starkdmi / swiftorientcrop

Working with oriented images in Swift

SwiftOrientCrop

Project content:

• Oriented image generator
• Load and orient CGImage and CIImage
• Orient CGRect based on image orientation
• Crop CGImage, CIImage and vImage
• Benchmarks

Code located in Tests.

Oriented image generator

Those images looks the same when correctly displayed, but under the hood they pretty different.

Usage

try OrientedGenerator.generateFrom(
  source: sourceImageFile,
  destination: destinationDirectory,
  format: .jpeg,
  size: CGSize(width: 1280, height: 1280),
  quality: 0.75
)

Image Crop Benchmarks

One call equals to loading 8 images, crop them and write image data to file. Full execution is 10 single calls - 80 images in summary.

Method	Full Execution Time (seconds)	Average Execution Time per call (seconds)	Average CPU Time (seconds)	Memory Usage (kB)	Memory Peak Physical (MB)	Disk Writes (MB)	CPU Usage (% relative to CGImage)
CGImage	38.719	6.372	5.365	101.6	11.6	9.0	100%
CIImage	14.432	2.352	1.344	62.3	15.0	10.9	29.3%
vImage (CG)*	31.458	5.186	5.162	55.7	11.7	9.0	23.8%
vImage (CI)*	30.431	4.933	4.445	-	15.4	11.0	28.8%

* vImage doesn't have API to load and save image files, so the CGImage and CIImage was used for it.