Aspect ratio

Aspect ratio is the proportional relationship between an image’s width and height, usually written as two numbers such as 16:9. It describes shape independently of the image’s absolute size.

Image scaling: Image scaling changes an image’s displayed dimensions while preserving or altering its proportions. Uniform scaling changes size without changing aspect ratio.
Widescreen television: Widescreen television uses a broad rectangular display, commonly with a 16:9 aspect ratio. The 16:9 format became a standard target for television pictures.
Display resolution: Display resolution is the number of pixels a screen uses horizontally and vertically. A screen can change resolution while retaining the same aspect ratio.
Ratio: A ratio expresses the relative sizes of two quantities through division. Aspect ratio is a specific ratio comparing width with height.
4:3 aspect ratio: The 4:3 aspect ratio describes an image four units wide for every three units high. It was common in traditional television and many early computer displays.
Letterboxing: Letterboxing fits an image into a frame with a different shape by adding empty bars. It preserves the image’s aspect ratio when the frame is wider or taller.
CinemaScope: CinemaScope is a widescreen filmmaking process that uses anamorphic lenses to capture a broad image. Its theatrical presentation popularized very wide movie frames.
Image dimensions: Image dimensions are the absolute width and height of an image in pixels or physical units. Dimensions state size, whereas aspect ratio reduces width and height to a proportion.
Proportion: A proportion is an equation stating that two ratios are equal. Proportions let image dimensions be resized while preserving shape.
16:9 aspect ratio: The 16:9 aspect ratio describes an image sixteen units wide for every nine units high. It is a widespread format for modern televisions, video, and displays.

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