TiffIO 1.2.0
Jean-Dominique <dot> Gascuel <at> imag.fr

TiffIO is a plugin that add TIFF images read/write capabilities to all Qt3 and Qt4 applications using the QImage class.

Adding the plugin in the Qt's tree (or linking it witinh your own application) enables any Qt application to manipulate TIFF images transparently along with all other formats already managed by Qt.

TiffIO come with a self-test suite (test.pro), and have been compiled and used successfully on a wide variety of systems, compilers and Qt version combination. A demo application (demo.pro) enables to quickly test image loading & viewing on any platform.

Current support for reading .tif into a QImage :

• Images created on any architecture (big endians or little endians byte ordering, LSB or MSB bit ordering)
• Uncompressed, or compressed images (lossless Packbits, LZW, ZIP, JPEG, bitmap FaxG4, etc.).
• Various color schemes (RGB, RGBA, LAB, LUV, CYMK, CIEXY, ...)
• 2, 4, 8 and 16 bits per components RGB and RGBA images (automatically rounded to 8 bits images, as required by Qt).
• 2, 4, 8, and 16 bits paletted images with RGB colors (always loaded as 8 bits images, with color table truncated to 8 bits because of Qt).
• up to 8 bits per components for all the other color schemes (CYMK, LAB, etc.).
• 2, 4, 8 and 16 bits gray images (always loaded as 8 bits images, with an allGray() linear color table).
• Bitmap (1-bit images), loaded as a QImage bitmap (depth= 1), with a colortable.
• Accepts TIFF multi-layered images (eg. layers from Photoshop).
• Accepts scan-line based or tile-based images.
• Accepts image with any storage orientation.
• Accepts huge image size (limits from Qt and libtiff : 64k*64k ?).

Current support for writting a QImage :

• Always store planar, scan-line based, top-left oriented images, using LZW compression and big endians architecture.
• Bitmaps (depth=1) as one-chanel TIFF, with BPS= 1, and MINISBLACK mode.
• Gray images (depth= 8 bit/pixel) are one-chanel TIFF, in MINISBLACK mode.
• Other 1 or 8 bit/pixel images are saved as PALETTE images, with up to 256 RGB colors.
• True color images (24 or 32 bit/pixels) are saved as 3x8 bits RGB images, or 4x8 bits RGBA images, without a colormap.

What is not supported at the time :

• Transparency (alpha channel) when in a different plane than colors, ie. except for reading/writting RGBA (ie. 4 channels) images.
• Compact writting of 2 or 4 bits images (instead, they are promoted to 8 bits, then LZW compressed).
• Fancy capabilities of Qt4 (eg. animations, fast scaled/cropped read, choice of compression mode and quality, etc.).
• JPEG compression/uncompression within TIFF on win32 platform (except if you hack the Qt distribution, or provide your own libjpeg).
  See comments in TiffIO.pri for details.

All TIFF operations are based on libtiff 3.8.0, this plugin is just a wrapper that enable to use it transparently from the QImage class, and the QImageIO architecture defined by Qt.

Source download

• The latest sources and .pro, packaged for Qt' style qmake installation, on either Windows or Unix platforms: WinZip and Tar archives
  RPM package of the same files, for easy rebuild on linux platforms: src.rpm
  Warning: this version is based on a beta libtiff 3.8.0++. Release 3.8.0 of libtiff do have problems. This Beta is from the CVS repository, of what will become libtiff 3.8.1 someday I guess... This is to cure certain combination of YCrCb color space and compression schemes that have been reported to crash TiffIO on the dark side of libtiff...
• The previous release 1.1.0c based on libtiff 3.7.4 (see History below) is there: WinZip, Tar archives, and src.rpm
• Old sources are there

Pre-compiled download

None at that time: because there is too many combination of versions of Qt, versions of compiler, and systems flavors...

Status

• The plugin have been compiled and tested with Qt 3.2.3, Qt 3.3.5, Qt 4.0.1, and Qt 4.1.
• The plugin have beed compiled and tested on MacOSX, Solaris, Irix, Tru64, AIX, Linux, HP-UX, and Windows XP (SP1 & SP2).
• The plugin have been compiled and tested with MS Visual C++ (6, .NET and .NET 2003), with g++ (3.2 and 3.3), and mingw++.

I am using TiffIO on Win32/Qt 3.2.3, ``every days'', and I am not aware of any bugs. The self-test suite (just compile and execute the provided test.pro project) enable a quick checking of the plugin consistency for a given platform. If you have a doubt, you can also compile the demo.pro micro-application to have a look at any dubious .tiff file.

