Class: TIFFReader

• Inheritance
• Description
• Related information
• Class protocol
  • initialization
  • testing
• Instance protocol
  • private
  • private-data reading
  • private-reading
  • private-writing
  • reading
  • writing

Inheritance:

   Object
   |
   +--ImageReader
      |
      +--TIFFReader

Package:

stx:libview2

Category:

Graphics-Images-Readers

Version:

rev: 1.83 date: 2004/03/05 19:07:44

user: stefan

file: TIFFReader.st directory: libview2

module: stx stc-classLibrary: libview2

Author:

Claus Gittinger

Description:

This class knows how to read TIFF files and how to
write uncompressed TIFF files.

Implemented & Missing Features:

  - Only single image files are supported.
  - Not all formats are implemented, and of those that are, not all are tested.
    It should read with most rgb, palette, mono and greyscale images, 
    although the alpha channel is currently not supported and ignored.
    It supports reading of uncompressed, LZW, packbits and CCITT-G3 compressed images
    JPEG and many other formats are currently not implemented.

  - Only writing of uncompressed images is currently implemented.
    It should write (at least) mono, 8-bit palette and 24 bit rgb formats.

More formats will come... (will they ever be needed ?)

TODO (?): since I dont want to spend all of my life adding more formats here and
reinventing the wheel, this code should be changed to use the tiff library.
That would give us most formats and also writing capabilities for free.
Late note: 
    I hate C and interfacing to C libraries: it almost always leads to trouble
    w.r.t. memory leaks, non-reentrancy, non-interruptability etc.
    (we recently fixed a malloc-non-reentrant bug for some architecture...)
    So its robably better to do it all in a real programming language ;-)

Related information:

    Image
    Form
    Icon
    BlitImageReader
    FaceReader
    GIFReader
    JPEGReader
    PBMReader
    PCXReader
    ST80FormReader
    SunRasterReader
    TargaReader
    WindowsIconReader
    XBMReader
    XPMReader
    XWDReader

Class protocol:

 initialize

install myself in the Image classes fileFormat table
for the `.tiff' and `.tif' extensions.

 canRepresent: anImage

return true, if anImage can be represented in my file format.
Any image is supported.

 isValidImageFile: aFileName

return true, if aFileName contains a GIF image

Instance protocol:

 decodeTiffTag: tagType numberType: numberType length: length

 decompressPackBits: nIn from: srcBytes to: dstBytes startingAt: dstOffset

 readCCITT3RLETiffImageData

 readCCITT3RLEWTiffImageData

 readCCITTGroup3TiffImageData

not really tested - all I got is a single fax from NeXT step

 readCCITTGroup4TiffImageData

 readCCITTRLEWTiffImageData

 readDCSTiffImageData

 readDeflateTiffImageData

 readJBIGTiffImageData

 readJPEGTiffImageData

 readLZWTiffImageData

read LZW compressed tiff data; this method only
handles 3x8 rgb and 1x2 or 2x2 greyscale images.
For 2x2 greyscale images, the alpha plane is ignored.
(maybe other formats work also - its simply not
tested)

 readNeXTJPEGTiffImageData

 readNeXTRLE2TiffImageData

 readNewJPEGTiffImageData

 readPackbitsTiffImageData

this has only been tested with monochrome images

 readPixarFilmTiffImageData

 readPixarLogTiffImageData

 readThunderScanTiffImageData

 readTiffImageData

 readUncompressedTiffImageData

 positionToStrip: stripNr

 readBytes: n signed: isSigned

read n 8bit signed or unsigned integers and return them in an array or byteArray

 readChars: n

read n characters and return them in a string

 readDoubles: nFloats

read nFloats IEEE 32bit floats and return them in an array

 readFloats: nFloats

read nFloats IEEE 32bit floats and return them in an array

 readFracts: nFracts signed: isSigned

read nFracts fractions (2 32bit words) and return them in an array

 readLongs: nLongs signed: isSigned

read nLongs signed or unsigned long numbers (32bit) and return them in an array

 readShorts: nShorts signed: isSigned

read nShorts signed or unsigned short numbers (16bit) and return them in an array

 writeBitsPerSample

'bitsPerSample: ' print. bitsPerSample printNewline.
'store bitspersample at: ' print. outStream position printNewline.

 writeColorMap

 writeStripByteCounts

'stripByteCounts: ' print. stripByteCounts printNewline.
'store stripbytecounts at: ' print. outStream position printNewline.

 writeStripOffsets

'stripOffsets: ' print. stripOffsets printNewline.
'store stripoffsets at: ' print. outStream position printNewline.

 writeTag: tagType

 writeTiffTag: tagType

 writeUncompressedBits

write bits as one or multiple strips

 fromStream: aStream

read a stream containing a TIFF image.
Leave image description in instance variables.

 save: image onStream: aStream

save image as (uncompressed) TIFF file on aFileName