Rotated Background Patterns in CSS with SVG

While working on the WordPress theme Tìtsyul Amip Twenty Twenty-Five, a need arose for a more flexible way to implement rotated background patterns in CSS. Existing methods often involve trade-offs, and this exploration led to a technique leveraging the power of SVG.

Existing Approaches and Their Limitations

Traditionally, achieving rotated background images in CSS has involved several workarounds, each with its own set of challenges:

• CSS Transforms: Using the transform: rotate() property. This rotates the entire element, including its content, which is often not the desired outcome.
• Pseudo-elements: Employing ::before or ::after pseudo-elements to create a rotated background. While this allows rotating the background independently of the content, it can be complex to manage sizing and positioning. Additionally, if the html or body elements have a background color, pseudo-elements with a negative z-index may fall behind them.
• Pre-rotated Images: Rotating the image using image editing software and then using the rotated image as the background. This is impractical for seamless patterns in most rotation angles or when dynamic canvas size is required.

The SVG Pattern Technique

Building on these insights, let’s now explore a method that leverages SVG to achieve rotated background patterns—a solution that delivers both flexibility and precise control.

At the core of this approach is the SVG <pattern> feature, a versatile tool that enables the creation of seamless, repeating background patterns. The <pattern> element defines a tileable area that can be used as a fill for other SVG shapes, allowing for intricate and scalable designs. By leveraging attributes such as patternTransform, you can easily manipulate these patterns with transformations like rotation, scaling, and translation, making it an ideal choice for dynamic and responsive backgrounds.

Draw the Pattern Using SVG ⸻ Begin by creating the desired pattern using SVG elements. This can include vector graphics or embedded bitmaps.

<polygon points="0,0 2,5 0,10 5,8 10,10 8,5 10,0 5,2" />

Wrap in a <pattern> Definition ⸻ Encapsulate the pattern within a <pattern> element inside the <defs> section of the SVG, specify the dimensions for the pattern, and use the patternTransform attribute to apply transformations, such as rotation.

<defs>


  <pattern id="star" width="10" height="10" patternUnits="userSpaceOnUse" patternTransform="rotate(20)">


    <polygon points="0,0 2,5 0,10 5,8 10,10 8,5 10,0 5,2" />


  </pattern>


</defs>

Create the Main SVG ⸻ Create a new SVG element without a viewBox attribute. Set the width and height to 100% to ensure it covers the entire area of the element. Then add a <rect> element to cover the entire SVG area, and set its fill attribute to reference the pattern defined in step 2.

<svg xmlns="http://www.w3.org/2000/svg" width="100%" height="100%">


  <defs>


    <pattern id="star" width="10" height="10" patternUnits="userSpaceOnUse" patternTransform="rotate(20)">


      <polygon points="0,0 2,5 0,10 5,8 10,10 8,5 10,0 5,2" />


    </pattern>


  </defs>


  <rect width="100%" height="100%" fill="url(#star)" />


</svg>

Encode and Use in CSS ⸻ Encode the SVG as a data URL. Use the data URL as the background-image in your CSS.

div {


  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='100%25' height='100%25'%3E%3Cdefs%3E%3Cpattern id='star' width='10' height='10' patternUnits='userSpaceOnUse' patternTransform='rotate(20)'%3E%3Cpolygon points='0,0 2,5 0,10 5,8 10,10 8,5 10,0 5,2' /%3E%3C/pattern%3E%3C/defs%3E%3Crect width='100%25' height='100%25' fill='url(%23star)' /%3E%3C/svg%3E");

}

Using this technique, the pattern background can be transformed on its own, while still behave like any other CSS background to enjoy other features like background stacking and blend mode settings.

SVG Rotated Background Generator

You can also try it out using the generator below to create custom rotated background patterns with SVG. You can also adjust parameters such as pattern size, scaling, and rotation angle.