PDF Reader/Viewer V2.5 for iOS

INTRODUCTION
============

I've crafted this open source PDF reader/viewer for fellow iOS
developers struggling with wrangling PDF files onto iOS device
screens. Version 2.x is a complete rethink and rewrite of the
original 1.x code. Please see my contact info below if you find
any bugs or have questions about the code.

The code is universal and does not require any XIBs (as all UI
elements are code generated, allowing for greatest flexibility).
It runs on iPad, iPhone and iPod touch with iOS 4.0 and up. Also
supported are the Retina displays in all new devices and is ready
to be fully internationalized. The idea was to provide a complete
project template that you could start building from, or, just pull
the required files into an existing project to enable PDF
reading/viewing in your app(s).

After launching the sample app, tap on the left hand side of the
screen to go back a page. Tap on the right hand side to go to the
next page. You can also swipe left and right to change pages. Tap
on the screen to fade in the toolbar and page slider. Double-tap
with one finger (or pinch out) to zoom in. Double tap with two
fingers (or pinch in) to zoom out.

This implementation has been tested with large PDF files (over
250MB in size and over 2800 pages in length) and with PDF files of
all flavors (from text only documents to graphics heavy magazines).
It also works rather well on older devices (such as the iPod touch
2nd generation and iPhone 3G) and takes advantage of the dual-core
processor (via CATiledLayer and multi-threading) in new devices.

FEATURES
========

Multithreaded: The UI is always quite smooth and responsive.

Supports:

 - iBooks-like document navigation.
 - Device rotation and all orientations.¹
 - Encrypted (password protected) PDFs.
 - PDF links (URI and go to page).
 - PDFs with rotated pages.

NOTES
=====

Version 2.x of the PDF reader/viewer code was originally developed
and tested under Xcode 3.2.6, LLVM 1.7, iOS 4.3.5, iOS 4.2.1 with
current development and testing under Xcode 4.3.2, LLVM 3.1, iOS 5.
The code uses manual memory management and will continue to do so.

The overall PDF reader/viewer functionality is encapsulated in the
ReaderViewController class. To present a document with this class,
you first need to create a ReaderDocument object with the file path
to the PDF document and then initialize a new ReaderViewController
with this ReaderDocument object. The ReaderViewController class uses
a ReaderDocument object to store information about the document and
to keep track of document properties (thumb cache directory path,
bookmarks and the current page number for example).

An initialized ReaderViewController can then be presented
modally, pushed onto a UINavigationController stack, placed in
a UITabBarController tab, or be used as a root view controller.
Please note that since ReaderViewController implements its own
toolbar, you need to hide the UINavigationController navigation
bar before pushing it and then show the navigation bar after
popping it. The ReaderDemoController class shows how this is
done with a bundled PDF file. To create a 'book as an app',
please see the ReaderBookDelegate class.

Required Files
--------------

The following files are required to incorporate the PDF
reader/viewer into one of your projects:

	CGPDFDocument.h		CGPDFDocument.m
	ReaderDocument.h	ReaderDocument.m
	ReaderConstants.h	ReaderConstants.m
	ReaderViewController.h	ReaderViewController.m
	ReaderMainToolbar.h	ReaderMainToolbar.m
	ReaderMainPagebar.h	ReaderMainPagebar.m
	ReaderContentView.h	ReaderContentView.m
	ReaderContentPage.h	ReaderContentPage.m
	ReaderContentTile.h	ReaderContentTile.m
	ReaderThumbCache.h	ReaderThumbCache.m
	ReaderThumbRequest.h	ReaderThumbRequest.m
	ReaderThumbQueue.h	ReaderThumbQueue.m
	ReaderThumbFetch.h	ReaderThumbFetch.m
	ReaderThumbRender.h	ReaderThumbRender.m
	ReaderThumbView.h	ReaderThumbView.m
	ReaderThumbsView.h	ReaderThumbsView.m
	ThumbsViewController.h	ThumbsViewController.m
	ThumbsMainToolbar.h	ThumbsMainToolbar.m
	UIXToolbarView.h	UIXToolbarView.m

