js-dicom/src/ImageUtility/unpackBinaryFrame.js

this is js-dicom

/* eslint no-bitwise: 0 */

function isBitSet (byte, bitPos) {
    return byte & (1 << bitPos);
}

/**
 * Function to deal with unpacking a binary frame
 */
function unpackBinaryFrame (byteArray, frameOffset, pixelsPerFrame) {
    // Create a new pixel array given the image size
    const pixelData = new Uint8Array(pixelsPerFrame);

    for (let i = 0; i < pixelsPerFrame; i++) {
        // Compute byte position
        const bytePos = Math.floor(i / 8);

        // Get the current byte
        const byte = byteArray[bytePos + frameOffset];

        // Bit position (0-7) within byte
        const bitPos = (i % 8);

        // Check whether bit at bitpos is set
        pixelData[i] = isBitSet(byte, bitPos) ? 1 : 0;
    }

    return pixelData;
}

export default unpackBinaryFrame;