objc vImage PixelBuffer crop

Question

Created Nov ’22

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I need for an objc implementation exactly the functionality of this swift documentation: https://developer.apple.com/documentation/accelerate/vimage/pixelbuffer/3951652-cropped?changes=_7_1&language=objc

It seems that there is no objc documentation present. Does anyone know how to call the crop function in objc?

Answered by Engineer in 737637022

Take a look at Applying vImage Operations to Regions of Interest.

In summary, you need to create a vImage buffer that shares data with your source buffer but with a data pointer that points to the top-left pixel of your region of interest and a height and width that matches your region of interest. Then call vImageCopyBuffer to copy from the source to your crop destination.

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Answer 1

Engineer OP

Apple

Nov ’22

Accepted Answer

Take a look at Applying vImage Operations to Regions of Interest.

In summary, you need to create a vImage buffer that shares data with your source buffer but with a data pointer that points to the top-left pixel of your region of interest and a height and width that matches your region of interest. Then call vImageCopyBuffer to copy from the source to your crop destination.

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Answer 2

cguenther OP

Nov ’22

Is that than ensured that the underlying data layout is not changed? I need an image buffer that is densly packed without some 16bit alignment like here: https://developer.apple.com/documentation/accelerate/vimage_buffer?changes=_7_1&language=objc

Or do i than have to ensure 16byte aligned cropping, to get dense packed crop area?

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