imagick returned a merged color pdf but seemed to hit a limit as to how many PDF's imagick was able to merge at once. Ghostscript doesn't have any problems or limits as to how many PDFs it merges so would like to continue with this method as opposed to Imagick, however I need to resolve this issue of PDF's outputting in grayscale, not color. Can anyone help please?

Thanks!

Upvotes: 0

Views: 507

Answers (1)

KenS
KenS

Reputation: 31199

Firstly, Ghostscript doesn't 'merge' PDF files. When you present it with a list of PDF files as input, and use the pdfwrite device to output a single PDF file, it isn't 'merging' the PDF files.

What happens is that each PDF file is fully interpreted to produce a sequence of marking operations, these operations are then passed to the device. For rendering devices they render a bitmap. For PDF output, they are emitted as PDF equivalent operations.

So the content of the output PDF file bears no relation to the content of the input files. The appearance should be the same, but it's not 'merging'.

You haven't said what version of Ghostscript you are using, or where you sourced it from (or even what OS you are using, but I guess some flavour of Linux). There's nothing obviously wrong with the command line, but if I were you I'd start by not using a script. Just use Ghostscript manually from the shell to see what happens. If that works, and the script doesn't, then there's something wrong with the script, and you aren't mimicking it properly from the shell. Have the script print out the precise command line and try to see if there's some difference in what you typed at the shell.

If it behaves the same, then it's puzzling. But without some example to look at, there's little I can advise.

Upvotes: 0

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