---
title: kCVImageBufferDisplayMaskRectangle_RectangleTopKey
framework: corevideo
role: symbol
role_heading: Global Variable
path: corevideo/kcvimagebufferdisplaymaskrectangle_rectangletopkey
---

# kCVImageBufferDisplayMaskRectangle_RectangleTopKey

Specifies the vertical pixel offset of the rectangle from the top of the bounding raster.

## Declaration

```swift
let kCVImageBufferDisplayMaskRectangle_RectangleTopKey: CFString
```

## Discussion

Discussion The top offset value is a CFNumber of an unsigned 16-bit integer that’s less than the reference raster height value.

## See Also

### Constants

- [kCVImageBufferDisplayMaskRectangle_LeftEdgePointsKey](corevideo/kcvimagebufferdisplaymaskrectangle_leftedgepointskey.md)
- [kCVImageBufferDisplayMaskRectangle_RectangleHeightKey](corevideo/kcvimagebufferdisplaymaskrectangle_rectangleheightkey.md)
- [kCVImageBufferDisplayMaskRectangle_RectangleLeftKey](corevideo/kcvimagebufferdisplaymaskrectangle_rectangleleftkey.md)
- [kCVImageBufferDisplayMaskRectangle_RectangleWidthKey](corevideo/kcvimagebufferdisplaymaskrectangle_rectanglewidthkey.md)
- [kCVImageBufferDisplayMaskRectangle_ReferenceRasterHeightKey](corevideo/kcvimagebufferdisplaymaskrectangle_referencerasterheightkey.md)
- [kCVImageBufferDisplayMaskRectangle_ReferenceRasterWidthKey](corevideo/kcvimagebufferdisplaymaskrectangle_referencerasterwidthkey.md)
- [kCVImageBufferDisplayMaskRectangle_RightEdgePointsKey](corevideo/kcvimagebufferdisplaymaskrectangle_rightedgepointskey.md)