Example usage for com.lowagie.text.pdf PdfTransparencyGroup setKnockout

Introduction

In this page you can find the example usage for com.lowagie.text.pdf PdfTransparencyGroup setKnockout.

Prototype

public void setKnockout(boolean knockout) 

Source Link

Document

Determining whether the objects within the stack are composited with one another or only with the group's backdrop.

Usage

From source file:questions.images.TransparentEllipse2.java

public static void main(String[] args) {

    Document document = new Document(PageSize.POSTCARD);
    try {// w ww . ja va  2 s  . c om
        PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(RESULT));
        document.open();
        PdfContentByte cb = writer.getDirectContent();

        // clipped image
        cb.ellipse(1, 1, PageSize.POSTCARD.getWidth() - 2, PageSize.POSTCARD.getHeight() - 2);
        cb.clip();
        cb.newPath();
        Image img = Image.getInstance(RESOURCE);
        img.scaleToFit(PageSize.POSTCARD.getWidth(), PageSize.POSTCARD.getHeight());
        cb.addImage(img, PageSize.POSTCARD.getWidth(), 0, 0, PageSize.POSTCARD.getHeight(), 0, 0);

        //Prepare gradation list
        int gradationStep = 40;
        float[] gradationRatioList = new float[gradationStep];
        for (int i = 0; i < gradationStep; i++) {
            gradationRatioList[i] = 1 - (float) Math.sin(Math.toRadians(90.0f / gradationStep * (i + 1)));
        }

        //Create template
        PdfTemplate template = cb.createTemplate(PageSize.POSTCARD.getWidth(), PageSize.POSTCARD.getHeight());

        //Prepare transparent group
        PdfTransparencyGroup transGroup = new PdfTransparencyGroup();
        transGroup.put(PdfName.CS, PdfName.DEVICEGRAY);
        transGroup.setIsolated(true);
        transGroup.setKnockout(false);
        template.setGroup(transGroup);

        //Prepare graphic state
        PdfGState gState = new PdfGState();
        PdfDictionary maskDict = new PdfDictionary();
        maskDict.put(PdfName.TYPE, PdfName.MASK);
        maskDict.put(PdfName.S, new PdfName("Luminosity"));
        maskDict.put(new PdfName("G"), template.getIndirectReference());
        gState.put(PdfName.SMASK, maskDict);
        cb.setGState(gState);

        //Create gradation for mask
        for (int i = 1; i < gradationStep + 1; i++) {
            template.setLineWidth(gradationStep + 1 - i);
            template.setGrayStroke(gradationRatioList[gradationStep - i]);
            template.ellipse(0, 0, PageSize.POSTCARD.getWidth(), PageSize.POSTCARD.getHeight());
            template.stroke();
        }

        //Place template
        cb.addTemplate(template, 0, 0);
    } catch (DocumentException de) {
        System.err.println(de.getMessage());
    } catch (IOException ioe) {
        System.err.println(ioe.getMessage());
    }

    document.close();
}

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