TiffIO 1.0.6
mail: Jean-Dominique <dot> Gascuel <at> imag.fr

TiffIO is a plugin that add TIFF images read/write capabilities to the Qt's QImage class. Adding the generated plugin in the Qt's tree enable any Qt application to manipulate TIFF images. TiffIO come with a self-test suite, and have been compiled and used successfully on a variety of windows and unixes platforms.

All TIFF operations are based on libtiff 3.7.1, this plugin is just a wrapper that enable to use it transparently from the QImage class, and the QImageFormatPlugin architecture defined by Qt.

Current support for reading .tif into a QImage :

• Images created on any architecture (big endians or little endians)
• Uncompressed, or compressed images (mainly lossless LZW and ZIP, FaxG4, etc.).
• Various color schemes (RGB, RGBA, LAB, LUV, CYMK, CIEXY, ...)
• 8 and 16 bits per components RGB and RGBA images (automatically rounded to 8 bits images, as required by Qt).
• 8 bits per components for the other true color schemes.
• Bitmap (1-bit images), loaded as a QImage bitmap (depth=1), with a colortable.
• Gray level images from 1 to 16 bits (always loaded as 8 bits images, with a allGray() linear color table).
• Paletted images with up to 256 RGB colors (defined with up to 16bits per components, and truncated to 8 bits because of Qt).
• Accepts multi-layered images (eg. from Photoshop).
• Maximum image size from Qt and libtiff : 64k*64k ?

Current support for writting a QImage :

• Always use LZW compression and big endians architecture.
• Bitmaps (depth=1) as one-chanel TIFF, with BPS= 1, and either MINISBLACK or 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.

What is not supported at the time :

• JPEG compression on WIN32 (I have to figure out how to use 3rdparty/jpeg in the Qt architecture).
• Transparency (alpha channel), except for reading 4 channels images.

Status

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 test.pro project) enable a quick checking of the plugin consistency for a given platform.

The plugin have beed tested on Solaris, Irix, Tru64, AIX, Linux, HP-UX, and Windows XP (SP1 & SP2).

I you find some bugs, send e-mails to Jean-Dominique.Gascuel at imag.fr.

History

• 2004-11-08 : Creation
  
• 2004-11-22 / 1.0.2:
  • FIX a minor bug about the regexp to recognize TIFF formats.
• 2004-12-17 / 1.0.3:
  • FIX Add "TIFF" as recognized format (as well as TIF).
  • FIX RGBA/ABGR color inversion on win32 platforms.
• 2005-01-14 / 1.0.4:
  • 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).
• 2005-02-01 / 1.0.5:
  • NEW self-test program and examples files.
  • FIX compiler issues on HU-UX and AIX, thanks to Till Oliver Knoll.
• 2005-03-22 / 1.0.6:
• NEW Added support (and self-test) for bitmaps i/o, and FaxG4 reading.

Source download

• TiffIO-106.zip The full sources and .pro. Packaged on a win32 platform.
• TiffIO-106.tgz Idem, packaged on a unix-type platform.

Pre-compiled download

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

Installation

On unix :

qmake TiffIO.pro
make
make install

On MSVC++ .NET :

• Generate the .vcproj with the IDE Qt icon, or with the command:
  qmake -tp vc TiffIO.pro
• Build the project.
• Exit any Qt application (including Designer or Assistant), because they lock the $QTDIR/plugin/imageformats directory.
• Copy the plugin (TiffIO.dll) into the $QTDIR/plugins/imageformats/ directory.

Testing

To run the self-test program, use the test.pro and run the generated executable. It should end saying all the images checked ok. The corresponding cases are in the Example/ subdirectory.

Files