Save image by custom strategy Leave feedback
Use CustomImagesStrategy with the IImageSavingHandler interface for full control over how each image is saved during conversion. You can rename files, redirect output to a custom stream, or replace image content entirely.
IImageSavingHandler is a functional interface, so a stateless handler can be written as a lambda. This one keeps a running counter, so it is written as a named class:
import com.groupdocs.markdown.*;
import com.groupdocs.markdown.imageexport.IImageSavingHandler;
public class CustomStrategyRename {
// Implement the IImageSavingHandler interface
static class RenameHandler implements IImageSavingHandler {
private int index;
@Override
public void handle(CustomImageSavingArgs args) {
args.setOutputImageFileName("img_" + index + "_" + args.getImageFileName());
index++;
}
}
public static void main(String[] args) {
// Use the handler with CustomImagesStrategy
RenameHandler handler = new RenameHandler();
DocumentConvertOptions options = new DocumentConvertOptions();
options.setImageExportStrategy(new CustomImagesStrategy("output/images", handler));
MarkdownConverter.toFile("business-plan.docx", "output/document.md", options);
}
}
business-plan.docx is a sample file used in this example. Click here to download it.
output/document.md (5 KB)
output/images/img_0_img-001.png (4 KB)
output/images/img_1_img-002.jpg (41 KB)
output/images/img_2_img-003.png (14 KB)
Use setReplacementImage to substitute the original image with different content (e.g., a watermarked version or a placeholder):
import com.groupdocs.markdown.*;
import com.groupdocs.markdown.imageexport.IImageSavingHandler;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
public class CustomStrategyReplace {
static class WatermarkHandler implements IImageSavingHandler {
@Override
public void handle(CustomImageSavingArgs args) {
try {
// Replace the original image with a custom placeholder
InputStream placeholder = new FileInputStream("placeholder.png");
args.setReplacementImage(placeholder);
args.setOutputImageFileName("placeholder.png");
} catch (IOException e) {
throw new IllegalStateException("placeholder.png not found", e);
}
}
}
public static void main(String[] args) {
WatermarkHandler handler = new WatermarkHandler();
DocumentConvertOptions options = new DocumentConvertOptions();
options.setImageExportStrategy(new CustomImagesStrategy("output/images", handler));
MarkdownConverter.toFile("business-plan.docx", "output/document.md", options);
}
}
business-plan.docx is a sample file used in this example. Click here to download it.
output/document.md (5 KB)
output/images/placeholder.png (14 KB)
NoteNote the stream direction.setReplacementImagetakes anInputStream– the library reads your replacement bytes from it.setOutputStream, by contrast, takes anOutputStream, because the library writes the image into it. C# blurs this distinction behind a singleStreamtype; Java makes it explicit.
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