Solved

Setting Font Color Based on Background Color

Posted on 2014-01-10
3
1,673 Views
Last Modified: 2014-01-10
This isn't anything pressing, just a shot at an enhancement that would be pretty darn cool if I could get it to work right.  We have an application that allows its users to set the background color of a content area.  The text is black, so if you select a dark color, there are major contrast issues.  Up until now, we've asked the users to manually set the font color via the inline editor to correct the contrast issue.  On a whim, I threw something together that I thought would rightly handle the contrast issue on the fly.  For the most part, it works, but there are exceptions.  Basically, what I am doing is checking the NaN of the first character of the hex value that the user chooses for the background.  If it's a number, of if it is 'f', I set the font color to black.  Otherwise, I set the font color to white.  Has anyone done something like this and worked out all of the 'exceptions'?  The boss doesn't feel like we should spend any more time on it, since we have other more pressing issues, but I'd sure like to see it work.  :)

Here's my code:
$('#contentCallBack').jPicker(
	{},
	function(color, context){
		var all = color.val('all');
		$('#layoutBG').attr('bgcolor',(all && '#' + all.hex));
		$('#sideBarGBG').attr('bgcolor',(all && '#' + all.hex));
		var positionOne = all.hex.substring(0,1);
		if(isNaN(positionOne) == false || positionOne == 'f'){
			$('#layoutBG').css({
				color: '#ffffff'
			});
		} else {
			$('#layoutBG').css({
				color: '#000000'
			});
		}
	},
	function(color, context){
		if (context == layoutBGCallbackButton.get(0)) alert('Color set from button');
		var hex = color.val('hex');
		layoutBGCallbackElement.css({
			backgroundColor: hex && '#' + hex || 'transparent'
		});
	},
	function(color, context){
		//alert('"Cancel" Button Clicked');
	}
);

Open in new window

0
Comment
Question by:brianmfalls
3 Comments
 
LVL 25

Assisted Solution

by:Lee Savidge
Lee Savidge earned 400 total points
ID: 39771086
If you have a function that decides if a colour is "dark" then you can set a "light" text colour.

I've not personally done it myself but I've seen this used with some success:

stackoverflow.com/questions/6750695/jquery-change-text-color-based-on-containing-elements-background-color

Basically it determines if the colour is a dark one and if so it sets the text as white, otherwise it uses black.

I had some code a while ago which I wrote which altered the text color based on a background colour in a windows application by XORing the values. Can't find it now. It works for most colours. Some don't work, some look awful but do work but then it wasn't me that had to look at the colours a user had chosen for themselves.
0
 
LVL 33

Accepted Solution

by:
Big Monty earned 100 total points
ID: 39771358
taken from stackoverflow.com/questions/9600295/automatically-change-text-color-to-assure-readability, this may give you what you're looking for:

function invertColor(hexTripletColor) {
    var color = hexTripletColor;
    color = color.substring(1);           // remove #
    color = parseInt(color, 16);          // convert to integer
    color = 0xFFFFFF ^ color;             // invert three bytes
    color = color.toString(16);           // convert to hex
    color = ("000000" + color).slice(-6); // pad with leading zeros
    color = "#" + color;                  // prepend #
    return color;
}
$("h1")
    .css("background-color", "#FFCC00")
    .css("color", invertColor("#FFCC00"));

Open in new window

0
 
LVL 1

Author Closing Comment

by:brianmfalls
ID: 39771863
Thanks for the help friends.  Here's the finished product, all cleaned up, dynamically looped, and so on...

	<script type="text/javascript">
		$(document).ready( function() {
			
				function isDark(color) {
					var match = /rgb\((\d+).*?(\d+).*?(\d+)\)/.exec(color);
					return parseFloat(match[1])
						 + parseFloat(match[2])
						 + parseFloat(match[3])
						   < 3 * 256 / 2; // r+g+b should be less than half of max (3 * 256)
				}
			
				<cfoutput query="gto">

					$('###gto.containerID#').attr('bgcolor','###gto.value#');
					$('###gto.containerID#').css({
						backgroundColor: '###gto.value#'
					});
					<cfif len(gto.supportContainerID)>
						$('###gto.supportContainerID#').attr('bgcolor','###gto.value#');
						$('###gto.supportContainerID#').css({
							backgroundColor: '###gto.value#'
						});
					</cfif>
					
					var #gto.fieldID#CallbackElement = $('###gto.containerID#')
					$('###gto.fieldID#').jPicker(
						{},
						function(color, context){
							var all = color.val('all');
							var hex = color.val('hex');
							$('###gto.containerID#').attr('bgcolor',(all && '##' + all.hex));
							$('###gto.containerID#').css({
								backgroundColor: hex && '##' + hex || 'transparent'
							});
							<cfif len(gto.supportContainerID)>
								$('###gto.supportContainerID#').attr('bgcolor',(all && '##' + all.hex));
								$('###gto.supportContainerID#').css({
									backgroundColor: hex && '##' + hex || 'transparent'
								});
							</cfif>
							$('###gto.containerID#').css("color", isDark($(this).css("background-color")) ? 'white' : 'black');
							var emailID = '#session.emailID#'
							var fieldID = '#gto.fieldID#'
							$('##templateOptionBlock').load('http://#cgi.server_name#/admin/#application.module#/act/act.template.options.cfm',{'emailID': emailID, 'fieldID': fieldID, 'value': hex}, function() {
								//alert('#gto.title# Saved');
							});
						}
					);
				</cfoutput>
					
			});
	</script>

Open in new window

0

Featured Post

Free Tool: IP Lookup

Get more info about an IP address or domain name, such as organization, abuse contacts and geolocation.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

When writing CSS, there are a few simple rules that will make your life easier.    1. Using ‘* {box-sizing:border-box;}’. Using this will wrap all your elements in a nice little compact box-model that will give you the width you want, like so... …
International Data Corporation (IDC) prognosticates that before the current the year gets over disbursing on IT framework products to be sent in cloud environs will be $37.1B.
In this tutorial viewers will learn how to embed custom externally-hosted Google Fonts using the Google Font API in CSS Go to the Google Fonts website at google.com/fonts: Browse or search based on font properties or name to find a suitable font for…
The viewer will learn the basics of jQuery including how to code hide show and toggles. Reference your jQuery libraries: (CODE) Include your new external js/jQuery file: (CODE) Write your first lines of code to setup your site for jQuery…

861 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question