I have a script that scans a document for all image types, converts them all to black and white, and then exports the black and white images to a new folder.
It seems as if InDesign will export these image file-formats:
JPEG, TIFF, and PNG (it does not export GIF files).
However, it seems that InDesign doesn't have the
ColorSpace.GRAY or ColorSpaceEnum.GRAY properties for TIFF and PNG files (it does have this property for JPEG files, though).
So, is there a way to convert TIFF and PNG files to black and white in InDesign's Extendscript?
If there is not, what would be the reasoning for not providing black and white conversion for these file types?
Here is my code, that as of now exports only black and white JPEG files:
var document = app.activeDocument;
var newFolder = createFolder(document); // if subdirectory DNE, create this folder with the function below
saveAllImages(document, newFolder); // with the function below
function createFolder(doc)
{
try
{
/*
* type-casting the filePath property (of type object) into a String type;
* must be a String type to concatenate with the subdirectory variable (also of type String)
*/
var docPath = String(doc.filePath);
var subdirectory = "/BLACK AND WHITE IMAGES";
}
catch(e)
{
alert(e.message);
exit();
}
var imagesFolder = docPath + subdirectory; // concatenating the two variables
if(!Folder(imagesFolder).exists)
{
Folder(imagesFolder).create();
}
return imagesFolder; // for instantiation outside of this function
} // end of function createFolder
function saveAllImages(doc, folder)
{
var imgs = doc.allGraphics;
var fileName = "";
var img = "";
var imgType = "";
for(var i = 0; i < imgs.length; i++)
{
if(imgs[i].itemLink != null)
{
fileName = imgs[i].itemLink.name;
img = new File(folder + "/" + fileName); // each image instantiated here
imgType = imgs[i].imageTypeName; // image type is determined here (.tif, .jpg, .png, etc..)
alert("This is a " + imgType + " file.");
/*
* array for image options, instantiated from the function below;
* options[0] is the "MAXIMUM" image quality property, &
* options[1] is the "GRAY" image conversion property;
*/
var options = convertToBlackAndWhite(imgType);
// each image exported to the new folder here, by file type
switch(imgType)
{
case "GIF":
alert("This script cannot convert and export the GIF file:\n\t" + fileName + " !");
break;
case "TIFF":
case "EPS":
case "JPG":
options[0]; // maximum image quality
options[1]; // black & white conversion
imgs[i].exportFile(ExportFormat.JPG, img, false);
break;
case "PNG":
options[0]; // maximum image quality
options[1]; // black & white conversion
imgs[i].exportFile(ExportFormat.PNG_TYPE, img, false);
break;
default:
alert("\tUnlisted image type: " + imgType + "!\nAdd this type to the switch statement.");
break;
} // end of switch statement
} // end of if statement
} // end of for loop
} // end of function saveAllImages
function convertToBlackAndWhite(fileType)
{
// array for image-quality and color-conversion values
var settings = [];
// each image exported to the new folder here, by file type
switch(fileType)
{
case "TIFF":
case "PNG":
case "EPS":
case "JPG":
settings[0] = "app.jpegExportPreferences.jpegQuality = JPEGOptionsQuality.MAXIMUM"; // maximum image quality
settings[1] = "app.jpegExportPreferences.jpegColorSpace = JpegColorSpaceEnum.GRAY"; // black & white conversion
break;
default:
break;
} // end of switch statement
return settings; // for instantiation outside of this function
} // end of function convertToBlackAndWhite
