v0.2.2

Release v0.2.2

The last release of JpegKit, v0.2.0 introduced new wrappers for libjpeg-turbo. This was a major redesign to the JpegKit library. While these changes improved performance and readability of the code, it was incomplete for the scope of JpegKit functionality.

v0.2.2 un-deprecates the Jpeg methods to be used until the wrappers are finalized in an upcoming release, v0.3.0.

What's new

Bug Fixes

• Closed #4: Edge corruption when rotating a Jpeg
• Fixed JpegView render function

Deprecation

Un-deprecated the following classes:

• JpegKit
• Jpeg
• JpegFile
• JpegImageView

v0.2.0

Release v0.2.0

Artifact: com.camerakit:jpegkit:0.2.0

What's New

TurboJpeg

• Adds a wrapper class so you can work with libjpeg-turbo running in the Android JNI, all from higher level java methods.
• See turbojpeg.h in libjpeg-turbo's repository for official documentation. Our wrapper is mostly the same.

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JpegView

• A view class for rendering a jpeg.
• Uses a pixel allocation reference to the JNI layer created by the TurboJpeg wrapper.
• Pixel RGB data always stays off JVM.
  • Lower risk of memory issues.
• Executes a memcpy directly to the window's low-level pixel buffer.

Render latency comparison:

Jpeg Input	ImageView	JpegView
3264 x 2448, 4.3MB	613ms	140ms
8277 x 5393, 15.3MB	1900ms	540ms
22921 x 4510, 23.6MB	crashes	620ms

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JpegDecoder

• This class receives a jpeg byte[] in it's constructor, which is subsequently marshalled to the JNI layer.
• The jpeg's header data is decompressed immediately in the constructor, so metadata methods will work immediately with low overhead:
  • getWidth()
  • getHeight()
  • getSubsampling()
• Decode methods available:
  • decode()
  • decode(...)
    • int width
    • int height
    • int pitch
    • @PixelFormat int pixelFormat
    • @Flag int flags
  • decodeToYuv()
  • decodeToYuv(...)
    • @Flag int flags
  • When unsure about a value in the parameterized versions of these methods, it's always safe and handled internally if you put 0
• You must call release() when you are finished.

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JpegTransformer

• This class receives a jpeg byte[] in it's constructor, which is subsequently marshalled to the JNI layer.
• Transformations available:
  • flipHorizontal()
  • flipVertical()
  • rotate(...)
    • int degrees
  • cropWithOffsets(...)
    • int leftOffset, int topOffset, int rightOffset, int bottomOffset
  • cropWithRegion(...)
    • int x, int y, int width, int height
• When finished, you can have the transformed jpeg data unmarshalled back to the android JVM with obtain().
• You must call release() when you are finished.

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Deprecated:

• Most JpegKit class methods
• Jpeg class
• JpegFile class
• JpegImageView class