Key takeaways:

Centering elements in UI design is often overlooked despite the simplicity of the underlying CSS principles.
Common issues include misaligned text, inconsistent line height, and improperly aligned icons.
Solutions involve understanding font metrics, adjusting CSS properties, and opting for better design practices.
Icon fonts introduce additional challenges and are generally discouraged in favor of image formats with defined dimensions.
Designers and developers must pay close attention to detail and work collaboratively to achieve visually balanced UIs.

Introduction to Centering in UI Design #

Fonts and Text Alignment #

Fonts are a significant source of alignment issues due to inconsistent metrics.
Examples of poorly aligned text are prevalent across major companies' interfaces.
Solutions involve adjusting line height and using fonts with consistent metrics.

Line height is a complex property that affects vertical centering.
Inconsistencies in line height lead to misalignment, especially across different containers.
Addressing line height requires a deep understanding of CSS specifications and font metrics.

Icons suffer from the same alignment issues as text, compounded by their rectangular nature.
Aligning icons next to text is particularly challenging due to varying font and icon sizes.
CSS's property offers multiple values but fails to provide a perfect solution for icon alignment.

Icon fonts complicate alignment and sizing, leading to inconsistent appearances.
Despite their drawbacks, icon fonts are widely used, resulting in poorly aligned UI elements.
A switch to image-based icons with defined dimensions is recommended for better control over alignment.

Both designers and developers struggle with centering elements, leading to visual imbalances.
Designers must account for the shape of icons and adjust for optical compensation.
Developers need to understand font metrics and CSS properties to achieve precise alignment.

Designers should create tight bounding boxes for text to facilitate accurate centering.
Tools like Figma offer features to improve text alignment, though they may not be enabled by default.

Font designers are encouraged to set metrics that ensure balanced ascender and descender spaces.
Choosing fonts with aligned metrics, such as SF Pro Text, Inter, and Martian Mono, can simplify the centering process.

Web developers should use specific font metrics to calculate the correct padding and alignment for text and icons.
Tools like opentype.js can provide the necessary metrics for precise alignment adjustments.

The use of icon fonts should be discontinued in favor of traditional image formats that are easier to align.
Aligning rectangles (icons as images) is more straightforward than aligning text or icon fonts.

Developers should use visual balancing techniques to manually adjust elements within their containers for optimal optical alignment.

Everyone involved in UI creation must prioritize alignment for a polished final product.
Bad centering can detract from the overall UI quality, while well-aligned elements can significantly enhance it.

Achieving well-centered and balanced UIs is a collective effort that requires attention to detail and a willingness to tackle design and development challenges.
By following best practices and avoiding common pitfalls, such as the overuse of icon fonts, designers and developers can create visually appealing and functional interfaces.

The article acknowledges the challenges of centering and encourages readers to support the author's work on Patreon for early access to future content.

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The author invites discussions on HackerNews and shares their open-source contributions, including Fira Code, DataScript, Clojure Sublimed, and Humble UI.

last updated: 2024-04-27