Recreating all the flags of the nations of the world in pure CSS, using only one
div per flag.
You can see it live on https://pixelastic.github.io/css-flags/
This side-project has no real-world application, it was just an exercise to push the boundaries of what I know about CSS. Trying to use the language to do things it wasn't meant to do in the first place taught me a lot about the language.
Running the project locally
bundle install npm install npm run serve
The website will then be available on http://localhost:4001/.
If you've spotted an issue with the rendering of a specific flag or if you know how to do one of the missing flags, I'm open to pull requests.
I've only tested the rendering on Chrome and Safari so far. I plan on making it cross-browser but I need to add visual non-regression testing first.
To create the flags, my three most important sources were the Wikipedia, CRWFlags and Vexilla Mundi. CRWFlags contains valuable information about every flag history, allowing me to better understand how they were constructed. Vexilla Mundi contains handy construction sheet images with dimensions and angles.
Not all flags have an exact definition of the colors to use. Best case scenario, we have the official RGB/Hexa (or even Pantone) name of the color. Worst case, we have nothing and have to use the color used on the Wikipedia or Vexilla Mundi, even if it is not the official one.
To be able to display some of the very specific symbols used on some flags, I had to craft my own icon font, using icomoon.io.
I had to find svg versions of all the symbols used. Sometimes the symbols already exists in the UTF8 table, so I just have to grab them from existing fonts (or use utf8icons.com).
But more often, I had to use Vexilla Mundi. The website provides nice png images of all the symbols. Unfortunately, the symbols they provide are already colored, and I needed them black to use in the font so I was able to define the color myself.
The following script will do exactly that:
convert input.png \ -alpha off \ -fill black \ -colorize 100 \ -alpha on \ output.png
I then had to trim the image to remove any whitespace left around the symbol:
convert input.png -trim output.png
Then, I need to convert the png to an svg. I couldn't find any commandline tool giving satisfying results, so I had to use an online service to do it: online-convert.com
Once I got the svg, it is just a matter of uploading it to icomoon, center the symbol, scale it and adjust the border. I also used the reserved namespace in the UTF8 table for custom characters. And finally exported the font.
You're using half pixels. That does not make any sense.
Ok, that's not really a question, but I'll explain anyway.
I try to use percentage as much as I can, when it makes sense. Percentage are relative to either the width or the height of the flag. When doing a tricolore flag, I will use 33.33% as the width of each stripe for example. But as soon as I need to draw a square that has the same width than height, I can no longer user percentage values, I need real, absolute, pixel values.
Commandline tool to convert any image (jpg or png) to full CSS. This will
replicate all pixels of the initial image using numerous
This works wel but results in really heavy generated CSS (several MB), so I choose not to use it in this project.
Commandline tool to get an approximation in hexadecimal of a Pantone color value. Really useful as Vexilla Mundi gives color values in Pantone.
Someone else had the same idea.
Tips and tricks
Here is an incomplete list of the tricks I had to use:
I sometimes put an invisible symbol in an
before element (through
color: transparent) and positioned it at
top:0; left: 0.
Then I added several
text-shadow to it, with a full color. Doing so helped in
getting the coordinates right because everything is then relative to the origin
first-letter / first-line
When I needed to add more than 1 symbol in an
before, or if I needed
the same symbol, but on different sizes, I had to be sneaky.
By setting a
"XY\AZ" and then using both
first-line, I was able to independently target
\A is the
special character to add a new line in a
Doing so let me use three different symbols, with different color and sizes with only one pseudo-element.
It is impossible to apply any
transform (like a rotation) on those elements,
This project is not over, there are still some elements that I would like to add:
- Link to codepen to let users play with the code
- Making it work on more browsers...
- ...which implies that I need to add a visual testing framework on top if it
- Adding the missing flags
- Using a clip-path when only one star instead of a font
- Building the font with npm instead of icomoon.io
- Adding stars to Brazil
- Doing the Nepal flag
- Check if Lea Verou has a background pattern close to the British India
- Add the Leather Pride flag as an easter egg