Known Bugs

• Qt 4.0.1 Evaluation seems to fail to link on windows, when using command line qmake/nmake tools.
  Use Visual environment instead (typing devenv in the Qt 4.0.1 shell window).
• On some version of borland bcc, you will need to ignore hundreds of spurious warnings araising from the libtiff sources, that abort compiling somewhere in the installation.
  One should be able to shut warnings off, and finish compiling. Please e-mail me the right bcc options !

I you find some bugs, or need support never encountered before TIFF variant, send e-mails to Jean-Dominique.Gascuel at imag.fr.

History

• 2006-02-06 / 1.2.0d :
  • NEW Upgrade to beta libtiff 3.8.0 (CVS), because brand 380 crash on some uncommon TIFF features (eg. uncompressed YCrCb color space) crashes and compile errors.
  • FIX demo for Qt4.
  • FIX bug preventing tiff to be in the list of Qt4.1 recognized formats.
  
  
• 2006-01-11 / 1.2.0 :
  • FIX linux-g++-64 compile (Thanks to Michael Kettner).
  • NEW allow (but discourage) compiling with a pre-compiled libtiff.
  • FIX bit order is different from byte order. So don't messup endianness with LSBfirst in bitmaps (Thanks to Frank Warmerdam).
  • FIX bug in Qt4 QIODevice API preventing writting TIFF.
  • NEW Upgrade to libtiff 3.8.0, with some patches to avoid crashes and compile errors.
  
  
• 2005-09-29 / 1.1.0 :
  • FIX missing checking of libtiff error code while reading/writting scan-lines.
  • FIX TiffIO generates qWarning() on fatal libtiff error, to avoid crashing the application.
  • FIX support for compiling with no-jpeg, no-lzw, no-zlib qmake config options.
  • NEW remove depedancy to GetFocus and MessageBox on win32 build.
  • NEW Save 32 bits QImage 24 bits TIFF when no alpha, and 32 bits TIFF when the image have an alpha channel.
  • NEW support for statically linked code (see test.pro for an example).
  • NEW add support for Qt 4.x image IO architecture.
    
  
  
• 2005-06-17 / 1.0.7:
  • FIX Upgraded to libTiff 3.7.2, due to security alerts.
  • FIX 16/32bits truncation warnings (that turns to compile errors on Boreland bcc32.
  • NEW handler to redirect TIFF errors/warnings to Qt's qFatal() and qWarning().
    This enables uniform application-wide policy using Qt's installMsgHandler().
  • NEW Test suite now checks that unsupported files don't crash and do generate Qt style errors/warnings.
  • NEW Experimental support for reading 2 bits and 4 bits gray or color mapped images.
  • FIX crash when reading bitmaps to hardware that needs a swap-bits.
  • FIX byte swapping problem when writting 24/32 bit images on SGI.
  • NEW support for JPEG-in-TIFF when the Qt installation contains sources, or on unix with libjpeg 6.2 devel package.
  
  
• 2005-03-22 / 1.0.6:
  • NEW Added support (and self-test) for bitmaps i/o, and FaxG4 reading.
    
• 2005-02-01 / 1.0.5:
  • NEW self-test program and examples files.
  • FIX compiler issues on HP-UX and AIX, thanks to Till Oliver Knoll.
    
• 2005-01-14 / 1.0.4:
  • FIX Upgrade to libtiff 3.7.1, because of security alert.
  • FIX libtiff 3.7.1 not to crash when displaying warnings or error messages.
  • FIX libtiff 3.7.1 to have readable error message when reading unsupported pixel formats (eg. CYMK 16 bits).
    
• 2004-12-17 / 1.0.3:
  • FIX Add "TIFF" as recognized format (as well as TIF).
  • FIX RGBA/ABGR color inversion on win32 platforms.
    
  
  
• 2004-11-22 / 1.0.2:
  • FIX a minor bug about the regexp to recognize TIFF formats.
    
• 2004-11-08 : Creation

Installation

Pre-requisite

On windows, to have zip compression support, you need to have installed Qt with internal zlib support, or you need to provide argument TIFF=pathToIncludeAndLib to any qmake call.

• On unix :
  • qmake TiffIO.pro
make
sudo make install
• On windows command line :
  • qmake TiffIO.pro
nmake

• On MS Visual Studio (6, .NET and .NET2003) :
  • Generate the .vcproj with the IDE Qt icon, or with the command:
    qmake -tp vc TiffIO.pro
  • Exit any Qt application (including Designer or Assistant), because they lock the $QTDIR/plugin/imageformats directory.
  • Open the project file, and build the solution.