Prism

Fast Go image encoding, decoding, and transformations using OpenCV, libpng, and libjpeg-turbo.

Dependencies (dynamically linked)

• opencv 2.4.x
• libturbo-jpeg 1.4+

Example

import(
  "os"

  "github.com/cotap/prism"
)

func main() {
  f, _ := os.Open("example.jpg")

  img, _ := prism.Decode(f)
  defer img.Release() // ensures timely release of C heap memory

  _ = img.FlipV()
  _ = img.Fit(500, 500)

  w, _ := os.Create("resized.jpg")
  defer w.Close()

  // fast encoding with libjpeg-turbo
  prism.EncodeJPEG(w, img, 90)

  // or, since prism.Image implements image.Image:
  //   jpeg.Encode(w, img, &jpeg.Options{Quality: 90})
}

Memory Management

Prism allocates memory for image decoding and processing using the OpenCV allocator on the C heap. In order to avoid long-term leaks, prism uses Go's runtime.SetFinalizer to release C memory when the Go object is GC'd.

HOWEVER, because Go's collector can't see into the C heap, it may not run as frequently as needed to keep memory usage low. In order to ensure most efficient memory usage, always call func (img *prism.Image) Release() after you're done with an image.