pdfsignatureappearance.java

iText是一个能够快速产生PDF文件的java类库。iText的java类对于那些要产生包含文本

    public PdfTemplate getTopLayer() {
        if (frm == null) {
            frm = new PdfTemplate(writer);
            frm.setBoundingBox(rect);
            writer.addDirectTemplateSimple(frm, new PdfName("FRM"));
        }
        return frm;
    }
    
    /**
     * Gets the main appearance layer.
     * <p>
     * Consult <A HREF="http://partners.adobe.com/asn/developer/pdfs/tn/PPKAppearances.pdf">PPKAppearances.pdf</A>
     * for further details.
     * @return the main appearance layer
     * @throws DocumentException on error
     */    
    public PdfTemplate getAppearance() throws DocumentException {
        if (isInvisible()) {
            PdfTemplate t = new PdfTemplate(writer);
            t.setBoundingBox(new Rectangle(0, 0));
            writer.addDirectTemplateSimple(t, null);
            return t;
        }
        if (app[0] == null) {
            PdfTemplate t = app[0] = new PdfTemplate(writer);
            t.setBoundingBox(new Rectangle(100, 100));
            writer.addDirectTemplateSimple(t, new PdfName("n0"));
            t.setLiteral("% DSBlank\n");
        }
        if (app[1] == null && !acro6Layers) {
            PdfTemplate t = app[1] = new PdfTemplate(writer);
            t.setBoundingBox(new Rectangle(100, 100));
            writer.addDirectTemplateSimple(t, new PdfName("n1"));
            t.setLiteral(questionMark);
        }
        if (app[2] == null) {
            String text;
            if (layer2Text == null) {
                StringBuffer buf = new StringBuffer();
                buf.append("Digitally signed by ").append(PdfPKCS7.getSubjectFields((X509Certificate)certChain[0]).getField("CN")).append('\n');
                SimpleDateFormat sd = new SimpleDateFormat("yyyy.MM.dd HH:mm:ss z");
                buf.append("Date: ").append(sd.format(signDate.getTime()));
                if (reason != null)
                    buf.append('\n').append("Reason: ").append(reason);
                if (location != null)
                    buf.append('\n').append("Location: ").append(location);
                text = buf.toString();
            }
            else
                text = layer2Text;
            PdfTemplate t = app[2] = new PdfTemplate(writer);
            t.setBoundingBox(rect);
            writer.addDirectTemplateSimple(t, new PdfName("n2"));
            if (image != null) {
                if (imageScale == 0) {
                    t.addImage(image, rect.getWidth(), 0, 0, rect.getHeight(), 0, 0);
                }
                else {
                    float usableScale = imageScale;
                    if (imageScale < 0)
                        usableScale = Math.min(rect.getWidth() / image.getWidth(), rect.getHeight() / image.getHeight());
                    float w = image.getWidth() * usableScale;
                    float h = image.getHeight() * usableScale;
                    float x = (rect.getWidth() - w) / 2;
                    float y = (rect.getHeight() - h) / 2;
                    t.addImage(image, w, 0, 0, h, x, y);
                }
            }
            Font font;
            if (layer2Font == null)
                font = new Font();
            else
                font = new Font(layer2Font);
            float size = font.getSize();

            Rectangle dataRect = null;
            Rectangle signatureRect = null;

            if (render == SignatureRenderNameAndDescription || 
                (render == SignatureRenderGraphicAndDescription && this.signatureGraphic != null)) {
                // origin is the bottom-left
                signatureRect = new Rectangle(
                    MARGIN, 
                    MARGIN, 
                    rect.getWidth() / 2 - MARGIN,
                    rect.getHeight() - MARGIN);
                dataRect = new Rectangle(
                    rect.getWidth() / 2 +  MARGIN / 2, 
                    MARGIN, 
                    rect.getWidth() - MARGIN / 2,
                    rect.getHeight() - MARGIN);

                if (rect.getHeight() > rect.getWidth()) {
                    signatureRect = new Rectangle(
                        MARGIN, 
                        rect.getHeight() / 2, 
                        rect.getWidth() - MARGIN,
                        rect.getHeight());
                    dataRect = new Rectangle(
                        MARGIN, 
                        MARGIN, 
                        rect.getWidth() - MARGIN,
                        rect.getHeight() / 2 - MARGIN);
                }
            }
            else {
                dataRect = new Rectangle(
                    MARGIN, 
                    MARGIN, 
                    rect.getWidth() - MARGIN,
                    rect.getHeight() * (1 - TOP_SECTION) - MARGIN);
            }

            if (render == SignatureRenderNameAndDescription) {
                String signedBy = PdfPKCS7.getSubjectFields((X509Certificate)certChain[0]).getField("CN");
                Rectangle sr2 = new Rectangle(signatureRect.getWidth() - MARGIN, signatureRect.getHeight() - MARGIN );
                float signedSize = fitText(font, signedBy, sr2, -1, runDirection);

