API Reference: Data

The Data class is an immutable wrapper around a raw memory buffer (byte array). It is used throughout Skija to pass binary data (like encoded images, fonts, or shaders) between Java and the native C++ Skia library efficiently.

Creation

From Java Byte Array

Copies the data from a Java byte[].

byte[] bytes = new byte[] { 1, 2, 3, 4 };
Data data = Data.makeFromBytes(bytes);

From File

Efficiently maps a file into memory (using mmap where possible).

Data data = Data.makeFromFileName("assets/image.png");
if (data == null) {
    System.err.println("File not found");
}

Empty

Creates an empty data object.

Data empty = Data.makeEmpty();

Modification (Subsetting)

Since Data is immutable, you cannot change its content, but you can create a view into a subset of it (zero-copy if supported, or cheap copy).

// Create a new Data object representing bytes 10-20
Data subset = data.makeSubset(10, 10);

Accessing Content

As Byte Array

Copies the native data back into a Java byte[].

byte[] content = data.getBytes();

// Or a range
byte[] part = data.getBytes(0, 10);

As ByteBuffer

Wraps the native memory directly in a Java ByteBuffer. This is the most efficient way to read data without copying.

ByteBuffer buffer = data.toByteBuffer();
// Read from buffer...

Size

long size = data.getSize();

Lifecycle

Data extends Managed and uses native memory. Ideally, use try-with-resources or call close() when done, although the garbage collector will eventually free it.

try (Data data = Data.makeFromFileName("large_file.dat")) {
    // use data...
} // data.close() called automatically