Displaying Decimal Average Ratings Using Star Icons With Percentage Glyphs

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Hey guys! Have you ever needed to display average ratings using star icons, but the ratings have decimal values? It can be a bit tricky to get those partially filled stars looking just right. In this article, we'll dive into how to build percentage glyphs for star icons to accurately represent decimal average ratings. We'll be focusing on using JavaScript, AngularJS, HTML, Twitter Bootstrap 3, and WOFF fonts to achieve this. So, grab your coffee, and let's get started!

Understanding the Problem

When dealing with average ratings like 4.3, we need a way to visually represent the decimal part. Simply displaying four full stars won't cut it; we need that extra 0.3 to be reflected in the fifth star. This is where percentage glyphs come in handy. A percentage glyph allows us to fill a star icon partially, giving a more accurate representation of the rating.

Average ratings can come in various forms, but the key is to translate that decimal value into a visual representation that users can easily understand. The common approach is to use a star rating system, where each star represents a point in the rating scale (usually 1 to 5). The challenge arises when the average rating falls between these whole numbers. For instance, an average rating of 4.3 indicates that the feedback is slightly above 4 stars but not quite 5. To accurately depict this, we need to partially fill the fifth star to reflect the decimal portion (0.3 in this case).

Implementing this requires a combination of technologies and techniques. We'll be using HTML to structure the star rating display, CSS (specifically with Twitter Bootstrap 3) to style the stars, and JavaScript (along with AngularJS) to handle the logic of calculating and applying the partial fill. Additionally, we'll leverage WOFF fonts to render the star icons, providing flexibility and scalability. The core idea is to dynamically adjust the width of a filled star glyph based on the decimal value of the average rating. For example, if the average rating is 4.7, we would display four full stars and one star that is 70% filled. This method provides a visually intuitive way for users to grasp the rating's nuances.

Technologies We'll Use

Before we jump into the code, let's quickly recap the technologies we'll be using:

  • HTML: For structuring the star rating display.
  • CSS (Twitter Bootstrap 3): For styling the stars and providing a visually appealing layout. Bootstrap's grid system and glyphicons will be particularly useful.
  • JavaScript: For the core logic of calculating and applying the partial fill to the star icons.
  • AngularJS: A powerful JavaScript framework that will help us manage the data and dynamically update the star rating display.
  • WOFF (Web Open Font Format): For rendering the star icons. WOFF fonts provide scalability and flexibility, ensuring the icons look crisp on different screen sizes and resolutions.

These technologies combined provide a robust and efficient way to implement the percentage glyphs for star icons. HTML will lay the foundation for the structure, while CSS will handle the styling and appearance. JavaScript, enhanced by AngularJS, will manage the dynamic calculations and updates, ensuring that the star ratings accurately reflect the underlying data. WOFF fonts will ensure that the star icons are displayed clearly and consistently across various devices and browsers.

Step-by-Step Implementation

Alright, let's get our hands dirty with some code! We'll break down the implementation into manageable steps.

1. Setting up the HTML Structure

First, we need to create the basic HTML structure for our star rating display. We'll use Bootstrap's grid system to create a container and then add the star icons within that container.

<div class="container">
    <div class="star-rating">
        <span class="glyphicon glyphicon-star"></span>
        <span class="glyphicon glyphicon-star"></span>
        <span class="glyphicon glyphicon-star"></span>
        <span class="glyphicon glyphicon-star"></span>
        <span class="glyphicon glyphicon-star"></span>
    </div>
</div>

In this HTML snippet, we've created a div with the class container to hold our star rating. Inside, we have another div with the class star-rating, which will contain the star icons. We're using Bootstrap's glyphicon glyphicon-star classes to display the star icons. This approach leverages the built-in glyphicons provided by Bootstrap, making it easy to render the star symbols without needing external image files.

2. Adding CSS Styles

Next, we'll add some CSS styles to make our star rating look nice and handle the partial fill. We'll create a custom CSS class called .star-rating and add styles for the filled stars.

.star-rating {
    font-size: 24px; /* Adjust the size as needed */
    color: #ccc; /* Default color for empty stars */
    display: inline-block;
}

.star-rating .filled {
    color: #ffc107; /* Color for filled stars */
    position: relative;
    display: inline-block;
}

.star-rating .filled:before {
    content: "\e005"; /* Unicode for the star glyphicon */
    position: absolute;
    left: 0;
    top: 0;
    overflow: hidden;
    width: 0;
}

In this CSS, we first define the base styles for the .star-rating container, setting the font size and default color for the stars. The display: inline-block; property ensures that the stars are displayed in a row. We then define styles for the .filled class, which will be applied to the filled stars. The color is set to a golden yellow (#ffc107), a common choice for star ratings. The position: relative; and display: inline-block; properties are crucial for positioning the filled portion of the star correctly.

The key part of this CSS is the .star-rating .filled:before pseudo-element. Here, we set the content property to "\e005", which is the Unicode for the star glyphicon in Bootstrap. We position this pseudo-element absolutely within the .filled star and set overflow: hidden;. This is what allows us to control the visible portion of the star. By setting width: 0;, we initially hide the entire star. We will dynamically adjust this width using JavaScript to create the partial fill effect.

