iText Image Resize

Question

I have a watermark that I would like to put into my pdf. The watermark is a .bmp image, and is 2290 x 3026. I am having a lot of trouble trying to resize this picture to fit the page, does anyone have any suggestions?

Document document = new Document(); 
PdfWriter.getInstance(document, new FileOutputStream("result.pdf")); 
document.open(); 
document.add(new Paragraph("hello")); 
document.close(); 
PdfReader reader = new PdfReader("result.pdf"); 
int number_of_pages = reader.getNumberOfPages(); 
PdfStamper pdfStamper = new PdfStamper(reader, new FileOutputStream("result_watermark.pdf")); 
// Get the PdfContentByte type by pdfStamper. 
Image watermark_image = Image.getInstance("abstract(0307).bmp"); 
int i = 0; 
watermark_image.setAbsolutePosition(0, 0);
watermark_image.scaleToFit(826, 1100);
System.out.println(watermark_image.getScaledWidth());
System.out.println(watermark_image.getScaledHeight()); 
PdfContentByte add_watermark; 
while (i < number_of_pages) { 
    i++; 
    add_watermark = pdfStamper.getUnderContent(i); 
    add_watermark.addImage(watermark_image); 
} 
pdfStamper.close();

Here is the output for the getScaled() methods.

826.0 - Width
1091.4742 - Height

I would share the picture of the pdf with you guys but unfortunately I can't.

Should I try using a .jpg instead? I don't really know how well iText handles different image extensions.

Answer 1

I do it like that:

//if you would have a chapter indentation
int indentation = 0;
//whatever
Image image = coolPic;

float scaler = ((document.getPageSize().getWidth() - document.leftMargin()
               - document.rightMargin() - indentation) / image.getWidth()) * 100;

image.scalePercent(scaler);

Answer 2

use

watermark_image.scaleAbsolute(826, 1100);

instead of

watermark_image.scaleToFit(826, 1100);

Answer 3

Just in case if the image height exceeds the document height:

float documentWidth = document.getPageSize().width() - document.leftMargin() - document.rightMargin();
float documentHeight = document.getPageSize().height() - document.topMargin() - document.bottomMargin();
image.scaleToFit(documentWidth, documentHeight);

Answer 4

you can use

imageInstance.scaleAbsolute(requiredWidth, requiredHeight);

Answer 5

You could use another approach : resize the image "manually" (i.e. through an image processing software) instead of programmatically through iText.

Since the final dimension seems hardcoded, you could use an already resized image and save yourself some processing time every time you watermark PDF documents.

Answer 6

Document document = new Document();
PdfWriter.getInstance(document, new 
FileOutputStream("F:\\Directory1\\sample1.pdf"));
document.open();

Image img = 
Image.getInstance("F:\\Server\\Xyz\\WebContent\\ImageRestoring\\Rohit.jpg");
img.scaleToFit(200, 200);
document.add(new Paragraph("Sample 1: This is simple image demo."));
document.add(img);
document.close();
System.out.println("Done");

Answer 7

Sometimes it is useful to only scale down if the image is too large and not scale up if the image fits OK. In other words, the scaling will only happen if the width doesn't fit in the available width or the height doesn't fit in the available height. This can be done as follows:

float scaleRatio = calculateScaleRatio(doc, image);
if (scaleRatio < 1F) {
    image.scalePercent(scaleRatio * 100F);
}

with this calculateScaleRatio method:

/**
 * Calculate scale ratio required to fit supplied image in the supplied PDF document.
 * @param doc    PDF to fit image in.
 * @param image  Image to be converted into a PDF.
 * @return       Scale ratio (0.0 - 1.0), or 1.0 if no scaling is required.
 */
private float calculateScaleRatio(Document doc, Image image) {
    float scaleRatio;
    float imageWidth = image.getWidth();
    float imageHeight = image.getHeight();
    if (imageWidth > 0 && imageHeight > 0) {
        // Firstly get the scale ratio required to fit the image width
        Rectangle pageSize = doc.getPageSize();
        float pageWidth = pageSize.getWidth() - doc.leftMargin() - doc.rightMargin();
        scaleRatio = pageWidth / imageWidth;

        // Get scale ratio required to fit image height - if smaller, use this instead
        float pageHeight = pageSize.getHeight() - doc.topMargin() - doc.bottomMargin();
        float heightScaleRatio = pageHeight / imageHeight;
        if (heightScaleRatio < scaleRatio) {
            scaleRatio = heightScaleRatio;
        }

        // Do not upscale - if the entire image can fit in the page, leave it unscaled.
        if (scaleRatio > 1F) {
            scaleRatio = 1F;
        }
    } else {
        // No scaling if the width or height is zero.
        scaleRatio = 1F;
    }
    return scaleRatio;
}