Develop Reference

How to add space between images while creating pdf - Android

My app is using user-selected images and creating a PDF out of it using itextpdf.
It is successfully creating PDF but there is no space between images
Ex.
My Code
public void createPdf(String dest) throws IOException, DocumentException {
Image img = Image.getInstance(allSelectedImages.get(0).getPath());
Document document = new Document(img);
PdfWriter.getInstance(document, new FileOutputStream(dest));
document.open();
for (Uri image : allSelectedImages) {
img = Image.getInstance(image.getPath());
document.newPage();
document.setMargins(100, 100, 100, 100);
img.setAbsolutePosition(0, 0);
document.add(img);
}
document.close();
}

You are adding one image per page, so the space between images is equivalent to the space between pages which is determined by your PDF viewer.
What you can do it adding some margins around your images - this is what you are trying to do already but there are some things that need to be fixed.
Here is an example on how your code can be adapted to add 100pt margin for all sides of the page (note that I am calculating page sizes dynamically so that the page size adapts to the image size in case images are of different size):
Document document = new Document();
PdfWriter.getInstance(document, new FileOutputStream("path/to.pdf"));
document.open();
for (File image : allSelectedImages) {
Image img = Image.getInstance(image.getPath());
float leftMargin = 100;
float rightMargin = 100;
float topMargin = 100;
float bottomMargin = 100;
document.setPageSize(new Rectangle(img.getWidth() + leftMargin + rightMargin, img.getHeight() + topMargin + bottomMargin));
document.newPage();
document.setMargins(leftMargin, rightMargin, topMargin, bottomMargin);
img.setAbsolutePosition(leftMargin, bottomMargin);
document.add(img);
}

itext : How to detect PDF orientation

I'm using itext5 to scale down pdf document, however i notice that the rotation information is rarely used in pdf documents metadata, it's still possible to find out the orientation by checking the width and the height of the page but with the following pdf document i end up with a pdf that has both pages in landscape orientation and in portrait orientation however all the pages are rendered in the same orientation (in the common pdf viewers).
My question is where is that information stored ? How the pdf viewer is able to render the document as it should ?
This the orignal pdf file
This is the metadata i'm able to retrieve
This is the method used :
Document document = new Document(MarginsPDFHelper.DIM_PAGE, MarginsPDFHelper.MARGIN_GEN, MarginsPDFHelper.MARGIN_GEN, MarginsPDFHelper.MARGIN_TOP, MarginsPDFHelper.MARGIN_BOT);
try {
PdfReader reader = new PdfReader(pdfByte);
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
PdfWriter writer = PdfWriter.getInstance(document, outputStream);
document.open();
PdfContentByte content = writer.getDirectContent();
for (int i = 1; i <= reader.getNumberOfPages(); i++) {
document.newPage();
PdfImportedPage page = writer.getImportedPage(reader, i);
Rectangle pageSize = reader.getPageSizeWithRotation(i);
float scaleX = MarginsPDFHelper.DIM_PAGE.getWidth() / pageSize.getWidth();
float scaleY = MarginsPDFHelper.DIM_PAGE.getHeight() / pageSize.getHeight();
float scale = Math.min(scaleX, scaleY);
content.addTemplate(page, scale, 0, 0, scale, 0, 0);
}
return outputStream.toByteArray();
} catch (Exception e) {
LOGGER.error("Can not scale pdf", e);
} finally {
if (document.isOpen()) {
document.close();
} }
This the result i get after scaling down with itext5

create a one page PDF from two PDFs using PDFBOX

I have a small (quarter inch) one page PDF I created with PDFBOX with text (A). I want to put that small one page PDF (A) on the top of an existing PDF page (B), preserving the existing content of the PDF page (B). In the end, I will have a one page PDF, representing the small PDF on top(A), and the existing PDF intact making up the rest (B). How can I accomplish this with PDFBOX?

