TopLeftCorner

TopLeftCorner is a term used in computing and graphics to denote the point positioned at the upper-left edge of a two-dimensional rectangle or image. It is often used as a reference point or origin from which other coordinates measure.

Coordinate conventions: In most image processing and screen coordinate systems, the origin is at the top-left corner of the image or viewport, with x increasing to the right and y increasing downward. This differs from the standard Cartesian plane where y increases upward. Some frameworks or mathematical contexts use bottom-left origin, requiring conversion when interfacing with such systems. The top-left corner can be identified as (0,0) in zero-based indexing.

Applications: In computer vision and image processing, a common bounding box representation uses the top-left coordinate along with width and height; alternative representations specify the center or bottom-right corner. In GUI design and web development, the top-left corner is often the default anchor for positioning and sizing elements; properties such as transform-origin may specify the pivot point for transformations.

In programming, accessing the top-left element of a two-dimensional array uses indices [0][0] in zero-based indexing languages. Understanding this corner helps with tasks like image cropping, region-of-interest extraction, and coordinate transforms between systems.