function main() {
var files, sourceDoc, targetFile;

var fileType = "*.pdf"; // �ļ����
var sourceFolder = Folder.selectDialog('�x����Ҫ�M�Љ��sPDF���ļ��A', '~');

if (sourceFolder != null) {
files = new Array();
files = sourceFolder.getFiles(fileType); // �@ȡ�����ļ��A����ƥ�������ļ�

if (files.length > 0) {
for (i = 0; i < files.length; i++) {
sourceDoc = app.open(files[i]);

targetFile = getNewName();

sourceDoc.saveAs(targetFile, getPDFOptions());

sourceDoc.close();
}
alert("��"+ files.length + '���ļ����s�ɹ�~');
}
else {
alert('�]�ҵ����Pƥ���ļ�.');
}
} else {
alert("ȡ����(zh��)��,�]���x��Ŀ���ļ��A.")
}


function getNewName() {
var ext, docName, newName, saveInFile, docName;
docName = sourceDoc.name;
ext = '_low.pdf';
newName = "";

for (var i = 0; docName[i] != "."; i++) {
newName += docName[i];
}
newName += ext;

saveInFile = new File(sourceFolder + '/' + newName);

return saveInFile;
}

function getPDFOptions() {
// Create the PDFSaveOptions object to set the PDF options
var saveOpts;

saveOpts = new PDFSaveOptions();

// ������
saveOpts.compatibility = PDFCompatibility.ACROBAT6;

// �P�]���ɿs�ԈD
saveOpts.generateThumbnails = false;

// ��������݋����
saveOpts.preserveEditability = false;

// ���s -> �Ҷ�λ�D�D�� �Ԅ�JPEG low
saveOpts.grayscaleCompression = CompressionQuality.AUTOMATICJPEGLOW

saveOpts.colorCompression = CompressionQuality.AUTOMATICJPEGLOW

saveOpts.colorDownsampling = 100
saveOpts.colorDownsamplingImageThreshold = 150

// saveOpts.colorConversionID = ColorDestination.COLORDESTINATIONPROFILE


return saveOpts;
}
}

main()