To join two pages one atop the other onto one target page, you can make use of the PDFBox LayerUtility for importing pages as form XObjects in a fashion similar to PDFBox SuperimposePage example, e.g. with this helper method:
void join(PDDocument target, PDDocument topSource, PDDocument bottomSource) throws IOException {
LayerUtility layerUtility = new LayerUtility(target);
PDFormXObject topForm = layerUtility.importPageAsForm(topSource, 0);
PDFormXObject bottomForm = layerUtility.importPageAsForm(bottomSource, 0);
float height = topForm.getBBox().getHeight() + bottomForm.getBBox().getHeight();
float width, topMargin, bottomMargin;
if (topForm.getBBox().getWidth() > bottomForm.getBBox().getWidth()) {
width = topForm.getBBox().getWidth();
topMargin = 0;
bottomMargin = (topForm.getBBox().getWidth() - bottomForm.getBBox().getWidth()) / 2;
} else {
width = bottomForm.getBBox().getWidth();
topMargin = (bottomForm.getBBox().getWidth() - topForm.getBBox().getWidth()) / 2;
bottomMargin = 0;
}
PDPage targetPage = new PDPage(new PDRectangle(width, height));
target.addPage(targetPage);
PDPageContentStream contentStream = new PDPageContentStream(target, targetPage);
if (bottomMargin != 0)
contentStream.transform(Matrix.getTranslateInstance(bottomMargin, 0));
contentStream.drawForm(bottomForm);
contentStream.transform(Matrix.getTranslateInstance(topMargin - bottomMargin, bottomForm.getBBox().getHeight()));
contentStream.drawForm(topForm);
contentStream.close();
}
(JoinPages method join)
You use it like this:
try ( PDDocument document = new PDDocument();
PDDocument top = ...;
PDDocument bottom = ...) {
join(document, top, bottom);
document.save("joinedPage.pdf");
}
(JoinPages test testJoinSmallAndBig)
The result looks like this:

Just as an additional point to #mkl's answer.
If anybody is looking to scale the PDFs before placing them on the page use,
contentStream.transform(Matrix.getScaleInstance(<scaling factor in x axis>, <scaling factor in y axis>)); //where 1 is the scaling factor if you want the page as the original size
This way you can rescale your PDFs.

How to watermark PDFs using text or images?

I have a bunch of PDF documents in a folder and I want to augment them with a watermark. What are my options from a Java serverside context?
Preferably the watermark will support transparency. Both vector and raster is desirable.

Please take a look at the TransparentWatermark2 example. It adds transparent text on each odd page and a transparent image on each even page of an existing PDF document.
This is how it's done:
public void manipulatePdf(String src, String dest) throws IOException, DocumentException {
PdfReader reader = new PdfReader(src);
int n = reader.getNumberOfPages();
PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest));
// text watermark
Font f = new Font(FontFamily.HELVETICA, 30);
Phrase p = new Phrase("My watermark (text)", f);
// image watermark
Image img = Image.getInstance(IMG);
float w = img.getScaledWidth();
float h = img.getScaledHeight();
// transparency
PdfGState gs1 = new PdfGState();
gs1.setFillOpacity(0.5f);
// properties
PdfContentByte over;
Rectangle pagesize;
float x, y;
// loop over every page
for (int i = 1; i <= n; i++) {
pagesize = reader.getPageSizeWithRotation(i);
x = (pagesize.getLeft() + pagesize.getRight()) / 2;
y = (pagesize.getTop() + pagesize.getBottom()) / 2;
over = stamper.getOverContent(i);
over.saveState();
over.setGState(gs1);
if (i % 2 == 1)
ColumnText.showTextAligned(over, Element.ALIGN_CENTER, p, x, y, 0);
else
over.addImage(img, w, 0, 0, h, x - (w / 2), y - (h / 2));
over.restoreState();
}
stamper.close();
reader.close();
}
As you can see, we create a Phrase object for the text and an Image object for the image. We also create a PdfGState object for the transparency. In our case, we go for 50% opacity (change the 0.5f into something else to experiment).
Once we have these objects, we loop over every page. We use the PdfReader object to get information about the existing document, for instance the dimensions of every page. We use the PdfStamper object when we want to stamp extra content on the existing document, for instance adding a watermark on top of each single page.
When changing the graphics state, it is always safe to perform a saveState() before you start and to restoreState() once you're finished. You code will probably also work if you don't do this, but believe me: it can save you plenty of debugging time if you adopt the discipline to do this as you can get really strange effects if the graphics state is out of balance.
We apply the transparency using the setGState() method and depending on whether the page is an odd page or an even page, we add the text (using ColumnText and an (x, y) coordinate calculated so that the text is added in the middle of each page) or the image (using the addImage() method and the appropriate parameters for the transformation matrix).
Once you've done this for every page in the document, you have to close() the stamper and the reader.
Caveat:
You'll notice that pages 3 and 4 are in landscape, yet there is a difference between those two pages that isn't visible to the naked eye. Page 3 is actually a page of which the size is defined as if it were a page in portrait, but it is rotated by 90 degrees. Page 4 is a page of which the size is defined in such a way that the width > the height.
This can have an impact on the way you add a watermark, but if you use getPageSizeWithRotation(), iText will adapt. This may not be what you want: maybe you want the watermark to be added differently.
Take a look at TransparentWatermark3:
public void manipulatePdf(String src, String dest) throws IOException, DocumentException {
PdfReader reader = new PdfReader(src);
int n = reader.getNumberOfPages();
PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest));
stamper.setRotateContents(false);
// text watermark
Font f = new Font(FontFamily.HELVETICA, 30);
Phrase p = new Phrase("My watermark (text)", f);
// image watermark
Image img = Image.getInstance(IMG);
float w = img.getScaledWidth();
float h = img.getScaledHeight();
// transparency
PdfGState gs1 = new PdfGState();
gs1.setFillOpacity(0.5f);
// properties
PdfContentByte over;
Rectangle pagesize;
float x, y;
// loop over every page
for (int i = 1; i <= n; i++) {
pagesize = reader.getPageSize(i);
x = (pagesize.getLeft() + pagesize.getRight()) / 2;
y = (pagesize.getTop() + pagesize.getBottom()) / 2;
over = stamper.getOverContent(i);
over.saveState();
over.setGState(gs1);
if (i % 2 == 1)
ColumnText.showTextAligned(over, Element.ALIGN_CENTER, p, x, y, 0);
else
over.addImage(img, w, 0, 0, h, x - (w / 2), y - (h / 2));
over.restoreState();
}
stamper.close();
reader.close();
}
In this case, we don't use getPageSizeWithRotation() but simply getPageSize(). We also tell the stamper not to compensate for the existing page rotation: stamper.setRotateContents(false);
Take a look at the difference in the resulting PDFs:
In the first screen shot (showing page 3 and 4 of the resulting PDF of TransparentWatermark2), the page to the left is actually a page in portrait rotated by 90 degrees. iText however, treats it as if it were a page in landscape just like the page to the right.
In the second screen shot (showing page 3 and 4 of the resulting PDF of TransparentWatermark3), the page to the left is a page in portrait rotated by 90 degrees and we add the watermark as if the page is in portrait. As a result, the watermark is also rotated by 90 degrees. This doesn't happen with the page to the right, because that page has a rotation of 0 degrees.
This is a subtle difference, but I thought you'd want to know.
If you want to read this answer in French, please read Comment créer un filigrane transparent en PDF?

