Scrimage is an immutable, functional, and performant JVM library for manipulation of images.

The aim of this library is to provide a simple and concise way to do common image operations, such as resizing to fit a required width and height, converting between formats, applying filters and so on. It is not intended to provide functionality that might be required by a more "serious" image processing application - such as face recognition or movement tracking.

A typical use case for this library would be creating thumbnails of images uploaded by users in a web app, or bounding a set of product images so that they all have the same dimensions, or optimizing PNG uploads by users to apply maximum compression, or applying a grayscale filter in a print application.

Scrimage mostly builds on the functionality provided by java.awt.* along with selected other third party libraries, such as drewnoakes/metadata-extractor and haraldk/TwelveMonkeys.

Creation methods

Creation methods create a new image by specifying the dimensions. They can start with a specified colour using fill or undefined using blank. An image can be created by copying an existing image.

Input / Output

The heart of any image library is reading and writing in the various formats. Scrimage supports all the formats provided by javax.imageio along with extra formats in the modules scrimage-formats-extra and scrimage-webp.

Image Operations

These operations operate on an image, returning a copy of that image. For instance, fit will resize an image to fit into a specified set of bounds, and scale will change the size of an image.

For the full list of operations, see the menu on the left.

Filters

Scrimage comes with a wide array of filters in the module scrimage-filters.

Composites

Metadata

Scrimage builds on the metadata-extractor project to provide the ability to read metadata from an image.

Read more details here.

Quick Examples

Reading an image, scaling it to 50% using the Bicubic method, and writing out as PNG

val in = ... // input stream
val out = ... // output stream
ImmutableImage.loader().fromStream(in).scale(0.5, Bicubic).output(out) // an implicit PNG writer is in scope by default

Reading an image from a java File, applying a blur filter, then flipping it on the horizontal axis, then writing out as a Jpeg

val inFile = ... // input File
val outFile = ... // output File
ImmutableImage.loader().fromFile(inFile).filter(BlurFilter).flipX.output(outFile)(JpegWriter()) // specified Jpeg

Padding an image with a 20 pixel border around the edges in red

val in = ... // input stream
val out = ... // output stream
ImmutableImage.loader().fromStream(in).pad(20, Color.Red)

Enlarging the canvas of an image without scaling the image. Note: the resize methods change the canvas size, and the scale methods are used to scale/resize the actual image. This terminology is consistent with Photoshop.

val in = ... // input stream
val out = ... // output stream
ImmutableImage.loader().fromStream(in).resize(600,400)

Scaling an image to a specific size using a fast non-smoothed scale

val in = ... // input stream
val out = ... // output stream
ImmutableImage.loader().fromStream(in).scaleTo(300, 200, FastScale)

Writing out a heavily compressed Jpeg thumbnail

implicit val writer = JpegWriter().withCompression(50)
val in = ... // input stream
val out = ... // output stream
ImmutableImage.loader().fromStream(in).fit(180,120).output(new File("image.jpeg"))

Printing the sizes and ratio of the image

val in = ... // input stream
val out = ... // output stream
val image = ImmutableImage.loader().fromStream(in)
println("Width: ${image.width} Height: ${image.height} Ratio: ${image.ratio}")

Converting a byte array in JPEG to a byte array in PNG

val in : Array[Byte] = ... // array of bytes in JPEG say
val out = Image(in).write // default is PNG
val out2 = ImmutableImage.loader().fromBytes(in).bytes) // an implicit PNG writer is in scope by default with max compression

Coverting an input stream to a PNG with no compression

implicit val writer = PngWriter.NoCompression
val in : InputStream = ... // some input stream
val out = ImmutableImage.loader().fromStream(in).stream