Improving DocView quality for PDFs?

Improving DocView quality for PDFs?

[Christopher Howard]

Hi, I like viewing PDFs inside Emacs using DocView, but the quality is noticeable lower than in Evince. It looks blocky, like it needs aliasing or something. Could I improve this with some setting changes? I see some variables like Doc View Ghostscript Options but I don't know what options I need to pass in. I see some discussions about this on the Internet but they are very old discussions with unclear guidance.

I am running GNU Emacs 30.0.91 (build 10, x86_64-pc-linux-gnu, GTK+ Version 3.24.41, cairo version 1.18.0) of 2024-10-04.

-- 
📛 Christopher Howard
🚀 gemini://gem.librehacker.com
🌐 http://gem.librehacker.com

בראשית ברא אלהים את השמים ואת הארץ

Improving DocView quality for PDFs?

[Christopher Howard]

Hi, I like viewing PDFs inside Emacs using DocView, but the quality is noticeable lower than in Evince. It looks blocky, like it needs aliasing or something. Could I improve this with some setting changes? I see some variables like Doc View Ghostscript Options but I don't know what options I need to pass in. I see some discussions about this on the Internet but they are very old discussions with unclear guidance.

I am running GNU Emacs 30.0.91 (build 10, x86_64-pc-linux-gnu, GTK+ Version 3.24.41, cairo version 1.18.0) of 2024-10-04.

-- 
📛 Christopher Howard
🚀 gemini://gem.librehacker.com
🌐 http://gem.librehacker.com

בראשית ברא אלהים את השמים ואת הארץ

Re: Improving DocView quality for PDFs?

[Kristoffer Balintona]

On Mon, Oct 07 2024, Christopher Howard wrote:

> Hi, I like viewing PDFs inside Emacs using DocView, but the quality is noticeable lower than in Evince. It looks blocky, like it needs aliasing or something. Could I improve this with some setting changes? I see some variables like Doc View Ghostscript Options but I don't know what options I need to pass in. I see some discussions about this on the Internet but they are very old discussions with unclear guidance.
>
> I am running GNU Emacs 30.0.91 (build 10, x86_64-pc-linux-gnu, GTK+ Version 3.24.41, cairo version 1.18.0) of 2024-10-04.

Hi,

Have you given pdf-tools
(https://github.com/vedang/pdf-tools?tab=readme-ov-file#about-pdf-tools)
a go yet? If you haven't heard of it, I think this is the go-to Emacs
PDF viewer for many users because it is very fast and supports many
features that non-Emacs PDF viewers support, like making and viewing
annotations as well as jumping to different points in a document's
outline (though that requires certain metadata to be present in the
document).

If you want to stick with the built-in DocView, I don't have any tips
there since I use pdf-tools's pdf-view-mode in place of it.

-- 
Take care,
Kristoffer

Re: Improving DocView quality for PDFs?

[Christopher Howard]

Kristoffer Balintona <krisbalintona@gmail.com> writes:

> Have you given pdf-tools
> (https://github.com/vedang/pdf-tools?tab=readme-ov-file#about-pdf-tools)
> a go yet? If you haven't heard of it, I think this is the go-to Emacs
> PDF viewer for many users because it is very fast and supports many
> features that non-Emacs PDF viewers support, like making and viewing
> annotations as well as jumping to different points in a document's
> outline (though that requires certain metadata to be present in the
> document).
>

Okay, thanks, I'm giving this a try now.

-- 
Christopher Howard

Re: Improving DocView quality for PDFs?

[Stefan Monnier via Users list for the GNU Emacs text editor]

> Hi, I like viewing PDFs inside Emacs using DocView, but the quality is
> noticeable lower than in Evince. It looks blocky, like it needs aliasing or
> something. Could I improve this with some setting changes?

It's not completely clear how to control this.  It's largely a result of
the PDF renderer used and I don't think the renderer used in Evince can
be used for DocView.  But you may want to try and install `mupdf-tools`
(variously also called Pdfdraw, Mudraw, or Mutool`) which is a different
PDF renderer than Ghostscript, which DocView can also use.

IIRC it's sometimes better, but not always.

And of course, someone else already mentioned `pdf-tools` (available
from a NonGNU ELPA archive near you).


        Stefan

Re: Improving DocView quality for PDFs?

[Neal Becker]

Kristoffer Balintona wrote:

> On Mon, Oct 07 2024, Christopher Howard wrote:
> 
>> Hi, I like viewing PDFs inside Emacs using DocView, but the quality is
>> noticeable lower than in Evince. It looks blocky, like it needs aliasing
>> or something. Could I improve this with some setting changes? I see some
>> variables like Doc View Ghostscript Options but I don't know what options
>> I need to pass in. I see some discussions about this on the Internet but
>> they are very old discussions with unclear guidance.
>>
>> I am running GNU Emacs 30.0.91 (build 10, x86_64-pc-linux-gnu, GTK+
>> Version 3.24.41, cairo version 1.18.0) of 2024-10-04.
> 
> Hi,
> 
> Have you given pdf-tools
> (https://github.com/vedang/pdf-tools?tab=readme-ov-file#about-pdf-tools)
> a go yet? If you haven't heard of it, I think this is the go-to Emacs
> PDF viewer for many users because it is very fast and supports many
> features that non-Emacs PDF viewers support, like making and viewing
> annotations as well as jumping to different points in a document's
> outline (though that requires certain metadata to be present in the
> document).
> 
> If you want to stick with the built-in DocView, I don't have any tips
> there since I use pdf-tools's pdf-view-mode in place of it.
> 

Interesting.  I'm also trying pdf-tools.  But how do I know if emacs is 
using it?

