Vivaldi public key issue

After several unsuccessfull attempts to fix a Vivaldi NO_PUBKEY error, I found this working solution:

wget -qO- https://repo.vivaldi.com/archive/linux_signing_key.pub | gpg --dearmor | sudo dd of=/usr/share/keyrings/vivaldi-browser.gpg

and then:

sudo apt update

link from outside to a part of a file

pdf

It is possible to link a page of a pdf, with the following syntax:

file:///your-path-here/your-pdf-filename-here.pdf#pag=[the-page-number]

or, if the file is within your localhost folder

http://localhost/your-path-here/your-pdf-filename-here.pdf#pag=[the-page-number]

epub

It is possible to link to a given location of an epub file, i.g. with calibre viewer, with a code like the following

file:///your-path-here/your-epub-filename.epub?open_at=epubcfi(/10/2/4/2/132/18/1:65)

You can get the string after open_at (in the above case: epubcfi(/10/2/4/2/132/18/1:65) in the calibre viewer, this way:

  • right click
  • -> go to
  • -> location
  • -> current location (above in the window) : copy

video file

with VLC you can use this code

vlc file:///my-path/my-video.mp4 --start-time=90

where ’90’ are the seconds (after the start of video).

I didn’t manage, so far, to open a video with such a code from a browser.

audio file

You ca do it in several ways. With play (sox) in Linux you can use a code setting not only the start time, but the end one as well:

play '/your-path/your-file.ogg' trim 5:18 =7:01

where 5:18 is the start time, and 7:01 the end one (=7.01 and not = 7:01)

embed a playlist in a web page

After many attempts I finally figured taht it’s impossible embed an audio playlist (such as m3u) to a webpage: you can add only multiple (audio) files, but not a playlist.

I tried with the <audio> tag: nothing to to, even with jquery or javascript. Neither with <embed> or <object> html tags: html developers allow only a single audio playing, not a playlist.

The mimetype “audio/x-mpegurl” doesn’t work.

svg rounded corner and shadow

shadow (like css shadow-box)

At least with Firefox you can use a filter, like the following:

.shadow{filter: drop-shadow(8px 6px 6px gray);}

rounded corner

The simplest way to round the corners of a box is to

  • use rect element with rx and ry attributes (such as rx="20" ry="20")
  • and define the style of rect with stroke-linejoin:round; and something like stroke:[your color]; stroke-width:[the width you like];

You can see the following example

box rounded

svg with external image embedded

All browsers have this limitation: they not allow to show an svg with an external image embedded, such as

<image x="2" y="2" width="somewidth" height="someheight" xlink:href="myimage.jpg">

even though the image is in local.

For security reasons.