                ColumnText ct2 = new ColumnText(t);
                ct2.setRunDirection(runDirection);
                ct2.setSimpleColumn(new Phrase(signedBy, font), signatureRect.getLeft(), signatureRect.getBottom(), signatureRect.getRight(), signatureRect.getTop(), signedSize, Element.ALIGN_LEFT);

                ct2.go();
            }
            else if (render == SignatureRenderGraphicAndDescription) {
                ColumnText ct2 = new ColumnText(t);
                ct2.setRunDirection(runDirection);
                ct2.setSimpleColumn(signatureRect.getLeft(), signatureRect.getBottom(), signatureRect.getRight(), signatureRect.getTop(), 0, Element.ALIGN_RIGHT);

                Image im = Image.getInstance(signatureGraphic);
                im.scaleToFit(signatureRect.getWidth(), signatureRect.getHeight());

                Paragraph p = new Paragraph();
                // must calculate the point to draw from to make image appear in middle of column
                float x = 0;
                // experimentation found this magic number to counteract Adobe's signature graphic, which
                // offsets the y co-ordinate by 15 units
                float y = -im.getScaledHeight() + 15;

                x = x + (signatureRect.getWidth() - im.getScaledWidth()) / 2;
                y = y - (signatureRect.getHeight() - im.getScaledHeight()) / 2;
                p.add(new Chunk(im, x + (signatureRect.getWidth() - im.getScaledWidth()) / 2, y, false));
                ct2.addElement(p);
                ct2.go();
            }
            
            if (size <= 0) {
                Rectangle sr = new Rectangle(dataRect.getWidth(), dataRect.getHeight());
                size = fitText(font, text, sr, 12, runDirection);
            }
            ColumnText ct = new ColumnText(t);
            ct.setRunDirection(runDirection);
            ct.setSimpleColumn(new Phrase(text, font), dataRect.getLeft(), dataRect.getBottom(), dataRect.getRight(), dataRect.getTop(), size, Element.ALIGN_LEFT);
            ct.go();
        }
        if (app[3] == null && !acro6Layers) {
            PdfTemplate t = app[3] = new PdfTemplate(writer);
            t.setBoundingBox(new Rectangle(100, 100));
            writer.addDirectTemplateSimple(t, new PdfName("n3"));
            t.setLiteral("% DSBlank\n");
        }
        if (app[4] == null && !acro6Layers) {
            PdfTemplate t = app[4] = new PdfTemplate(writer);
            t.setBoundingBox(new Rectangle(0, rect.getHeight() * (1 - TOP_SECTION), rect.getRight(), rect.getTop()));
            writer.addDirectTemplateSimple(t, new PdfName("n4"));
            Font font;
            if (layer2Font == null)
                font = new Font();
            else
                font = new Font(layer2Font);
            float size = font.getSize();
            String text = "Signature Not Verified";
            if (layer4Text != null)
                text = layer4Text;
            Rectangle sr = new Rectangle(rect.getWidth() - 2 * MARGIN, rect.getHeight() * TOP_SECTION - 2 * MARGIN);
            size = fitText(font, text, sr, 15, runDirection);
            ColumnText ct = new ColumnText(t);
            ct.setRunDirection(runDirection);
            ct.setSimpleColumn(new Phrase(text, font), MARGIN, 0, rect.getWidth() - MARGIN, rect.getHeight() - MARGIN, size, Element.ALIGN_LEFT);
            ct.go();
        }
        int rotation = writer.reader.getPageRotation(page);
        Rectangle rotated = new Rectangle(rect);
        int n = rotation;
        while (n > 0) {
            rotated = rotated.rotate();
            n -= 90;
        }
        if (frm == null) {
            frm = new PdfTemplate(writer);
            frm.setBoundingBox(rotated);
            writer.addDirectTemplateSimple(frm, new PdfName("FRM"));
            float scale = Math.min(rect.getWidth(), rect.getHeight()) * 0.9f;
            float x = (rect.getWidth() - scale) / 2;
            float y = (rect.getHeight() - scale) / 2;
            scale /= 100;
            if (rotation == 90)
                frm.concatCTM(0, 1, -1, 0, rect.getHeight(), 0);
            else if (rotation == 180)
                frm.concatCTM(-1, 0, 0, -1, rect.getWidth(), rect.getHeight());
            else if (rotation == 270)
                frm.concatCTM(0, -1, 1, 0, 0, rect.getWidth());
            frm.addTemplate(app[0], 0, 0);
            if (!acro6Layers)
                frm.addTemplate(app[1], scale, 0, 0, scale, x, y);
            frm.addTemplate(app[2], 0, 0);
            if (!acro6Layers) {
                frm.addTemplate(app[3], scale, 0, 0, scale, x, y);
                frm.addTemplate(app[4], 0, 0);
            }
        }
        PdfTemplate napp = new PdfTemplate(writer);
        napp.setBoundingBox(rotated);
        writer.addDirectTemplateSimple(napp, null);
        napp.addTemplate(frm, 0, 0);
        return napp;
    }
    
