readme.md

Aspose.Imaging Java API allows to easy grayscale your images or photos in your Java application or Web service.

You can:

• easily grayscale (make only black-white) your images and save to specified format.

Interested ?

You may go further at : https://products.aspose.com/imaging/java/

grayscale-images.java

import com.aspose.imaging.IMultipageImage;
import com.aspose.imaging.Image;
import com.aspose.imaging.RasterImage;
import com.aspose.imaging.imageoptions.PngOptions;
import java.io.File;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
import java.util.function.Consumer;


grayscale();


public static void grayscale()
{
	filterImages(RasterImage::grayscale, "grayscale");
}

static String templatesFolder = "D:\\";

public static void filterImages(Consumer<RasterImage> doFilter, String filterName)
{
	List<String> rasterFormats = Arrays.asList("jpg", "png", "bmp", "apng", "dicom",
			"jp2", "j2k", "tga", "webp", "tif", "gif", "ico");
	List<String> vectorFormats = Arrays.asList("svg", "otg", "odg", "eps", "wmf", "emf", "wmz", "emz", "cmx", "cdr");

	List<String> allFormats = new LinkedList<>(rasterFormats);
	allFormats.addAll(vectorFormats);

	allFormats.forEach(
			formatExt ->
			{
				String inputFile = templatesFolder + "template." + formatExt;
				boolean isVectorFormat = vectorFormats.contains(formatExt);

				//Need to rasterize vector formats before background remove
				if (isVectorFormat)
				{
					inputFile = rasterizeVectorImage(formatExt, inputFile);
				}

				String outputFile = templatesFolder + String.format("%s_%s.png", filterName, formatExt);

				System.out.println("Processing " + formatExt);

				try (RasterImage image = (RasterImage) Image.load(inputFile))
				{
					doFilter.accept(image);

					//If image is multipage save each page to png to demonstrate results
					if (image instanceof IMultipageImage && ((IMultipageImage) image).getPageCount() > 1)
					{
						IMultipageImage multiPage = (IMultipageImage) image;
						final int pageCount = multiPage.getPageCount();
						final Image[] pages = multiPage.getPages();
						for (int pageIndex = 0; pageIndex < pageCount; pageIndex++)
						{
							String fileName = String.format("%s_page%d_%s.png", filterName, pageIndex, formatExt);
							pages[pageIndex].save(fileName, new PngOptions());
						}
					}
					else
					{
						image.save(outputFile, new PngOptions());
					}
				}

				//Remove rasterized vector image
				if (isVectorFormat)
				{
					new File(inputFile).delete();
				}
			}
	);
}

private static String rasterizeVectorImage(String formatExt, String inputFile)
{
	String outputFile = templatesFolder + "rasterized."+ formatExt + ".png";
	try (Image image = Image.load(inputFile))
	{
		image.save(outputFile, new PngOptions());
	}

	return outputFile;
}