Simple Lorem Icon service

TL;DR:

• bookmarkable image urls
• pseudo random images
• uses node-canvas and express
• simple frontend to try out the service is at /help-me/
• if you want really permanent permalinks to the images, you should host this yourself somewhere, a dockerfile is included

A service to create random but bookmarkable placeholder images.

The service takes a number of parameters, you can see the structure of the image URLs on the page at /help-me/ (it is linked from the index page).

Image URL patterns

These URL patterns will return an image, the shorter URL patterns always redirect to the fully specified format.

• Just Dimensions: /:x/:y
• Style + Dimensions: /:style/:x/:y
• Style, Dimensions, Format: /:style/:x/:y/:format
• Fully specified: /:style/:x/:y/:seed/:format

Dimensions (:x and :y) can be specified without unit, which will be taken as px.

Other supported units are:

• pt -- either 96ppi or 72dpi (for :format = pdf)
• in -- either 96pixels or 72pixels (for :format = pdf)
• cm -- converted at 2.54 cm / in
• mm -- converted at 25.4 cm / in
• px -- same as not specifying a unit

Supported :format values:

• png -- lossless compression, ideal for icons; the default value
• jpeg -- lossy compression, ideal for larger gradient images
• jpg -- same as jpeg
• svg -- vector format, pre-sized to given size
• pdf -- your favourite paper replacement format

These will redirect you to a data: URL containing the generated image:

• datapng -- convert image to png and encode as data: url
• datajpeg -- convert image to jpeg and encode as data: url
• data -- convert image to png and jpeg and redirect to the shorter one encoded as data: url

Examples:

• https://loremicon.com/ngon/16/16/64110306/jpeg (16x16 pixel jpeg)
• https://loremicon.com/ngon/297mm/210mm/64110306/pdf (a4 pdf)
• https://loremicon.com/grad/20pt/20pt/64110306/svg (20pt svg)

To get additional control over the generated image, some part of the randomly determined image parameters can be overridden using the :extra part of the image URL (and this is only supported as an extension of the fully specified form, for now):

• Extended specification: /:style/:x/:y/:seed/:extra/:format

The :extra can be specified as either of these:

• colors=<hexcolor>,<hexcolor>,...
• colors=<color>;<color>;...
• palette=<hexcolor>,<hexcolor>,...
• palette=<color>;<color>;...

where the colors are either 3 or 6 hexadecimal digits (when separated with commas) or just general color strings (when separated with semicolons).

So these are equivalent:

1. /ngon/128/128/64110306/colors=0ff,00f/jpeg
2. /ngon/128/128/64110306/palette=cyan;blue/jpeg
3. /ngon/128/128/64110306/palette=rgb(0 255 255);rgb(0 0 255)/jpeg
4. /ngon/128/128/64110306/palette=rgb(0,255,255);rgb(0,0,255)/jpeg

Note: the spaces in the third example must, of course, be escaped as %20, but browsers should also accept commas as in the fourth example.

Styles

The following examples all use the same seed, so will not change on reload:

/grad/128/128/577251899890/jpg
grad: Random number of gradient stops, random angle

/poly/128/128/577251899890/jpg
poly: Polygon, random number of vertices

/ngon/128/128/577251899890/jpg
ngon: Regular N-Gon, random number of edges / corners

/rect/128/128/577251899890/jpg
rect: Random number of rectangles at random coordinates

/pxls/128/128/577251899890/jpg
pxls: Just random noise, more useful with color palette

/lclr/128/128/577251899890/jpg
lclr: light colors (an experiment with color)

/dclr/128/128/577251899890/jpg
dclr: dark colors (another experiment with colors)

/mclr/128/128/577251899890/jpg
mclr: mixed colors (yet another experiment with colors)

Random Styles

Two kinds of random:

/drnd/128/128/577251899890/jpg
(Deterministic based on seed)

/rndm/128/128/577251899890/jpg
(Completely random, does not depend on seed, different every time, but always one of the above since it uses the same seed)

More examples

/poly/128/128/577251899890/jpg

/ngon/128/128/264039499501/png

/poly/128/128/486310823847/jpg

/poly/128/128/13188643/png

/grad/128/128/14942979907/jpg

/poly/128/128/13188643/colors=red;yellow/png

/pxls/128/128/64110306/colors=333,343,353,363,373,383,393,3a3/jpeg

/pxls/128/128/64110306/palette=333,343,353,363,373,383,393,3a3/jpeg

/grad/128/128/26798732/colors=lime;aqua;cornflowerblue;coral;hotpink/png

/pxls/128/128/26798732/colors=lime;aqua;cornflowerblue;coral;hotpink/png

Controlling the colors

In order to replace the randomly generated colors with a set of pre-determined colors, you can specify either colors=ccc,... or palette=ccc,... as an additional path segment before the format (which must always come last).

The difference between the two is how colors are selected:

• with colors, every time a color is needed, the next one from your list is used (and re-used, if more colors are needed than were given)
• palette just provides a list to select from, and every use of a color chooses one at random -- which means that it can use the same one every time, if that happens, maybe add another color to your list; this works because all "randomness" derives from the seed in the URL and is the same every time you request an image using the same seed

/poly/128/128/577251899890/colors=ccc,777/jpg

/poly/128/128/577251899890/palette=ccc,777/jpg

/ngon/128/128/264039499501/colors=ccc,777/jpg

/ngon/128/128/264039499501/palette=ccc,777/jpg

/poly/128/128/486310823847/colors=ccc,777/jpg

/poly/128/128/486310823847/palette=ccc,777/jpg

/rect/128/128/26798739/colors=f34,43f,567,3f4/png

/rect/128/128/26798739/palette=f34,43f,567,3f4/png

Building

Currently builds on macOS using node 13.

Docker image uses Alpine Linux and node 14.