Thursday, May 5, 2016

Create Dynamic Half Circular Progress Bar With HTML 5 CSS 3 - Create Gauge Chart In HTML 5

Recently in one of my project there was a requirement to create half circle gauge chart to show progress of some actions. Something like below image

So first of all I decided to use some charts library to create UI like this but since this was mobile application I do not find any suitable chart library. So I decided to build UI from scratch. So here is the step by step guide. 

First our basic HTML and CSS

<div style="visibility: hidden" class="container" id="container">
                       <div id="border" class="active-border">
                            <div id="circle" class="circle">
                               <div id="needle" class="needle"></div> 

Now the basic CSS.

    width: 100%;
    height: 100%;
    overflow: hidden;
    position: relative;
    top: -25%;

    position: relative;
    top: 5px;
    left: 5px;
    text-align: center;
    width: 200px;
    height: 200px;
    border-radius: 100%;
    background-color: rgba(0,0,0,1);

    position: relative;
    text-align: center;
    width: 210px;
    height: 210px;
    border-radius: 100%;
    top : 50%;

.needle {
    position: absolute;
    background-color: #f0566f;
    height: 100%;
    width: 0.5%;
    left: 50%;

.needle:before {
    content: "";
    position: absolute;
    top: 0px;
    left: -10px;
    width: 0px;
    height: 0px;
    border-top: 10px solid transparent;
    border-right: 20px solid #f0566f;
    border-bottom: 10px solid transparent;
    -webkit-transform: rotate(90deg);

Now here comes the dynamic things. first of we have to set height and width of all the elements inside container to screen width and height.

var containerWidth = 0;

if(document.getElementById('container').clientHeight > document.getElementById('container').clientWidth){
containerWidth = document.getElementById('container').clientWidth;
containerWidth = document.getElementById('container').clientHeight;

var circleWidth =  containerWidth - 10;
var activeBorderWidth =  containerWidth;
var padding = (document.getElementById('container').clientWidth - document.getElementById('container').clientHeight) / 2;

document.getElementById('circle').style.width = circleWidth + 'px';
document.getElementById('circle').style.height = circleWidth + 'px';
document.getElementById('container').style.paddingLeft = padding + 'px';

document.getElementById('border').style.width = activeBorderWidth + 'px';
document.getElementById('border').style.height = activeBorderWidth + 'px';

So as you can see we are setting border with to container width and make it fit inside container and setting inner circle width to bit less than border width to create circular progress bar. Now we calculate transform degrees to set up liner gradient to show progress. 

var degree = (180 * Number(count)) / (Number(total));

document.getElementById('border').style.background = '-webkit-linear-gradient('+degree+'deg, #9a9a9a 50%, #00a651 50%)';

As you can see since we have half circle we are calculating degrees by 180. If you want full circle progress bar then calculate it with 360 degree.                 

Now set needle transformation.

var needleTransformDegree = 180 - degree;

document.getElementById('needle').style.webkitTransform = 'rotate('+needleTransformDegree+'deg)';
document.getElementById('container').style.visibility = 'visible'

That's it and end result look something like below.

Hope this helps you.

CSS Border Radius Not Working in Android WebView or Chrome

Recently while working on mobile app project which was cross platform application we were creating pie shaped menu where we faced a very strange issue.

Actually I was trying to create following menu and I created that successfully while I was working in Xcode and iPhone simulator.

And it worked fine but as soon as I checked it in Android phone it came up like following.

Now that was so embarrassing. Off course, after spending couple of days to make such menu and it came up like this, that is so disappointing. How ever after spending some time over it I found out a solution, in this blog I am going to explain this. There more than one solutions so I posting each one. 

1) Some older version does not support percentage value. 

Some older version of chrome does not support percentage values for border radius. So instead of percentage give pixel values.

Use border-radius : 50px in stead of border-radius : 10%

2) Specify top, left right and bottom property separately. 

some Chrome does understand single value like border-radius : 50px. So here you have to specify each border radius saperately.

border-top-left-radius: 50px;border-top-right-radius: 50px;border-bottom-right-radius: 50px;border-bottom-left-radius: 50px;

In stead of 

border-radius : 50px

3) Now here comes the issue which I have faced,  background-color "leaking" outside of a border when border-radius is present. In my case there were few div tags which was having background color and was going out side of main container because of transformation.  So here are the two solutions you can do.

Apply overflow: hidden property to main container

If that does not work apply following CSS property to main container.

-webkit-background-clip: padding-box; -moz-background-clip: padding; background-clip: padding-box;

This should solve your all border radius related problem in all the versions of Chrome. Hope this helps you.