ImageLength

ImageLength is a term used in digital imaging and document rendering to denote a dimension of an image, most commonly the width or the height. In software, ImageLength is typically represented as a value paired with a unit, for example 300 pixels, 5 centimeters, or 50 percent. Some systems support a purely numeric form interpreted in a default unit, while others offer a range of units including pixels, points, inches, millimeters, and percentages. Relative lengths (percent) express a size in relation to a reference dimension such as the containing box or the original image size.

Units and conversion: Converting an ImageLength to a concrete pixel amount requires a defined density or resolution, usually expressed as dots per inch (DPI) or pixels per millimeter. When a length is specified in percent, the actual pixel value depends on the base dimension. Some image frameworks also distinguish between device pixels and logical points, adding an extra conversion step.

Applications: ImageLength is used in resizing and layout operations, cropping boundaries, and in rendering pipelines where image size must be specified before decoding or drawing. Maintaining aspect ratio often involves storing one length and deriving the other from the image's intrinsic aspect ratio.

Context: The concept appears across formats and libraries, from document styles and CSS-like layouts to vector graphics and image processing toolkits. Different systems may implement ImageLength as a simple scalar with a unit, a structured object with field accessors, or a union type that can hold absolute or relative values.

See also: ImageSize, DPI, resolution, aspect ratio, unit conversion.