    /**
     * Fits the text to some rectangle adjusting the font size as needed.
     * @param font the font to use
     * @param text the text
     * @param rect the rectangle where the text must fit
     * @param maxFontSize the maximum font size
     * @param runDirection the run direction
     * @return the calculated font size that makes the text fit
     */    
    public static float fitText(Font font, String text, Rectangle rect, float maxFontSize, int runDirection) {
        try {
            ColumnText ct = null;
            int status = 0;
            if (maxFontSize <= 0) {
                int cr = 0;
                int lf = 0;
                char t[] = text.toCharArray();
                for (int k = 0; k < t.length; ++k) {
                    if (t[k] == '\n')
                        ++lf;
                    else if (t[k] == '\r')
                        ++cr;
                }
                int minLines = Math.max(cr, lf) + 1;
                maxFontSize = Math.abs(rect.getHeight()) / minLines - 0.001f;
            }
            font.setSize(maxFontSize);
            Phrase ph = new Phrase(text, font);
            ct = new ColumnText(null);
            ct.setSimpleColumn(ph, rect.getLeft(), rect.getBottom(), rect.getRight(), rect.getTop(), maxFontSize, Element.ALIGN_LEFT);
            ct.setRunDirection(runDirection);
            status = ct.go(true);
            if ((status & ColumnText.NO_MORE_TEXT) != 0)
                return maxFontSize;
            float precision = 0.1f;
            float min = 0;
            float max = maxFontSize;
            float size = maxFontSize;
            for (int k = 0; k < 50; ++k) { //just in case it doesn't converge
                size = (min + max) / 2;
                ct = new ColumnText(null);
                font.setSize(size);
                ct.setSimpleColumn(new Phrase(text, font), rect.getLeft(), rect.getBottom(), rect.getRight(), rect.getTop(), size, Element.ALIGN_LEFT);
                ct.setRunDirection(runDirection);
                status = ct.go(true);
                if ((status & ColumnText.NO_MORE_TEXT) != 0) {
                    if (max - min < size * precision)
                        return size;
                    min = size;
                }
                else
                    max = size;
            }
            return size;
        }
        catch (Exception e) {
            throw new ExceptionConverter(e);
        }
    }
    
    /**
     * Sets the digest/signature to an external calculated value.
     * @param digest the digest. This is the actual signature
     * @param RSAdata the extra data that goes into the data tag in PKCS#7
     * @param digestEncryptionAlgorithm the encryption algorithm. It may must be <CODE>null</CODE> if the <CODE>digest</CODE>
     * is also <CODE>null</CODE>. If the <CODE>digest</CODE> is not <CODE>null</CODE>
     * then it may be "RSA" or "DSA"
     */    
    public void setExternalDigest(byte digest[], byte RSAdata[], String digestEncryptionAlgorithm) {
        externalDigest = digest;
        externalRSAdata = RSAdata;
        this.digestEncryptionAlgorithm = digestEncryptionAlgorithm;
    }

    /**
     * Gets the signing reason.
     * @return the signing reason
     */    
    public String getReason() {
        return this.reason;
    }
    
    /**
     * Sets the signing reason.
     * @param reason the signing reason
     */    
    public void setReason(String reason) {
        this.reason = reason;
    }
    
    /**
     * Gets the signing location.
     * @return the signing location
     */    
    public String getLocation() {
        return this.location;
    }
    
    /**
     * Sets the signing location.
     * @param location the signing location
     */    
    public void setLocation(String location) {
        this.location = location;
    }
        
    /**
     * Returns the Cryptographic Service Provider that will sign the document.
     * @return provider the name of the provider, for example "SUN",
     * or <code>null</code> to use the default provider.
     */
    public String getProvider() {
        return this.provider;
    }
    
    /**
     * Sets the Cryptographic Service Provider that will sign the document.
     *
     * @param provider the name of the provider, for example "SUN", or
     * <code>null</code> to use the default provider.
     */
    public void setProvider(String provider) {
        this.provider = provider;
    }
    
    /**
     * Gets the private key.
     * @return the private key
     */    
    public java.security.PrivateKey getPrivKey() {
        return privKey;
    }
    
    /**
     * Gets the certificate chain.
     * @return the certificate chain
     */    
    public java.security.cert.Certificate[] getCertChain() {
        return this.certChain;
    }
    
    /**
     * Gets the certificate revocation list.
     * @return the certificate revocation list
     */    
    public java.security.cert.CRL[] getCrlList() {