Best option is iText. Check a watermark demo here
Important part of the code (where the watermar is inserted) is this:
public class Watermark extends PdfPageEventHelper {
#Override
public void onEndPage(PdfWriter writer, Document document) {
// insert here your watermark
}
Read carefully the example.
onEndPage() method will be something like (in my logo-watermarks I use com.itextpdf.text.Image;):
Image image = Image.getInstance(this.getClass().getResource("/path/to/image.png"));
// set transparency
image.setTransparency(transparency);
// set position
image.setAbsolutePosition(absoluteX, absoluteY);
// put into document
document.add(image);

Shrink PDF pages with rotation using Rectangle in existing PDF

I am using following code to shrink every pages (Top and bottom) of existing pdf using iText library.
Code working fine.
But now if i process result pdf, i get 0 value for rotation of every page, while old pdf has other rotation too(i.e. 90deg).
I want to keep rotation as it is but unable to do it.
Code i am using As below to shrink pages
public void shrinkPDFPages() throws Exception {
PdfReader reader = new PdfReader("D:/testpdfs/test.pdf");
Document doc = new Document();
PdfWriter writer = PdfWriter.getInstance(doc, new FileOutputStream(
"D://testpdfs/result.pdf"));
doc.open();
PdfContentByte cb = writer.getDirectContent();
for (int i = 1; i <= reader.getNumberOfPages(); i++) {
PdfImportedPage page = writer.getImportedPage(reader, i);
float pageHeight = reader.getPageSizeWithRotation(i).getHeight();
float pageWidth = reader.getPageSizeWithRotation(i).getWidth();
int rotation = reader.getPageRotation(i);
Rectangle pageRectangle = reader.getPageSizeWithRotation(i);
Rectangle PageRect = null;
System.out.println(rotation);
switch (rotation) {
case 0:
PageRect = new Rectangle(pageRectangle.getWidth(), pageRectangle
.getHeight());
doc.setPageSize(PageRect);
doc.newPage();
AffineTransform af = new AffineTransform();
af.scale(1, 0.84f);
af.translate(1, 50);
cb.addTemplate(page, af);
break;
case 90:
PageRect = new Rectangle(pageRectangle.getWidth(), pageRectangle
.getHeight());
doc.setPageSize(PageRect);
doc.newPage();
cb.addTemplate(page, 0, -1f, 0.84f, 0, 50, pageHeight);
break;
case 270:
PageRect = new Rectangle(pageRectangle.getWidth(), pageRectangle
.getHeight());
doc.setPageSize(PageRect);
doc.newPage();
cb.addTemplate(page, 0, 1f, -0.84f, 0, pageWidth - 50, 0);
break;
case 180:
PageRect = new Rectangle(pageRectangle.getWidth(), pageRectangle
.getHeight());
doc.setPageSize(PageRect);
doc.newPage();
cb.addTemplate(page, -1f, 0, 0, -0.84f, pageWidth,
pageHeight - 50);
break;
default:
break;
}
}
doc.close();
}
What should i do? so rotation remains as it is.
One more problem i am fetching is, unable to preserve internal hyper links.
Actual pdf page:
After Shrink(Scale Down Content):

