ImageGeneratorPlugin

Generates images from text

Description

ImageGeneratorPlugin is a plugin that lets you generate images based on textual information such as a person's first and last name. It will then generate a kind of thumbnail or avatar image by taking the initials of the name and generate an image that is automatically colored. The algorithm for that is the same as in the JQAutoColorContrib extension.

You type:

%GENIMAGE{"Foswiki"}%

You get:

You type:

%GENIMAGE{
   "John Doe" 
   form="initials" 
   style="border-radius:50%"
}%

You get:

In additon to the text input say "FW" an additional seed may be used to create further color variations.

You type:

%FORMATLIST{"0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23"
   format="$percntGENIMAGE{\"Foswiki\" 
               label=\"FW\" 
               seed=\"$1\" 
               title=\"$1\"
               align=\"left\" 
               width=\"100\" 
               height=\"100\" 
           }$percnt"
   separator=""
}%
%CLEAR%

You get:

Syntax

The %GENIMAGE makes takes the following arguments:

Parameter	Description	Default
"...", text="..."	text source for the image; colors will be generated on its base
seed="..."	any character sequence provided here will be added to the text while computing colors
size="..."	imagemagick geometry; if unset params width and height take over
style="..."	css styles
title="..."	title attribute of the img elemenent
alt="..."	alt attribute of the img elemenent
align="left/right/middle/top/bottom"	alignment of the img elemenent
huefrom="0..359"	start range of hues to be chosen from	0
light="..."	HLS values of a foreground color to be used on a dark background	0, 0, 100
dark="..."	HLS value of a foreground color to be used on a light background	0, 0, 0
lightness="..."	one or more lightness values	35, 50, 65, 80
saturation="..."	one or more saturation values	50, 60, 00
width="..."	width of the image being generated	150
height="..."	height of the image being generated	150
hueto="0..359"	end range of hues to be chosen from	359
format="..."	format string to render the result	<img src="$url" \ width="$width" \ height="$height" \ $class \ $align \ $title \ $alt />
from="initials/firstletter"	specifies the way a label is generated from the text: mode "initials" will extract the first letters from each word in the text; mode "firstletter" will take the first letter of the text	firstletter
label="..."	explicit label to be displayed, if undefined will use the from parameter to generate a label from the text	generated from text
class="..."	a css class	genImage
font="..."	ttf font to be used	see configure, e.g. Helvetica

All colors are calculated in HLS space. While hashing the text a hue value is selected in the range specified by huefrom ... hueto. Lightness and staturation as selected in modulo fashion from the given list of values. The resulting background color is analyzed: if it is considered dark or light, a light on dark or dark on light backgrounds will be used as can be seen in the above examples.

Hue values are between 0 and 359, lightness and saturation are on a scale between 0 and 100.

The format parameter may contain the following variables:

• $url
• $width
• $height
• $class
• $align
• $alt

Installation Instructions

You do not need to install anything in the browser to use this extension. The following instructions are for the administrator who installs the extension on the server.

Open configure, and open the "Extensions" section. "Extensions Operation and Maintenance" Tab -> "Install, Update or Remove extensions" Tab. Click the "Search for Extensions" button. Enter part of the extension name or description and press search. Select the desired extension(s) and click install. If an extension is already installed, it will not show up in the search results.

You can also install from the shell by running the extension installer as the web server user: (Be sure to run as the webserver user, not as root!)

cd /path/to/foswiki
perl tools/extension_installer <NameOfExtension> install

If you have any problems, or if the extension isn't available in configure, then you can still install manually from the command-line. See https://foswiki.org/Support/ManuallyInstallingExtensions for more help.

Dependencies

Name	Version	Description
Digest::HMAC	>=0	Required
Image::Magick	>=7	Required

Change History

13 Jan 2025	added size parameter
25 Jan 2024	initial release