Creating Doughnut Charts with Conical Gradients
Conical gradients, a feature introduced in Chrome 69, allow developers to create visually appealing doughnut charts with ease. This article will explore how to create these charts using conical gradients and semantic HTML.
The Power of Conical Gradients
Conical gradients are a type of fill gradient that has its color stops around the circumference of a circle. They can be used to create a variety of effects, from simple directional lighting to complex, multi-colored patterns. In the context of doughnut charts, conical gradients provide a simple and efficient way to display data.
Semantic HTML for Doughnut Charts
When creating doughnut charts, it’s essential to use semantic HTML to ensure accessibility and search engine optimization (SEO). The <progress> and <meter> elements are ideal for this purpose, as they provide a clear indication of progress or measurement.
Styling the Elements
To style the <progress> and <meter> elements, we need to remove the default browser styling and apply our own CSS rules. This involves setting the appearance property to none and defining custom styles for the elements.
Creating the Doughnut Chart
With our elements styled, we can now create the doughnut chart using conical gradients. We define the chart sizes and use the border-radius property to turn the element into a circle. Then, we fill the circle with a single-step conical gradient, using CSS custom properties to define the gradient colors.
Adding a Mask
To create a doughnut effect, we need to add a mask to the chart. We can achieve this by overlaying a pseudo-element on top of the chart, with a solid background color. This mask will hide the center of the chart, creating a doughnut shape.
Cross-Browser Compatibility
While conical gradients are currently only supported in Chrome 69 and WebKit-based browsers, we can use Lea Verou’s polyfill to enable support in other modern browsers. However, this polyfill has some limitations, including lack of support for calc() and var().
Conclusion
Conical gradients offer a powerful tool for creating visually appealing doughnut charts. By combining semantic HTML with CSS conical gradients, we can create accessible and engaging charts that display data in a clear and concise manner. As browser support for conical gradients expands, we can expect to see more widespread adoption of this technique.