	Reader-Button-H.png	Reader-Button-H@2x.png
	Reader-Button-N.png	Reader-Button-N@2x.png
	Reader-Email.png	Reader-Email@2x.png
	Reader-Mark-N.png	Reader-Mark-N@2x.png
	Reader-Mark-Y.png	Reader-Mark-Y@2x.png
	Reader-Print.png	Reader-Print@2x.png
	Reader-Thumbs.png	Reader-Thumbs@2x.png

	Localizable.strings (UTF-16 encoding)

Required iOS Frameworks
-----------------------

To incorporate the PDF reader/viewer into one of your projects,
all of the following iOS frameworks are required by the code:

	UIKit		Foundation
	CoreGraphics	QuartzCore
	ImageIO		MessageUI

Compile Time Options
--------------------

In ReaderConstants.h the following #define options are available:

READER_BOOKMARKS - If TRUE, enables page bookmark support.

READER_ENABLE_MAIL - If TRUE, an email button is added to the toolbar
(if the device is properly configured for email support).

READER_ENABLE_PRINT - If TRUE, a print button is added to the toolbar
(if printing is supported and available on the device).

READER_ENABLE_THUMBS - If TRUE, a thumbs button is added to the toolbar
(enabling page thumbnail document navigation).

READER_DISABLE_IDLE - If TRUE, the iOS idle timer is disabled while
viewing a document (beware of battery drain).

READER_SHOW_SHADOWS - If TRUE, a shadow is shown around each page
and the page content is inset by a couple of extra points.

READER_STANDALONE - If FALSE, a "Done" button is added to the toolbar
and the -dismissReaderViewController: delegate method is messaged when
it is tapped.

READER_DISABLE_RETINA - If TRUE, sets the CATiledLayer contentScale
to 1.0f. This effectively disables retina support and results in
non-retina device rendering speeds on retina display devices at
the loss of retina display quality.

ReaderDocument Archiving
------------------------

To change where the property list for ReaderDocument objects is stored
(~/Library/Application Support/ by default), see the +archiveFilePath:
method in the ReaderDocument.m source file. Archiving and unarchiving
of the ReaderDocument object for a document is mandatory since this is
where the current page number, bookmarks and directory of the document
page thumb cache is kept.

Caveats
-------

¹ There appears to be a bug in iOS 4 with its view controller rotation
handling when a modal view controller is presented in landscape from a
modal view controller when the status bar is visible on iPhone and iPod
touch. The good news is that iOS 5 appears to have this bug fixed.

HISTORY
=======

2011-07-29: Version 2.0.0

	- Released v2.0 into the wild for general use.

2011-08-25: Version 2.1.0

	- Added PDF link (URI and document page) support.
	- Assorted code cleanup, optimizations and bug fixes.

2011-08-27: Version 2.1.1

	- Fixed rotation handling when in a UITabBarController.

2011-09-09: Version 2.2.0

	- A medium resolution page preview image is now shown first.
	- The page bar now uses small page thumbs instead of a slider.

2011-09-10: Version 2.2.1

	- Added password handling to ReaderDocument plist unarchive.

2011-09-14: Version 2.3.0

	- Added page thumbnail document navigation.
	- Added support for page bookmarks.

2011-09-20: Version 2.4.0

	- Replaced UIToolbars with custom UIView-based toolbars.

2011-10-05: Version 2.5.0

	- Critical bug fixes and various assorted tweaks.

2011-10-06: Version 2.5.1

	- Fixed content view centering under iOS 5.

2011-10-15: Version 2.5.2

	- One (crashing) bug fix and one minor UI tweak.

2011-11-08: Version 2.5.3

	- Various refinements and minor bug fixes.

2012-01-14: Version 2.5.4

	- Bug fix to PDF link handling in older format PDFs.
	- Changed from CC BY 3.0 License to MIT License.

2012-04-10: Version 2.5.5

	- Handles PDF web links without http:// as the prefix.
	- Bug fix to PDF link handling with cropboxed PDF files.
	- Some performance improvements on iPad 3rd generation.

2012-04-16: Version 2.5.6

	- Now loads and decodes thumbnail PNGs on a background thread.
	- Added READER_DISABLE_RETINA #define performance option.

CONTACT INFO
============

Questions, feedback and iOS development work welcome:

Email: joklamcak(at)gmail(dot)com

Website: http://www.vfr.org/

ACKNOWLEDGEMENTS
================

The PDF link support code in the ReaderContentPage class is based on
the links navigation code by Sorin Nistor from http://ipdfdev.com/