filledunfilled

filledunfilled is a term used in design and information visualization to describe a binary state system in which elements are described as either filled or unfilled. The concept is commonly applied to graphical user interfaces and data displays to convey activation, selection, presence, or completeness without relying on color alone.

In user interfaces, filled and unfilled states signal activation versus deselection. A filled checkbox indicates selection; an unfilled checkbox shows a potential or inactive state. Rating components often use filled stars to indicate achieved rating and unfilled stars to show remaining capacity. Similar pairs appear in toggle indicators, progress visuals, and iconography where a filled glyph conveys presence and an unfilled glyph conveys absence.

In data visualization, filledunfilled describes how portions of a chart are rendered: filled areas or segments represent quantified values, while unfilled areas show the portion that remains to be accounted for. This binary representation can improve readability in low-contrast settings and contributes to a consistent visual language across charts and icons.

Design considerations include contrast, stroke width, and fill opacity to ensure clear distinction between states. Accessibility guidelines emphasize that filled vs unfilled must be distinguishable independently of color, using shape, texture, or sufficient luminance difference.

Variants of the concept include solid (fully filled) versus hollow (unfilled or outline) icons, and semi-filled states that use partial opacity to indicate intermediate values. Related terms include two-state indicators, binary glyphs, and stateful UI controls.