3. Implementing the AngularJS Logic

Now, let's dive into the AngularJS part. We'll create an AngularJS controller to handle the average rating and calculate the filled star percentages.

angular.module('myApp', [])
.controller('RatingController', function($scope) {
    $scope.averageRating = 4.3; // Example average rating
    $scope.maxRating = 5;

    $scope.getStars = function() {
        var stars = [];
        var fullStars = Math.floor($scope.averageRating);
        var partialStar = $scope.averageRating - fullStars;

        for (var i = 0; i < $scope.maxRating; i++) {
            if (i < fullStars) {
                stars.push({ filled: '100%' });
            } else if (i === fullStars) {
                stars.push({ filled: (partialStar * 100) + '%' });
            } else {
                stars.push({ filled: '0%' });
            }
        }
        return stars;
    };
});

In this AngularJS controller, we first define the module myApp and create a controller named RatingController. We inject the $scope service to allow us to bind data to the view. We initialize $scope.averageRating with an example value of 4.3 and $scope.maxRating with 5, representing the maximum possible rating.

The getStars function is the heart of our logic. It calculates how many stars should be fully filled and how much the last star should be partially filled. We start by determining the number of full stars using Math.floor($scope.averageRating). Then, we calculate the decimal portion by subtracting the full stars from the average rating. We loop through the total number of stars (5 in this case) and check if the current star index is less than the number of full stars. If it is, we push an object with filled: '100%' into the stars array, indicating a fully filled star. If the current star index is equal to the number of full stars, we calculate the percentage fill for the partial star and push an object with filled set to that percentage. For the remaining stars, we push objects with filled: '0%', indicating empty stars. Finally, we return the stars array, which contains objects representing the fill percentage for each star.

4. Binding to the HTML

Now, let's bind our AngularJS controller and data to the HTML.

<div ng-app="myApp" ng-controller="RatingController">
    <div class="container">
        <div class="star-rating">
            <span ng-repeat="star in getStars() track by $index" class="glyphicon glyphicon-star" ng-class="{'filled': star.filled !== '0%'}" style="width: {{star.filled}};"></span>
        </div>
        <p>Average Rating: {{averageRating}}</p>
    </div>
</div>

In this HTML snippet, we add the ng-app and ng-controller directives to the root div, associating our AngularJS app and controller with the view. We use ng-repeat to iterate over the stars array returned by the getStars() function. For each star, we create a span element with the glyphicon glyphicon-star classes. We use ng-class to conditionally add the filled class if the star.filled property is not '0%'. This allows us to apply the filled star styles we defined in the CSS.

The key part here is the style="width: {{star.filled}};" attribute. This dynamically sets the width of the :before pseudo-element based on the star.filled percentage. This is what creates the partial fill effect. If star.filled is '50%', the pseudo-element's width will be set to 50%, effectively filling half of the star. Finally, we display the average rating using {{averageRating}}.

Complete Code Example

Here's the complete code example for your reference:

HTML:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Star Rating with Percentage Glyphs</title>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
    <style>
        .star-rating {
            font-size: 24px; /* Adjust the size as needed */
            color: #ccc; /* Default color for empty stars */
            display: inline-block;
        }

        .star-rating .filled {
            color: #ffc107; /* Color for filled stars */
            position: relative;
            display: inline-block;
        }

        .star-rating .filled:before {
            content: "\e005"; /* Unicode for the star glyphicon */
            position: absolute;
            left: 0;
            top: 0;
            overflow: hidden;
            width: 0;
        }
    </style>
</head>
<body ng-app="myApp" ng-controller="RatingController">
    <div class="container">
        <div class="star-rating">
            <span ng-repeat="star in getStars() track by $index" class="glyphicon glyphicon-star" ng-class="{'filled': star.filled !== '0%'}" style="width: {{star.filled}};"></span>
        </div>
        <p>Average Rating: {{averageRating}}</p>
    </div>

    <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.9/angular.min.js"></script>
    <script>
        angular.module('myApp', [])
        .controller('RatingController', function($scope) {
            $scope.averageRating = 4.3; // Example average rating
            $scope.maxRating = 5;

            $scope.getStars = function() {
                var stars = [];
                var fullStars = Math.floor($scope.averageRating);
                var partialStar = $scope.averageRating - fullStars;

                for (var i = 0; i < $scope.maxRating; i++) {
                    if (i < fullStars) {
                        stars.push({ filled: '100%' });
                    } else if (i === fullStars) {
                        stars.push({ filled: (partialStar * 100) + '%' });
                    } else {
                        stars.push({ filled: '0%' });
                    }
                }
                return stars;
            };
        });
    </script>
</body>
</html>

This complete example includes the HTML structure, CSS styles, and AngularJS code we discussed. You can copy and paste this code into an HTML file and open it in your browser to see the star rating in action. The HTML includes links to Bootstrap's CSS and AngularJS library from CDNs, making it easy to run the example without needing to download any files. The CSS is embedded in the <style> tag within the <head> section, and the AngularJS code is placed in a <script> tag at the end of the <body>. This setup ensures that the page loads quickly and the AngularJS code runs after the DOM is fully loaded.

Conclusion

And there you have it! We've successfully built percentage glyphs for star icons to display decimal average ratings. By combining HTML, CSS, JavaScript, and AngularJS, we've created a dynamic and visually appealing rating system. This approach ensures that your star ratings accurately reflect the underlying data, providing users with a clear and intuitive understanding of the feedback.

Remember, this is just one way to tackle the problem. Feel free to experiment with different approaches and technologies to find what works best for you. The key is to understand the core concepts and adapt them to your specific needs. Whether you're building a review system, a product rating feature, or any other application that requires displaying average ratings, this technique will help you create a more polished and informative user experience.

So, go ahead and implement this in your projects, guys! You'll be surprised at how much it enhances the user experience. If you have any questions or suggestions, feel free to drop them in the comments below. Happy coding!