# Image Buffer Display Mask Rectangle Keys Keys that describe the display dimensions of an image buffer mask. ## Discussion Use [`kCVImageBufferDisplayMaskRectangleKey`](/documentation/CoreVideo/kCVImageBufferDisplayMaskRectangleKey) to attach a dictionary value containing display mask information to the image buffer. [`kCVImageBufferDisplayMaskRectangleStereoLeftKey`](/documentation/CoreVideo/kCVImageBufferDisplayMaskRectangleStereoLeftKey) and [`kCVImageBufferDisplayMaskRectangleStereoRightKey`](/documentation/CoreVideo/kCVImageBufferDisplayMaskRectangleStereoRightKey) perform the same function for left- and right-eye stereo images. ## Topics ### Constants [`let kCVImageBufferDisplayMaskRectangle_LeftEdgePointsKey: CFString`](/documentation/CoreVideo/kCVImageBufferDisplayMaskRectangle_LeftEdgePointsKey) Specifies inset points on the left vertical edge of the rectangle. [`let kCVImageBufferDisplayMaskRectangle_RectangleHeightKey: CFString`](/documentation/CoreVideo/kCVImageBufferDisplayMaskRectangle_RectangleHeightKey) Specifies the height of the rectangle starting at the rectangle’s top offset toward the rectangle’s bottom edge. [`let kCVImageBufferDisplayMaskRectangle_RectangleLeftKey: CFString`](/documentation/CoreVideo/kCVImageBufferDisplayMaskRectangle_RectangleLeftKey) Specifies the horizontal pixel offset of the rectangle from the left of the bounding raster. [`let kCVImageBufferDisplayMaskRectangle_RectangleTopKey: CFString`](/documentation/CoreVideo/kCVImageBufferDisplayMaskRectangle_RectangleTopKey) Specifies the vertical pixel offset of the rectangle from the top of the bounding raster. [`let kCVImageBufferDisplayMaskRectangle_RectangleWidthKey: CFString`](/documentation/CoreVideo/kCVImageBufferDisplayMaskRectangle_RectangleWidthKey) Specifies the width of the rectangle starting at the rectangle’s left offset toward the rectangle’s right edge. [`let kCVImageBufferDisplayMaskRectangle_ReferenceRasterHeightKey: CFString`](/documentation/CoreVideo/kCVImageBufferDisplayMaskRectangle_ReferenceRasterHeightKey) Specifies the height in pixels of the 2D coordinate system to define the rectangle. [`let kCVImageBufferDisplayMaskRectangle_ReferenceRasterWidthKey: CFString`](/documentation/CoreVideo/kCVImageBufferDisplayMaskRectangle_ReferenceRasterWidthKey) Specifies the width in pixels of the 2D coordinate system to define the rectangle. [`let kCVImageBufferDisplayMaskRectangle_RightEdgePointsKey: CFString`](/documentation/CoreVideo/kCVImageBufferDisplayMaskRectangle_RightEdgePointsKey) Specifies inset points on the right vertical edge of the rectangle. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)