iPDFdev Tips & Tricks for PDF development

PDF page imposition using CoreGraphics on iOS

June 11th, 2013

A recent question on StackOverflow asked about how to create a single large PDF page from multiple PDF pages. This process is known as page imposition, it lets you combine multiple PDF pages onto larger sheets to create books, booklets or other special arrangements.

My answer to that question handled only the situation when all the source pages had the same size and rotation. The code here is more complex and it handles any combination of page sizes and rotation.

PDF Frameworks and Tools for iOS and Mac OS X

March 13th, 2013

Working with PDF files using the native APIs provided by iOS and Mac OSX can be a daunting task so I decided to find projects and products that will make your life easier. The list is open for updates, feel free to leave a comment if you know a PDF related project that is not on the list.

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IFXPDFFactory – part 6 – Vector graphics

March 12th, 2013

After a long break and finishing the implementation of several internal details that will support the future public APIs, the library is ready to create content. For the beginning I added support for vector graphics: lines, curves, etc.

Lets see how they work.

IFXPDFFactory – part 5 – Pens and brushes

January 10th, 2013

In the previous post I showed the color support in IFXPDFFactory. How are these colors actually used? Pens and brushes enter the scene here.

IFXPDFFactory – part 4 – Colors and colorspaces

December 20th, 2012

I finished implementing support for PDF colors and colorspaces. The following colors are supported: RGB, CMYK, Gray, CalRGB, CalGray, Indexed, Icc, Lab and Separation.

IFXPDFFactory – part 3 – PDF functions

September 03rd, 2012

I have finished implementing support for PDF functions. Usually they are a niche feature in PDF libraries and you might wonder why did I choose to implement them in such an early stage of the development. The answer is they are heavily used for defining separation colorspaces (does Pantone colors ring a bell?), PDF smooth shadings (gradients) and for other features.

Functions in PDF represent static, self-contained numerical transformations. In general, a function can take any number (m) of input values and produce any number (n) of output values. In PDF functions, all the input values and all the output values are numbers, and functions have no side effects.

IFXPDFFactory – part 2 – page size and page boxes

August 13th, 2012

In the previous post I showed how PDF pages are created with iFXPDFFactory library. The default page size is Letter but it can be easily changed using the width and height properties.

IFXPDFDocument* doc = [[IFXPDFDocument alloc] init];
IFXPDFPage* page = [IFXPDFPage emptyPage];
[doc.pages addPage: page];
// Set page size to A4
page.width = 595;
page.height = 842;
[doc writeToFile: pathToPdfFile];
[doc release];

iFXPDFFactory – the PDF library for iOS and OS X

August 04th, 2012

In July I started working on iFXPDFFactory, a new PDF library for iOS and OS X. It is being developed entirely in Objective-C with a native Objective-C public interface.

The reason I started this library is that there is no native Objective-C library for iOS and Mac OS X. PDFKit for Mac OS X, although has an Objective-C interface, is very limited in features and libHaru, PoDoFo and CGPDF* API are all C/C++ based so no ARC or garbage collection. PDFKit is mainly designed to display PDF files, libHaru can only create PDF files, PoDoFo can create and modify PDF files but it has to be built from source code, not a simple thing for novices, and CGPDF* API is a readonly API for reading PDF files at very low level. The graphic context on iOS/OS X lets you also create PDF files but it is limited to graphic features available in all types of graphic contexts so no standard PDF features such as annotations or form fields.

With iFXPDFFactory I plan to fix several of the problems above. It is designed specifically for iOS/OS X and being written in Objective-C lets you take advantage of ARC or garbage collection on OS X. It will support both PDF creation and editing of existing PDF files. Some of the planned PDF features are: multiple colorspaces, fonts, images, vector graphics, form XObjects, annotations, form fields, encryption, content extraction and many more.

Find images on PDF pages on iPhone and iPad

July 02nd, 2012

There are situations when we need to know if a PDF page contains, images, where on the page are the images located, what is the size on the page of a displayed image or other information about images in a PDF page.
Some of this information is available directly in the PDF file, other information needs to be computed.

Links navigation in a PDF document on iPhone and iPad

June 21st, 2011

iOS provides good support for displaying PDF files, but it lacks any support for the interactive features in the PDF files, such as annotations, links, form fields. In this article I'll show how to implement navigation in a PDF document using the links defined on document's pages. The project attached to this article is based on Apple's ZoomingPDFViewer sample that has been updated to support links navigation.