This project generates the current background image in the resolution needed for the computer making the request. What?? Why???

Description

This server takes assets and slaps them together to create a wallpaper image of the requested resolution. Because the wallpaper image is created on the fly, the wallpaper server can generate a wallpaper for any aspect ratio requested; even portrait (sideways) monitors.

There are three assets used:

• Background: The background image of the wallpaper. This is currently just a single pixel of the green color that we want.
• TopLeft: This is the an image we want in the top left; like the company logo.
• BottomRight: This is an image we want in the bottom right; like support contact information.

Usage

The main issue presented iteself in OS X when the Lock Screen Wallpaper image had to fit the screen resolution because OS X wouldn't resize or stretch it as needed.

We also use it for Windows because we can only specify one file (via GPO) to force as the Lock Screen Wallpaper. Since logos stretch and stretched logos make VIPs sad ... we decided we needed to to be a little more creative with choosing the image for the Lock Screen Wallpaper. This server allows an unskewed image with the the exact resolution to be used for the Lock Screen Wallpaper.

Getting Your Assets In

If you're going to use this, you're likely going to want a simple way of getting your assets loaded into the container. Well, there's an environment variable for that: WALLPAPER_CURL_CONFIG.

When the container launches, before Apache runs (via run.sh) we pull in the assets defined in the curl config file. During this process, all assets are purged from the assets directory and your assets are downloaded.

For more detail about the format of the config file, see the curl man page. Keep in mind, the working directory during this is the assets directory, so there's no need to specify a file name or path. See our development curl config file for some guidance.

Query String Parameters

See for yourself with two quick examples (please feel free to play; submit an issue when you break it):

• 4:3: https://unt-wallpaper-dev.azurewebsites.net?w=800&h=600
• 16:9: https://unt-wallpaper-dev.azurewebsites.net?w=848&h=480

By default, this will return a BMP; for windows.

However, OS X needs PNG with Alpha Channel:

• 4:3: https://unt-wallpaper-dev.azurewebsites.net?w=800&h=600&f=png
• 16:9: https://unt-wallpaper-dev.azurewebsites.net?w=848&h=480&f=png

Note: Only bmp and png are supported formats.

More Query String Parameters

Here's a list and quick desciption of all of the current Query String Parameters:

Parameter	Name	Default Value	Expected Value(s)/Type	Description
bg	Background	bg	Check the /assets folder for possible images; supply the case-sensitive name without extension.	This image will be stretch to the height and width needed to fill the background.
bl	Bottom Left	NULL	Check the /assets folder for possible images; supply the case-sensitive name without extension.	This image will be used in the appropriate corner.
blp	Bottom Left Percentage	0	Should be a number less than or equal to 1.	This is the percentage of the width of the Bottom Left image.
blm	Bottom Left Margin Percentage	0	Should be a postive number less than or equal to 1. Two numbers can be supplied, seperated by a comma (no space). i.e.: .05 or .05,.07	This is the percentage of the width that will be used to apply a margin around the Bottom Left image. It works like CSS's margin shorthand property; however, only one or two values are supported.
br	Bottom Right	NULL	Check the /assets folder for possible images; supply the case-sensitive name without extension.	This image will be used in the appropriate corner.
brp	Bottom Right Percentage	0	Should be a number less than or equal to 1.	This is the percentage of the width of the Bottom Right image.
brm	Bottom Right Margin Percentage	0	Should be a postive number less than or equal to 1. Two numbers can be supplied, seperated by a comma (no space). i.e.: .05 or .05,.07	This is the percentage of the width that will be used to apply a margin around the Bottom Right image. It works like CSS's margin shorthand property; however, only one or two values are supported.
f	Format	bmp	bmp, png	The format of the image.
h	Height	REQUIRED	int	The desired height of the image.
tl	Top Left	est-1890-UNT-University-of-North-Texas-white	Check the /assets folder for possible images; supply the case-sensitive name without extension.	This image will be used in the appropriate corner.
tlp	Top Left Percentage	.6	Should be a number less than or equal to 1.	This is the percentage of the width of the Top Left image.
tlm	Top Left Margin Percentage	0	Should be a postive number less than or equal to 1. Two numbers can be supplied, seperated by a comma (no space). i.e.: .05 or .05,.07	This is the percentage of the width that will be used to apply a margin around the Bottom Right image. It works like CSS's margin shorthand property; however, only one or two values are supported.
tr	Top Right	NULL	Check the /assets folder for possible images; supply the case-sensitive name without extension.	This image will be used in the appropriate corner.
trp	Top Right Percentage	0	Should be a number less than or equal to 1.	This is the percentage of the width of the Top Right image.
trm	Top Right Margin Percentage	0	Should be a postive number less than or equal to 1. Two numbers can be supplied, seperated by a comma (no space). i.e.: .05 or .05,.07	This is the percentage of the width that will be used to apply a margin around the Bottom Right image. It works like CSS's margin shorthand property; however, only one or two values are supported.
w	Width	REQUIRED	int	The desired width of the image.

Cache

Cached requests are here; in case you're curious:

• https://unt-wallpaper-dev.azurewebsites.net/cache

Note: Cached files are touched everytime they are accessed. Note: Server time is in GMT.

Docker

This has been setup to run in Docker. Simply use git to clone this repo to the Docker server. Then, build and run the Docker image with docker-compose:

docker-compose up -d

Force a rebuild:

docker-compose build

Get a bash shell inside of the container (on the php service):

docker-compose exec php /bin/bash

Production

Add it to the swarm:

docker stack deploy -c wallpaper-server.yml wallpaper-server

Environment Variables

All of the query string parameters are available as an environment variable. Here's a couple of quick examples of setting the br, brm, and brp parameters via environment variables:

# The rest of this code block is one line
docker run -it -p 8080:80 -e WALLPAPER_BR=other_image -e WALLPAPER_BRP=.3 -e WALLPAPER_BRM=0 --rm wallpaper

environment:
  - WALLPAPER_BR=other_image
  - WALLPAPER_BRP=.3
  - WALLPAPER_BRM=0

Addtionally, there are a couple of additional environment variable available:

Parameter	Name	Default Value	Expected Value(s)/Type	Description
WALLPAPER_README	ReadMe	https://github.com/UNT-CAS-ITS/Wallpaper-Server	A URL.	This is used to overwrite the error messages, in case you've forked this project and would prefer to point to it.
WALLPAPER_CURL_CONFIG	Curl Config	https://raw.githubusercontent.com/UNT-CAS-ITS/Wallpaper-Server/master/docker/apache/curl.config	A URL.	This is used to specify a custom curl config file. This is pretty much a required environment variable if you're going to use this for your own purposes.
WALLPAPER_CURL_CONFIG_HEADER	Curl Header	NULL	A Header, like: PRIVATE-TOKEN:R2WwRii944lO6d7bvk8FDo	If a private token is needed to authenticate to your URL, you can supply it here.

Note: Query string parameters (aka: GET parameters) will overwrite environment variable settings.