Ghostscript Multipage PDF to PNG - pdf

Question

I've been using ghostscript to do pdf to image generation of a single page from the pdf. Now I need to be able to pull multiple pages from the pdf and produce a long vertical image.
Is there an argument that I'm missing that would allow this?
So far I'm using the following arguments when I call out to ghostscript:
string[] args ={
"-q",
"-dQUIET",
"-dPARANOIDSAFER", // Run this command in safe mode
"-dBATCH", // Keep gs from going into interactive mode
"-dNOPAUSE", // Do not prompt and pause for each page
"-dNOPROMPT", // Disable prompts for user interaction
"-dFirstPage="+start,
"-dLastPage="+stop,
"-sDEVICE=png16m",
"-dTextAlphaBits=4",
"-dGraphicsAlphaBits=4",
"-r300x300",
// Set the input and output files
String.Format("-sOutputFile={0}", tempFile),
originalPdfFile
};

Answer 1

I ended up adding "%d" to the "OutputFile" parameter so that it would generate one file per page. Then I just read up all of the files and stitched them together in my c# code like so:
var images =pdf.GetPreview(1,8); //All of the individual images read in one per file
using (Bitmap b = new Bitmap(images[0].Width, images.Sum(img=>img.Height))) {
using (var g = Graphics.FromImage(b)) {
for (int i = 0; i < images.Count; i++) {
g.DrawImageUnscaled(images[i], 0, images.Take(i).Sum(img=>img.Height));
}
}
//Do Stuff
}

Answer 2

If you can use ImageMagick, you could use one of its good commands:
montage -mode Concatenate -tile 1x -density 144 -type Grayscale input.pdf output.png
where
-density 144 determins resolution in dpi, increase it if needed, default is 72
-type Grayscale use it if your PDF has no colors, you'll save some KBs in the resulting image

Answer 3

First check the output device options; but I don't think there's an option for that.
Most probably you'll need to do some imposition yourself, either make GhostScript do it (you'll have to write a PostScript program), or stitch the resulting rendered pages with ImageMagick or something similar.
If you want to try the PostScript route (likely to be the most efficient), check the N-up examples included in the GhostScript package.