Re: docview issues on windows: pdf and png files

[Eli Zaretskii <eliz@gnu.org>]

> From: Vinh Nguyen <vinhdizzo@gmail.com>
> Date: Thu, 1 Aug 2013 18:50:21 -0700
> 
> I am having issues with rendering pdf files using doc view on windows.
> I downloaded emacs 24.3 windows binaries, have ghostscript installed
> via cygwin (M-! gs confirms gs works), and placed libpng dll (libxpm,
> jpeg, etc) in my emacs/bin directory (and installed via the setup
> installation file). I’ve also installed these libraries using cygwin.
> When I open an actual png file (ghostscript converts pdf to png, so
> testing this), the image also does not render. I get this message:
> “Cannot display image: (Invalid image specification)”.
> 
> Would appreciate if anyone could guide me to getting this to work on
> windows. Thanks so much!

What does this produce in Emacs:

  M-: (image-type-available-p 'png) RET

My guess is it says "nil", which means you don't have PNG image
support in your Emacs.

In a nutshell, don't mix a native Windows build of Emacs with Cygwin
libraries -- that will never work.  Even Cygwin Ghostscript could give
you trouble, when used from a native Windows Emacs.

If you want a Cygwin environment, install a Cygwin Emacs.  If you want
a native Windows environment, install native Windows image libraries
(see the file README.W32 for URLs) and a native Windows build of
Ghostscript.