Function getPngMetadata

docs/app/js/sanddance-app.js:57785–57794

(binaryData)

    return getPngMetadata(dataView) || getJpegMetadata(dataView) || getGifMetadata(dataView) || getBmpMetadata(dataView);
}
function getPngMetadata(binaryData) {
    var dataView = toDataView(binaryData);
    var isPng = dataView.byteLength >= 24 && dataView.getUint32(0, BIG_ENDIAN) === 0x89504e47;
    if (!isPng) return null;
    return {
        mimeType: "image/png",
        width: dataView.getUint32(16, BIG_ENDIAN),
        height: dataView.getUint32(20, BIG_ENDIAN)
    };
}
function getGifMetadata(binaryData) {
    var dataView = toDataView(binaryData);
    var isGif = dataView.byteLength >= 10 && dataView.getUint32(0, BIG_ENDIAN) === 0x47494638;