Scaling a PDF to make pages larger is easy. This is shown in the ScaleRotate example. It's only a matter of changing the default version of the user unit. By default, this unit is 1, meaning that 1 user unit equals to 1 point. You can increase this value to 75,000. Larger values of the user unit, will result in larger pages.
Unfortunately, the user unit can never be smaller than 1, so you can't use this technique to shrink a page. If you want to shrink a page, you need to introduce a transformation (resulting in a new CTM).
This is shown in the ShrinkPdf example. In this example, I take a PDF named hero.pdf that measures 8.26 by 11.69 inch, and we shrink it by 50%, resulting in a PDF named hero_shrink.pdf that measures 4.13 by 5.85 inch.
To achieve this, we need a dirty hack:
public void manipulatePdf(String src, String dest) throws IOException, DocumentException {
PdfReader reader = new PdfReader(src);
PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest));
int n = reader.getNumberOfPages();
PdfDictionary page;
PdfArray crop;
PdfArray media;
for (int p = 1; p <= n; p++) {
page = reader.getPageN(p);
media = page.getAsArray(PdfName.CROPBOX);
if (media == null) {
media = page.getAsArray(PdfName.MEDIABOX);
}
crop = new PdfArray();
crop.add(new PdfNumber(0));
crop.add(new PdfNumber(0));
crop.add(new PdfNumber(media.getAsNumber(2).floatValue() / 2));
crop.add(new PdfNumber(media.getAsNumber(3).floatValue() / 2));
page.put(PdfName.MEDIABOX, crop);
page.put(PdfName.CROPBOX, crop);
stamper.getUnderContent(p).setLiteral("\nq 0.5 0 0 0.5 0 0 cm\nq\n");
stamper.getOverContent(p).setLiteral("\nQ\nQ\n");
}
stamper.close();
reader.close();
}
We loop over every page and we take the crop box of each page. If there is no crop box, we take the media box. These boxes are stored as arrays of 4 numbers. In this example, I assume that the first two numbers are zero and I divide the next two values by 2 to shrink the page to 50% (if the first two values are not zero, you'll need a more elaborate formula).
Once I have the new array, I change the media box and the crop box to this array, and I introduce a CTM that scales all content down to 50%. I need to use the setLiteral() method to fool iText.
Based on your feedback in the comments section, it appears that you do not understand the mechanics explained in my example. Hence I have made a second example, named ShrinkPdf2:
public void manipulatePdf(String src, String dest) throws IOException, DocumentException {
PdfReader reader = new PdfReader(src);
PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest));
int n = reader.getNumberOfPages();
float percentage = 0.8f;
for (int p = 1; p <= n; p++) {
float offsetX = (reader.getPageSize(p).getWidth() * (1 - percentage)) / 2;
float offsetY = (reader.getPageSize(p).getHeight() * (1 - percentage)) / 2;
stamper.getUnderContent(p).setLiteral(
String.format("\nq %s 0 0 %s %s %s cm\nq\n", percentage, percentage, offsetX, offsetY));
stamper.getOverContent(p).setLiteral("\nQ\nQ\n");
}
stamper.close();
reader.close();
}
In this example, I don't change the page size (no changes to the media or crop box), I only shrink the content (in this case to 80%) and I center the shrunken content on the page, leaving bigger margins to the top, bottom, left and right.
As you can see, this is only a matter of applying the correct Math. This second example is even more simple than the first, so I introduced some extra complexity: now you can easily change the percentage (in the first example I hardcoded 50%. in this case I introduced the percentage variable and I defined it as 80%).
Note that I apply the scaling in the X direction as well as in the Y direction to preserve the aspect ratio. Looking at your screen shots, it looks like you only want to shrink the content in the Y direction. For instance like this:
String.format("\nq 1 0 0 %s 0 %s cm\nq\n", percentage, offsetY)
Feel free to adapt the code to meet your need, but... the result will be ugly: all text will look funny and if you apply it to photos of people standing up vertically, you'll make them look fat.