Linked content

The Current State of Telephone Links | CSS-Tricks

The linked article shows what current browsers do when you click a link like this:

<a href="tel:1-562-867-5309">1-562-867-5309</a>

Spoiler: The current state is sad

It's still the case that most desktop browsers can't do something useful with tel: links. They will usually open a dialog confirming that an external application will be opened. If the user confirms, she will see an error, or nothing at all.

On mobile browsers on the other hand, these links just open…

Linked content

Name that Color

This service gives you a kind-of standard color name for any hex code.

This is useful if you want to extract some colors into a Sass $variable and are looking for a proper variable name.

Linked content

About the HTML and the BODY tag

The <html> and <body> tags both come with some non-default behavior that you know from other tags.
Do not try to style html or body for positioning, width/heigth, or similar. Every browser has its own caveats and you can not test them all.

Generally speaking:

  • Use the html tag to define your page's default background color (because on short pages or large screens, your body may not be as tall as the browser window).
  • Use the html tag to define a base font-size so you can use [rem units](…

Images darken when getting converted with ImageMagick

When using ImageMagick to manipulate images, you might see that images get darker when beeing modified by newer versions of ImageMagick.

This usually happens with CMYK images beeing converted to RGB by IM.


At least in our version of ImageMagick (6.7.7) you can solve this by passing this parameter to ImageMagick -colorspace sRGB.
The RGB colorspace was okay for ImageMagick until version 6.6.9. RGB and sRGB switched obviously.

Linked content

object-fit polyfill by lazysizes

All new browsers support the new object-fit CSS property. It allows to specify how an element behaves within its parent element and is intended for images and videos. The most useful values are contain (fit-in) and cover (crop).

Unfortunately, IE does not support this yet. However, if you're already using lazysizes, you can use its object-fit polyfill!


In your Javascript manifest, require them like this:

#= require plugins/object-fit/ls.obj…

Linked content

Lazysizes 2 is here

It claims to be even faster and brings a new plugin that polyfills object-fit and object-position. This allows for easy arrangement of e.g. images and videos inside containers.

As puts it, object-fit/object-position is a:

Method of specifying how an object (image or video) should fit inside its box. object-fit options include "contain" (fit according to aspect ratio), "fill" (stretches object to fill) and "cover" (overflows box but maintains ratio), where object-position allows the object to be repositioned like backg…

Dynamically uploading files to Rails with jQuery File Upload

Say we want …

  • to create a Gallery that has a name and has_many :images, which in turn have a caption
  • to offer the user a single form to create a gallery with any number of images
  • immediate uploads with a progress bar per image
  • a snappy UI

Enter jQuery File Upload. It's a mature library that can do the job frontend-wise. On the server, we'll use Carrierwave, because it's capable of caching images.

(FYI, [here's how to do the u…

Javascript: Wait until an image has finished loading

The attached ImageLoader helper will start fetching an image and return an image that is resolved once the image is loaded:

ImageLoader.load('/my/image.png').then(function(image) {

The image argument that is yielded to the promise callback is an HTMLImageElement. This is the kind of object you get when you call new Image().

Deleted: Validate the presence of a CarrierWave attachment

Deleted the card. You can just use validates_presence_of.

Background is that CarrierWave::Uploader::Base delegates blank? to the attached file.

Linked content

Preloading images with CSS

Sometimes you want to preload images that you will be using later. E.g. if hovering over a an area changes its background image, the new image should be preloaded. If you only load it once the user starts hovering, there will be a delay until the background image flips.

The attached article explains how to preload images with only CSS. No Javascript required.

The gist is:

.element:after {
  content: url(img01.jpg) url(img02.jpg) url(img03.jpg);
  display: none;
Linked content

Official Color Codes for the World's Biggest Brands provides you with the colors of the world's biggest brands, easily searchable.

Linked content

How to preview an image before uploading it

When building a form with a file select field, you may want to offer your users a live preview before they upload the file to the server.

HTML5 via jQuery

Luckily, HTML5 has simple support for this. Just create an object URL and set it on an <img> tag's src attribute:

$('img').attr('src', URL.createObjectURL(this.files[0]))

Unpoly Compiler

As an Unpoly compiler, it looks like this:

up.compiler '[image_p…

Install MySQL 5.6 in Ubuntu 16.04

Instead of using this hack you might want to use MariaDB 10.x which can work with both old and new apps.

An alternative could be to use the MySQL Docker image which is still updated for 5.6.

Ubuntu 16.04 only provides packages for MySQL 5.7 which has a range of backwards compatibility issues with code written against older MySQL versions.

Oracle maintains a list of official APT repositories for MySQL 5.6, but those repositories do…

Geordi 1.3 released


  • Geordi is now (partially) tested with Cucumber. Yay!
  • geordi cucumber supports a new @solo tag. Scenarios tagged with @solo will be excluded from parallel runs, and run sequentially in a second run
  • Support for Capistrano 2 AND 3 (will deploy without :migrations on Capistrano 3)
  • Now requires a .firefox-version file to set up a test firefox. By default now uses the system Firefox/a test Chrome/whatever and doesn't print warnings any more.
  • geordi deploy --no-migrations (aliased -M): Deploy with `cap …
Linked content

Shrine - A file upload toolkit

Now that CarrierWave is no longer maintained, Shrine might be worth a look.

Linked content

pgAdmin has a "graphical EXPLAIN" feature

When working with PostgreSQL, you can use pgAdmin as a GUI.
While you can do most things just like on an SQL console, you can use it to display EXPLAIN results in a more human-readable way.

(image from the Postgres manual)

  1. Open up pgAdmin, connect to your server
  2. Pick a database from the left pane
  3. Click the "SQL" icon in the toolbar, or press Ctrl+E to open the query tool.
  4. Paste any queries that you'd like to explain.
  5. Go to "Query" → "Explain analyze", or …
Linked content

Retina revolution

Looking for a way to embed raster images for both low- and high-DPI displays, this developer had some good results with using a high resolution with more JPEG compression than you would use normally.

He argues that the image looked great on both low- and high-DPI displays. Also the compression artifacts were now so small that they are not as noticable then when an 1:1 image is highly compressed.

Openstack: nova resize

To change RAM size, VDISK size or VCPU count of an openstack instance you have to use nova resize. You can't change for e.g. just the RAM size with a parameter, you have to assign a new/other flavor. If there is no suitable flavor for the new properties of the VM, create a new one.

nova resize [--poll] <server> <flavor>

The resize could take a while, after it is finished, the VM boots up with the new specifications. SSH into the VM and check if everything is alright…

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