Re: Improving DocView quality for PDFs?

[Kristoffer Balintona]

On Sun, Oct 13 2024, Neal Becker wrote:

> Kristoffer Balintona wrote:
>
>> On Mon, Oct 07 2024, Christopher Howard wrote:
>>
>>> Hi, I like viewing PDFs inside Emacs using DocView, but the quality is
>>> noticeable lower than in Evince. It looks blocky, like it needs aliasing
>>> or something. Could I improve this with some setting changes? I see some
>>> variables like Doc View Ghostscript Options but I don't know what options
>>> I need to pass in. I see some discussions about this on the Internet but
>>> they are very old discussions with unclear guidance.
>>>
>>> I am running GNU Emacs 30.0.91 (build 10, x86_64-pc-linux-gnu, GTK+
>>> Version 3.24.41, cairo version 1.18.0) of 2024-10-04.
>>
>> Hi,
>>
>> Have you given pdf-tools
>> (https://github.com/vedang/pdf-tools?tab=readme-ov-file#about-pdf-tools)
>> a go yet? If you haven't heard of it, I think this is the go-to Emacs
>> PDF viewer for many users because it is very fast and supports many
>> features that non-Emacs PDF viewers support, like making and viewing
>> annotations as well as jumping to different points in a document's
>> outline (though that requires certain metadata to be present in the
>> document).
>>
>> If you want to stick with the built-in DocView, I don't have any tips
>> there since I use pdf-tools's pdf-view-mode in place of it.
>>
>
> Interesting.  I'm also trying pdf-tools.  But how do I know if emacs is
> using it?
>

Well, the pdf-tools repository[1] details the installation procedure
well: you should call `M-x pdf-tools-install'. After that, you can open
up a PDF and its major mode should be `pdf-view-mode'.

If it isn't already in that mode but works if you directly invoke `M-x
pdf-view-mode', then it'll probably be a problem with your config.

Footnotes:
[1]  https://github.com/vedang/pdf-tools?tab=readme-ov-file#installing-pdf-tools-elisp-code

-- 
Best,
Kristoffer

Re: Improving DocView quality for PDFs?

[Rudolf Adamkovič]

Christopher Howard <christopher@librehacker.com> writes:

> Hi, I like viewing PDFs inside Emacs using DocView, but the quality is
> noticeable lower than in Evince. It looks blocky, like it needs
> aliasing or something.

It does not need aliasing.  It needs a higher resolution:

    (setq doc-view-resolution 192)

[I have just tested it on a HiDPI screen.]

That said, PDF Tools is the way to go.

Rudy
-- 
"Be especially critical of any statement following the word
'obviously.'"  --- Anna Pell Wheeler, 1883-1966

Rudolf Adamkovič <rudolf@adamkovic.org> [he/him]
http://adamkovic.org

Re: Improving DocView quality for PDFs?

[Neal Becker]

Kristoffer Balintona wrote:

> On Sun, Oct 13 2024, Neal Becker wrote:
> 
>> Kristoffer Balintona wrote:
>>
>>> On Mon, Oct 07 2024, Christopher Howard wrote:
>>>
>>>> Hi, I like viewing PDFs inside Emacs using DocView, but the quality is
>>>> noticeable lower than in Evince. It looks blocky, like it needs
>>>> aliasing or something. Could I improve this with some setting changes?
>>>> I see some variables like Doc View Ghostscript Options but I don't know
>>>> what options I need to pass in. I see some discussions about this on
>>>> the Internet but they are very old discussions with unclear guidance.
>>>>
>>>> I am running GNU Emacs 30.0.91 (build 10, x86_64-pc-linux-gnu, GTK+
>>>> Version 3.24.41, cairo version 1.18.0) of 2024-10-04.
>>>
>>> Hi,
>>>
>>> Have you given pdf-tools
>>> (https://github.com/vedang/pdf-tools?tab=readme-ov-file#about-pdf-tools)
>>> a go yet? If you haven't heard of it, I think this is the go-to Emacs
>>> PDF viewer for many users because it is very fast and supports many
>>> features that non-Emacs PDF viewers support, like making and viewing
>>> annotations as well as jumping to different points in a document's
>>> outline (though that requires certain metadata to be present in the
>>> document).
>>>
>>> If you want to stick with the built-in DocView, I don't have any tips
>>> there since I use pdf-tools's pdf-view-mode in place of it.
>>>
>>
>> Interesting.  I'm also trying pdf-tools.  But how do I know if emacs is
>> using it?
>>
> 
> Well, the pdf-tools repository[1] details the installation procedure
> well: you should call `M-x pdf-tools-install'. After that, you can open
> up a PDF and its major mode should be `pdf-view-mode'.
> 
> If it isn't already in that mode but works if you directly invoke `M-x
> pdf-view-mode', then it'll probably be a problem with your config.
> 
> Footnotes:
> [1] 
> [https://github.com/vedang/pdf-tools?tab=readme-ov-file#installing-pdf-tools-elisp-code
> 

Thanks!  Now I got it!  I was confused because my OS (Fedora) has a package 
called pdf-tools, which is something different.