Re: doc-view: Document quality and find-file

[Peter Dyballa <Peter_Dyballa@Web.DE>]

Am 17.09.2007 um 17:17 schrieb Amy Templeton:

> (1)  Is there any way to increase the image quality? The letters of  
> the PDF
>      files seem to end up somewhat butchered, making some hard to  
> read.

The xpdf suite also contains the programmes pdfinfo and pdffonts. The  
latter can be useful to determine whether the PDF file has real fonts  
(vector based fonts in PostScript or TrueType format [OpenType is  
some wrapper around PostScript or TrueType]) or just bitmaps from  
TeX. The "real fonts" are clear names while the TeX fonts seem to  
come from some cryptographic engine ...


One option could be to correct the default resolution with which  
Ghostscript is converting the vector fonts in a PDF document to  
bitmaps ("-r100"). Maybe your screen has coarser or finer resolution,  
so you might update the value.

	(defcustom doc-view-ghostscript-options
	  '("-dNOPAUSE" "-sDEVICE=png16m" "-dTextAlphaBits=4"
	    "-dBATCH" "-dGraphicsAlphaBits=4" "-dQUIET"
	    "-r100")
	  "A list of options to give to ghostview."
	  :type '(sexp)
	  :group 'doc-view)

Another cause could be that -dGraphicsAlphaBits=4" can make lines  
that should join end before the joint. Setting the numerical value of  
4 to 1 can correct this behaviour.

Another option might be to substitute the default output format  
"png16m" (best suited for 24 bit RGB displays) with any of "pnggray"  
for greyscale, "png256" for 8-bit colour, "png16" for 4-bit colour,  
or "pngmono" for black-and-white. They all won't show the same amount  
of anti-aliasing power!

--
Greetings

   Pete

"One person with a belief is a social power equal to ninety-nine who  
have only interests."
                                                  - John Stuart Mill